Disease or Syndrome

MeSH ID: T047

Related Concepts:

• Abdominal Abscess [M0028122]
  An abscess located in the abdominal cavity, i.e., the cavity between the diaphragm above and the pelvis below. (From Dorland, 27th ed)
  
• Abdominal Epilepsy [M0334947]
  
• Abdominal Migraine [M0335689]
  
• Abducens Nerve Diseases [M0328086]
  Diseases of the sixth cranial (abducens) nerve or its nucleus in the pons. The nerve may be injured along its course in the pons, intracranially as it travels along the base of the brain, in the cavernous sinus, or at the level of superior orbital fissure or orbit. Dysfunction of the nerve causes lateral rectus muscle weakness, resulting in horizontal diplopia that is maximal when the affected eye is abducted and ESOTROPIA. Common conditions associated with nerve injury include INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; ISCHEMIA; and INFRATENTORIAL NEOPLASMS.
  
• Abducens Palsy, Childhood, Benign Recurrent [M0335865]
  
• Abetalipoproteinemia [M0000012]
  An autosomal recessive disorder of lipid metabolism. It is caused by mutation of the microsomal triglyceride transfer protein that catalyzes the transport of lipids (TRIGLYCERIDES; CHOLESTEROL ESTERS; PHOSPHOLIPIDS) and is required in the secretion of BETA-LIPOPROTEINS (low density lipoproteins or LDL). Features include defective intestinal lipid absorption, very low serum cholesterol level, and near absent LDL.
  
• Abortion, Habitual [M0000032]
  Three or more consecutive spontaneous abortions.
  
• Abortion, Incomplete [M0000033]
  Premature loss of PREGNANCY in which not all the products of CONCEPTION have been expelled.
  
• Abortion, Missed [M0000048]
  The retention in the UTERUS of a dead FETUS two months or more after its DEATH.
  
• Abortion, Septic [M0000050]
  Any type of abortion, induced or spontaneous, that is associated with infection of the UTERUS and its appendages. It is characterized by FEVER, uterine tenderness, and foul discharge.
  
• Abortion, Spontaneous [M0000024]
  Expulsion of the product of FERTILIZATION before completing the term of GESTATION and without deliberate interference.
  
• Abortion, Threatened [M0000052]
  UTERINE BLEEDING from a GESTATION of less than 20 weeks without any CERVICAL DILATATION. It is characterized by vaginal bleeding, lower back discomfort, or midline pelvic cramping and a risk factor for MISCARRIAGE.
  
• Abortion, Tubal [M0000025]
  
• Abortion, Veterinary [M0000053]
  Premature expulsion of the FETUS in animals.
  
• Abruptio Placentae [M0000058]
  Premature separation of the normally implanted PLACENTA from the UTERUS. Signs of varying degree of severity include UTERINE BLEEDING, uterine MUSCLE HYPERTONIA, and FETAL DISTRESS or FETAL DEATH.
  
• Abscess, Amebic [M0000881]
  
• Abscess, Tubercular, Intracranial [M0336258]
  
• Acalculous Cholecystitis [M0440433]
  Inflammation of the GALLBLADDER wall in the absence of GALLSTONES.
  
• Acanthamoeba Keratitis [M0024241]
  Infection of the cornea by an ameboid protozoan which may cause corneal ulceration leading to blindness.
  
• Acanthocheilonemiasis [M0006506]
  
• Acanthosis Nigricans [M0000078]
  A circumscribed melanosis consisting of a brown-pigmented, velvety verrucosity or fine papillomatosis appearing in the axillae and other body folds. It occurs in association with endocrine disorders, underlying malignancy, administration of certain drugs, or as in inherited disorder.
  
• Acatalasia [M0328366]
  A rare autosomal recessive disorder resulting from the absence of CATALASE activity. Though usually asymptomatic, a syndrome of oral ulcerations and gangrene may be present.
  
• Accelerated Idioventricular Rhythm [M0024684]
  A transient and intermittent type of arrhythmia with episodes lasting from a few seconds to a minute which usually occurs in patients with acute myocardial infarction or with digitalis toxicity. Suppressive therapy is rarely necessary because the ventricular rate is generally less than 100 beats per minute.
  
• Accessory Nerve Diseases [M0328088]
  Diseases of the eleventh cranial (spinal accessory) nerve. This nerve originates from motor neurons in the lower medulla (accessory portion of nerve) and upper spinal cord (spinal portion of nerve). The two components of the nerve join and exit the skull via the jugular foramen, innervating the sternocleidomastoid and trapezius muscles, which become weak or paralyzed if the nerve is injured. The nerve is commonly involved in MOTOR NEURON DISEASE, and may be injured by trauma to the posterior triangle of the neck.
  
• Achromatopsia [M0368535]
  Severely deficient color perception, typically with monochromacy and reduced visual acuity. The atypical form can include normal visual acuity with pseudomonochromacy.
  
• Acid Aspiration Syndrome [M0017067]
  
• Acidosis, Lactic [M0000214]
  Acidosis caused by accumulation of lactic acid more rapidly than it can be metabolized. It may occur spontaneously or in association with diseases such as diabetes mellitus, leukemia, or liver failure.
  
• Acidosis, Renal Tubular [M0000215]
  A group of genetic disorders of the KIDNEY TUBULES characterized by the accumulation of metabolically produced acids with elevated plasma chloride, hyperchloremic metabolic ACIDOSIS. Defective renal acidification of URINE (proximal tubules) or low renal acid excretion (distal tubules) can lead to complications such as HYPOKALEMIA, hypercalcinuria with NEPHROLITHIASIS and NEPHROCALCINOSIS, and RICKETS.
  
• Acidosis, Respiratory [M0000219]
  Respiratory retention of carbon dioxide. It may be chronic or acute.
  
• Acinetobacter Infections [M0000230]
  Infections with bacteria of the genus ACINETOBACTER.
  
• Acne Keloid [M0000232]
  A type of acneiform disorder in which secondary pyogenic infection in and around pilosebaceous structures ends in keloidal scarring. It manifests as persistent folliculitis of the back of the neck associated with occlusion of the follicular orifices. It is most often encountered in black or Asian men.
  
• Acne Vulgaris [M0000231]
  A chronic disorder of the pilosebaceous apparatus associated with an increase in sebum secretion. It is characterized by open comedones (blackheads), closed comedones (whiteheads), and pustular nodules. The cause is unknown, but heredity and age are predisposing factors.
  
• Acneiform Eruptions [M0026528]
  Visible efflorescent lesions of the skin caused by acne or resembling acne. (Dorland, 28th ed, p18, 575)
  
• Acoustic Nerve Diseases [M0333671]
  
• Acquired Facial Neuropathy [M0335901]
  
• Acquired Gerstmann Syndrome [M0337454]
  
• Acquired Hyperostosis Syndrome [M0029804]
  Syndrome consisting of synovitis, acne, palmoplantar pustulosis, hyperostosis, and osteitis (SAPHO). The most common site of the disease is the upper anterior chest wall, characterized by predominantly osteosclerotic lesions, hyperostosis, and arthritis of the adjacent joints. The association of sterile inflammatory bone lesions and neutrophilic skin eruptions is indicative of this syndrome.
  
• Acquired Immunodeficiency Syndrome [M0000245]
  An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.
  
• Acquired Metabolic Diseases, Nervous System [M0392800]
  
• Acquired Nephrogenic Diabetes Insipidus [M0471344]
  
• Acquired Neuromyotonia [M0335867]
  
• Acquired Vocal Cord Palsy [M0336420]
  
• Acro-Osteolysis [M0393325]
  A condition with congenital and acquired forms causing recurrent ulcers in the fingers and toes. The congenital form exhibits autosomal dominant inheritance; the acquired form is found in workers who handle VINYL CHLORIDE. When acro-osteolysis is accompanied by generalized OSTEOPOROSIS and skull deformations, it is called HAJDU-CHENEY SYNDROME.
  
• Acrocephaly [M0005289]
  
• Acrodermatitis [M0000257]
  Inflammation involving the skin of the extremities, especially the hands and feet. Several forms are known, some idiopathic and some hereditary. The infantile form is called Gianotti-Crosti syndrome.
  
• Acromegaly [M0000261]
  A condition caused by prolonged exposure to excessive HUMAN GROWTH HORMONE in adults. It is characterized by bony enlargement of the FACE; lower jaw (PROGNATHISM); hands; FEET; HEAD; and THORAX. The most common etiology is a GROWTH HORMONE-SECRETING PITUITARY ADENOMA. (From Joynt, Clinical Neurology, 1992, Ch36, pp79-80)
  
• ACTH Syndrome, Ectopic [M0000272]
  Symptom complex due to ACTH production by non-pituitary neoplasms.
  
• Actinic Reticuloid Syndrome [M0016759]
  
• Actinobacillosis [M0000280]
  A disease characterized by suppurative and granulomatous lesions in the respiratory tract, upper alimentary tract, skin, kidneys, joints, and other tissues. Actinobacillus lignieresii infects cattle and sheep while A. equuli infects horses and pigs.
  
• Actinobacillus Infections [M0000282]
  Infections with bacteria of the genus ACTINOBACILLUS.
  
• Actinomycetales Infections [M0000289]
  Infections with bacteria of the order ACTINOMYCETALES.
  
• Actinomycosis [M0000290]
  Infections with bacteria of the genus ACTINOMYCES.
  
• Actinomycosis, Cervicofacial [M0000291]
  A form of ACTINOMYCOSIS characterized by slow-growing inflammatory lesions of the lymph nodes that drain the mouth (lumpy jaw), reddening of the overlying skin, and intraperitoneal abscesses.
  
• Action Myoclonus-Renal Failure Syndrome [M0335755]
  
• Acute Bacterial Prostatitis [M0489746]
  
• Acute Confusional Migraine [M0335686]
  
• Acute Disease [M0000322]
  Disease having a short and relatively severe course.
  
• Acute Peripheral Vestibulopathy [M0337542]
  
• Adams-Stokes Syndrome [M0000337]
  Transient asystole or ventricular fibrillation in the presence of atrioventricular block.
  
• Addison Disease [M0000346]
  An adrenal disease characterized by the progressive destruction of the ADRENAL CORTEX, resulting in insufficient production of ALDOSTERONE and HYDROCORTISONE. Clinical symptoms include ANOREXIA; NAUSEA; WEIGHT LOSS; MUSCLE WEAKNESS; and HYPERPIGMENTATION of the SKIN due to increase in circulating levels of ACTH precursor hormone which stimulates MELANOCYTES.
  
• Adenomyosis [M0406917]
  The extension of endometrial tissue into the MYOMETRIUM.
  
• Adenophorea Infections [M0026092]
  Infections with nematodes of the subclass ADENOPHOREA.
  
• Adenoviridae Infections [M0000404]
  Virus diseases caused by the ADENOVIRIDAE.
  
• Adenovirus Infections, Human [M0000405]
  Respiratory and conjunctival infections caused by 33 identified serotypes of human adenoviruses.
  
• Adhesions [M0000418]
  Pathological processes consisting of the union of the opposing surfaces of a wound.
  
• Adhesive Capsulitis [M0003071]
  
• Adie Syndrome [M0000423]
  A syndrome characterized by a TONIC PUPIL that occurs in combination with decreased lower extremity reflexes. The affected pupil will respond more briskly to accommodation than to light (light-near dissociation) and is supersensitive to dilute pilocarpine eye drops, which induce pupillary constriction. Pathologic features include degeneration of the ciliary ganglion and postganglionic parasympathetic fibers that innervate the pupillary constrictor muscle. (From Adams et al., Principles of Neurology, 6th ed, p279)
  
• Adiposis Dolorosa [M0000426]
  A rare disease characterized by multiple tumor-like fatty deposits that press on nerves in various sites causing pain and weakness. Often these lipoma-like structures are located on the trunk and limbs but sparing the face and hands.
  
• Adnexal Diseases [M0000457]
  Diseases of the uterine appendages (ADNEXA UTERI) including diseases involving the OVARY, the FALLOPIAN TUBES, and ligaments of the uterus (BROAD LIGAMENT; ROUND LIGAMENT).
  
• Adnexitis [M0000458]
  Inflammation of the uterine appendages (ADNEXA UTERI) including infection of the FALLOPIAN TUBES (SALPINGITIS), the ovaries (OOPHORITIS), or the supporting ligaments (PARAMETRITIS).
  
• Adolescent Gynecomastia [M0458829]
  
• Adrenal Cortex Diseases [M0000478]
  Pathological processes of the ADRENAL CORTEX.
  
• Adrenal Gland Diseases [M0000482]
  Pathological processes of the ADRENAL GLANDS.
  
• Adrenal Hyperplasia, Congenital [M0000487]
  A group of inherited disorders of the ADRENAL GLANDS, caused by enzyme defects in the synthesis of cortisol (HYDROCORTISONE) and/or ALDOSTERONE leading to accumulation of precursors for ANDROGENS. Depending on the hormone imbalance, congenital adrenal hyperplasia can be classified as salt-wasting, hypertensive, virilizing, or feminizing. The most common defect is in STEROID 21-HYDROXYLASE. Other defects occur in STEROID 11-BETA-HYDROXYLASE; STEROID 17-ALPHA-HYDROXYLASE; or 3-beta-hydroxysteroid dehydrogenase (3-HYDROXYSTEROID DEHYDROGENASES).
  
• Adrenal Insufficiency [M0000484]
  Conditions in which the production of adrenal CORTICOSTEROIDS falls below the requirement of the body. Adrenal insufficiency can be caused by defects in the ADRENAL GLANDS, the PITUITARY GLAND, or the HYPOTHALAMUS.
  
• Adrenocortical Hyperfunction [M0000483]
  Excess production of ADRENAL CORTEX HORMONES such as ALDOSTERONE; HYDROCORTISONE; DEHYDROEPIANDROSTERONE; and/or ANDROSTENEDIONE. Hyperadrenal syndromes include CUSHING SYNDROME; HYPERALDOSTERONISM; and VIRILISM.
  
• Adrenogenital Syndrome [M0000488]
  Abnormal SEX DIFFERENTIATION caused by disorders of the GONADS or the ADRENAL GLANDS, such as CONGENITAL ADRENAL HYPERPLASIA and ADRENAL CORTEX NEOPLASMS. Due to abnormal steroid biosynthesis, clinical features include VIRILISM in females; FEMINIZATION in males; or precocious sexual development in children.
  
• Adrenoleukodystrophy [M0000501]
  An X-linked recessive disorder characterized by the accumulation of saturated very long chain fatty acids in the LYSOSOMES of ADRENAL CORTEX and the white matter of CENTRAL NERVOUS SYSTEM. This disease occurs almost exclusively in the males. Clinical features include the childhood onset of ATAXIA; NEUROBEHAVIORAL MANIFESTATIONS; HYPERPIGMENTATION; ADRENAL INSUFFICIENCY; SEIZURES; MUSCLE SPASTICITY; and DEMENTIA. The slowly progressive adult form is called adrenomyeloneuropathy. The defective gene ABCD1 is located at Xq28, and encodes the adrenoleukodystrophy protein (ATP-BINDING CASSETTE TRANSPORTERS).
  
• Adrenoleukodystrophy, Neonatal [M0028261]
  
• Adrenomyeloneuropathy [M0000502]
  
• Adult Glycogen Storage Disease Type II [M0335240]
  
• Adult Neuroaxonal Dystrophy [M0335764]
  
• Adult Neuronal Ceroid Lipfuscinosis [M0014733]
  
• Adult Onset Nemaline Myopathy [M0335629]
  
• Adult Pelizaeus-Merzbacher Disease [M0336642]
  
• Adult Sandhoff Disease [M0335921]
  
• Adult-Onset Dystonias [M0334824]
  
• Adult-Onset Idiopathic Focal Dystonias [M0334825]
  
• Adult-Onset Idiopathic Torsion Dystonias [M0334826]
  
• Afferent Loop Syndrome [M0000528]
  A complication of gastrojejunostomy (BILLROTH II PROCEDURE), a reconstructive GASTROENTEROSTOMY. It is caused by acute (complete) or chronic (intermittent) obstruction of the afferent jejunal loop due to HERNIA, intussusception, kinking, VOLVULUS, etc. It is characterized by PAIN and VOMITING of BILE-stained fluid.
  
• Afibrinogenemia [M0000532]
  A deficiency or absence of fibrinogen (coagulation factor I) in the blood. (Dorland, 27th ed)
  
• African Horse Sickness [M0000543]
  An insect-borne reovirus infection of horses, mules and donkeys in Africa and the Middle East; characterized by pulmonary edema, cardiac involvement, and edema of the head and neck.
  
• African Swine Fever [M0000545]
  A sometimes fatal ASFIVIRUS infection of pigs, characterized by fever, cough, diarrhea, hemorrhagic lymph nodes, and edema of the gallbladder. It is transmitted between domestic swine by direct contact, ingestion of infected meat, or fomites, or mechanically by biting flies or soft ticks (genus Ornithodoros).
  
• Agammaglobulinemia [M0000551]
  An immunologic deficiency state characterized by an extremely low level of generally all classes of gamma-globulin in the blood.
  
• Age-Related Maculopathy [M0012876]
  
• Agglutination, Intravascular [M0448036]
  Aggregation of ERYTHROCYTES in vivo, caused by specific interactions such as those induced by antibodies.
  
• Aggressive Systemic Mastocytosis [M0406102]
  A form of systemic mastocytosis in which patients have impaired organ functions due to multifocal infiltrates of pathological MAST CELLS in bone marrow, liver, spleen, gastrointestinal tract, or skeletal system. The cytomorphology shows a low to high grade.
  
• Agranulocytosis [M0000580]
  A decrease in the number of GRANULOCYTES; (BASOPHILS; EOSINOPHILS; and NEUTROPHILS).
  
• Agricultural Workers' Diseases [M0000582]
  Diseases in persons engaged in cultivating and tilling soil, growing plants, harvesting crops, raising livestock, or otherwise engaged in husbandry and farming. The diseases are not restricted to farmers in the sense of those who perform conventional farm chores: the heading applies also to those engaged in the individual activities named above, as in those only gathering harvest or in those only dusting crops.
  
• AIDS Arteritis, Central Nervous System [M0328089]
  Inflammation of blood vessels of the CENTRAL NERVOUS SYSTEM that occurs in association with the ACQUIRED IMMUNODEFICIENCY SYNDROME. In children, this condition may be associated with INTRACRANIAL ANEURYSM formation. Cerebral vasculitis in this setting is frequently associated with AIDS-RELATED OPPORTUNISTIC INFECTIONS including varicella, CMV, fungal, tuberculosis, and syphilis. (From Neurol Clin 1997 Nov;15(4):927-44; Neurology 1998 Aug;51(2):560-5)
  
• AIDS Dementia Complex [M0023886]
  A neurologic condition associated with the ACQUIRED IMMUNODEFICIENCY SYNDROME and characterized by impaired concentration and memory, slowness of hand movements, ATAXIA, incontinence, apathy, and gait difficulties associated with HIV-1 viral infection of the central nervous system. Pathologic examination of the brain reveals white matter rarefaction, perivascular infiltrates of lymphocytes, foamy macrophages, and multinucleated giant cells. (From Adams et al., Principles of Neurology, 6th ed, pp760-1; N Engl J Med, 1995 Apr 6;332(14):934-40)
  
• AIDS-Associated Cerebral Aneurysmal Arteriopathy [M0333924]
  
• AIDS-Associated Nephropathy [M0024856]
  Renal syndrome in human immunodeficiency virus-infected patients characterized by nephrotic syndrome, severe proteinuria, focal and segmental glomerulosclerosis with distinctive tubular and interstitial changes, enlarged kidneys, and peculiar tubuloreticular structures. The syndrome is distinct from heroin-associated nephropathy as well as other forms of kidney disease seen in HIV-infected patients.
  
• AIDS-Related Complex [M0000590]
  A prodromal phase of infection with the human immunodeficiency virus (HIV). Laboratory criteria separating AIDS-related complex (ARC) from AIDS include elevated or hyperactive B-cell humoral immune responses, compared to depressed or normal antibody reactivity in AIDS; follicular or mixed hyperplasia in ARC lymph nodes, leading to lymphocyte degeneration and depletion more typical of AIDS; evolving succession of histopathological lesions such as localization of Kaposi's sarcoma, signaling the transition to the full-blown AIDS.
  
• AIDS-Related Opportunistic Infections [M0025965]
  Opportunistic infections found in patients who test positive for human immunodeficiency virus (HIV). The most common include PNEUMOCYSTIS PNEUMONIA, Kaposi's sarcoma, cryptosporidiosis, herpes simplex, toxoplasmosis, cryptococcosis, and infections with Mycobacterium avium complex, Microsporidium, and Cytomegalovirus.
  
• Ainhum [M0000591]
  Spontaneous autoamputation of the fourth or fifth toe.
  
• Airflow Obstruction, Chronic [M0012747]
  
• Airsickness [M0014103]
  
• Airway Obstruction [M0000610]
  Any hindrance to the passage of air into and out of the lungs.
  
• Akathisia, Drug-Induced [M0025992]
  A condition associated with the use of certain medications and characterized by an internal sense of motor restlessness often described as an inability to resist the urge to move.
  
• Akathisia, Tardive [M0025991]
  
• Akinetic Petit Mal [M0007576]
  
• Akinetic-Rigid Variant of Huntington Disease [M0332775]
  
• Alagille Syndrome [M0025493]
  An autosomal dominant MUTATION involving CHROMOSOME 20. It is characterized by the almost normal LIVER that has few or no intrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC). Other extrahepatic malformations include those in the heart, the eyes, the vertebral column, and the facies. Major clinical features include JAUNDICE, and congenital heart disease with peripheral PULMONARY STENOSIS.
  
• Albright's Syndrome [M0008458]
  
• Albuminuria [M0000630]
  The presence of albumin in the urine, an indicator of KIDNEY DISEASES.
  
• Alcohol Withdrawal Delirium [M0000652]
  An acute organic mental disorder induced by cessation or reduction in chronic alcohol consumption. Clinical characteristics include CONFUSION; DELUSIONS; vivid HALLUCINATIONS; TREMOR; agitation; insomnia; and signs of autonomic hyperactivity (e.g., elevated blood pressure and heart rate, dilated pupils, and diaphoresis). This condition may occasionally be fatal. It was formerly called delirium tremens. (From Adams et al., Principles of Neurology, 6th ed, p1175)
  
• Alcohol Withdrawal Hallucinosis [M0335565]
  
• Alcohol Withdrawal Seizures [M0328090]
  A condition where seizures occur in association with ethanol abuse (ALCOHOLISM) without other identifiable causes. Seizures usually occur within the first 6-48 hours after the cessation of alcohol intake, but may occur during periods of alcohol intoxication. Single generalized tonic-clonic motor seizures are the most common subtype, however, STATUS EPILEPTICUS may occur. (Adams et al., Principles of Neurology, 6th ed, p1174)
  
• Alcohol Withdrawal-Induced Major Motor Seizure [M0335568]
  
• Alcohol-Induced Disorders, Nervous System [M0328091]
  Acute and chronic neurologic disorders associated with the various neurologic effects of ETHANOL. Primary sites of injury include the brain and peripheral nerves.
  
• Alcohol-Related Disorders [M0029672]
  Disorders related to or resulting from abuse or mis-use of alcohol.
  
• Alcoholic Axonal Neuropathy [M0335569]
  
• Alcoholic Neuropathy [M0328092]
  A condition where damage to the peripheral nervous system (including the peripheral elements of the autonomic nervous system) is associated with chronic ingestion of alcoholic beverages. The disorder may be caused by a direct effect of alcohol, an associated nutritional deficiency, or a combination of factors. Clinical manifestations include variable degrees of weakness; ATROPHY; PARESTHESIAS; pain; loss of reflexes; sensory loss; diaphoresis; and postural hypotension. (From Arch Neurol 1995;52(1):45-51; Adams et al., Principles of Neurology, 6th ed, p1146)
  
• Aleutian Mink Disease [M0000690]
  A slow progressive disease of mink caused by the ALEUTIAN MINK DISEASE VIRUS. It is characterized by poor reproduction, weight loss, autoimmunity, hypergammaglobulinemia, increased susceptibility to bacterial infections, and death from renal failure. The disease occurs in all color types, but mink which are homozygous recessive for the Aleutian gene for light coat color are particularly susceptible.
  
• Alexander Disease [M0415670]
  A rare inherited disorder of myelin formation. Alexander disease is a progressive leukoencephalopathy whose hallmark is the widespread accumulation of cytoplasmic inclusions called Rosenthal fibers. The fibers contain GLIAL FIBRILLARY ACIDIC PROTEIN in association with ALPHA-CRYSTALLIN B CHAIN. Rosenthal fibers are found predominantly in ASTROCYTES located in the subependymal, subpial, and periventricular areas of the BRAIN.
  
• Algodystrophic Syndrome [M0018686]
  
• Alkalosis [M0000714]
  A pathological condition that removes acid or adds base to the body fluids.
  
• Alkaptonuria [M0000717]
  An inborn error of amino acid metabolism resulting from a defect in the enzyme HOMOGENTISATE 1,2-DIOXYGENASE, an enzyme involved in the breakdown of PHENYLALANINE and TYROSINE. It is characterized by accumulation of HOMOGENTISIC ACID in the urine, OCHRONOSIS in various tissues, and ARTHRITIS.
  
• Alopecia [M0000757]
  Absence of hair from areas where it is normally present.
  
• Alopecia Areata [M0000760]
  A microscopically inflammatory, usually reversible, patchy hair loss occurring in sharply defined areas and usually involving the beard or scalp. (Dorland, 27th ed)
  
• Alpers Syndrome [M0003894]
  
• alpha 1-Antitrypsin Deficiency [M0029552]
  Deficiency of the protease inhibitor ALPHA 1-ANTITRYPSIN, leading primarily to degradation of elastin of the alveolar walls, as well as other structural proteins of a variety of tissues. (From Scriver, Beaudet, Sly, & Valle, The Metabolic and Molecular Bases of Inherited Disease, 7th ed, p4125)
  
• Alpha-Aminoadipic Semialdehyde Deficiency Disease [M0335291]
  
• alpha-Mannosidosis [M0013006]
  An inborn error of metabolism marked by a defect in the lysosomal isoform of ALPHA-MANNOSIDASE activity that results in lysosomal accumulation of mannose-rich intermediate metabolites. Virtually all patients have psychomotor retardation, facial coarsening, and some degree of dysostosis multiplex. It is thought to be an autosomal recessive disorder.
  
• alpha-Thalassemia [M0025958]
  A disorder characterized by reduced synthesis of the alpha chains of hemoglobin. The severity of this condition can vary from mild anemia to death, depending on the number of genes deleted.
  
• Alphavirus Infections [M0027587]
  Virus diseases caused by members of the ALPHAVIRUS genus of the family TOGAVIRIDAE.
  
• Alport Syndrome [M0483241]
  
• Alport Syndrome, Autosomal Dominant [M0483243]
  
• Alport Syndrome, Autosomal Recessive [M0483244]
  
• Alport Syndrome, X-Linked [M0483242]
  
• Alternating Exotropia [M0336199]
  
• Altitude Sickness [M0000819]
  A morbid condition of ANOXIA caused by the reduced available oxygen at high altitudes.
  
• Alveolalgia [M0006863]
  
• Alveolar Bone Loss [M0024914]
  The resorption of bone in the supporting structures of the MAXILLA or MANDIBLE.
  
• Alveolitis, Extrinsic Allergic [M0000840]
  Conditions in which inhalation of organic dusts results in hypersensitivity reactions at the alveolar level, associated with the production of precipitins.
  
• Alveolitis, Fibrosing [M0018135]
  
• Alzheimer Disease [M0000842]
  A degenerative disease of the BRAIN characterized by the insidious onset of DEMENTIA. Impairment of MEMORY, judgment, attention span, and problem solving skills are followed by severe APRAXIAS and a global loss of cognitive abilities. The condition primarily occurs after age 60, and is marked pathologically by severe cortical atrophy and the triad of SENILE PLAQUES; NEUROFIBRILLARY TANGLES; and NEUROPIL THREADS. (From Adams et al., Principles of Neurology, 6th ed, pp1049-57)
  
• Alzheimer Disease, Early Onset [M0333931]
  
• Amaurosis [M0002663]
  
• Amaurotic Familial Idiocy [M0012567]
  An outdated term for Tay-Sachs disease.
  
• Amblyopia [M0000854]
  A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications.
  
• Amblyopia, Developmental [M0332635]
  
• Amblyopia, Suppression [M0332637]
  
• Amebiasis [M0000878]
  Infection with any of various amebae. It is an asymptomatic carrier state in most individuals, but diseases ranging from chronic, mild diarrhea to fulminant dysentery may occur.
  
• Ameboma [M0000879]
  
• Amelogenesis Imperfecta [M0000886]
  An autosomal dominant or X-linked disorder in which there is faulty development of the dental enamel owing to agenesis, hypoplasia, or hypocalcification of the enamel. It is marked by enamel that is very thin and friable and frequently stained in various shades of brown. (Dorland, 27th ed)
  
• Amenorrhea [M0000887]
  Absence of menstruation.
  
• Ametropia [M0018701]
  
• Amino Acid Metabolism, Inborn Errors [M0000918]
  Disorders affecting amino acid metabolism. The majority of these disorders are inherited and present in the neonatal period with metabolic disturbances (e.g., ACIDOSIS) and neurologic manifestations. They are present at birth, although they may not become symptomatic until later in life.
  
• Amino Acid Metabolism, Inherited Disorders [M0333991]
  
• Amino Acid Transport Disorders, Inborn [M0328095]
  Disorders characterized by defective transport of amino acids across cell membranes. These include deficits in transport across brush-border epithelial cell membranes of the small intestine (MICROVILLI) and KIDNEY TUBULES; transport across the basolateral membrane; and transport across the membranes of intracellular organelles. (From Nippon Rinsho 1992 Jul;50(7):1587-92)
  
• Amnionitis [M0004337]
  
• Amniotic Band Syndrome [M0000994]
  A disorder present in the newborn infant in which constriction rings or bands, causing soft tissue depressions, encircle digits, extremities, or limbs and sometimes the neck, thorax, or abdomen. They may be associated with intrauterine amputations.
  
• Amputation, Intrauterine [M0000995]
  
• Amygdalo-Hippocampal Epilepsy [M0334949]
  
• Amyloid Neuropathies [M0026863]
  Disorders of the peripheral nervous system associated with the deposition of AMYLOID in nerve tissue. Familial, primary (nonfamilial), and secondary forms have been described. Some familial subtypes demonstrate an autosomal dominant pattern of inheritance. Clinical manifestations include sensory loss, mild weakness, autonomic dysfunction, and CARPAL TUNNEL SYNDROME. (Adams et al., Principles of Neurology, 6th ed, p1349)
  
• Amyloid Neuropathies, Familial [M0026861]
  Inherited disorders of the peripheral nervous system associated with the deposition of AMYLOID in nerve tissue. The different clinical types based on symptoms correspond to the presence of a variety of mutations in several different proteins including transthyretin (PREALBUMIN); APOLIPOPROTEIN A-I; and GELSOLIN.
  
• Amyloid Neuropathy, Secondary [M0335819]
  
• Amyloid Polyneuropathy, British Type [M0335820]
  
• Amyloid Polyneuropathy, Swiss Type [M0335918]
  
• Amyloidosis [M0001053]
  A group of sporadic, familial and/or inherited, degenerative, and infectious disease processes, linked by the common theme of abnormal protein folding and deposition of AMYLOID. As the amyloid deposits enlarge they displace normal tissue structures, causing disruption of function. Various signs and symptoms depend on the location and size of the deposits.
  
• Amyloidosis, Familial [M0383396]
  Diseases in which there is a familial pattern of AMYLOIDOSIS.
  
• Amyloidosis, Hereditary [M0381838]
  Diseases in which there is an inherited mutation leading to AMYLOIDOSIS.
  
• Amyotrophic Lateral Sclerosis [M0001056]
  A degenerative disorder affecting upper MOTOR NEURONS in the brain and lower motor neurons in the brain stem and SPINAL CORD. Disease onset is usually after the age of 50 and the process is usually fatal within 3 to 6 years. Clinical manifestations include progressive weakness, atrophy, FASCICULATION, hyperreflexia, DYSARTHRIA, dysphagia, and eventual paralysis of respiratory function. Pathologic features include the replacement of motor neurons with fibrous ASTROCYTES and atrophy of anterior SPINAL NERVE ROOTS and corticospinal tracts. (From Adams et al., Principles of Neurology, 6th ed, pp1089-94)
  
• Amyotrophic Lateral Sclerosis With Dementia [M0334021]
  
• Amyotrophic Lateral Sclerosis, Guam Form [M0334022]
  
• Analgesic Overuse Headache [M0335245]
  
• Analgesic Rebound Headache [M0335248]
  
• Anaphylaxis [M0001076]
  An acute hypersensitivity reaction due to exposure to a previously encountered ANTIGEN. The reaction may include rapidly progressing URTICARIA, respiratory distress, vascular collapse, systemic SHOCK, and death.
  
• Anaplasmataceae Infections [M0001081]
  Infections with bacteria of the family ANAPLASMATACEAE.
  
• Anaplasmosis [M0001083]
  A disease of cattle caused by parasitization of the red blood cells by bacteria of the genus ANAPLASMA.
  
• Ancylostomiasis [M0001101]
  Infection of humans or animals with hookworms of the genus ANCYLOSTOMA. Characteristics include anemia, dyspepsia, eosinophilia, and abdominal swelling.
  
• Andersen Syndrome [M0472066]
  A clinical triad consisting of potassium-sensitive periodic paralysis, ventricular ectopy, and dysmorphic features. It results from mutations in the KCNJ2 gene which codes for the INWARD RECTIFIER POTASSIUM CHANNELS subfamily J, member 2 (KCNJ2 protein, human.)
  
• Androgen-Insensitivity Syndrome [M0021189]
  A familial form of PSEUDOHERMAPHRODITISM transmitted as an X-linked recessive trait. These patients have a karyotype of 46,XY with end-organ resistance to androgen due to mutations in the androgen receptor (RECEPTORS, ANDROGEN) gene. Severity of the defect in receptor quantity or quality correlates with their phenotypes. In these genetic males, the phenotypic spectrum ranges from those with normal female external genitalia, through those with genital ambiguity as in Reifenstein Syndrome, to that of a normal male with INFERTILITY.
  
• Androgenetic Alopecia [M0000759]
  
• Anemia [M0001119]
  A reduction in the number of circulating erythrocytes or in the quantity of hemoglobin.
  
• Anemia, Aplastic [M0001120]
  A form of anemia in which the bone marrow fails to produce adequate numbers of peripheral blood elements.
  
• Anemia, Diamond-Blackfan [M0384815]
  A rare congenital hypoplastic anemia that usually presents early in infancy. The disease is characterized by a moderate to severe macrocytic anemia, occasional neutropenia or thrombocytosis, a normocellular bone marrow with erythroid hypoplasia, and an increased risk of developing leukemia. (Curr Opin Hematol 2000 Mar;7(2):85-94)
  
• Anemia, Dyserythropoietic, Congenital [M0001122]
  A familial disorder characterized by ANEMIA with multinuclear ERYTHROBLASTS, karyorrhexis, asynchrony of nuclear and cytoplasmic maturation, and various nuclear abnormalities of bone marrow erythrocyte precursors (ERYTHROID PROGENITOR CELLS). Type II is the most common of the 3 types; it is often referred to as HEMPAS, based on the Hereditary Erythroblast Multinuclearity with Positive Acidified Serum test.
  
• Anemia, Dyserythropoietic, Congenital, Type I [M0483792]
  
• Anemia, Dyserythropoietic, Congenital, Type II [M0483791]
  
• Anemia, Dyserythropoietic, Congenital, Type III [M0483793]
  
• Anemia, Hemolytic [M0001123]
  Anemia due to decreased life span of erythrocytes.
  
• Anemia, Hemolytic, Acquired [M0001124]
  
• Anemia, Hemolytic, Autoimmune [M0001127]
  Acquired hemolytic anemia due to the presence of AUTOANTIBODIES which agglutinate or lyse the patient's own RED BLOOD CELLS.
  
• Anemia, Hemolytic, Congenital [M0001129]
  Hemolytic anemia due to various intrinsic defects of the erythrocyte.
  
• Anemia, Hemolytic, Congenital Nonspherocytic [M0001130]
  Any one of a group of congenital hemolytic anemias in which there is no abnormal hemoglobin or spherocytosis and in which there is a defect of glycolysis in the erythrocyte. In some cases, pyruvate kinase deficiency has been demonstrated; in other cases, glucose-6-phosphate dehydrogenase deficiency has been demonstrated.
  
• Anemia, Hemolytic, Idiopathic Acquired [M0001128]
  
• Anemia, Hypochromic [M0001131]
  Anemia characterized by a decrease in the ratio of the weight of hemoglobin to the volume of the erythrocyte, i.e., the mean corpuscular hemoglobin concentration is less than normal. The individual cells contain less hemoglobin than they could have under optimal conditions. Hypochromic anemia may be caused by iron deficiency from a low iron intake, diminished iron absorption, or excessive iron loss. It can also be caused by infections or other diseases, therapeutic drugs, lead poisoning, and other conditions. (Stedman, 25th ed; from Miale, Laboratory Medicine: Hematology, 6th ed, p393)
  
• Anemia, Hypoplastic [M0001121]
  
• Anemia, Hypoplastic, Congenital [M0384816]
  An inborn condition characterized by deficiencies of red cell precursors that sometimes also includes LEUKOPENIA and THROMBOCYTOPENIA.
  
• Anemia, Iron-Deficiency [M0028144]
  Anemia characterized by decreased or absent iron stores, low serum iron concentration, low transferrin saturation, and low hemoglobin concentration or hematocrit value. The erythrocytes are hypochromic and microcytic and the iron binding capacity is increased.
  
• Anemia, Macrocytic [M0001133]
  Anemia characterized by larger than normal erythrocytes, increased mean corpuscular volume (MCV) and increased mean corpuscular hemoglobin (MCH).
  
• Anemia, Megaloblastic [M0001134]
  A disorder characterized by the presence of ANEMIA, abnormally large red blood cells (megalocytes or macrocytes), and MEGALOBLASTS.
  
• Anemia, Microangiopathic [M0001125]
  
• Anemia, Myelophthisic [M0001135]
  Anemia characterized by appearance of immature myeloid and nucleated erythrocytes in the peripheral blood, resulting from infiltration of the bone marrow by foreign or abnormal tissue.
  
• Anemia, Neonatal [M0001136]
  The mildest form of erythroblastosis fetalis in which anemia is the chief manifestation.
  
• Anemia, Pernicious [M0001137]
  A megaloblastic anemia occurring in children but more commonly in later life, characterized by histamine-fast achlorhydria, in which the laboratory and clinical manifestations are based on malabsorption of vitamin B 12 due to a failure of the gastric mucosa to secrete adequate and potent intrinsic factor. (Dorland, 27th ed)
  
• Anemia, Refractory [M0001138]
  A severe sometimes chronic anemia, usually macrocytic in type, that does not respond to ordinary antianemic therapy.
  
• Anemia, Refractory, with Excess of Blasts [M0001139]
  Chronic refractory anemia with granulocytopenia, and/or thrombocytopenia. Myeloblasts and progranulocytes constitute 5 to 40 percent of the nucleated marrow cells.
  
• Anemia, Sickle Cell [M0001140]
  A disease characterized by chronic hemolytic anemia, episodic painful crises, and pathologic involvement of many organs. It is the clinical expression of homozygosity for hemoglobin S.
  
• Anemia, Sideroblastic [M0001141]
  Anemia characterized by the presence of erythroblasts containing excessive deposits of iron in the marrow.
  
• Anemia, Splenic [M0010856]
  
• Aneurysm [M0001174]
  A sac formed by the dilatation of the wall of an artery, a vein, or the heart.
  
• Aneurysm, Anterior Cerebral Artery [M0335412]
  
• Aneurysm, Anterior Communicating Artery [M0335413]
  
• Aneurysm, Bacterial [M0001177]
  
• Aneurysm, Basilar Artery [M0335414]
  
• Aneurysm, Dissecting [M0001175]
  Splitting or dissection of an arterial wall by blood entering through an intimal tear or by interstitial hemorrhage. It is most common in the aorta.
  
• Aneurysm, False [M0026603]
  An aneurysm in which the entire wall is injured and the blood is contained by the surrounding tissues, with eventual formation of a sac communicating with the artery or heart. (Dorland, 28th ed)
  
• Aneurysm, Infected [M0001176]
  Aneurysm due to growth of microorganisms in the arterial wall, or infection arising within preexisting arteriosclerotic aneurysms.
  
• Aneurysm, Middle Cerebral Artery [M0335415]
  
• Aneurysm, Mycotic [M0001178]
  
• Aneurysm, Posterior Cerebral Artery [M0335416]
  
• Aneurysm, Posterior Communicating Artery [M0335417]
  
• Aneurysm, Ruptured [M0026605]
  The tearing or herniation of the weakened wall of the aneurysmal sac.
  
• Angelman Syndrome [M0026107]
  A syndrome characterized by multiple abnormalities, MENTAL RETARDATION, and movement disorders. Present usually are skull and other abnormalities, frequent infantile spasms (SPASMS, INFANTILE); easily provoked and prolonged paroxysms of laughter (hence "happy"); jerky puppetlike movements (hence "puppet"); continuous tongue protrusion; motor retardation; ATAXIA; MUSCLE HYPOTONIA; and a peculiar facies. It is associated with maternal deletions of chromosome 15q11-13 and other genetic abnormalities. (From Am J Med Genet 1998 Dec 4;80(4):385-90; Hum Mol Genet 1999 Jan;8(1):129-35)
  
• Angina Pectoris [M0001180]
  The symptom of paroxysmal pain consequent to MYOCARDIAL ISCHEMIA usually of distinctive character, location and radiation. It is thought to be provoked by a transient stressful situation during which the oxygen requirements of the MYOCARDIUM exceed that supplied by the CORONARY CIRCULATION.
  
• Angina Pectoris, Variant [M0001181]
  A clinical syndrome characterized by the development of CHEST PAIN at rest with concomitant transient ST segment elevation in the electrocardiogram, but with preserved exercise capacity.
  
• Angiodysplasia [M0025698]
  Degenerative, acquired lesions consisting of distorted, dilated, thin-walled vessels lined by vascular endothelium. This pathological state is seen especially in the gastrointestinal tract and is frequently a cause of upper and lower gastrointestinal hemorrhage in the elderly.
  
• Angiogranuloma [M0026878]
  
• Angioid Streaks [M0001189]
  Small breaks in the elastin-filled tissue of the retina.
  
• Angiolymphoid Hyperplasia with Eosinophilia [M0001192]
  Solitary or multiple benign cutaneous nodules comprised of immature and mature vascular structures intermingled with endothelial cells and a varied infiltrate of eosinophils, histiocytes, lymphocytes, and mast cells.
  
• Angiomatosis [M0001196]
  
• Angiomatosis, Bacillary [M0025744]
  An infectious bacterial disease characterized by cutaneous vascular lesions. It is caused by BARTONELLA HENSELAE and is seen in AIDS patients and other immunocompromised hosts.
  
• Anguilluliasis [M0020616]
  
• Anhidrosis [M0010907]
  
• Animal Diseases [M0001223]
  
• Anisakiasis [M0026023]
  Infection with roundworms of the genus ANISAKIS. Human infection results from the consumption of fish harboring roundworm larvae. The worms may cause acute NAUSEA; VOMITING; or penetrate into the wall of the DIGESTIVE TRACT where they give rise to EOSINOPHILIC GRANULOMA in the STOMACH; INTESTINES; or the OMENTUM.
  
• Anisometropia [M0024284]
  A condition of an inequality of refractive power of the two eyes.
  
• Anisometropic Amblyopia [M0332634]
  
• Ankylosis [M0001254]
  Fixation and immobility of a joint.
  
• Annular Grooves [M0000996]
  
• Anovulation [M0001281]
  Suspension or cessation of OVULATION in animals or humans with follicle-containing ovaries (OVARIAN FOLLICLE). Depending on the etiology, OVULATION may be induced with appropriate therapy.
  
• Anoxia-Ischemia, Brain [M0335365]
  
• Anoxia-Ischemia, Cerebral [M0335387]
  
• Anoxic-Ischemic Encephalopathy [M0335388]
  
• Antenatal Myasthenia Gravis [M0335261]
  
• Anterior Cerebral Artery Syndrome [M0335394]
  
• Anterior Cerebral Circulation Infarction [M0334193]
  
• Anterior Choroidal Artery Infarction [M0334511]
  
• Anterior Circulation Brain Infarction [M0334194]
  
• Anterior Compartment Syndrome [M0001298]
  Rapid swelling, increased tension, pain, and ischemic necrosis of the muscles of the anterior tibial compartment of the leg, often following excessive exertion.
  
• Anterior Horn Cell Disease [M0337052]
  
• Anterior Ischemic Optic Neuropathy [M0336260]
  
• Anterior Pituitary Diseases [M0335868]
  
• Anterior Spinal Artery Dissection [M0334034]
  
• Anterior Spinal Artery Syndrome [M0328098]
  Ischemia or infarction of the spinal cord in the distribution of the anterior spinal artery, which supplies the ventral two-thirds of the spinal cord. This condition is usually associated with ATHEROSCLEROSIS of the aorta and may result from dissection of an AORTIC ANEURYSM or rarely dissection of the anterior spinal artery. Clinical features include weakness and loss of pain and temperature sensation below the level of injury, with relative sparing of position and vibratory sensation. (From Adams et al., Principles of Neurology, 6th ed, pp1249-50)
  
• Anterior Urethral Stricture [M0491662]
  
• Anthracosilicosis [M0001304]
  A mixed condition of anthracosis and silicosis. (Dorland, 27th ed)
  
• Anthrax [M0001315]
  An acute infection caused by the spore-forming bacteria BACILLUS ANTHRACIS. It commonly affects hoofed animals such as sheep and goats. Infection in humans often involves the skin (cutaneous anthrax), the lungs (inhalation anthrax), or the gastrointestinal tract. Anthrax is not contagious and can be treated with antibiotics.
  
• Anti-Glomerular Basement Membrane Disease [M0029493]
  An autoimmune disease of the KIDNEY and the LUNG. It is characterized by the presence of circulating autoantibodies targeting the epitopes in the non-collagenous domains of COLLAGEN TYPE IV in the basement membranes of kidney glomeruli (KIDNEY GLOMERULUS) and lung alveoli (PULMONARY ALVEOLI), and the subsequent destruction of these basement membranes. Clinical features include pulmonary alveolar hemorrhage and glomerulonephritis.
  
• Antibiotic-Associated Colitis [M0007480]
  
• Antibody Deficiency Syndrome [M0011154]
  
• Antiphospholipid Syndrome [M0025484]
  The presence of antibodies directed against phospholipids (ANTIBODIES, ANTIPHOSPHOLIPID). The condition is associated with a variety of diseases, notably systemic lupus erythematosus and other connective tissue diseases, thrombopenia, and arterial or venous thromboses. In pregnancy it can cause abortion. Of the phospholipids, the cardiolipins show markedly elevated levels of anticardiolipin antibodies (ANTIBODIES, ANTICARDIOLIPIN). Present also are high levels of lupus anticoagulant (LUPUS COAGULATION INHIBITOR).
  
• Antithrombin III Deficiency [M0029883]
  An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.
  
• Anton Syndrome [M0336562]
  
• Anuria [M0001524]
  Absence of urine formation. It is usually associated with complete bilateral ureteral (URETER) obstruction, complete lower urinary tract obstruction, or unilateral ureteral obstruction when a solitary kidney is present.
  
• Anus Diseases [M0001528]
  
• Anus Prolapse [M0018659]
  
• Anus, Imperforate [M0001530]
  A congenital abnormality characterized by the persistence of the anal membrane, resulting in a thin membrane covering the normal ANAL CANAL. Imperforation is not always complete and is treated by surgery in infancy. This defect is often associated with NEURAL TUBE DEFECTS; MENTAL RETARDATION; and DOWN SYNDROME.
  
• Aortic Aneurysm, Abdominal [M0026607]
  An aneurysm in that part of the aorta continuing from the thoracic region and giving rise to the inferior phrenic, lumbar, median sacral, mesenteric, renal, and ovarian or testicular arteries.
  
• Aortic Aneurysm, Ruptured [M0356457]
  
• Aortic Aneurysm, Thoracic [M0026608]
  An aneurysm in the proximal portion of the descending aorta proceeding from the arch of the aorta and giving rise to the bronchial, esophageal, pericardiac, and mediastinal branches.
  
• Aortic Arch Syndromes [M0001546]
  Any of a group of disorders leading to occlusion of the arteries arising from the aortic arch. Such occlusion may be caused by atherosclerosis, arterial embolism, syphilitic or tuberculous arteritis, etc. (Dorland, 27th ed)
  
• Aortic Arteritis, Giant Cell [M0335459]
  
• Aortic Diseases [M0001550]
  
• Aortic Rupture [M0001551]
  Tearing of aortic tissue. It may be rupture of an aneurysm or it may be due to trauma.
  
• Aortic Stenosis, Subvalvular [M0001552]
  A narrowing of the aorta in the region below the aortic valve.
  
• Aortic Stenosis, Supravalvular [M0001556]
  A narrowing of the aorta in the region above the aortic valve.
  
• Aortic Valve Insufficiency [M0001554]
  Backflow of blood from the aorta into the left ventricle, owing to imperfect functioning of the aortic semilunar valve.
  
• Aortic Valve Prolapse [M0001555]
  The downward displacement of the cuspal material (misalignment of the cusps) below a line joining points of attachment of the aortic valve leaflets. The prolapsed cusp may occlude the ventricular septal defect during ventricular diastole.
  
• Aortic Valve Stenosis [M0001557]
  Constriction in the opening of the aortic valve or of the supravalvular or subvalvular regions.
  
• Aortitis [M0001559]
  Inflammation of the wall of the aorta.
  
• Aortitis Syndrome [M0001547]
  
• Aortitis, Syphilitic [M0020970]
  
• Ape Diseases [M0027648]
  Diseases of chimpanzees, gorillas, and orangutans.
  
• Aplasia Cutis Congenita [M0007035]
  
• Apolipoprotein C-II Deficiency [M0486996]
  
• Appendicitis [M0001610]
  Acute inflammation of the APPENDIX. Acute appendicitis is classified as simple, gangrenous, or perforated.
  
• Arachnodactyly [M0013028]
  
• Arachnoiditis [M0001656]
  Acute or chronic inflammation of the arachnoid membrane of the meninges most often involving the spinal cord or base of the brain. This term generally refers to a persistent inflammatory process characterized by thickening of the ARACHNOID membrane and dural adhesions. Associated conditions include prior surgery, infections, trauma, SUBARACHNOID HEMORRHAGE, and chemical irritation. Clinical features vary with the site of inflammation, but include cranial neuropathies, radiculopathies, and myelopathies. (From Joynt, Clinical Neurology, 1997, Ch48, p25)
  
• Arbovirus Infections [M0001658]
  Infections caused by arthropod-borne viruses, general or unspecified.
  
• Arenaviridae Infections [M0001676]
  Virus diseases caused by the ARENAVIRIDAE.
  
• Argininosuccinic Acid Synthetase Deficiency Disease, Partial [M0334694]
  
• Argininosuccinic Acid Synthetase Deficiency, Complete [M0334695]
  
• Arrhythmogenic Right Ventricular Dysplasia [M0029061]
  A congenital cardiomyopathy in which transmural infiltration of adipose tissue results in weakness and aneurysmal bulging of the infundibulum, apex, and posterior basilar region of the right ventricle and leads to ventricular tachycardia arising in the right ventricle. (Dorland, 28th ed)
  
• Arsenic Encephalopathy [M0335660]
  
• Arsenic Induced Polyneuropathy [M0335661]
  
• Arterial Diseases, Common Carotid [M0334303]
  
• Arterial Occlusive Diseases [M0001730]
  Diseases in which arterial vessels are partially or completely obstructed or in which the blood flow through the vessels is impeded.
  
• Arteriosclerosis Obliterans [M0001735]
  Arteriosclerosis in which proliferation of the intima leads to occlusion of the lumen of the arteries.
  
• Arteriosclerotic Dementia [M0023276]
  
• Arteritis [M0001740]
  Inflammation of an artery.
  
• Arterivirus Infections [M0027401]
  Infections caused by viruses of the genus ARTERIVIRUS.
  
• Arthritis [M0001741]
  
• Arthritis, Bacterial [M0001744]
  
• Arthritis, Gouty [M0023372]
  Arthritis, especially of the great toe, as a result of gout. Acute gouty arthritis often is precipitated by trauma, infection, surgery, etc. The initial attacks are usually monoarticular but later attacks are often polyarticular.
  
• Arthritis, Infectious [M0001745]
  Arthritis caused by BACTERIA; RICKETTSIA; MYCOPLASMA; VIRUSES; FUNGI; or PARASITES.
  
• Arthritis, Juvenile Rheumatoid [M0001748]
  Rheumatoid arthritis of children occurring in three major subtypes defined by the symptoms present during the first six months following onset: systemic-onset (Still's Disease, Juvenile-Onset), polyarticular-onset, and pauciarticular-onset. Adult-onset cases of Still's disease (STILL'S DISEASE, ADULT-ONSET) are also known. Only one subtype of juvenile rheumatoid arthritis (polyarticular-onset, rheumatoid factor-positive) clinically resembles adult rheumatoid arthritis and is considered its childhood equivalent.
  
• Arthritis, Psoriatic [M0023901]
  Syndrome in which psoriasis is associated with arthritis, often involving inflammation in terminal interphalangeal joints. A rheumatoid factor is not usually present in the sera of affected individuals.
  
• Arthritis, Reactive [M0025745]
  An abacterial form of arthritis developing after infection at a site distant from the affected joint or joints. The causative bacteria cannot be cultured from synovial specimens but bacterial antigens have been demonstrated in cells from the synovial fluid and membrane. It often follows Yersinia infection.
  
• Arthritis, Rheumatoid [M0001750]
  A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.
  
• Arthritis, Viral [M0001747]
  
• Arthropathy, Neurogenic [M0001755]
  Chronic progressive degeneration of the stress-bearing portion of a joint, with bizarre hypertrophic changes at the periphery. It is probably a complication of a variety of neurologic disorders, particularly TABES DORSALIS, involving loss of sensation, which leads to relaxation of supporting structures and chronic instability of the joint. (Dorland, 27th ed)
  
• Arthus Reaction [M0001761]
  A dermal inflammatory reaction produced under conditions of antibody excess, when a second injection of antigen produces intravascular antigen-antibody complexes which bind complement, causing cell clumping, endothelial damage, and vascular necrosis.
  
• Asbestosis [M0001784]
  A form of lung disease (pneumoconiosis) caused by inhaling fibers of asbestos and marked by interstitial fibrosis of the lung varying in extent from minor involvement of the basal areas to extensive scarring. It is associated with pleural mesothelioma and bronchogenic carcinoma. (Dorland, 27th ed)
  
• Ascariasis [M0001785]
  Infection by nematodes of the genus ASCARIS. Ingestion of infective eggs causes diarrhea and pneumonitis. Its distribution is more prevalent in areas of poor sanitation and where human feces are used for fertilizer.
  
• Ascaridiasis [M0001788]
  Infection with nematodes of the genus ASCARIDIA. This condition usually occurs in fowl, often manifesting diarrhea.
  
• Ascaridida Infections [M0026096]
  Infections with nematodes of the order ASCARIDIDA.
  
• Ascorbic Acid Deficiency [M0001803]
  A condition due to a dietary deficiency of ascorbic acid (vitamin C), characterized by malaise, lethargy, and weakness. As the disease progresses, joints, muscles, and subcutaneous tissues may become the sites of hemorrhage. Ascorbic acid deficiency frequently develops into SCURVY in young children fed unsupplemented cow's milk exclusively during their first year. It develops also commonly in chronic alcoholism. (Cecil Textbook of Medicine, 19th ed, p1177)
  
• Asherman Syndrome [M0009715]
  A condition with obliterated endometrial cavity causing secondary AMENORRHEA.
  
• Asperger Syndrome [M0328420]
  A childhood disorder predominately affecting boys and similar to autism (AUTISTIC DISORDER). It is characterized by severe, sustained, clinically significant impairment of social interaction, and restricted repetitive and stereotyped patterns of behavior. In contrast to autism, there are no clinically significant delays in language or cognitive development. (From DSM-IV)
  
• Aspergillosis [M0001850]
  Infections with fungi of the genus ASPERGILLUS.
  
• Aspergillosis, Allergic Bronchopulmonary [M0001851]
  Aspergillosis of the lung occurring in an individual with long-standing bronchial asthma. It is characterized by pulmonary infiltrates, eosinophilia, elevated serum IgE and immediate type skin reactivity to aspergillus antigen.
  
• Aspergillosis, Nervous System Invasive [M0335762]
  
• Aspermia [M0495723]
  A condition characterized by the complete absence of SEMEN. This disorder should be differentiated from AZOOSPERMIA, absence of sperm in the semen.
  
• Asphyxia Neonatorum [M0001860]
  Respiratory failure in the newborn. (Dorland, 27th ed)
  
• Aspiculariasis [M0015706]
  
• Asthenia [M0001883]
  Clinical sign or symptom manifested as debility, or lack or loss of strength and energy.
  
• Asthenopia [M0001884]
  Term generally used to describe complaints related to refractive error, ocular muscle imbalance, including pain or aching around the eyes, burning and itchiness of the eyelids, ocular fatigue, and headaches.
  
• Asthenozoospermia [M0495054]
  A condition in which the percentage of progressively motile sperm is abnormally low. In men, it is defined as <25% rapid motility or <50% progression in a semen sample (World Health Organization, 1992).
  
• Asthma [M0001885]
  A form of bronchial disorder associated with airway obstruction, marked by recurrent attacks of paroxysmal dyspnea, with wheezing due to spasmodic contraction of the bronchi.
  
• Asthma, Exercise-Induced [M0001886]
  Asthma attacks following a period of exercise. Usually the induced attack is short-lived and regresses spontaneously. The magnitude of postexertional airway obstruction is strongly influenced by the environment in which exercise is performed (i.e. inhalation of cold air during physical exertion markedly augments the severity of the airway obstruction; conversely, warm humid air blunts or abolishes it).
  
• Astigmatism [M0001888]
  Unequal curvature of the refractive surfaces of the eye. Thus a point source of light cannot be brought to a point focus on the retina but is spread over a more or less diffuse area. This results from the radius of curvature in one plane being longer or shorter than the radius at right angles to it. (Dorland, 27th ed)
  
• Astroviridae Infections [M0028803]
  Infections with ASTROVIRUS, causing gastroenteritis in human infants, calves, lambs, and piglets.
  
• Asymmetric Diabetic Proximal Motor Neuropathy [M0335861]
  
• Asymmetric Septal Hypertrophy [M0003465]
  
• Asymptomatic Inflammatory Prostatitis [M0489749]
  
• Ataxia Telangiectasia [M0001898]
  An autosomal recessive inherited disorder characterized by choreoathetosis beginning in childhood, progressive CEREBELLAR ATAXIA; TELANGIECTASIS of CONJUNCTIVA and SKIN; DYSARTHRIA; B- and T-cell immunodeficiency, and RADIOSENSITIVITY to IONIZING RADIATION. Affected individuals are prone to recurrent sinobronchopulmonary infections, lymphoreticular neoplasms, and other malignancies. Serum ALPHA-FETOPROTEINS are usually elevated. (Menkes, Textbook of Child Neurology, 5th ed, p688) The gene for this disorder (ATM) encodes a cell cycle checkpoint protein kinase and has been mapped to chromosome 11 (11q22-q23).
  
• Ataxia with Lactic Acidosis, Type I [M0335905]
  
• Ataxias, Hereditary [M0020334]
  
• Atelectasis, Congestive [M0018892]
  
• Atherosclerotic Parkinsonism [M0332991]
  
• Atonic Absence Seizures [M0334960]
  
• Atrial Premature Complexes [M0028235]
  Premature contractions of the heart arising from an ectopic atrial focus. With ventricular premature complexes, they represent one of the most common causes of irregular pulse. They are more apt to occur if there is atrial or conduction system disease such as left atrial enlargement in mitral stenosis. In community prospective studies, atrial premature complexes are not related to sudden death, as are ventricular premature beats in coronary disease. (From Stedman, 25th ed; Braunwald, Heart Disease, 4th ed, p679; Sokolow, et al., Clinical Cardiology, 5th ed, p472)
  
• Atrioventricular Block [M0009943]
  
• Atrophy, Disuse [M0337348]
  
• Atrophy, Muscular, Spinobulbar [M0337349]
  
• Atypical Cluster Headache [M0334705]
  
• Atypical Endometrial Hyperplasia [M0406716]
  A benign form of endometrial hyperplasia with increased number of cells with atypia. The atypical cells are large and irregular and have an increased nuclear/cytoplasmic ratio. The risk of progression to endometrial carcinoma rises with the increasing degree of cell atypia.
  
• Atypical Inclusion-Body Disease [M0335759]
  
• Auditory Cortex Disorder [M0332667]
  
• Auditory Diseases, Central [M0001964]
  Disorders of hearing or auditory perception resulting from disease of the central auditory pathways or auditory association cortical areas. These include HEARING LOSS, CENTRAL; cortical deafness; and AUDITORY PERCEPTUAL DISORDERS. Above the level of the pons, bilateral lesions are usually required to produce auditory dysfunction.
  
• Auriculo-Ventricular Dissociation [M0009944]
  
• Auriculotemporal Syndrome [M0020925]
  
• Autoimmune Demyelinating Disease, Peripheral [M0333443]
  
• Autoimmune Demyelinating Diseases, Cerebral [M0334185]
  
• Autoimmune Diseases [M0001989]
  Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides.
  
• Autoimmune Diseases of the Nervous System [M0328129]
  Disorders caused by cellular or humoral immune responses primarily directed towards nervous system autoantigens. The immune response may be directed towards specific tissue components (e.g., myelin) and may be limited to the central nervous system (e.g., MULTIPLE SCLEROSIS) or the peripheral nervous system (e.g., GUILLAIN-BARRE SYNDROME).
  
• Autoimmune Diseases, Demyelinating, Brain [M0334186]
  
• Autoimmune Thrombocytopenia [M0025254]
  
• Autonomic Central Nervous System Diseases [M0335520]
  
• Autonomic Dysreflexia [M0328142]
  A syndrome associated with damage to the spinal cord above the mid thoracic level (see SPINAL CORD INJURIES) characterized by a marked increase in the sympathetic response to minor stimuli such as bladder or rectal distention. Manifestations include HYPERTENSION; TACHYCARDIA (or reflex bradycardia); FEVER; FLUSHING; and HYPERHIDROSIS. Extreme hypertension may be associated with a CEREBROVASCULAR ACCIDENT. (From Adams et al., Principles of Neurology, 6th ed, pp538 and 1232; J Spinal Cord Med 1997;20(3):355-60)
  
• Autonomic Hyperactivity, Alcohol Withdrawal Associated [M0335566]
  
• Autonomic Nervous System Diseases [M0002014]
  Diseases of the parasympathetic or sympathetic divisions of the AUTONOMIC NERVOUS SYSTEM; which has components located in the CENTRAL NERVOUS SYSTEM and PERIPHERAL NERVOUS SYSTEM. Autonomic dysfunction may be associated with HYPOTHALAMIC DISEASES; BRAIN STEM disorders; SPINAL CORD DISEASES; and PERIPHERAL NERVOUS SYSTEM DISEASES. Manifestations include impairments of vegetative functions including the maintenance of BLOOD PRESSURE; HEART RATE; pupil function; SWEATING; REPRODUCTIVE AND URINARY PHYSIOLOGY; and DIGESTION.
  
• Autosomal Chromosome Disorders [M0373510]
  
• Autosomal Dominant Emery-Dreifuss Muscular Dystrophy [M0464070]
  
• Autosomal Dominant Familial Dystonia [M0334827]
  
• Autosomal Dominant Juvenile Parkinson Disease [M0332503]
  
• Autosomal Dominant Parkinsonism [M0335827]
  
• Autosomal Recessive Emery-Dreifuss Muscular Dystrophy [M0464071]
  
• Autosomal Recessive Familial Dystonia [M0334828]
  
• Autosomal Recessive Hereditary Spastic Paraplegia [M0336750]
  
• Autosomal Recessive Juvenile Parkinson Disease [M0332913]
  
• Autosomal Recessive Parkinsonism [M0335828]
  
• Avitaminosis [M0002041]
  A condition due to a deficiency of one or more essential vitamins. (Dorland, 27th ed)
  
• Avulavirus Infections [M0448313]
  Infections with viruses of the genus AVULAVIRUS, family PARAMYXOVIRIDAE. This includes NEWCASTLE DISEASE and other infections of domestic fowl.
  
• Awakening Epilepsy [M0334958]
  
• Ayerza Syndrome [M0010864]
  A syndrome with pathological changes in the pulmonary arteries and impaired PULMONARY CIRCULATION that can be the result of PULMONARY HYPERTENSION. Ayerza syndrome is characterized by slowly developing ASTHMA; BRONCHITIS; DYSPNEA; and CYANOSIS in association with POLYCYTHEMIA.
  
• Azoospermia [M0015282]
  A condition of having no sperm present in the ejaculate (SEMEN).
  
• Babesiosis [M0002099]
  A group of tick-borne diseases of mammals including ZOONOSES in humans. They are caused by PROTOZOANS of the genus BABESIA, which parasitize erythrocytes, producing hemolysis. In the U.S., the organism's natural host is mice and transmission is by the deer tick IXODES SCAPULARIS.
  
• Bacillaceae Infections [M0025666]
  Infections with bacteria of the family BACILLACEAE.
  
• Bacteremia [M0025156]
  The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.
  
• Bacterial Infections [M0002126]
  Infections by bacteria, general or unspecified.
  
• Bacterial Infections and Mycoses [M0002125]
  Infections caused by bacteria and fungi, general, specified, or unspecified.
  
• Bacteriuria [M0002143]
  The presence of bacteria in the urine which is normally bacteria-free. These bacteria are from the URINARY TRACT and are not contaminants of the surrounding tissues. Bacteriuria can be symptomatic or asymptomatic. Significant bacteriuria is an indicator of urinary tract infection.
  
• Bacteroidaceae Infections [M0025669]
  Infections with bacteria of the family BACTEROIDACEAE.
  
• Bacteroides Infections [M0002147]
  Infections with bacteria of the genus BACTEROIDES.
  
• Bagassosis [M0017056]
  
• Balanitis [M0002151]
  Inflammation of the head of the PENIS, glans penis.
  
• Balanitis Xerotica Obliterans [M0002152]
  An atrophic and sclerotic condition of the head of the PENIS, glans penis. Sometimes it leads to stenosis and occasionally obliteration of the external meatal orifice.
  
• Balantidiasis [M0002153]
  Infection by parasitic PROTOZOA of the genus BALANTIDIUM. The presence of Balantidium in the LARGE INTESTINE leads to DIARRHEA; DYSENTERY; and occasionally ULCER.
  
• Balkan Nephropathy [M0002155]
  A form of chronic interstitial nephritis that is endemic to limited areas of BULGARIA, the former YUGOSLAVIA, and ROMANIA. It is characterized by a progressive shrinking of the KIDNEYS that is often associated with uroepithelial tumors.
  
• Balo Concentric Sclerosis [M0007338]
  
• Bardet-Biedl Syndrome [M0328149]
  An autosomal recessive disorder characterized by RETINITIS PIGMENTOSA; POLYDACTYLY; OBESITY; MENTAL RETARDATION; hypogenitalism; renal dysplasia; and short stature. This syndrome has been distinguished as a separate entity from LAURENCE-MOON SYNDROME. (From J Med Genet 1997 Feb;34(2):92-8)
  
• Bare Lymphocyte Syndrome [M0025204]
  
• Barre-Lieou Syndrome [M0020325]
  
• Barrett Epithelium [M0449096]
  
• Barrett Esophagus [M0002186]
  A condition with damage to the lining of the lower ESOPHAGUS resulting from chronic acid reflux (ESOPHAGITIS, REFLUX). Through the process of metaplasia, the squamous cells are replaced by a columnar epithelium with cells resembling those of the INTESTINE or the salmon-pink mucosa of the STOMACH. Barrett's columnar epithelium is a marker for severe reflux and precursor to ADENOCARCINOMA of the esophagus.
  
• Bartonella Infections [M0002189]
  Infections by the genus BARTONELLA. Bartonella bacilliformis can cause acute febrile anemia, designated Oroya fever, and a benign skin eruption, called verruga peruana. BARTONELLA QUINTANA causes TRENCH FEVER, while BARTONELLA HENSELAE is the etiologic agent of bacillary angiomatosis (ANGIOMATOSIS, BACILLARY) and is also one of the causes of CAT-SCRATCH DISEASE in immunocompetent patients.
  
• Bartonellaceae Infections [M0002193]
  Infections with bacteria of the family BARTONELLACEAE.
  
• Bartter Syndrome [M0002194]
  A group of disorders caused by the defective salt reabsorption in the ascending LOOP OF HENLE. It is characterized by severe salt-wasting, HYPOKALEMIA, hypercalciuria, metabolic ALKALOSIS, and hyper-reninemic HYPERALDOSTERONISM without HYPERTENSION. There are several subtypes resulting from mutations of autosomal recessive genes for SODIUM-POTASSIUM-CHLORIDE COTRANSPORTERS.
  
• Basal Ganglia Cerebrovascular Disease [M0328151]
  Infarction, hemorrhage, ischemia, or hypoxia of any component of the BASAL GANGLIA of the brain. Clinical manifestations may include involuntary or dyskinetic movements and hemiparesis (secondary to involvement of the INTERNAL CAPSULE). Etiologies include atherosclerosis, hypertension, inflammatory conditions (e.g., vasculitis), and emboli of arterial or cardiac origin. Lacunar infarctions frequently occur in the basal ganglia. Hemorrhages in this region are associated with hypertension, but may also result from the rupture of vascular malformations.
  
• Basal Ganglia Diseases [M0002198]
  Diseases of the BASAL GANGLIA including the PUTAMEN; GLOBUS PALLIDUS; claustrum; AMYGDALA; and CAUDATE NUCLEUS. DYSKINESIAS (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. Common etiologies include CEREBROVASCULAR DISORDERS; NEURODEGENERATIVE DISEASES; and CRANIOCEREBRAL TRAUMA.
  
• Basilar Artery Insufficiency [M0022625]
  
• Basilar Artery Stenosis [M0336309]
  
• Basilar-Type Migraine [M0334698]
  
• Battered Child Syndrome [M0002231]
  Repeated physical injuries inflicted on the child by the parent, parents, or surrogate parent; often triggered by the child's minor and normal irritating behavior.
  
• Becker Generalized Myotonia [M0337012]
  
• Becker Muscular Dystrophy [M0014255]
  
• Beckwith-Wiedemann Syndrome [M0002257]
  A syndrome of multiple defects characterized primarily by umbilical hernia (HERNIA, UMBILICAL); MACROGLOSSIA; and GIGANTISM; and secondarily by visceromegaly; HYPOGLYCEMIA; and ear abnormalities.
  
• Behcet Syndrome [M0002296]
  Rare chronic inflammatory disease involving the small blood vessels. It is of unknown etiology and characterized by mucocutaneous ulceration in the mouth and genital region and uveitis with hypopyon. The neuro-ocular form may cause blindness and death. SYNOVITIS; THROMBOPHLEBITIS; gastrointestinal ulcerations; RETINAL VASCULITIS; and OPTIC ATROPHY may occur as well.
  
• Bejel [M0021877]
  
• Bell Palsy [M0008127]
  A syndrome characterized by the acute onset of unilateral FACIAL PARALYSIS which progresses over a 2-5 day period. Weakness of the orbicularis oculi muscle and resulting incomplete eye closure may be associated with corneal injury. Pain behind the ear often precedes the onset of paralysis. This condition may be associated with HERPESVIRUS 1, HUMAN infection of the facial nerve. (Adams et al., Principles of Neurology, 6th ed, p1376)
  
• Benedict Syndrome [M0334261]
  
• Benign Familial Neonatal Epilepsy [M0334981]
  
• Benign Focal Epilepsy, Childhood [M0334950]
  
• Benign Infantile Myoclonic Epilepsy [M0334941]
  
• Benign Neonatal Epilepsy, Nonfamilial [M0334982]
  
• Beriberi [M0002399]
  A disease caused by a deficiency of thiamine (vitamin B1) and characterized by polyneuritis, cardiac pathology, and edema. The epidemic form is found primarily in areas in which white (polished) rice is the staple food, as in Japan, China, the Philippines, India, and other countries of southeast Asia. (Dorland, 27th ed)
  
• Bernard-Soulier Syndrome [M0002403]
  A familial coagulation disorder characterized by a prolonged bleeding time, unusually large platelets, and impaired prothrombin consumption.
  
• Berry Aneurysm [M0003868]
  
• Bertielliasis [M0003955]
  
• Berylliosis [M0002404]
  A lung disease caused by exposure to metallic beryllium or its soluble salts.
  
• Besnoitiasis [M0004677]
  
• beta-Mannosidosis [M0446530]
  An inborn error of metabolism marked by a defect in the lysosomal isoform of BETA-MANNOSIDASE that results in lysosomal accumulation of mannose-rich intermediate metabolites containing 1,4-beta linkages. The human disease occurs through autosomal recessive inheritance and manifests itself with variety of symptoms that depend upon the type of gene mutation.
  
• beta-Thalassemia [M0025960]
  A disorder characterized by reduced synthesis of the beta chains of hemoglobin. There is retardation of hemoglobin A synthesis in the heterozygous form (thalassemia minor), which is asymptomatic, while in the homozygous form (thalassemia major, Cooley's anemia, Mediterranean anemia, erythroblastic anemia), which can result in severe complications and even death, hemoglobin A synthesis is absent.
  
• Bifidobacteriales Infections [M0419929]
  Infections with BACTERIA of the order Bifidobacteriales. This includes infections in the genera BIFIDOBACTERIUM and GARDNERELLA, in the family Bifidobacteriaceae.
  
• Bilateral Multicystic Dysplastic Kidneys [M0482863]
  
• Bilateral Vocal Cord Paresis [M0336421]
  
• Bile Duct Diseases [M0002478]
  Diseases in any part of the ductal system of the BILIARY TRACT from the smallest BILE CANALICULI to the largest COMMON BILE DUCT.
  
• Bile Reflux [M0002486]
  Retrograde bile flow. Reflux of bile can be from the duodenum to the stomach (DUODENOGASTRIC REFLUX); to the esophagus (GASTROESOPHAGEAL REFLUX); or to the PANCREAS.
  
• Biliary Atresia [M0002487]
  Progressive destruction or the absence of all or part of the extrahepatic BILE DUCTS, resulting in the complete obstruction of BILE flow. Usually, biliary atresia is found in infants and accounts for one third of the neonatal cholestatic JAUNDICE.
  
• Biliary Cirrhosis, Primary [M0012639]
  
• Biliary Cirrhosis, Secondary [M0012641]
  
• Biliary Dyskinesia [M0002488]
  A motility disorder characterized by biliary COLIC, absence of GALLSTONES, and an abnormal GALLBLADDER ejection fraction. It is caused by gallbladder dyskinesia and/or SPHINCTER OF ODDI DYSFUNCTION.
  
• Biliary Tract Diseases [M0002491]
  Diseases in any part of the BILIARY TRACT including the BILE DUCTS and the GALLBLADDER.
  
• Bilophila Infections [M0449408]
  
• Binswanger Disease [M0334727]
  
• Biotin-Responsive Encephalopathy [M0335756]
  
• Biotinidase Deficiency [M0381891]
  The late onset form of MULTIPLE CARBOXYLASE DEFICIENCY (deficiency of the activities of biotin-dependent enzymes propionyl-CoA carboxylase, methylcrotonyl-CoA carboxylase, and PYRUVATE CARBOXYLASE) due to a defect or deficiency in biotinidase which is essential for recycling BIOTIN.
  
• Bird Diseases [M0002575]
  Diseases of birds not considered poultry, therefore usually found in zoos, parks, and the wild. The concept is differentiated from POULTRY DISEASES which is for birds raised as a source of meat or eggs for human consumption, and usually found in barnyards, hatcheries, etc.
  
• Bird Fancier's Lung [M0002576]
  A respiratory disorder due to an acquired hypersensitivity to the dust of bird droppings.
  
• Birdpox [M0008795]
  
• Birnaviridae Infections [M0027402]
  Virus diseases caused by the BIRNAVIRIDAE.
  
• Blackwater Fever [M0002627]
  A complication of MALARIA, FALCIPARUM characterized by the passage of dark red to black urine.
  
• Blast Crisis [M0002638]
  Rapid increase in the proportion of blast cells in the blood and bone marrow.
  
• Blastocystis Infections [M0025568]
  Infections with PROTOZOA of the genus BLASTOCYSTIS. The species B. hominis is responsible for most infections. Parasitologic surveys have generally found small numbers of this species in human stools, but higher positivity rates and organism numbers in AIDS patients and other immunosuppressed patients (IMMUNOCOMPROMISED HOST). Symptoms include ABDOMINAL PAIN; DIARRHEA; CONSTIPATION; VOMITING; and FATIGUE.
  
• Blastomycosis [M0002647]
  A fungal infection that may appear in two forms: 1, a primary lesion characterized by the formation of a small cutaneous nodule and small nodules along the lymphatics that may heal within several months; and 2, chronic granulomatous lesions characterized by thick crusts, warty growths, and unusual vascularity and infection in the middle or upper lobes of the lung.
  
• Blastomycosis, North American [M0002648]
  
• Blepharitis [M0002658]
  Inflammation of the eyelids.
  
• Blepharoptosis [M0002659]
  Drooping of the upper lid due to deficient development or paralysis of the levator palpebrae muscle.
  
• Blepharospasm [M0002660]
  Excessive winking; tonic or clonic spasm of the orbicularis oculi muscle.
  
• Blind Loop Syndrome [M0002661]
  A malabsorption syndrome that is associated with a blind loop in the upper SMALL INTESTINE that is characterized by the lack of peristaltic movement, stasis of INTESTINAL CONTENTS, and the overgrowth of BACTERIA. Such bacterial overgrowth interferes with BILE SALTS action, FATTY ACIDS processing, MICROVILLI integrity, and the ABSORPTION of nutrients such as VITAMIN B12 and FOLIC ACID.
  
• Blindness [M0002662]
  The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.
  
• Blindness, Acquired [M0336554]
  
• Blindness, Complete [M0336555]
  
• Blindness, Cortical [M0029065]
  Total loss of vision in all or part of the visual field due to bilateral OCCIPITAL LOBE (i.e., VISUAL CORTEX) damage or dysfunction. Anton syndrome is characterized by the psychic denial of true, organic cortical blindness. (Adams et al., Principles of Neurology, 6th ed, p460)
  
• Blindness, Cortical, Post-Ictal [M0336563]
  
• Blindness, Cortical, Transient [M0337571]
  
• Blindness, Legal [M0336552]
  
• Blindness, Monocular [M0336553]
  
• Blindness, Transient [M0336559]
  
• Blood Coagulation Disorders [M0002683]
  Hemorrhagic and thrombotic disorders that occur as a consequence of abnormalities in blood coagulation due to a variety of factors such as COAGULATION PROTEIN DISORDERS; BLOOD PLATELET DISORDERS; BLOOD PROTEIN DISORDERS or nutritional conditions.
  
• Blood Coagulation Disorders, Inherited [M0376236]
  Hemorrhagic and thrombotic disorders that occur as a consequence of inherited abnormalities in blood coagulation.
  
• Blood Group Incompatibility [M0002697]
  A mismatch between donor and recipient blood. Antibodies present in the recipient's serum are directed against antigens in the donor product. Such a mismatch may result in a transfusion reaction in which, for example, donor blood is hemolyzed. (From Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)
  
• Blood Platelet Disorders [M0002703]
  Disorders caused by abnormalities in platelet count or function.
  
• Blood Protein Disorders [M0002708]
  
• Bloom Syndrome [M0002734]
  An autosomal recessive disorder characterized by telangiectatic ERYTHEMA of the face, photosensitivity, DWARFISM and other abnormalities, and a predisposition toward developing cancer. The Bloom syndrome gene (BLM) encodes a RecQ-like DNA helicase.
  
• Blue Toe Syndrome [M0027662]
  Atherothrombotic microembolism of the lower extremities due to recurrent cholesterol embolic 'showers' with painful cyanotic discoloration of the toes and embolism to other sites that completely resolve between attacks. Despite the gangrene-like appearance, blue toes may respond to conservative therapy without amputation. (Segen, Dictionary of Modern Medicine, 1992)
  
• Bluetongue [M0002737]
  A reovirus infection, chiefly of sheep, characterized by a swollen blue tongue, catarrhal inflammation of upper respiratory and gastrointestinal tracts, and often by inflammation of sensitive laminae of the feet and coronet.
  
• BLV Infections [M0010636]
  
• Bone Cysts [M0002772]
  Benign unilocular lytic areas in the proximal end of a long bone with well defined and narrow endosteal margins. The cysts contain fluid and the cyst walls may contain some giant cells. Bone cysts usually occur in males between the ages 3-15 years.
  
• Bone Cysts, Aneurysmal [M0026931]
  Solitary lesions of bone that typically cause a bulging of the overlying cortex bearing some resemblance to the saccular protrusion of the aortic wall in aortic aneurysm, hence the name. (Dorland, 27th ed)
  
• Bone Demineralization, Pathologic [M0027730]
  Decrease, loss, or removal of the mineral constituents of bones. Temporary loss of bone mineral content is especially associated with space flight, weightlessness, and extended immobilization. OSTEOPOROSIS is permanent, includes reduction of total bone mass, and is associated with increased rate of fractures. CALCIFICATION, PHYSIOLOGIC is the process of bone remineralizing. (From Dorland, 27th ed; Stedman, 25th ed; Nicogossian, Space Physiology and Medicine, 2d ed, pp327-33)
  
• Bone Diseases [M0002776]
  Diseases of BONES.
  
• Bone Diseases, Developmental [M0002777]
  
• Bone Diseases, Endocrine [M0002778]
  Diseases of the bones related to hyperfunction or hypofunction of the endocrine glands.
  
• Bone Diseases, Infectious [M0002779]
  Bone diseases caused by pathogenic microorganisms.
  
• Bone Diseases, Metabolic [M0002780]
  
• Bone Marrow Diseases [M0002788]
  
• Bone Tuberculosis [M0022126]
  
• Bonnevie-Ullrich Syndrome [M0019729]
  This syndrome that was originally observed by Ullrich, and designated as identical to TURNER SYNDROME, related the webbing of the neck, loose skin and other anomalies of the syndrome to accumulation of fluid in the embryo starting at the head and dispersing to the extremities (as observed by Bonnevie in mice). Commonly observed at birth in Turner Syndrome and NOONAN SYNDROME; EDEMA of the extremities usually recedes by one year and is an early sign of Turner syndrome, especially in female neonates.
  
• Border Disease [M0002818]
  Congenital disorder of lambs caused by a virus closely related to or identical with certain strains of bovine viral diarrhea virus.
  
• Bordetella Infections [M0002821]
  Infections with bacteria of the genus BORDETELLA.
  
• Borna Disease [M0002826]
  An encephalomyelitis of horses, sheep and cattle caused by BORNA DISEASE VIRUS.
  
• Borrelia Infections [M0002836]
  Infections with bacteria of the genus BORRELIA.
  
• Botulism [M0002845]
  A disease caused by potent protein NEUROTOXINS produced by CLOSTRIDIUM BOTULINUM which interfere with the presynaptic release of ACETYLCHOLINE at the NEUROMUSCULAR JUNCTION. Clinical features include abdominal pain, vomiting, acute PARALYSIS (including respiratory paralysis), blurred vision, and DIPLOPIA. Botulism may be classified into several subtypes (e.g., food-borne, infant, wound, and others). (From Adams et al., Principles of Neurology, 6th ed, p1208)
  
• Botulism, Infantile [M0335649]
  
• Bouillaud Disease [M0019011]
  
• Boutonneuse Fever [M0002846]
  A febrile disease of the Mediterranean area, the Crimea, Africa, and India, caused by infection with RICKETTSIA CONORII.
  
• Bovine Pulmonary Adenomatosis [M0017069]
  
• Bovine Respiratory Disease Complex [M0460597]
  A multifactorial disease of CATTLE resulting from complex interactions between environmental factors, host factors, and pathogens. The environmental factors act as stressors adversely affecting the IMMUNE SYSTEM and other host defenses and enhancing transmission of infecting agents.
  
• Bovine Virus Diarrhea-Mucosal Disease [M0002851]
  Acute disease of cattle caused by the bovine viral diarrhea viruses (DIARRHEA VIRUSES, BOVINE VIRAL). Often mouth ulcerations are the only sign but fever, diarrhea, drop in milk yield, and loss of appetite are also seen. Severity of clinical disease varies and is strain dependent. Outbreaks are characterized by low morbidity and high mortality.
  
• Brachial Neuralgia [M0003934]
  
• Brachial Plexus Neuritis [M0328160]
  A syndrome associated with inflammation of the BRACHIAL PLEXUS. Clinical features include severe pain in the shoulder region which may be accompanied by MUSCLE WEAKNESS and loss of sensation in the upper extremity. This condition may be associated with VIRUS DISEASES; IMMUNIZATION; SURGERY; heroin use (see HEROIN DEPENDENCE); and other conditions. The term brachial neuralgia generally refers to pain associated with brachial plexus injury. (From Adams et al., Principles of Neurology, 6th ed, pp1355-6)
  
• Brachial Plexus Neuropathies [M0328162]
  Diseases of the cervical (and first thoracic) roots, nerve trunks, cords, and peripheral nerve components of the BRACHIAL PLEXUS. Clinical manifestations include regional pain, PARESTHESIA; MUSCLE WEAKNESS, and decreased sensation (HYPESTHESIA) in the upper extremity. These disorders may be associated with trauma (including BIRTH INJURIES); THORACIC OUTLET SYNDROME; NEOPLASMS; NEURITIS; RADIOTHERAPY; and other conditions. (From Adams et al., Principles of Neurology, 6th ed, pp1351-2)
  
• Bradyarrhythmia [M0002862]
  
• Brain Abscess [M0002867]
  A circumscribed collection of purulent exudate in the brain, due to bacterial and other infections. The majority are caused by spread of infected material from a focus of suppuration elsewhere in the body, notably the PARANASAL SINUSES, middle ear (see EAR, MIDDLE); HEART (see also ENDOCARDITIS, BACTERIAL), and LUNG. Penetrating CRANIOCEREBRAL TRAUMA and NEUROSURGICAL PROCEDURES may also be associated with this condition. Clinical manifestations include HEADACHE; SEIZURES; focal neurologic deficits; and alterations of consciousness. (Adams et al., Principles of Neurology, 6th ed, pp712-6)
  
• Brain Abscess, Child [M0333032]
  
• Brain Abscess, Multiple [M0334050]
  
• Brain Abscess, Pyogenic [M0334051]
  
• Brain Abscess, Sterile [M0334052]
  
• Brain Aneurysm [M0335409]
  
• Brain Damage, Chronic [M0002872]
  A condition characterized by long-standing brain dysfunction or damage, usually of three months duration or longer. Potential etiologies include BRAIN INFARCTION; certain NEURODEGENERATIVE DISORDERS; CRANIOCEREBRAL TRAUMA; ANOXIA, BRAIN; ENCEPHALITIS; certain NEUROTOXICITY SYNDROMES; metabolic disorders (see BRAIN DISEASES, METABOLIC); and other conditions.
  
• Brain Diseases [M0002874]
  Pathologic conditions affecting the BRAIN, which is composed of the intracranial components of the CENTRAL NERVOUS SYSTEM. This includes (but is not limited to) the CEREBRAL CORTEX; intracranial white matter; BASAL GANGLIA; THALAMUS; HYPOTHALAMUS; BRAIN STEM; and CEREBELLUM.
  
• Brain Diseases, Arterial [M0335425]
  
• Brain Diseases, Metabolic [M0002875]
  Acquired or inborn metabolic diseases that produce brain dysfunction or damage. These include primary (i.e., disorders intrinsic to the brain) and secondary (i.e., extracranial) metabolic conditions that adversely affect cerebral function.
  
• Brain Diseases, Metabolic, Acquired [M0328164]
  Brain dysfunction or damage caused by acquired (i.e., non-inborn) metabolic disorders. Associated conditions include ENDOCRINE DISEASES; WATER-ELECTROLYTE IMBALANCE; KIDNEY DISEASES; LIVER DISEASES; anoxia (HYPOXIA, BRAIN); nutritional disorders (see NUTRITIONAL AND METABOLIC DISEASES); an encephalopathy associated with HEMODIALYSIS; and other disorders. (From Plum & Posner, Diagnosis of Stupor and Coma, 3rd ed, pp208-260)
  
• Brain Diseases, Metabolic, Inborn [M0328165]
  Brain disorders resulting from inborn metabolic errors, primarily from enzymatic defects which lead to substrate accumulation, product reduction, or increase in toxic metabolites through alternate pathways. The majority of these conditions are familial, however spontaneous mutation may also occur in utero.
  
• Brain Diseases, Metabolic, Inherited [M0335526]
  
• Brain Embolism [M0335426]
  
• Brain Embolism and Thrombosis [M0335452]
  
• Brain Infarction [M0328169]
  The formation of an area of necrosis in the brain, including the cerebral hemispheres (see CEREBRAL INFARCTION), thalami, basal ganglia, brain stem (BRAIN STEM INFARCTIONS), or cerebellum secondary to an insufficiency of arterial or venous blood flow.
  
• Brain Infarction, Posterior Circulation [M0334195]
  
• Brain Ischemia [M0003886]
  Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.
  
• Brain Stem Infarctions [M0328180]
  Infarctions that occur in the brain stem which is comprised of the midbrain, pons, and medulla. There are several named syndromes characterized by their distinctive clinical manifestations and specific sites of ischemic injury.
  
• Brain Stem Ischemia, Transient [M0335462]
  
• Brain Thrombosis [M0335457]
  
• Brain Thrombus [M0337792]
  
• Branch Retinal Artery Occlusion [M0023641]
  
• Branchio-Oculo-Facial Syndrome [M0028710]
  
• Branchio-Oto-Renal Syndrome [M0028709]
  An autosomal dominant disorder manifested by various combinations of preauricular pits, branchial fistulae or cysts, lacrimal duct stenosis, hearing loss, structural defects of the outer, middle, or inner ear, and renal dysplasia. Associated defects include asthenic habitus, long narrow facies, constricted palate, deep overbite, and myopia. Hearing loss may be due to Mondini type cochlear defect and stapes fixation. (Jablonski's Dictionary of Syndromes & Eponymic Diseases, 2d ed)
  
• Breast Diseases [M0002906]
  Pathological processes of the BREAST.
  
• Bright Disease [M0490937]
  A historical classification which is no longer used. It described acute glomerulonephritis, acute nephritic syndrome, or acute nephritis. Named for Richard Bright.
  
• Brill-Zinsser Disease [M0022191]
  
• Bronchial Diseases [M0002963]
  
• Bronchial Hyperreactivity [M0025237]
  Tendency of the smooth muscle of the tracheobronchial tree to contract more intensely in response to a given stimulus than it does in the response seen in normal individuals. This condition is present in virtually all symptomatic patients with asthma. The most prominent manifestation of this smooth muscle contraction is a decrease in airway caliber that can be readily measured in the pulmonary function laboratory.
  
• Bronchial Spasm [M0002967]
  Spasmodic contraction of the smooth muscle of the bronchi.
  
• Bronchiectasis [M0002968]
  Persistent abnormal dilatation of the bronchi.
  
• Bronchiolitis [M0002969]
  Inflammation of the bronchioles.
  
• Bronchiolitis Obliterans [M0002970]
  Inflammation of the bronchioles with obstruction by fibrous granulation tissue or bronchial exudate. It may follow inhalation of irritating gases or foreign bodies and it complicates pneumonia.
  
• Bronchiolitis Obliterans Organizing Pneumonia [M0027812]
  A disease formerly considered a form of interstitial pneumonia. Its etiology is obscure but it may be associated with toxic fumes, infection, and connective tissue disease. Clinical symptoms include cough, dyspnea and influenza-like symptoms with the development of the usual interstitial pneumonia in many cases. Obstructive symptoms are limited to smokers. There are patchy polypoid masses of intra-alveolar granulation tissue in small airway lumina and alveolar ducts. "Organizing" refers to unresolved pneumonia (in which the alveolar exudate persists and eventually undergoes fibrosis) in which fibrous tissue forms in the alveoli. (From Segen, Dictionary of Modern Medicine, 1992; Stedman, 25th ed)
  
• Bronchiolitis, Viral [M0002971]
  An acute inflammatory disease of the upper RESPIRATORY TRACT, caused by paramyxoviruses, occurring primarily in infants and young children; the viruses most commonly implicated are PARAINFLUENZA VIRUS TYPE 3; RESPIRATORY SYNCYTIAL VIRUS, HUMAN; and METAPNEUMOVIRUS.
  
• Bronchitis [M0002972]
  
• Bronchitis, Chronic [M0384773]
  A subcategory of CHRONIC OBSTRUCTIVE PULMONARY DISEASE. The disease is characterized by hypersecretion of mucus accompanied by a chronic (more than 3 months in 2 consecutive years) productive cough. Infectious agents are a major cause of chronic bronchitis.
  
• Bronchoalveolar Lavage Fluid [M0002973]
  Fluid obtained by washout of the alveolar compartment of the lung. It is used to assess biochemical and inflammatory changes in and effects of therapy on the interstitial lung tissue.
  
• Bronchopneumonia [M0002979]
  Acute inflammation of the walls of the smaller bronchial tubes, with varying amounts of pulmonary consolidation due to spread of the inflammation into peribronchiolar alveoli and the alveolar ducts. (Stedman, 25th ed)
  
• Bronchopulmonary Dysplasia [M0002980]
  A chronic lung disease developed after OXYGEN INHALATION THERAPY or mechanical ventilation (VENTILATION, MECHANICAL) in certain premature infants (INFANT, PREMATURE) or newborn infants with respiratory distress syndrome (RESPIRATORY DISTRESS SYNDROME, NEWBORN). Histologically, it is characterized by the unusual abnormalities of the bronchioles, such as METAPLASIA, decrease in alveolar number, and formation of CYSTS. Severity of this disease and lung injuries depend on the duration of oxygen supplementation, positive pressure requirement, GESTATIONAL AGE, and BIRTH WEIGHT of the infant.
  
• Bronchospasm, Exercise-Induced [M0001887]
  
• Brown Tendon Sheath Syndrome [M0335795]
  
• Brown-Sequard Syndrome [M0027661]
  A syndrome associated with injury to the lateral half of the spinal cord. The condition is characterized by the following clinical features (which are found below the level of the lesion): contralateral hemisensory anesthesia to pain and temperature, ipsilateral loss of propioception, and ipsilateral motor paralysis. Tactile sensation is generally spared. (From Adams et al., Principles of Neurology, 6th ed, p162).
  
• Brown-Sequard's Paralysis [M0336348]
  
• Brucellosis [M0002989]
  Infection caused by bacteria of the genus BRUCELLA mainly involving the reticuloendothelial system. This condition is characterized by fever, weakness, malaise, and weight loss.
  
• Brucellosis, Bovine [M0002990]
  A disease of cattle caused by bacteria of the genus BRUCELLA leading to abortion in late pregnancy. BRUCELLA ABORTUS is the primary infective agent.
  
• Brugada Syndrome [M0496826]
  An autosomal dominant disease characterized by a SYNCOPAL EPISODE and/or aborted sudden death, a structurally normal heart, and a characteristic ELECTROCARDIOGRAM. The electrocardiogram shows ST segment elevation in V1 to V3, with a morphology of the QRS complex resembling a right bundle branch block. The episodes of syncope and sudden death are caused by fast polymorphic ventricular tachycardias (TACHYCARDIA, VENTRICULAR) or VENTRICULAR FIBRILLATION which appear without warning. Several mutations linked to this syndrome affect the cardiac SODIUM CHANNEL gene SCN5A which codes for the alpha subunit of type V sodium channel.
  
• Bruxism [M0002994]
  A disorder characterized by grinding and clenching of the teeth.
  
• Bubonic Plague [M0016947]
  
• Budgerigar Fancier's Lung [M0002578]
  
• Bulbar Palsy, Progressive [M0015879]
  A motor neuron disease marked by progressive weakness of the muscles innervated by cranial nerves of the lower brain stem. Clinical manifestations include dysarthria, dysphagia, facial weakness, tongue weakness, and fasciculations of the tongue and facial muscles. The adult form of the disease is marked initially by bulbar weakness which progresses to involve motor neurons throughout the neuroaxis. Eventually this condition may become indistinguishable from AMYOTROPHIC LATERAL SCLEROSIS. Fazio-Londe syndrome is an inherited form of this illness which occurs in children and young adults. (Adams et al., Principles of Neurology, 6th ed, p1091; Brain 1992 Dec;115(Pt 6):1889-1900)
  
• Bulbospinal Neuronopathy [M0335730]
  
• Bunostomiasis [M0010534]
  
• Bunyaviridae Infections [M0003043]
  Virus diseases caused by the BUNYAVIRIDAE.
  
• Burkholderia Infections [M0028527]
  Infections with bacteria of the genus BURKHOLDERIA.
  
• Burning Mouth Syndrome [M0003062]
  A group of painful oral symptoms associated with a burning or similar sensation. There is usually a significant organic component with a degree of functional overlay; it is not limited to the psychophysiologic group of disorders.
  
• Bursitis [M0003070]
  Inflammation of a bursa, occasionally accompanied by a calcific deposit in the underlying supraspinatus tendon. The most common site is the subdeltoid bursa. (Dorland, 27th ed)
  
• Byssinosis [M0003120]
  An airway obstruction due to the dust inhaled during the processing of cotton.
  
• CADASIL [M0334725]
  A familial, cerebral arteriopathy mapped to chromosome 19q12, and characterized by the presence of granular deposits in small CEREBRAL ARTERIES producing ischemic STROKE; PSEUDOBULBAR PALSY; and multiple subcortical infarcts (CEREBRAL INFARCTION). CADASIL is an acronym for Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy. CADASIL differs from BINSWANGER DISEASE by the presence of MIGRAINE WITH AURA and usually by the lack of history of arterial HYPERTENSION. (From Bradley et al, Neurology in Clinical Practice, 2000, p1146)
  
• CADASILM [M0454809]
  A subvariety of CADASIL characterized by the high frequency of MIGRAINE. The acronym stands for Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts, Leukoencephalopathy, and Migraine.
  
• Cafe-au-Lait Spots [M0028478]
  Light brown pigmented macules associated with NEUROFIBROMATOSIS and Albright's syndrome (see FIBROUS DYSPLASIA, POLYOSTOTIC).
  
• Calcinosis [M0003143]
  Pathologic deposition of calcium salts in tissues.
  
• Calciphylaxis [M0003144]
  Condition of induced systemic hypersensitivity in which tissues respond to appropriate challenging agents with a sudden local calcification.
  
• Calcium Metabolism Disorders [M0003174]
  Disorders in the processing of calcium in the body: its absorption, transport, storage, and utilization.
  
• Calcium Pyrophosphate Dihydrate Deposition [M0004307]
  
• Caliciviridae Infections [M0026172]
  Virus diseases caused by CALICIVIRIDAE. They include HEPATITIS E; VESICULAR EXANTHEMA OF SWINE; acute respiratory infections in felines, rabbit hemorrhagic disease, and some cases of gastroenteritis in humans.
  
• Callosities [M0003210]
  Localized hyperplasia of the horny layer of the epidermis due to pressure or friction. (Dorland, 27th ed)
  
• Campylobacter Infections [M0003245]
  Infections with bacteria of the genus CAMPYLOBACTER.
  
• Canavan Disease [M0026932]
  A rare neurodegenerative condition of infancy or childhood characterized by white matter vacuolization and demeylination that gives rise to a spongy appearance. Aspartoacylase deficiency leads to an accumulation of N-acetylaspartate in astrocytes. Inheritance may be autosomal recessive or the illness may occur sporadically. This illness occurs more frequently in individuals of Ashkenazic Jewish descent. The neonatal form features the onset of hypotonia and lethargy at birth, rapidly progressing to coma and death. The infantile form features developmental delay, DYSKINESIAS, hypotonia, spasticity, blindness, and megalencephaly. The juvenile form is characterized by ATAXIA; OPTIC ATROPHY; and DEMENTIA. (From Adams et al., Principles of Neurology, 6th ed, p944; Am J Med Genet 1988 Feb;29(2):463-71)
  
• Canavan Disease, Familial Form [M0336605]
  
• Canavan Disease, Infantile [M0336606]
  
• Canavan Disease, Juvenile [M0336607]
  
• Canavan Disease, Neonatal [M0336608]
  
• Canavan Disease, Sporadic Form [M0336609]
  
• Candidiasis [M0003258]
  Infection with a fungus of the genus CANDIDA. It is usually a superficial infection of the moist areas of the body and is generally caused by CANDIDA ALBICANS. (Dorland, 27th ed)
  
• Candidiasis, Chronic Mucocutaneous [M0003259]
  A clinical syndrome characterized by development, usually in infancy or childhood, of a chronic, often widespread candidiasis of skin, nails, and mucous membranes. It may be secondary to one of the immunodeficiency syndromes, inherited as an autosomal recessive trait, or associated with defects in cell-mediated immunity, endocrine disorders, dental stomatitis, or malignancy.
  
• Candidiasis, Cutaneous [M0003260]
  Candidiasis of the skin manifested as eczema-like lesions of the interdigital spaces, perleche, or chronic paronychia. (Dorland, 27th ed)
  
• Candidiasis, Oral [M0003261]
  Infection of the mucous membranes of the mouth by a fungus of the genus CANDIDA. (Dorland, 27th ed)
  
• Candidiasis, Vulvovaginal [M0003262]
  Infection of the VULVA and VAGINA with a fungus of the genus CANDIDA.
  
• Canine Distemper [M0006596]
  
• Cannabis Abuse [M0003275]
  
• Capillary Leak Syndrome [M0029047]
  A rare and sometimes fatal disease characterized by recurring attacks of leakage of intravascular fluids into the extravascular space. This syndrome is observed in patients who demonstrate a state of generalized leaky capillaries following shock syndromes, low-flow states, ischemia-reperfusion injuries, toxemias, or poisoning. It can lead to generalized edema and MULTIPLE ORGAN FAILURE. (Zikria, et al. (eds.), Reperfusion Injuries and Clinical Capillary Leak Syndrome, pp. 470-72, 1994)
  
• Caplan's Syndrome [M0003301]
  Pneumoconiosis associated with rheumatoid arthritis.
  
• Carbamoyl-Phosphate Synthase I Deficiency Disease [M0328185]
  A urea cycle disorder manifesting in infancy as lethargy, emesis, seizures, alterations of muscle tone, abnormal eye movements, and an elevation of serum ammonia. The disorder is caused by a reduction in the activity of hepatic mitochondrial CARBAMOYL-PHOSPHATE SYNTHASE (AMMONIA). (Menkes, Textbook of Child Neurology, 5th ed, pp50-1)
  
• Carbohydrate Metabolism, Inborn Errors [M0003357]
  
• Carbohydrate-Deficient Glycoprotein Syndrome [M0028352]
  An inborn error of carbohydrate metabolism manifesting as a genetic multisystem disorder of autosomal recessive inheritance. A predominant feature is severe central and peripheral nervous system involvement resulting in psychomotor retardation, seizures, cerebellar ataxia, and other symptoms which include growth retardation, retinitis pigmentosa, hypothyroidism, and fatty liver. The notable biochemical feature is the deficiency of a large number of blood glycoproteins and decreased activities of various blood coagulation factors.
  
• Carcinoid Heart Disease [M0003420]
  Cardiac manifestation of MALIGNANT CARCINOID SYNDROME. It is a unique form of fibrosis involving the endocardium, primarily of the right heart. The fibrous deposits tend to cause constriction of the tricuspid and pulmonary valves. (DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1307)
  
• Cardiac Complexes, Premature [M0008072]
  A premature contraction of the heart that is initiated somewhere other than the sinoatrial node.
  
• Cardiac Tamponade [M0003456]
  
• Cardiomyopathies [M0014337]
  A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).
  
• Cardiomyopathies, Primary [M0014338]
  
• Cardiomyopathies, Secondary [M0014339]
  
• Cardiomyopathy, Alcoholic [M0003462]
  Disease of CARDIAC MUSCLE resulting from chronic excessive alcohol consumption. Myocardial damage can be caused by: (1) a toxic effect of alcohol; (2) malnutrition in alcoholics such as THIAMINE DEFICIENCY; or (3) toxic effect of additives in alcoholic beverages such as COBALT. This disease is usually manifested by DYSPNEA and palpitations with CARDIOMEGALY and congestive heart failure (HEART FAILURE, CONGESTIVE).
  
• Cardiomyopathy, Dilated [M0003463]
  A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, contractile dysfunction of the left or both HEART VENTRICLES, and congestive heart failure (HEART FAILURE, CONGESTIVE) symptoms. Risk factors include ETHANOL and TOBACCO abuse, PREGNANCY; HYPERTENSION; INFECTION; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.
  
• Cardiomyopathy, Familial Idiopathic [M0453060]
  
• Cardiomyopathy, Hypertrophic [M0003464]
  A form of CARDIAC MUSCLE disease, characterized by left and/or right ventricular hypertrophy (HYPERTROPHY, LEFT VENTRICULAR; HYPERTROPHY, RIGHT VENTRICULAR), frequent asymmetrical involvement of the HEART SEPTUM, and normal or reduced left ventricular volume. Risk factors include HYPERTENSION; AORTIC STENOSIS; and gene MUTATION; (FAMILIAL HYPERTROPHIC CARDIOMYOPATHY).
  
• Cardiomyopathy, Hypertrophic, Familial [M0371730]
  An autosomal dominant inherited form of HYPERTROPHIC CARDIOMYOPATHY. It results from any of more than 50 mutations involving genes encoding contractile proteins such as VENTRICULAR MYOSINS; cardiac TROPONIN T; ALPHA-TROPOMYOSIN.
  
• Cardiomyopathy, Restrictive [M0003468]
  A form of CARDIAC MUSCLE disease in which the ventricular walls are excessively rigid, impeding ventricular filling. It is marked by reduced diastolic volume of either or both ventricles but normal or nearly normal systolic function. It may be idiopathic or associated with other diseases (ENDOMYOCARDIAL FIBROSIS or AMYLOIDOSIS) causing interstitial fibrosis.
  
• Cardiovascular Diseases [M0003473]
  Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.
  
• Cardiovascular Infections [M0496690]
  Pathological conditions of the CARDIOVASCULAR SYSTEM caused by infections.
  
• Cardiovirus Infections [M0027417]
  Infections caused by viruses of the genus CARDIOVIRUS, family PICORNAVIRIDAE.
  
• Carditis [M0393324]
  
• Caries, Cervical [M0026123]
  
• Caroli Disease [M0025558]
  Congenital cystic dilatation of the intrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC). It consists of 2 types: simple Caroli disease is characterized by bile duct dilatation (ectasia) alone; and complex Caroli disease is characterized by bile duct dilatation with extensive hepatic fibrosis and portal hypertension (HYPERTENSION, PORTAL). Benign renal tubular ectasia is associated with both types of Caroli disease.
  
• Carotid Artery Diseases [M0003540]
  Diseases of the common, internal, and external carotid arteries. ATHEROSCLEROSIS and trauma are relatively frequent causes of carotid artery pathology.
  
• Carotid Artery Thrombosis [M0003543]
  Blood clot formation in the common, internal, or external carotid artery which may produce stenosis or occlusion of the vessel, leading to ischemia or infarction of tissue supplied by these arteries. Thrombosis of the common and internal carotid arteries may result in ISCHEMIC ATTACKS, TRANSIENT; CEREBRAL INFARCTION; or AMAUROSIS FUGAX.
  
• Carotid Artery, Internal, Dissection [M0328204]
  A hemorrhage into the wall of the carotid artery, separating the intima from the media and leading to aneurysm formation. This process may occlude the carotid artery and result in thromboembolic complications, including CEREBRAL INFARCTION. Dissections may occur spontaneously or follow CRANIOCEREBRAL TRAUMA; NECK INJURIES; and rarely severe bouts of coughing. (Adams et al., Principles of Neurology, 6th ed, p830)
  
• Carotid Atherosclerosis [M0333551]
  
• Carotid Circulation Transient Ischemic Attack [M0335465]
  
• Carotid Pseudoaneurysm [M0334354]
  
• Carotid Stenosis [M0025703]
  Narrowing or stricture of the internal, common, or external carotid artery, most often as a result of atherosclerotic plaque formation. Ulcerations may form in atherosclerotic plaques and induce thrombus formation. Platelet or cholesterol emboli may arise from stenotic carotid lesions and induce a transient ischemic attack (ISCHEMIC ATTACK, TRANSIENT) or CEREBROVASCULAR ACCIDENT. Emboli which travel to the eye may manifest as AMAUROSIS FUGAX (temporary blindness). (From Adams et al., Principles of Neurology, 6th ed, pp822-3)
  
• Carotid-Cavernous Sinus Fistula [M0328206]
  Laceration of the intracavernous portion of the carotid artery or one of its intracavernous branches resulting in a direct communication between the internal carotid artery and the cavernous sinus. Clinically, this produces a pulsatile exophthalmus and a marked limitation of extraocular motion in the affected eye. CRANIOCEREBRAL TRAUMA, especially basilar skull fractures (SKULL FRACTURE, BASILAR) is the most common cause of this condition, but it may also occur spontaneously or in association with diseases featuring defective connective tissue, such as EHLERS-DANLOS SYNDROME. (Adams et al., Principles of Neurology, 6th ed, p877)
  
• Carpal Tunnel Syndrome [M0003553]
  Entrapment of the MEDIAN NERVE in the carpal tunnel, which is formed by the flexor retinaculum and the CARPAL BONES. This syndrome may be associated with repetitive occupational trauma (CUMULATIVE TRAUMA DISORDERS); wrist injuries; AMYLOID NEUROPATHIES; rheumatoid arthritis (see ARTHRITIS, RHEUMATOID); ACROMEGALY; PREGNANCY; and other conditions. Symptoms include burning pain and paresthesias involving the ventral surface of the hand and fingers which may radiate proximally. Impairment of sensation in the distribution of the median nerve and thenar muscle atrophy may occur. (Joynt, Clinical Neurology, 1995, Ch51, p45)
  
• Carsickness [M0014104]
  
• Cartilage Diseases [M0003568]
  
• Cat Diseases [M0003610]
  Diseases of the domestic cat (Felis catus or F. domesticus). This term does not include diseases of the so-called big cats such as CHEETAHS; LIONS; tigers, cougars, panthers, leopards, and other Felidae for which the heading CARNIVORA is used.
  
• Cat-Scratch Disease [M0003611]
  A self-limiting bacterial infection of the regional lymph nodes caused by AFIPIA felis, a gram-negative bacterium recently identified by the Centers for Disease Control and Prevention and by BARTONELLA HENSELAE. It usually arises one or more weeks following a feline scratch, with raised inflammatory nodules at the site of the scratch being the primary symptom.
  
• Cataplexy [M0003627]
  A condition characterized by transient weakness or paralysis of somatic musculature triggered by an emotional stimulus or physical exertion. Cataplexy is frequently associated with NARCOLEPSY. During a cataplectic attack, there is a marked reduction in muscle tone similar to the normal physiologic hypotonia that accompanies rapid eye movement sleep (SLEEP, REM). (From Adams et al., Principles of Neurology, 6th ed, p396)
  
• Cataract [M0003628]
  Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)
  
• Cataract, Membranous [M0003630]
  
• Catastrophic Illness [M0003633]
  An acute or prolonged illness usually considered to be life-threatening or with the threat of serious residual disability. Treatment may be radical and is frequently costly.
  
• Catatonia, Malignant [M0337450]
  
• Catatonia, Organic [M0337451]
  
• Cattle Diseases [M0003687]
  Diseases of domestic cattle of the genus Bos. It includes diseases of cows, yaks, and zebus.
  
• Cauda Equina Syndrome [M0336797]
  
• Causalgia [M0003692]
  A complex regional pain syndrome characterized by burning pain and marked sensitivity to touch (HYPERESTHESIA) in the distribution of an injured peripheral nerve. Autonomic dysfunction in the form of sudomotor (i.e., sympathetic innervation to sweat glands), vasomotor, and trophic skin changes may also occur. (Adams et al., Principles of Neurology, 6th ed, p1359)
  
• Cavernous Sinus Thrombophlebitis [M0334357]
  
• Cavernous Sinus Thrombosis [M0328208]
  Formation of a blood clot composed of platelets and fibrin in the CAVERNOUS SINUS of the brain. Infections of the paranasal sinuses and adjacent structures, CRANIOCEREBRAL TRAUMA, and THROMBOPHILIA are associated conditions. Clinical manifestations include dysfunction of cranial nerves III, IV, V, and VI, marked periorbital swelling, chemosis, fever, and visual loss. (From Adams et al., Principles of Neurology, 6th ed, p711)
  
• Cecal Diseases [M0003708]
  Pathological developments in the CECUM.
  
• Celiac Disease [M0003736]
  A malabsorption syndrome that is precipitated by the ingestion of GLUTEN-containing foods, such as wheat, rye, and barley. It is characterized by INFLAMMATION of the SMALL INTESTINE, loss of MICROVILLI structure, failed INTESTINAL ABSORPTION, and MALNUTRITION.
  
• Central Alveolar Hypoventilation Syndrome [M0334756]
  
• Central Nervous System Bacterial Infections [M0328211]
  Bacterial infections of the brain, spinal cord, and meninges, including infections involving the perimeningeal spaces.
  
• Central Nervous System Congenital Vascular Malformations [M0393003]
  
• Central Nervous System Diseases [M0003805]
  Diseases of any component of the brain (including the cerebral hemispheres, diencephalon, brain stem, and cerebellum) or the spinal cord.
  
• Central Nervous System Fungal Infections [M0328044]
  MYCOSES of the brain, spinal cord, and meninges which may result in ENCEPHALITIS; MENINGITIS, FUNGAL; MYELITIS; BRAIN ABSCESS; and EPIDURAL ABSCESS. Certain types of fungi may produce disease in immunologically normal hosts, while others are classified as opportunistic pathogens, causing illness primarily in immunocompromised individuals (e.g., ACQUIRED IMMUNODEFICIENCY SYNDROME).
  
• Central Nervous System Helminthiasis [M0328049]
  Infections of the BRAIN; SPINAL CORD; or MENINGES caused by HELMINTHS (parasitic worms).
  
• Central Nervous System Inborn Metabolic Diseases [M0335525]
  
• Central Nervous System Infections [M0003806]
  Pathogenic infections of the brain, spinal cord, and meninges. DNA VIRUS INFECTIONS; RNA VIRUS INFECTIONS; BACTERIAL INFECTIONS; MYCOPLASMA INFECTIONS; SPIROCHAETALES INFECTIONS; fungal infections; PROTOZOAN INFECTIONS; HELMINTHIASIS; and PRION DISEASES may involve the central nervous system as a primary or secondary process.
  
• Central Nervous System Lyme Disease [M0335550]
  
• Central Nervous System Metabolic Disorders [M0334162]
  
• Central Nervous System Origin Vertigo [M0337354]
  
• Central Nervous System Parasitic Infections [M0328052]
  Infections of the brain, spinal cord, and meninges caused by parasites, primarily PROTOZOA and HELMINTHS.
  
• Central Nervous System Protozoal Infections [M0328055]
  Infections of the brain, spinal cord, or meninges by single celled organisms of the subkingdom PROTOZOA. The central nervous system may be the primary or secondary site of protozoal infection. Examples of primary infections include cerebral amebiasis, granulomatous amebic encephalitis, primary amebic meningoencephalitis, and TRYPANOSOMIASIS, AFRICAN. Cerebral malaria, cerebral babesiosis, and chagasic meningoencephalitis are examples of secondary infections. These diseases may occur as OPPORTUNISTIC INFECTIONS or arise in immunocompetent hosts. (From Joynt, Clinical Neurology, 1998, Ch27, pp37-47)
  
• Central Nervous System Viral Diseases [M0328064]
  Viral infections of the brain, spinal cord, meninges, or perimeningeal spaces.
  
• Central Retinal Artery Occlusion [M0023642]
  
• Central Sleep Apnea, Primary [M0334909]
  
• Central Sleep Apnea, Secondary [M0334908]
  
• Centronuclear Myopathy [M0335640]
  
• Cenuriasis [M0003956]
  
• Cephalopelvic Disproportion [M0012107]
  A condition in which the HEAD of the FETUS is larger than the mother's PELVIS through which the fetal head must pass during a vaginal delivery.
  
• Cerebellar Ataxia, Early Onset [M0336205]
  
• Cerebellar Ataxia, Late Onset [M0336206]
  
• Cerebellar Degenerations, Primary [M0336207]
  
• Cerebellar Diseases [M0003858]
  Diseases that affect the structure or function of the cerebellum. Cardinal manifestations of cerebellar dysfunction include dysmetria, GAIT ATAXIA, and MUSCLE HYPOTONIA.
  
• Cerebral Abscess [M0334053]
  
• Cerebral Amyloid Angiopathy [M0025384]
  A heterogeneous group of disorders that includes sporadic and familial forms, characterized clinically by cerebral ischemia (see BRAIN ISCHEMIA); CEREBRAL INFARCTION; and CEREBRAL HEMORRHAGE. Pathologically the condition is marked by the deposition of AMYLOID in the walls of small blood vessels in the cerebral cortex and meninges. The sporadic form is associated with lobar cerebral hemorrhage in the elderly and ALZHEIMER DISEASE. (From Neuropathol Appl Neurobiol 1996 Jun;22(3):216-227; Adams et al., Principles of Neurology, 6th ed, p852)
  
• Cerebral Amyloid Angiopathy, Familial [M0334468]
  A familial condition marked by the deposition of AMYLOID in the walls of small blood vessels in the cerebral cortex and meninges and characterized clinically by cerebral ischemia (see BRAIN ISCHEMIA); CEREBRAL INFARCTION; and CEREBRAL HEMORRHAGE.
  
• Cerebral Amyloid Angiopathy, Hereditary [M0383413]
  
• Cerebral Aneurysm [M0003869]
  
• Cerebral Angiitis [M0335299]
  
• Cerebral Arterial Diseases [M0003877]
  Diseases of intracranial arteries which supply the cerebrum of the brain, including the ANTERIOR CEREBRAL ARTERY; MIDDLE CEREBRAL ARTERY; and POSTERIOR CEREBRAL ARTERY. Included in this category are atherosclerotic, congenital, traumatic, infectious, inflammatory, and other conditions.
  
• Cerebral Arteriosclerosis [M0003875]
  
• Cerebral Atherosclerosis [M0335418]
  
• Cerebral Cryptococcosis [M0335659]
  
• Cerebral Embolism [M0003881]
  
• Cerebral Embolism and Thrombosis [M0003882]
  Embolism or thrombosis occurring in a cerebral vessel often leading to cerebral infarction.
  
• Cerebral Embryonic Artery, Persistent [M0336793]
  
• Cerebral Helminthiasis [M0334370]
  
• Cerebral Hypoxia-Ischemia [M0335389]
  
• Cerebral Infarction [M0003885]
  The formation of an area of necrosis in the cerebrum caused by an insufficiency of arterial or venous blood flow. Infarcts of the cerebrum are generally classified by hemisphere (i.e., left vs. right), lobe (e.g., frontal lobe infarction), arterial distribution (e.g., INFARCTION, ANTERIOR CEREBRAL ARTERY), and etiology (e.g., embolic infarction).
  
• Cerebral Infarction, Left Hemisphere [M0334514]
  
• Cerebral Infarction, Right Hemisphere [M0334554]
  
• Cerebral Ischemia, Transient [M0335461]
  
• Cerebral Palsy [M0003888]
  A heterogeneous group of nonprogressive motor disorders caused by chronic brain injuries that originate in the prenatal period, perinatal period, or first few years of life. The four major subtypes are spastic, athetoid, ataxic, and mixed cerebral palsy, with spastic forms being the most common. The motor disorder may range from difficulties with fine motor control to severe spasticity (see MUSCLE SPASTICITY) in all limbs. Spastic diplegia (Little disease) is the most common subtype, and is characterized by spasticity that is more prominent in the legs than in the arms. Pathologically, this condition may be associated with LEUKOMALACIA, PERIVENTRICULAR. (From Dev Med Child Neurol 1998 Aug;40(8):520-7)
  
• Cerebral Palsy, Athetoid [M0334571]
  
• Cerebral Palsy, Atonic [M0334570]
  
• Cerebral Palsy, Congenital [M0334587]
  
• Cerebral Palsy, Diplegic, Infantile [M0334588]
  
• Cerebral Palsy, Dystonic-Rigid [M0334589]
  
• Cerebral Palsy, Mixed [M0334590]
  
• Cerebral Palsy, Monoplegic, Infantile [M0334600]
  
• Cerebral Palsy, Quadriplegic, Infantile [M0334586]
  
• Cerebral Palsy, Rolandic Type [M0334591]
  
• Cerebral Palsy, Spastic [M0334592]
  
• Cerebral Protozoal Infections [M0334429]
  
• Cerebral Thrombosis [M0003883]
  
• Cerebral Thrombus [M0335458]
  
• Cerebral Vasospasm [M0335469]
  
• Cerebrospinal Fluid Otorrhea [M0003910]
  Discharge of cerebrospinal fluid through the external auditory meatus or through the eustachian tube into the nasopharynx. This is usually associated with CRANIOCEREBRAL TRAUMA (e.g., SKULL FRACTURE involving the TEMPORAL BONE;), NEUROSURGICAL PROCEDURES; or other conditions, but may rarely occur spontaneously. (From Am J Otol 1995 Nov;16(6):765-71)
  
• Cerebrospinal Fluid Otorrhea, Spontaneous [M0335621]
  
• Cerebrospinal Fluid Rhinorrhea [M0003911]
  Discharge of cerebrospinal fluid through the nose. Common etiologies include trauma, neoplasms, and prior surgery, although the condition may occur spontaneously. (Otolaryngol Head Neck Surg 1997 Apr;116(4):442-9)
  
• Cerebrovascular Accident [M0328070]
  A sudden, nonconvulsive loss of neurologic function due to an ischemic or hemorrhagic intracranial vascular event. In general, cerebrovascular accidents are classified by anatomic location in the brain, vascular distribution, etiology, age of the affected individual, and hemorrhagic vs. nonhemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)
  
• Cerebrovascular Insufficiency [M0334622]
  
• Cerebrovascular Occlusion [M0334623]
  
• Cervical Migraine Syndrome [M0335690]
  
• Cervical Rib Syndrome [M0003930]
  A condition associated with compression of the BRACHIAL PLEXUS; SUBCLAVIAN ARTERY; and SUBCLAVIAN VEIN at the thoracic outlet and caused by a complete or incomplete anomalous cervical rib or fascial band connecting the tip of a cervical rib with the first thoracic rib. Clinical manifestations may include pain in the neck and shoulder which radiates into the upper extremity, PARESIS or PARALYSIS of brachial plexus innervated muscles; sensory loss; PARESTHESIAS; ISCHEMIA; and EDEMA. (Adams et al., Principles of Neurology, 6th ed, p214)
  
• Cervical Sympathetic Dystrophy [M0335547]
  
• Cervical-Rib-Cervical-Band Syndrome [M0336376]
  
• Cervico-Brachial Neuralgia [M0003933]
  
• Cervicogenic Headache [M0335250]
  
• Cestode Infections [M0003957]
  Infections with true tapeworms of the helminth subclass CESTODA.
  
• Chagas Cardiomyopathy [M0003982]
  A disease of the CARDIAC MUSCLE developed subsequent to the initial protozoan infection by TRYPANOSOMA CRUZI. After infection, less than 10% develop acute illness such as MYOCARDITIS (mostly in children). The disease then enters a latent phase without clinical symptoms until about 20 years later. Myocardial symptoms of advanced CHAGAS DISEASE include conduction defects (HEART BLOCK) and CARDIOMEGALY.
  
• Chagas Disease [M0022076]
  Infection with the protozoan parasite TRYPANOSOMA CRUZI, a form of TRYPANOSOMIASIS endemic in Central and South America. It is named after the Brazilian physician Carlos Chagas, who discovered the parasite. Infection by the parasite (positive serologic result only) is distinguished from the clinical manifestations that develop years later, such as destruction of PARASYMPATHETIC GANGLIA; CHAGAS CARDIOMYOPATHY; and dysfunction of the ESOPHAGUS or COLON.
  
• Chalazion [M0025898]
  A non-neoplastic cyst of the MEIBOMIAN GLANDS of the eyelid.
  
• Chancroid [M0003985]
  Acute, localized autoinoculable infectious disease usually acquired through sexual contact. Caused by HAEMOPHILUS DUCREYI, it occurs endemically almost worldwide, especially in tropical and subtropical countries and more commonly in seaports and urban areas than in rural areas.
  
• Channelopathies [M0493143]
  A variety of neuromuscular conditions resulting from MUTATIONS in ION CHANNELS manifesting as episodes of EPILEPSY; HEADACHE DISORDERS; and DYSKINESIAS.
  
• Charcot-Marie-Tooth Disease [M0003994]
  A hereditary motor and sensory neuropathy transmitted most often as an autosomal dominant trait and characterized by progressive distal wasting and loss of reflexes in the muscles of the legs (and occasionally involving the arms). Onset is usually in the second to fourth decade of life. This condition has been divided into two subtypes, hereditary motor and sensory neuropathy (HMSN) types I and II. HMSN I is associated with abnormal nerve conduction velocities and nerve hypertrophy, features not seen in HMSN II. (Adams et al., Principles of Neurology, 6th ed, p1343)
  
• Charcot-Marie-Tooth Disease, Type Ia [M0336970]
  
• Charcot-Marie-Tooth Disease, Type Ib [M0336971]
  
• Chediak-Higashi Syndrome [M0003997]
  A form of phagocyte bactericidal dysfunction characterized by unusual oculocutaneous albinism, high incidence of lymphoreticular neoplasms, and recurrent pyogenic infections. In many cell types, abnormal lysosomes are present leading to defective pigment distribution and abnormal neutrophil functions. The disease is transmitted by autosomal recessive inheritance and a similar disorder occurs in the beige mouse, the Aleutian mink, and albino Hereford cattle.
  
• Cheilitis [M0004001]
  Inflammation of the lips. It is of various etiologies and degrees of pathology.
  
• Cherubism [M0004034]
  A fibro-osseous hereditary disease of the jaws. The swollen jaws and raised eyes give a cherubic appearance; multiple radiolucencies are evident upon radiographic examination.
  
• Chiari-Frommel Syndrome [M0004038]
  A POSTPARTUM condition consists of persistent lactation (GALACTORRHEA) and AMENORRHEA in patients not BREAST FEEDING.
  
• Chickenpox [M0004041]
  A highly contagious infectious disease caused by the varicella-zoster virus (HERPESVIRUS 3, HUMAN). It usually affects children, is spread by direct contact or respiratory route via droplet nuclei, and is characterized by the appearance on the skin and mucous membranes of successive crops of typical pruritic vesicular lesions that are easily broken and become scabbed. Chickenpox is relatively benign in children, but may be complicated by pneumonia and encephalitis in adults. (From Dorland, 27th ed)
  
• Child Malnutrition [M0439621]
  Malnutrition occurring in children ages 2 to 12 years, which is due to insufficient intake of food, dietary nutrients, or a pathophysiologic condition which prevents the absorption and utilization of food. Growth and development are markedly affected.
  
• Child Nutrition Disorders [M0023649]
  Disorders caused by nutritional imbalance, either overnutrition or undernutrition, occurring in children ages 2 to 12 years.
  
• Child Overnutrition [M0440455]
  
• Childhood Benign Occipital Epilepsy [M0334951]
  
• Childhood Onset Dystonias [M0334829]
  
• Childhood Progressive Bulbar Palsy [M0337043]
  
• Childhood Tic Disorders [M0336232]
  
• Chlamydia Infections [M0004107]
  Infections with bacteria of the genus CHLAMYDIA.
  
• Chlamydiaceae Infections [M0004111]
  Infections with bacteria of the family CHLAMYDIACEAE.
  
• Chlamydophila Infections [M0363732]
  Infections with bacteria of the genus CHLAMYDOPHILA.
  
• Chloasma [M0013317]
  
• Chlorosis [M0001132]
  
• Cholangitis [M0004228]
  Inflammation of the biliary ductal system (BILE DUCTS); intrahepatic, extrahepatic, or both.
  
• Cholangitis, Sclerosing [M0023371]
  Chronic inflammatory disease of the BILIARY TRACT. It is characterized by fibrosis and hardening of the intrahepatic and extrahepatic biliary ductal systems leading to bile duct strictures, CHOLESTASIS, and eventual BILIARY CIRRHOSIS.
  
• Cholecystitis [M0004232]
  Inflammation of the GALLBLADDER; generally caused by impairment of BILE flow, GALLSTONES in the BILIARY TRACT, infections, or other diseases.
  
• Cholecystitis, Acute [M0439583]
  Acute inflammation of the GALLBLADDER wall. It is characterized by the presence of ABDOMINAL PAIN; FEVER; and LEUKOCYTOSIS. Gallstone obstruction of the CYSTIC DUCT is present in approximately 90% of the cases.
  
• Cholecystolithiasis [M0439321]
  Presence or formation of GALLSTONES in the GALLBLADDER.
  
• Choledochal Cyst [M0023892]
  A congenital anatomic malformation of a bile duct, including cystic dilatation of the extrahepatic bile duct or the large intrahepatic bile duct. Classification is based on the site and type of dilatation. Type I is most common.
  
• Choledochal Cyst, Type I [M0023893]
  Characterized by the fusiform or saccular dilatation of the COMMON BILE DUCT.
  
• Choledochal Cyst, Type II [M0442105]
  Characterized by the diverticulum arising from the extrahepatic biliary tree.
  
• Choledochal Cyst, Type III [M0442106]
  Characterized by the choledochocele dilatation of the distal portion of the COMMON BILE DUCT in the DUODENUM where the pancreatic duct (PANCREATIC DUCTS) enters.
  
• Choledochal Cyst, Type IV [M0442107]
  Characterized by the presence of multiple extrahepatic and intrahepatic cysts.
  
• Choledochal Cyst, Type V [M0442108]
  Characterized by the presence of a singular or multiple intrahepatic cysts.
  
• Choledocholithiasis [M0333984]
  Presence or formation of GALLSTONES in the COMMON BILE DUCT.
  
• Cholelithiasis [M0004241]
  Presence or formation of GALLSTONES in the BILIARY TRACT, usually in the gallbladder (CHOLECYSTOLITHIASIS) or the common bile duct (CHOLEDOCHOLITHIASIS).
  
• Cholera [M0004244]
  An acute diarrheal disease endemic in India and Southeast Asia whose causative agent is VIBRIO CHOLERAE. This condition can lead to severe dehydration in a matter of hours unless quickly treated.
  
• Cholera Infantum [M0480286]
  
• Cholera Morbus [M0026753]
  An old term that is no longer used in the scientific literature. Cholera morbus refers to acute GASTROENTERITIS occurring in summer or autumn; characterized by severe cramps, diarrhea, and vomiting.
  
• Cholestasis [M0004258]
  Impairment of bile flow due to obstruction in small bile ducts (INTRAHEPATIC CHOLESTASIS) or obstruction in large bile ducts (EXTRAHEPATIC CHOLESTASIS).
  
• Cholestasis, Extrahepatic [M0002480]
  Impairment of bile flow in the large BILE DUCTS by mechanical obstruction or stricture due to benign or malignant processes.
  
• Cholestasis, Intrahepatic [M0004262]
  Impairment of bile flow due to injury to the HEPATOCYTES; BILE CANALICULI; or the intrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC).
  
• Cholesteatoma [M0004265]
  A non-neoplastic keratinizing mass with stratified squamous epithelium, frequently occurring in the meninges, central nervous system, bones of the skull, and most commonly in the middle ear and mastoid region.
  
• Cholesteatoma, Middle Ear [M0027650]
  Cholesteatoma of the middle ear, usually associated with chronic infection, and commonly affecting the tympanum, epitympanum, and antrum.
  
• Cholesterol Ester Storage Disease [M0023379]
  An autosomal recessive disorder caused by mutations in the gene for acid lipase (CHOLESTEROL ESTERASE). It is characterized by the accumulation of neutral lipids, particularly CHOLESTEROL ESTERS in leukocytes, fibroblasts, and hepatocytes.
  
• Choline Deficiency [M0004290]
  A condition produced by a deficiency of CHOLINE in animals. Choline is known as a lipotropic agent because it has been shown to promote the transport of excess fat from the liver under certain conditions in laboratory animals. Combined deficiency of choline (included in the B vitamin complex) and all other methyl group donors causes liver cirrhosis in some animals. Unlike compounds normally considered as vitamins, choline does not serve as a cofactor in enzymatic reactions. (From Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)
  
• Chondrocalcinosis [M0004305]
  Presence of calcium salts, especially calcium pyrophosphate, in the cartilaginous structures of one or more joints. When accompanied by attacks of goutlike symptoms, it is called pseudogout. (Dorland, 27th ed)
  
• Chondrodysplasia Punctata [M0004308]
  A heterogeneous group of bone dysplasias, the common character of which is stippling of the epiphyses in infancy. The group includes a severe autosomal recessive form (CHONDRODYSPLASIA PUNCTATA, RHIZOMELIC), an autosomal dominant form (Conradi-Hunermann syndrome), and a milder X-linked form. Metabolic defects associated with impaired peroxisomes are present only in the rhizomelic form.
  
• Chondrodysplasia Punctata, Rhizomelic [M0028265]
  An autosomal recessive form of CHONDRODYSPLASIA PUNCTATA characterized by defective plasmalogen biosynthesis and impaired peroxisomes. Patients have shortened proximal limbs and severely disturbed endochondral bone formation. The metabolic defects associated with the impaired peroxisomes are present only in the rhizomelic form of chondrodysplasia punctata. (From Scriver et al, Metabolic Basis of Inherited Disease, 6th ed, p1497)
  
• Chondromalacia Patellae [M0455467]
  A degeneration of the ARTICULAR CARTILAGE of the PATELLA, caused by a decrease in sulfated MUCOPOLYSACCHARIDES in the ground substance. When accompanied by pain, it is sometimes considered part of or confused with PATELLOFEMORAL PAIN SYNDROME.
  
• Chondromatosis, Synovial [M0024254]
  Rare, benign, chronic, progressive metaplasia in which cartilage is formed in the synovial membranes of joints, tendon sheaths, or bursae. Some of the metaplastic foci can become detached producing loose bodies. When the loose bodies undergo secondary calcification, the condition is called synovial osteochondromatosis.
  
• Chorea Acanthocytosis Syndrome [M0334641]
  
• Chorea Gravidarum [M0328352]
  A rare movement disorder developed during PREGNANCY, characterized by involuntary jerky motion (CHOREA) and inability to maintain stable position of body parts (ATHETOSIS). RHEUMATIC FEVER and collagen vascular disorders are frequently associated with this disease. Chorea may vary from mild to severe and occurs in approximately 1 per 2,000 to 3,000 pregnancies. (From Md Med J 1997 Sep;46(8):436-9)
  
• Chorea, Benign Hereditary [M0334643]
  
• Chorea, Chronic Progressive [M0334644]
  
• Chorea, Rheumatic [M0334645]
  
• Chorea, Senile [M0334646]
  
• Choreatic Disorders [M0328355]
  Acquired and hereditary conditions which feature CHOREA as a primary manifestation of the disease process.
  
• Chorioamnionitis [M0004338]
  INFLAMMATION of the placental membranes (CHORION; AMNION) and connected tissues such as fetal BLOOD VESSELS and UMBILICAL CORD. It is often associated with intrauterine ascending infections during PREGNANCY.
  
• Chorioretinitis [M0004342]
  Inflammation of the choroid in which the sensory retina becomes edematous and opaque. The inflammatory cells and exudate may burst through the sensory retina to cloud the vitreous body.
  
• Choroid Diseases [M0024286]
  Disorders of the choroid including hereditary choroidal diseases, neoplasms, and other abnormalities of the vascular layer of the uvea.
  
• Choroideremia [M0024194]
  An X chromosome-linked abnormality characterized by atrophy of the choroid and degeneration of the retinal pigment epithelium causing night blindness.
  
• Choroiditis [M0004350]
  Inflammation of the choroid.
  
• Chromoblastomycosis [M0004392]
  Scaly papule or warty growth, caused by five fungi, that spreads as a result of satellite lesions affecting the foot or leg. The extremity may become swollen and, at its distal portion, covered with various nodular, tumorous, verrucous lesions that resemble cauliflower. In rare instances, the disease may begin on the hand or wrist and involve the entire upper extremity. (Arnold, Odom, and James, Andrew's Diseases of the Skin, 8th ed, p362)
  
• Chromosome Disorders [M0373367]
  Clinical conditions caused by an abnormal chromosome constitution in which there is extra or missing chromosome material (either a whole chromosome or a chromosome segment). (from Thompson et al., Genetics in Medicine, 5th ed, p429)
  
• Chromosome Instability Syndromes [M0471003]
  
• Chronic Actinic Dermatitis [M0016758]
  
• Chronic Alcoholic Hepatitis [M0010225]
  
• Chronic Bacterial Prostatitis [M0489747]
  
• Chronic Cystic Mastitis [M0008443]
  
• Chronic Daily Headache [M0335251]
  
• Chronic Disease [M0004447]
  Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)
  
• Chronic Headache [M0335246]
  
• Chronic Insomnia [M0334962]
  
• Chronic Paroxysmal Hemicrania [M0336308]
  
• Chronic Progressive Epilepsia Partialis Continua [M0334936]
  
• Chronic Prostatitis with Chronic Pelvic Pain Syndrome [M0489748]
  
• Chronically Ill [M0004448]
  
• Chronobiology Disorders [M0357545]
  Disruptions of the rhythmic cycle of bodily functions or activities.
  
• Churg-Strauss Syndrome [M0023506]
  Widespread necrotizing angiitis with granulomas. Pulmonary involvement is frequent. Asthma or other respiratory infection may precede evidence of vasculitis. Eosinophilia and lung involvement differentiate this disease from POLYARTERITIS NODOSA.
  
• Chylopericardium [M0016299]
  
• Chylothorax [M0004457]
  The presence of chyle in the thoracic cavity. (Dorland, 27th ed)
  
• Chylous Ascites [M0004456]
  Presence of milky lymph (CHYLE) in the PERITONEAL CAVITY, with or without infection.
  
• Chylous Peritonitis [M0455604]
  
• Ciliary Motility Disorders [M0004477]
  Disorders characterized by abnormal ciliary movement in the nose, paranasal sinuses, respiratory tract, and spermatozoa. Electron microscopy of the CILIA shows that dynein arms are missing. The disorders manifest as KARTAGENER SYNDROME, chronic respiratory disorders, chronic sinusitis, and/or chronic otitis.
  
• Ciliophora Infections [M0025560]
  Infections with protozoa of the phylum CILIOPHORA.
  
• Circadian Rhythm Disorders [M0334748]
  Disruptions of the rhythmic cycle of bodily functions or activities.
  
• Circoviridae Infections [M0027400]
  Virus diseases caused by the CIRCOVIRIDAE.
  
• Circovirus Infections [M0027399]
  
• Cirrhosis [M0008452]
  
• Citrullinemia [M0328360]
  A group of diseases related to a deficiency of the enzyme ARGININOSUCCINATE SYNTHASE which causes an elevation of serum levels of CITRULLINE. In neonates, clinical manifestations include lethargy, hypotonia, and SEIZURES. Milder forms also occur. Childhood and adult forms may present with recurrent episodes of intermittent weakness, lethargy, ATAXIA, behavioral changes, and DYSARTHRIA. (From Menkes, Textbook of Child Neurology, 5th ed, p49)
  
• Classic Maple Syrup Urine Disease [M0335651]
  
• Classic Pelizaeus-Merzbacher Disease [M0336644]
  
• Classical Swine Fever [M0010487]
  An acute, highly contagious disease affecting swine of all ages and caused by the CLASSICAL SWINE FEVER VIRUS. It has a sudden onset with high morbidity and mortality.
  
• Claude Syndrome [M0334262]
  
• Cleft Palate [M0004549]
  Congenital fissure of the soft and/or hard palate, due to faulty fusion.
  
• Cleidocranial Dysplasia [M0004550]
  A rare autosomal dominant condition in which there is defective ossification of the cranial bones with large fontanels and delayed closing of the sutures, complete or partial absence of the clavicles, wide pubic symphysis, short middle phalanges of the fifth fingers, and dental and vertebral anomalies. (From Dorland, 27th ed)
  
• Clinical Capillary Leak Syndrome [M0029048]
  
• Clonorchiasis [M0004618]
  Infection of the biliary passages with CLONORCHIS SINENSIS, also called Opisthorchis sinensis. It may lead to inflammation of the biliary tract, proliferation of biliary epithelium, progressive portal fibrosis, and sometimes bile duct carcinoma. Extension to the liver may lead to fatty changes and cirrhosis. (From Dorland, 27th ed)
  
• Clostridium Enterocolitis [M0443802]
  
• Clostridium Infections [M0004637]
  Infections with bacteria of the genus CLOSTRIDIUM.
  
• Cluster Headache [M0004652]
  A primary headache disorder that is characterized by severe, strictly unilateral PAIN which is orbital, supraorbital, temporal or in any combination of these sites, lasting 15-180 min. occurring 1 to 8 times a day. The attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial SWEATING, eyelid EDEMA, and miosis. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
  
• Coagulation Protein Disorders [M0029880]
  Hemorrhagic and thrombotic disorders resulting from abnormalities or deficiencies of coagulation proteins.
  
• Coccidioidomycosis [M0004676]
  Infection with a fungus of the genus COCCIDIOIDES, species C. immitis. The primary form is an acute, benign, self-limited respiratory infection due to inhalation of spores and varying in severity. The secondary form is a virulent, severe, chronic, progressive granulomatous disease with systemic involvement. (From Dorland, 27th ed)
  
• Coccidiosis [M0004678]
  Protozoan infection found in animals and man. It is caused by several different genera of COCCIDIA.
  
• Cochlear Diseases [M0024249]
  Diseases of the cochlea, the part of the inner ear that is concerned with hearing.
  
• Cochlear Neuritis [M0333672]
  
• Cockayne Syndrome [M0004689]
  A syndrome characterized by multiple system abnormalities including DWARFISM; PHOTOSENSITIVITY DISORDERS; PREMATURE AGING; and HEARING LOSS. It is caused by mutations of a number of autosomal recessive genes encoding proteins that involve transcriptional-coupled DNA REPAIR processes. Cockayne syndrome is classified by the severity and age of onset. Type I (classical; CSA) is early childhood onset in the second year of life; type II (congenital; CSB) is early onset at birth with severe symptoms; type III (xeroderma pigmentosum; XP) is late childhood onset with mild symptoms.
  
• Cockayne Syndrome, Type I [M0337665]
  Caused by mutations of gene CKN1.
  
• Cockayne Syndrome, Type II [M0337666]
  Caused by mutations of gene ERCC6.
  
• Cockayne Syndrome, Type III [M0337667]
  Type C is a rare form. Its genetic defect is not clear; appears to be a heterogeneous group. OMIM suggests that Type C should not be used anymore.
  
• Cockayne-Pelizaeus-Merzbacher Disease [M0336643]
  
• Cockayne-Touraine Disease [M0024600]
  
• Coenuriasis [M0003958]
  
• Coffin-Lowry Syndrome [M0417790]
  A rare, X-linked mental retardation syndrome that results from mutations in the RIBOSOMAL PROTEIN S6 KINASE gene. Typical manifestations of the disease include an intelligence quotient of less than 50, facial anomalies, and other malformations.
  
• Coin Lesion, Pulmonary [M0004726]
  Solitary, round, circumscribed shadows found in the lungs in x-ray examinations. Common causes are tuberculosis, neoplasms, cysts, or vascular anomalies. (Stedman, 25th ed)
  
• Cold Agglutinin Disease [M0483802]
  
• Cold Ischemia [M0474607]
  The chilling of a tissue or organ during decreased BLOOD perfusion or in the absence of blood supply. Cold ischemia time during ORGAN TRANSPLANTATION begins when the organ is cooled with a cold perfusion solution after ORGAN PROCUREMENT surgery, and ends after the tissue reaches physiological temperature during implantation procedures. WARM ISCHEMIA TIME starts then and ends with completion of SURGICAL ANASTOMOSIS.
  
• Cold Panniculitis [M0023783]
  
• Colitis [M0004770]
  Inflammation of the COLON section of the large intestine (INTESTINE, LARGE), usually with symptoms such as DIARRHEA (often with blood and mucus), ABDOMINAL PAIN, and FEVER.
  
• Colitis, Collagenous [M0455263]
  A subtype of MICROSCOPIC COLITIS, characterized by chronic watery DIARRHEA of unknown origin, a normal COLONOSCOPY but abnormal histopathology on BIOPSY. Microscopic examination of biopsy samples taken from the COLON show larger-than-normal band of subepithelial COLLAGEN.
  
• Colitis, Granulomatous [M0393459]
  
• Colitis, Ischemic [M0025968]
  Inflammation of the COLON due to colonic ISCHEMIA resulting from alterations in systemic circulation or local vasculature.
  
• Colitis, Lymphocytic [M0455264]
  A subtype of MICROSCOPIC COLITIS, characterized by chronic watery DIARRHEA of unknown origin, a normal COLONOSCOPY but abnormal histopathology on BIOPSY. Microscopic examination of biopsy samples taken from the COLON show infiltration of LYMPHOCYTES in the superficial EPITHELIUM and the underlying connective tissue (lamina propria).
  
• Colitis, Microscopic [M0455261]
  A condition characterized by chronic watery DIARRHEA of unknown origin, a normal COLONOSCOPY but abnormal histopathology on BIOPSY. This syndrome was first described in 1980 by Read and associates. Subtypes include COLLAGENOUS COLITIS and LYMPHOCYTIC COLITIS. Both have similar clinical symptoms and are distinguishable only by histology.
  
• Colitis, Pseudomembranous [M0443801]
  
• Colitis, Ulcerative [M0004771]
  Inflammation of the COLON that is predominantly confined to the MUCOSA. Its major symptoms include DIARRHEA, rectal BLEEDING, the passage of MUCUS, and ABDOMINAL PAIN.
  
• Collagen Diseases [M0004792]
  Historically, a heterogeneous group of acute and chronic diseases, including rheumatoid arthritis, systemic lupus erythematosus, progressive systemic sclerosis, dermatomyositis, etc. This classification was based on the notion that "collagen" was equivalent to "connective tissue", but with the present recognition of the different types of collagen and the aggregates derived from them as distinct entities, the term "collagen diseases" now pertains exclusively to those inherited conditions in which the primary defect is at the gene level and affects collagen biosynthesis, post-translational modification, or extracellular processing directly. (From Cecil Textbook of Medicine, 19th ed, p1494)
  
• Colonic Diseases [M0004814]
  Pathological processes in the COLON region of the large intestine (INTESTINE, LARGE).
  
• Colonic Diseases, Functional [M0004815]
  Chronic or recurrent colonic disorders without an identifiable structural or biochemical explanation. The widely recognized IRRITABLE BOWEL SYNDROME falls into this category.
  
• Colonic Pseudo-Obstruction [M0004819]
  Functional obstruction of the COLON leading to MEGACOLON in the absence of obvious COLONIC DISEASES or mechanical obstruction. When this condition is acquired, acute, and coexisting with another medical condition (trauma, surgery, serious injuries or illness, or medication), it is called Ogilvie's syndrome.
  
• Color Blindness [M0004827]
  
• Color Blindness, Acquired [M0336565]
  
• Color Blindness, Blue [M0336566]
  
• Color Blindness, Green [M0336567]
  
• Color Blindness, Inherited [M0336568]
  
• Color Blindness, Red [M0336569]
  
• Color Blindness, Red-Green [M0336570]
  
• Color Vision Defects [M0004826]
  Defects of color vision are mainly hereditary traits but can be secondary to acquired or developmental abnormalities in the CONES (RETINA). Severity of hereditary defects of color vision depends on the degree of mutation of the OPSIN genes (on X CHROMOSOME and CHROMOSOME 3) that code the photopigments for red, green and blue.
  
• Colorado Tick Fever [M0004832]
  A febrile illness characterized by chills, aches, vomiting, leukopenia, and sometimes encephalitis. It is caused by the COLORADO TICK FEVER VIRUS, a reovirus transmitted by the tick Dermacentor andersoni.
  
• Coma [M0004841]
  A profound state of unconsciousness associated with depressed cerebral activity from which the individual cannot be aroused. Coma generally occurs when there is dysfunction or injury involving both cerebral hemispheres or the brain stem RETICULAR FORMATION.
  
• Coma, Post-Head Injury [M0328365]
  Prolonged unconsciousness from which the individual cannot be aroused, associated with traumatic injuries to the BRAIN. This may be defined as unconsciousness persisting for 6 hours or longer. Coma results from injury to both cerebral hemispheres or the RETICULAR FORMATION of the BRAIN STEM. Contributing mechanisms include DIFFUSE AXONAL INJURY and BRAIN EDEMA. (From J Neurotrauma 1997 Oct;14(10):699-713)
  
• Coma, Post-Traumatic, Prolonged [M0337413]
  
• Common Bile Duct Diseases [M0004862]
  Diseases of the COMMON BILE DUCT including the AMPULLA OF VATER and the SPHINCTER OF ODDI.
  
• Common Carotid Artery Stenosis [M0334351]
  
• Common Carotid Artery Thrombosis [M0334341]
  
• Common Cold [M0004864]
  A catarrhal disorder of the upper respiratory tract, which may be viral, a mixed infection, or an allergic reaction. It is marked by acute coryza, slight rise in temperature, chilly sensations, and general indisposition. (Dorland, 27th ed)
  
• Common Variable Immunodeficiency [M0025944]
  Heterogeneous group of immunodeficiency syndromes characterized by hypogammaglobulinemia of most isotypes, variable B-cell defects, and the presence of recurrent bacterial infections.
  
• Communicable Diseases [M0004868]
  
• Communicable Diseases, Emerging [M0355553]
  Reporting of new and reemerging infectious diseases and studies that seek to improve the understanding of factors involved in disease emergence, prevention, and elimination.
  
• Communicating Hydrocephalus [M0335280]
  
• Community-Acquired Infections [M0026784]
  Any infection acquired in the community, that is, contrasted with those acquired in a health care facility (CROSS INFECTION). An infection would be classified as community-acquired if the patient had not recently been in a health care facility or been in contact with someone who had been recently in a health care facility.
  
• Compartment Syndromes [M0004909]
  Conditions in which increased pressure within a limited space compromises the circulation and function of tissue within that space. Compartmentation involves mainly the leg but also involved are the forearm, arm, thigh, shoulder, and buttock. Some of the causes of increased pressure are trauma, tight dressings, hemorrhage, and exercise. Sequelae include nerve compression, paralysis, and contracture.
  
• Compensatory Hyperinsulinemia [M0446735]
  A GLUCOSE-induced HYPERINSULINEMIA, a marker of insulin-resistant state. It is a mechanism to compensate for reduced sensitivity to insulin.
  
• Complex Endometrial Hyperplasia [M0406718]
  A benign form of endometrial hyperplasia with crowded endometrial glands and little stroma between the glands. Complex hyperplasia has low risk of progression to endometrial carcinoma.
  
• Complex Partial Status Epilepticus [M0336169]
  
• Complex Regional Pain Syndromes [M0328368]
  Conditions characterized by pain involving an extremity or other body region, HYPERESTHESIA, and localized autonomic dysfunction following injury to soft tissue or nerve. The pain is usually associated with ERYTHEMA; SKIN TEMPERATURE changes, abnormal sudomotor activity (i.e., changes in sweating due to altered sympathetic innervation) or edema. The degree of pain and other manifestations is out of proportion to that expected from the inciting event. Two subtypes of this condition have been described: type I; (REFLEX SYMPATHETIC DYSTROPHY) and type II; (CAUSALGIA). (From Pain 1995 Oct;63(1):127-33)
  
• Condylomata Acuminata [M0004994]
  Sexually transmitted form of anogenital warty growth caused by the human papillomaviruses.
  
• Congenital Disorders [M0014571]
  
• Congenital Fiber Type Disproportion [M0335641]
  
• Congenital Generalized Lipodystrophy Type 1 [M0487300]
  It is caused by mutations of gene encoding 1-acylglycerol-3-phosphate O-acyltransferase-2 (AGPAT2).
  
• Congenital Generalized Lipodystrophy Type 2 [M0487301]
  It is caused by mutation of gene encoding seipin (BSCL2).
  
• Congenital Hypothyroidism [M0005308]
  A condition in infancy or early childhood due to an in-utero deficiency of THYROID HORMONES that can be caused by genetic or environmental factors, such as thyroid dysgenesis or HYPOTHYROIDISM in infants of mothers treated with THIOURACIL during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe MENTAL RETARDATION, impaired skeletal development, short stature, and MYXEDEMA.
  
• Congenital Ichthyosiform Erythroderma, Dry Type [M0024613]
  
• Congenital Ichthyosiform Erythroderma, Wet Type [M0024614]
  
• Congenital Myasthenic Syndromes, Postsynaptic [M0337367]
  
• Congenital Myasthenic Syndromes, Presynaptic [M0337368]
  
• Congenital Nephrogenic Diabetes Insipidus [M0471343]
  
• Congenital, Hereditary, and Neonatal Diseases and Abnormalities [M0014570]
  Diseases existing at birth and often before birth, or that develop during the first month of life (INFANT, NEWBORN, DISEASES), regardless of causation. Of these diseases, those characterized by structural deformities are termed ABNORMALITIES.
  
• Congestive Ophthalmopathy [M0471765]
  
• Conjugate Nystagmus [M0333563]
  
• Conjunctival Diseases [M0005013]
  
• Conjunctivitis [M0005015]
  
• Conjunctivitis, Acute Hemorrhagic [M0005016]
  A highly contagious disease characterized by subconjunctival hemorrhage, sudden swelling of the eyelids and congestion, redness, and pain in the eye. Epidemic conjunctivitis caused by Enterovirus 70 (EV-70) was first described in Africa in 1969. It is caused also by Coxsackievirus A24 variant (CA24v). Epidemics by this organism have appeared most frequently in Asia.
  
• Conjunctivitis, Allergic [M0005017]
  Conjunctivitis due to hypersensitivity to various allergens.
  
• Conjunctivitis, Bacterial [M0005021]
  Purulent infections of the conjunctiva by several species of gram-negative, gram-positive, or acid-fast organisms. Some of the more commonly found genera causing conjunctival infections are Haemophilus, Streptococcus, Neisseria, and Chlamydia.
  
• Conjunctivitis, Giant Papillary [M0005018]
  
• Conjunctivitis, Inclusion [M0005022]
  An infection of the eyes characterized by the presence in conjunctival epithelial cells of inclusion bodies indistinguishable from those of trachoma. It is acquired by infants during birth and by adults from swimming pools. The etiological agent is CHLAMYDIA TRACHOMATIS whose natural habitat appears to be the genito-urinary tract. Inclusion conjunctivitis is a less severe disease than trachoma and usually clears up spontaneously.
  
• Conjunctivitis, Vernal [M0005019]
  
• Conjunctivitis, Viral [M0005023]
  Inflammation, often mild, of the conjunctiva caused by a variety of viral agents. Conjunctival involvement may be part of a systemic infection.
  
• Conn Syndrome [M0459781]
  Primary hyperaldosteronism caused by the excess production of ALDOSTERONE by an ADENOMA of the ZONA GLOMERULOSA or CONN ADENOMA.
  
• Connective Tissue Diseases [M0005027]
  A heterogeneous group of disorders, some hereditary, others acquired, characterized by abnormal structure or function of one or more of the elements of connective tissue, i.e., collagen, elastin, or the mucopolysaccharides.
  
• Conus Medullaris Syndrome [M0336081]
  
• Convergence Nystagmus [M0333555]
  
• Convergent Comitant Strabismus [M0336193]
  
• Convulsive Generalized Seizure Disorder [M0335029]
  
• Coproporphyria, Hereditary [M0025971]
  An autosomal dominant porphyria that is due to a deficiency of COPROPORPHYRINOGEN OXIDASE in the LIVER, the sixth enzyme in the 8-enzyme biosynthetic pathway of HEME. Clinical features include both neurological symptoms and cutaneous lesions. Patients excrete increased levels of porphyrin precursors, 5-AMINOLEVULINATE and COPROPORPHYRINS.
  
• Corneal Diseases [M0005177]
  Diseases of the cornea.
  
• Corneal Dystrophies, Hereditary [M0005178]
  Bilateral hereditary disorders of the cornea, usually autosomal dominant, which may be present at birth but more frequently develop during adolescence and progress slowly throughout life. Central macular dystrophy is transmitted as an autosomal recessive defect.
  
• Corneal Dystrophy, Juvenile Epithelial of Meesmann [M0494580]
  An autosomal dominant form of hereditary corneal dystrophy due to a defect in cornea-specific KERATIN formation. Mutations in the genes that encode KERATIN-3 and KERATIN-12 have been linked to this disorder.
  
• Corneal Edema [M0024096]
  An excessive amount of fluid in the cornea due to damage of the epithelium or endothelium causing decreased visual acuity.
  
• Corneal Opacity [M0005183]
  Disorder occurring in the central or peripheral area of the cornea. The usual degree of transparency becomes relatively opaque.
  
• Corneal Ulcer [M0005185]
  Loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.
  
• Coronary Aneurysm [M0005187]
  Aneurysm of a coronary vessel. A coronary artery aneurysm is rarely congenital; it is usually due to atherosclerosis, inflammatory processes, or a coronary fistula. (From Stedman, 26th ed)
  
• Coronary Arteriosclerosis [M0005188]
  Thickening and loss of elasticity of the coronary arteries, leading to progressive insufficiency of the arteries (CORONARY DISEASE).
  
• Coronary Disease [M0005191]
  An imbalance between myocardial functional requirements and the capacity of the coronary vessels to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.
  
• Coronary Occlusion [M0005192]
  
• Coronary Restenosis [M0368495]
  Recurrent narrowing or constriction of a coronary artery following surgical procedures performed to alleviate a prior obstruction.
  
• Coronary Stenosis [M0005193]
  Narrowing or constriction of a coronary artery.
  
• Coronary Thrombosis [M0005194]
  Presence of a thrombus in a coronary artery, often causing a myocardial infarction.
  
• Coronary Vasospasm [M0005195]
  Spasm of the large- or medium-sized coronary arteries.
  
• Coronaviridae Infections [M0005199]
  Virus diseases caused by CORONAVIRIDAE.
  
• Coronavirus Infections [M0027585]
  Virus diseases caused by the CORONAVIRUS genus. Some specifics include transmissible enteritis of turkeys (ENTERITIS, TRANSMISSIBLE, OF TURKEYS); FELINE INFECTIOUS PERITONITIS; and transmissible gastroenteritis of swine (GASTROENTERITIS, TRANSMISSIBLE, OF SWINE).
  
• Corpus Luteum Cyst [M0015588]
  
• Corridor Disease [M0021276]
  
• Cortical Deafness [M0332674]
  
• Corticostriatal-Spinal Degeneration [M0336208]
  
• Corynebacterium Infections [M0005225]
  Infections with bacteria of the genus CORYNEBACTERIUM.
  
• Coryza, Acute [M0004865]
  
• Costoclavicular Syndrome [M0021402]
  
• Cowpox [M0023948]
  A mild, eruptive skin disease of milk cows caused by COWPOX VIRUS, with lesions occurring principally on the udder and teats. Human infection may occur while milking an infected animal.
  
• Coxsackievirus Infections [M0005273]
  A heterogeneous group of infections produced by coxsackieviruses, including HERPANGINA, aseptic meningitis (MENINGITIS, ASEPTIC), a common-cold-like syndrome, a non-paralytic poliomyelitis-like syndrome, epidemic pleurodynia (PLEURODYNIA, EPIDEMIC) and a serious MYOCARDITIS.
  
• Cranial Epidural Abscess [M0334923]
  
• Cranial Nerve Diseases [M0005279]
  Disorders of one or more of the twelve cranial nerves. With the exception of the optic and olfactory nerves, this includes disorders of the brain stem nuclei from which the cranial nerves originate or terminate.
  
• Cranial Nerve Palsies [M0360800]
  
• Cranial Neuropathies, Multiple [M0335832]
  
• Craniofacial Dysostosis [M0005284]
  An autosomal dominant disorder characterized by acrocephaly, exophthalmos, hypertelorism, strabismus, parrot-beaked nose, and hypoplastic maxilla with relative mandibular prognathism. (Dorland, 27th ed)
  
• Craniomandibular Disorders [M0026214]
  Diseases or disorders of the muscles of the head and neck, with special reference to the masticatory muscles. The most notable examples are TEMPOROMANDIBULAR JOINT DISORDERS and TEMPOROMANDIBULAR JOINT DYSFUNCTION SYNDROME.
  
• Cranioschisis [M0333688]
  
• Craniosynostoses [M0005288]
  Premature closure of one or more sutures of the skull.
  
• Crescendo Transient Ischemic Attacks [M0335463]
  
• CREST Syndrome [M0026732]
  A mild form of LIMITED SCLERODERMA, a multi-system disorder. Its features include symptoms of CALCINOSIS; RAYNAUD DISEASE; ESOPHAGEAL MOTILITY DISORDERS; sclerodactyly, and TELANGIECTASIS. When the defect in esophageal function is not prominent, it is known as CRST syndrome.
  
• Creutzfeldt-Jakob Disease, Familial [M0334707]
  
• Creutzfeldt-Jakob Syndrome [M0011818]
  A rare transmissible encephalopathy most prevalent between the ages of 50 and 70 years. Affected individuals may present with sleep disturbances, personality changes, ATAXIA; APHASIA, visual loss, weakness, muscle atrophy, MYOCLONUS, progressive dementia, and death within one year of disease onset. A familial form exhibiting autosomal dominant inheritance and a new variant CJD (potentially associated with ENCEPHALOPATHY, BOVINE SPONGIFORM) have been described. Pathological features include prominent cerebellar and cerebral cortical spongiform degeneration and the presence of PRIONS. (From N Engl J Med, 1998 Dec 31;339(27))
  
• Cri-du-Chat Syndrome [M0005309]
  An infantile syndrome characterized by a cat-like cry, failure to thrive, microcephaly, MENTAL RETARDATION, spastic quadriparesis, micro- and retrognathia, glossoptosis, bilateral epicanthus, hypertelorism, and tiny external genitalia. It is caused by a deletion of the short arm of chromosome 5 (5p-).
  
• Crigler-Najjar Syndrome [M0005322]
  A familial form of congenital hyperbilirubinemia transmitted as an autosomal recessive trait. It is characterized by icterus and brain damage caused by a glucuronyl transferase deficiency in the liver and faulty bilirubin conjugation.
  
• Critical Illness [M0025358]
  A disease or state in which death is possible or imminent.
  
• Crohn Disease [M0005335]
  A chronic transmural inflammation that may involve any part of the DIGESTIVE TRACT from MOUTH to ANUS, mostly found in the ILEUM, the CECUM, and the COLON. In Crohn disease, the inflammation, extending through the intestinal wall from the MUCOSA to the serosa, is characteristically asymmetric and segmental. Epithelioid GRANULOMAS may be seen in some patients.
  
• Cronkhite-Canada Syndrome [M0445230]
  A nonfamilial polyposis syndrome that is characterized by the presence of diffuse gastrointestinal polyposis, DIARRHEA, and PROTEIN-LOSING ENTEROPATHY. It was first reported by Cronkhite and Canada in 1955.
  
• Cross Infection [M0005342]
  Any infection which a patient contracts in a health-care institution.
  
• Crossbite [M0012942]
  
• Croup [M0005366]
  A condition characterized by resonant barking cough, hoarseness and persistant stridor and caused by allergy, foreign body, infection, or neoplasm. It occurs chiefly in infants and children.
  
• CRST Syndrome [M0026731]
  
• Crush Syndrome [M0005369]
  Severe systemic manifestation of trauma and ischemia involving soft tissues, principally skeletal muscle, due to prolonged severe crushing. It leads to increased permeability of the cell membrane and to the release of potassium, enzymes, and myoglobin from within cells. Ischemic renal dysfunction secondary to hypotension and diminished renal perfusion results in acute tubular necrosis and uremia.
  
• Crutch Palsy [M0336149]
  
• Cruveilhier-Baumgarten Syndrome [M0010862]
  Liver cirrhosis with intrahepatic portal obstruction, HYPERTENSION, and patent UMBILICAL VEINS.
  
• Cryoglobulinemia [M0005376]
  A condition characterized by the presence of abnormal or abnormal quantities of cryoglobulins in the blood. They are precipitated into the microvasculature on exposure to cold and cause restricted blood flow in exposed areas.
  
• Cryptococcosis [M0005381]
  Infection with a fungus of the species CRYPTOCOCCUS NEOFORMANS.
  
• Cryptogenic Chronic Hepatitis [M0010229]
  
• Cryptogenic Infantile Spasms [M0336065]
  
• Cryptogenic Partial Complex Epilepsy [M0334994]
  
• Cryptogenic Tonic-Clonic Epilepsy [M0335129]
  
• Cryptosporidiosis [M0005385]
  Intestinal infection with PROTOZOA of the genus CRYPTOSPORIDIUM. It occurs in both animals and humans. Symptoms include severe DIARRHEA.
  
• Cubital Tunnel Syndrome [M0026855]
  Compression of the ULNAR NERVE in the cubital tunnel, which is formed by the two heads of the flexor carpi ulnaris muscle, humeral-ulnar aponeurosis, and medial ligaments of the elbow. This condition may follow trauma or occur in association with processes which produce nerve enlargement or narrowing of the canal. Manifestations include elbow pain and PARESTHESIA radiating distally, weakness of ulnar innervated intrinsic hand muscles, and loss of sensation over the hypothenar region, fifth finger, and ulnar aspect of the ring finger. (Joynt, Clinical Neurology, 1995, Ch51, p43)
  
• Cumulative Trauma Disorders [M0018794]
  Harmful and painful condition caused by overuse or overexertion of some part of the musculoskeletal system, often resulting from work-related physical activities. It is characterized by inflammation, pain, or dysfunction of the involved joints, bones, ligaments, and nerves.
  
• Curling Ulcer [M0006884]
  Acute stress DUODENAL ULCER, usually observed in patients with extensive third-degree burns.
  
• Cushing Syndrome [M0005427]
  A condition caused by prolonged exposure to excess levels of cortisol (HYDROCORTISONE) or other GLUCOCORTICOIDS from endogenous or exogenous sources. It is characterized by upper body OBESITY; OSTEOPOROSIS; HYPERTENSION; DIABETES MELLITUS; HIRSUTISM; AMENORRHEA; and excess body fluid. Endogenous Cushing syndrome or spontaneous hypercortisolism is divided into two groups, those due to an excess of ADRENOCORTICOTROPIN and those that are ACTH-independent.
  
• Cutaneous Larva Migrans [M0012223]
  
• Cutis Laxa [M0005430]
  A group of connective tissue diseases in which skin hangs in loose pendulous folds. It is believed to be associated with decreased elastic tissue formation as well as an abnormality in elastin formation. Cutis laxa is usually a genetic disease, but acquired cases have been reported. (From Dorland, 27th ed)
  
• Cyclosporiasis [M0355665]
  Infection with parasitic protozoa of the genus CYCLOSPORA. It is distributed globally and causes a diarrheal illness. Transmission is waterborne.
  
• Cystathionine beta-Synthase Deficiency Disease [M0335279]
  
• Cystic Breast Disease [M0458771]
  
• Cystic Fibrosis [M0005551]
  An autosomal recessive genetic disease of the EXOCRINE GLANDS. It is caused by mutations in the gene encoding the CYSTIC FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR expressed in several organs including the LUNG, the PANCREAS, the BILIARY SYSTEM, and the SWEAT GLANDS. Cystic fibrosis is characterized by epithelial secretory dysfunction associated with ductal obstruction resulting in AIRWAY OBSTRUCTION; chronic RESPIRATORY INFECTIONS; PANCREATIC INSUFFICIENCY; maldigestion; salt depletion; and HEAT PROSTRATION.
  
• Cystic Periventricular Leukomalacia [M0335523]
  
• Cysticercosis [M0005552]
  Infection with CYSTICERCUS, a larval form of the various tapeworms of the genus Taenia (usually T. solium in man). In humans they penetrate the intestinal wall and invade subcutaneous tissue, brain, eye, muscle, heart, liver, lung, and peritoneum. Brain involvement results in NEUROCYSTICERCOSIS. (From Dorland, 28th ed)
  
• Cystinosis [M0005556]
  A metabolic disease characterized by the defective transport of CYSTINE across the lysosomal membrane due to mutation of a membrane protein cystinosin. This results in cystine accumulation and crystallization in the cells causing widespread tissue damage. In the KIDNEY, nephropathic cystinosis is a common cause of RENAL FANCONI SYNDROME.
  
• Cystinuria [M0005557]
  An inherited disorder due to defective reabsorption of CYSTINE and other BASIC AMINO ACIDS by the PROXIMAL RENAL TUBULES. This form of aminoaciduria is characterized by the abnormally high urinary levels of cystine; LYSINE; ARGININE; and ORNITHINE. Mutations involve the amino acid transport protein gene SLC3A1.
  
• Cystitis [M0005558]
  Inflammation of the URINARY BLADDER, either from bacterial or non-bacterial causes. Cystitis is usually associated with painful urination (dysuria), increased frequency, urgency, and suprapubic pain.
  
• Cystitis, Chronic Interstitial [M0028209]
  
• Cystitis, Interstitial [M0028208]
  A condition with recurring discomfort or pain in the URINARY BLADDER and the surrounding pelvic region without an identifiable disease. Severity of pain in interstitial cystitis varies greatly and often is accompanied by increased urination frequency and urgency.
  
• Cystocele [M0002631]
  A HERNIA-like condition in which the weakened pelvic muscles cause the URINARY BLADDER to drop from its normal position. Fallen urinary bladder is more common in females with the bladder dropping into the VAGINA and less common in males with the bladder dropping into the SCROTUM.
  
• Cytochrome-c Oxidase Deficiency [M0335492]
  A disease that results from a congenital defect in ELECTRON TRANSPORT COMPLEX IV. Defects in ELECTRON TRANSPORT COMPLEX IV can be caused by mutations in the SURF1, SCO2, COX10, or SCO1 genes. ELECTRON TRANSPORT COMPLEX IV deficiency caused by mutation in SURF1 manifests itself as LEIGH DISEASE; that caused by mutation in SCO2 as fatal infantile cardioencephalomyopathy; that caused by mutation in COX10 as tubulopathy and leukodystrophy; and that caused by mutation in SCO1 as early-onset hepatic failure and neurologic disorder. (from Online Mendelian Inheritance in Man, http://www.ncbi.nlm.nih.gov/Omim, MIM#220110, May 17, 2001)
  
• Cytomegalovirus Infections [M0005604]
  Infection with CYTOMEGALOVIRUS, characterized by enlarged cells bearing intranuclear inclusions. Infection may be in almost any organ, but the salivary glands are the most common site in children, as are the lungs in adults.
  
• Cytomegalovirus Retinitis [M0026791]
  Infection of the retina by cytomegalovirus characterized by retinal necrosis, hemorrhage, vessel sheathing, and retinal edema. Cytomegalovirus retinitis is a major opportunistic infection in AIDS patients and can cause blindness.
  
• Dacryoadenitis [M0005640]
  
• Dacryocystitis [M0005639]
  Inflammation of the lacrimal sac. (Dorland, 27th ed)
  
• Dandy-Walker Syndrome [M0005653]
  A congenital abnormality of the central nervous system marked by failure of the midline structures of the cerebellum to develop, dilation of the fourth ventricle, and upward displacement of the transverse sinuses, tentorium, and torcula. Clinical features include occipital bossing, progressive head enlargement, bulging of anterior fontanelle, papilledema, ataxia, gait disturbances, nystagmus, and intellectual compromise. (From Menkes, Textbook of Child Neurology, 5th ed, pp294-5)
  
• De Lange Syndrome [M0005689]
  A syndrome characterized by growth retardation, severe MENTAL RETARDATION, short stature, a low-pitched growling cry, brachycephaly, low-set ears, webbed neck, carp mouth, depressed nasal bridge, bushy eyebrows meeting at the midline, hirsutism, and malformations of the hands. The condition may occur sporadically or be associated with an autosomal dominant pattern of inheritance or duplication of the long arm of chromosome 3. (Menkes, Textbook of Child Neurology, 5th ed, p231)
  
• De Quervain Disease [M0021166]
  Stenosing tenosynovitis of the abductor pollicis longus and extensor pollicis brevis tendons in the first dorsal wrist compartment. The presenting symptoms are usually pain and tenderness at the radial styloid. The cause is almost always related to OVERUSE INJURY or is associated with RHEUMATOID ARTHRITIS.
  
• Deaf-Mutism [M0005692]
  
• Deafness [M0005693]
  A general term for the complete loss of the ability to hear from both ears.
  
• Deafness, Acquired [M0336574]
  
• Decalcification, Pathologic [M0005712]
  The loss of calcium salts from bones and teeth. Bacteria may be responsible for this occurrence in teeth. Old age may be a factor contributing to calcium loss, as is the presence of diseases such as rheumatoid arthritis.
  
• Decision Making Reflex Epilepsy [M0335120]
  
• Decompression Sickness [M0005736]
  A condition occurring as a result of exposure to a rapid fall in ambient pressure. Gases, nitrogen in particular, come out of solution and form bubbles in body fluid and blood. These gas bubbles accumulate in joint spaces and the peripheral circulation impairing tissue oxygenation causing disorientation, severe pain, and potentially death.
  
• Decreased Intraocular Pressure-Associated Papilledema [M0393386]
  
• Deficiency Diseases [M0005753]
  A condition produced by dietary or metabolic deficiency. The term includes all diseases caused by an insufficient supply of essential nutrients, i.e., protein (or amino acids), vitamins, and minerals. It also includes an inadequacy of calories. (From Dorland, 27th ed; Stedman, 25th ed)
  
• Deficiency, Hexosediphosphatase [M0023588]
  
• Deficiency, Vitamin [M0002042]
  
• Degenerative Diseases, Central Nervous System [M0337101]
  
• Degenerative Diseases, Spinal Cord [M0337102]
  
• Deglutition Disorders [M0005756]
  Difficulty in SWALLOWING which may result from neuromuscular disorder or mechanical obstruction. Dysphagia is classified into two distinct types: oropharyngeal dysphagia due to malfunction of the PHARYNX and UPPER ESOPHAGEAL SPHINCTER; and esophageal dysphagia due to malfunction of the ESOPHAGUS.
  
• Dehydration [M0005757]
  The condition that results from excessive loss of water from a living organism.
  
• Dejerine-Roussy Syndrome [M0336227]
  
• Deltaretrovirus Infections [M0010635]
  Infections caused by the HTLV or BLV deltaretroviruses. They include human T-cell leukemia-lymphoma (LEUKEMIA-LYMPHOMA, T-CELL, ACUTE, HTLV-I-ASSOCIATED).
  
• Dementia, Multi-Infarct [M0023301]
  Loss of higher cortical functions with retained awareness due to multiple cortical or subcortical CEREBRAL INFARCTION. Memory, judgment, attention span, and impulse control are often impaired, and may be accompanied by PSEUDOBULBAR PALSY; HEMIPARESIS; reflex abnormalities, and other signs of localized neurologic dysfunction. (From Adams et al., Principles of Neurology, 6th ed, p1060)
  
• Dementia, Vascular [M0023275]
  An imprecise term referring to dementia associated with CEREBROVASCULAR DISORDERS, including CEREBRAL INFARCTION (single or multiple), and conditions associated with chronic BRAIN ISCHEMIA. Diffuse, cortical, and subcortical subtypes have been described. (From Gerontol Geriatr 1998 Feb;31(1):36-44)
  
• Demyelinating Autoimmune Diseases, CNS [M0328372]
  Conditions characterized by loss or dysfunction of myelin (see MYELIN SHEATH) in the brain, spinal cord, or optic nerves secondary to autoimmune mediated processes. This may take the form of a humoral or cellular immune response directed toward myelin or OLIGODENDROGLIA associated autoantigens.
  
• Demyelinating Diseases [M0005825]
  Diseases characterized by loss or dysfunction of myelin in the central or peripheral nervous system.
  
• Demyelination [M0005826]
  
• Demyelinative Myelitis [M0334304]
  
• Dengue [M0005831]
  An acute infectious, eruptive, febrile disease caused by four antigenically related but distinct serotypes of the DENGUE VIRUS. It is transmitted by the bite of infected Aedes mosquitoes, especially A. aegypti. Classical dengue (dengue fever) is self-limiting and characterized by fever, myalgia, headache, and rash. DENGUE HEMORRHAGIC FEVER is a more virulent form of dengue virus infection and a separate clinical entity. (From Dorland, 28th ed)
  
• Dengue Hemorrhagic Fever [M0029094]
  A distinct and virulent form of DENGUE characterized by thrombocytopenia and hemoconcentration (grades I and II) and distinguished by a positive tourniquet test. When accompanied by circulatory failure and shock (grades III and IV), it is called dengue shock syndrome. (From Dorland, 28th ed)
  
• Dengue Shock Syndrome [M0029095]
  
• Dental Caries [M0005854]
  Localized destruction of the tooth surface initiated by decalcification of the enamel followed by enzymatic lysis of organic structures and leading to cavity formation. If left unchecked, the cavity may penetrate the enamel and dentin and reach the pulp. The three most prominent theories used to explain the etiology of the disease are that acids produced by bacteria lead to decalcification; that micro-organisms destroy the enamel protein; or that keratolytic micro-organisms produce chelates that lead to decalcification.
  
• Dental Diseases [M0487914]
  
• Dental Enamel Hypoplasia [M0005875]
  A form of AMELOGENESIS IMPERFECTA characterized by incomplete formation of the dental enamel and transmitted as an X-linked or autosomal dominant trait. It is also associated with vitamin A, C, or D deficiency, infectious disease, prematurity, birth injury, Rh incompatibility, trauma, or local infection. Small grooves, pits, and fissures are seen in mild cases, deep horizontal rows of pits in severe cases, or absence of enamel in extreme cases. (Dorland, 27th ed)
  
• Dental Plaque [M0005910]
  A film that attaches to teeth, often causing DENTAL CARIES and GINGIVITIS. It is composed of MUCINS, secreted from salivary glands, and microorganisms.
  
• Dental Pulp Autolysis [M0005932]
  
• Dental Pulp Calcification [M0005923]
  
• Dental Pulp Diseases [M0005930]
  Endodontic diseases of the DENTAL PULP inside the tooth, which is distinguished from PERIAPICAL DISEASES of the tissue surrounding the root.
  
• Dental Pulp Exposure [M0005931]
  The result of pathological changes in the hard tissue of a tooth caused by carious lesions, mechanical factors, or trauma, which render the pulp susceptible to bacterial invasion from the external environment.
  
• Dental Pulp Necrosis [M0005933]
  Death of pulp tissue. When the necrosis is due to ischemia with superimposed bacterial infection, it is referred to as pulp gangrene.
  
• Dental White Spot [M0005855]
  
• Dentatorubral-Pallidoluysian Atrophy [M0335757]
  
• Dentigerous Cyst [M0005950]
  Most common follicular odontogenic cyst. Occurs in relation to a partially erupted or unerupted tooth with at least the crown of the tooth to which the cyst is attached protruding into the cystic cavity. May give rise to an ameloblastoma and, in rare instances, undergo malignant transformation.
  
• Dentin Dysplasia [M0005952]
  An apparently hereditary disorder of dentin formation, marked by a normal appearance of coronal dentin associated with pulpal obliteration, faulty root formation, and a tendency for peripheral lesions without obvious cause. (From Dorland, 27th ed)
  
• Dentin Sensitivity [M0005954]
  
• Dentinogenesis Imperfecta [M0005958]
  An autosomal dominant disorder of tooth development characterized by opalescent dentin resulting in discoloration of the teeth, ranging from dusky blue to brownish. The dentin is poorly formed with an abnormally low mineral content; the pulp canal is obliterated, but the enamel is normal. The teeth usually wear down rapidly, leaving short, brown stumps. (Dorland, 27th ed)
  
• Dermatitis [M0006046]
  Any inflammation of the skin.
  
• Dermatitis Herpetiformis [M0006048]
  Rare, chronic, papulo-vesicular disease characterized by an intensely pruritic eruption consisting of various combinations of symmetrical, erythematous, papular, vesicular, or bullous lesions. The disease is strongly associated with the presence of HLA-B8 and HLA-DR3 antigens. A variety of different autoantibodies has been detected in small numbers in patients with dermatitis herpetiformis.
  
• Dermatitis Seborrheica [M0019585]
  
• Dermatitis, Actinic [M0016760]
  
• Dermatitis, Allergic Contact [M0026474]
  A contact dermatitis due to allergic sensitization to various substances. These substances subsequently produce inflammatory reactions in the skin of those who have acquired hypersensitivity to them as a result of prior exposure.
  
• Dermatitis, Atopic [M0006050]
  A chronic inflammatory genetically determined disease of the skin marked by increased ability to form reagin (IgE), with increased susceptibility to allergic rhinitis and asthma, and hereditary disposition to a lowered threshold for pruritus. It is manifested by lichenification, excoriation, and crusting, mainly on the flexural surfaces of the elbow and knee. In infants it is known as infantile eczema.
  
• Dermatitis, Contact [M0006052]
  A type of acute or chronic skin reaction in which sensitivity is manifested by reactivity to materials or substances coming in contact with the skin. It may involve allergic or non-allergic mechanisms.
  
• Dermatitis, Irritant [M0026484]
  A non-allergic contact dermatitis caused by prolonged exposure to irritants and not explained by delayed hypersensitivity mechanisms.
  
• Dermatitis, Occupational [M0015189]
  A recurrent contact dermatitis caused by substances found in the work place.
  
• Dermatitis, Periocular [M0029045]
  
• Dermatitis, Perioral [M0029044]
  A papular eruption of unknown etiology that progresses to residual papular erythema and scaling usually confined to the area of the mouth, and almost exclusively occurring in young women. It may also be localized or extend to involve the eyelids and adjacent glabella area of the forehead (periocular dermatitis). (Dorland, 28th ed)
  
• Dermatitis, Photoallergic [M0026485]
  A delayed hypersensitivity involving the reaction between sunlight or other radiant energy source and a chemical substance to which the individual has been previously exposed and sensitized. It manifests as a papulovesicular, eczematous, or exudative dermatitis occurring chiefly on the light-exposed areas of the skin.
  
• Dermatitis, Phototoxic [M0026524]
  A nonimmunologic, chemically induced type of photosensitivity producing a sometimes vesiculating dermatitis. It results in hyperpigmentation and desquamation of the light-exposed areas of the skin.
  
• Dermatitis, Poison Ivy [M0017098]
  
• Dermatitis, Seborrheic [M0019584]
  A chronic inflammatory disease of the skin of unknown etiology. It is characterized by moderate erythema, dry, moist, or greasy scaling, and yellow crusted patches on various areas, especially the scalp. On the scalp, it generally appears first as small patches of scales, progressing to involve the entire scalp with exfoliation of excessive amounts of dry scales (dandruff).
  
• Dermatitis, Toxicodendron [M0017097]
  An allergic contact dermatitis caused by exposure to plants of the genus Toxicodendron (formerly Rhus). These include poison ivy, poison oak, and poison sumac, all plants that contain the substance urushiol, a potent skin sensitizing agent. (From Dorland, 27th ed)
  
• Dermatomycoses [M0006059]
  Superficial infections of the skin or its appendages by any of various fungi.
  
• Dermatomyositis [M0006061]
  A subacute or chronic inflammatory disease of muscle and skin, marked by proximal muscle weakness and a characteristic skin rash. The illness occurs with approximately equal frequency in children and adults. The skin lesions usually take the form of a purplish rash (or less often an exfoliative dermatitis) involving the nose, cheeks, forehead, upper trunk, and arms. The disease is associated with a complement mediated intramuscular microangiopathy, leading to loss of capillaries, muscle ischemia, muscle-fiber necrosis, and perifascicular atrophy. The childhood form of this disease tends to evolve into a systemic vasculitis. Dermatomyositis may occur in association with malignant neoplasms. (From Adams et al., Principles of Neurology, 6th ed, pp1405-6)
  
• Dermatomyositis, Adult Type [M0337306]
  
• Dermatomyositis, Childhood Type [M0337307]
  
• Dermatophytosis [M0006060]
  
• Dermatosclerosis [M0019541]
  
• Desulfovibrio Infections [M0449409]
  
• Desulfovibrionaceae Infections [M0449407]
  Infections with bacteria of the family Desulfovibrionaceae.
  
• Developmental Coordination Disorder [M0029632]
  
• Developmental Gerstmann's Syndrome [M0337453]
  
• Diabetes Complications [M0462957]
  Conditions or pathological processes associated with the disease of diabetes mellitus. Due to the impaired control of BLOOD GLUCOSE level in diabetic patients, pathological processes develop in numerous tissues and organs including the EYE, the KIDNEY, the BLOOD VESSELS, and the NERVE TISSUE.
  
• Diabetes Insipidus [M0006146]
  A disease that is characterized by frequent urination, excretion of large amounts of dilute URINE, and excessive THIRST. Etiologies of diabetes insipidus include deficiency of ANTIDIURETIC HORMONE (also known as ADH or VASOPRESSIN) secreted by the NEUROHYPOPHYSIS, impaired KIDNEY response to ADH, and impaired hypothalamic regulation of thirst.
  
• Diabetes Insipidus, Nephrogenic [M0027741]
  A genetic or acquired polyuric disorder characterized by persistent hypotonic urine and HYPOKALEMIA. This condition is due to renal tubular insensitivity to VASOPRESSIN and failure to reduce urine volume. It may be the result of mutations of genes encoding VASOPRESSIN RECEPTORS or aquaporin-2 (AQUAPORINS); KIDNEY DISEASES; adverse drug effects; or complications from PREGNANCY.
  
• Diabetes Insipidus, Neurogenic [M0328375]
  A genetic or acquired polyuric disorder caused by a deficiency of VASOPRESSINS secreted by the NEUROHYPOPHYSIS. Clinical signs include the excretion of large volumes of dilute URINE; HYPERNATREMIA; THIRST; and polydipsia. Etiologies include HEAD TRAUMA; surgeries and diseases involving the HYPOTHALAMUS and the PITUITARY GLAND. This disorder may also be caused by mutations of genes such as ARVP encoding vasopressin and its corresponding neurophysin (NEUROPHYSINS).
  
• Diabetes Mellitus [M0006148]
  A heterogeneous group of disorders characterized by HYPERGLYCEMIA and GLUCOSE INTOLERANCE.
  
• Diabetes Mellitus, Lipoatrophic [M0006154]
  A type of diabetes mellitus that is characterized by severe INSULIN RESISTANCE and LIPODYSTROPHY. The latter may be generalized, partial, acquired, or congenital (LIPODYSTROPHY, CONGENITAL GENERALIZED).
  
• Diabetes Mellitus, Type 1 [M0006152]
  A subtype of DIABETES MELLITUS that is characterized by INSULIN deficiency. It is manifested by the sudden onset of severe HYPERGLYCEMIA, rapid progression to DIABETIC KETOACIDOSIS, and DEATH unless treated with insulin. The disease may occur at any age, but is most common in childhood or adolescence.
  
• Diabetes Mellitus, Type 2 [M0006155]
  A subclass of DIABETES MELLITUS that is not INSULIN-responsive or dependent (NIDDM). It is characterized initially by INSULIN RESISTANCE and HYPERINSULINEMIA; and eventually by GLUCOSE INTOLERANCE; HYPERGLYCEMIA; and overt diabetes. Type II diabetes mellitus is no longer considered a disease exclusively found in adults. Patients seldom develop KETOSIS but often exhibit OBESITY.
  
• Diabetes, Autoimmune [M0447381]
  
• Diabetes, Gestational [M0025360]
  Diabetes mellitus induced by PREGNANCY but resolved at the end of pregnancy. It does not include previously diagnosed diabetics who become pregnant (PREGNANCY IN DIABETICS). Gestational diabetes usually develops in late pregnancy when insulin antagonistic hormones peaks leading to INSULIN RESISTANCE; GLUCOSE INTOLERANCE; and HYPERGLYCEMIA.
  
• Diabetic Amyotrophy [M0335857]
  
• Diabetic Angiopathies [M0006156]
  VASCULAR DISEASES that are associated with DIABETES MELLITUS.
  
• Diabetic Asymmetric Polyneuropathy [M0335862]
  
• Diabetic Autonomic Neuropathy [M0335858]
  
• Diabetic Coma [M0006158]
  A state of unconsciousness as a complication of diabetes mellitus. It occurs in cases of extreme HYPERGLYCEMIA or extreme HYPOGLYCEMIA as a complication of INSULIN therapy.
  
• Diabetic Foot [M0026785]
  Common foot problems in persons with DIABETES MELLITUS, caused by any combination of factors such as DIABETIC NEUROPATHIES; PERIPHERAL VASCULAR DISEASES; and INFECTION. With the loss of sensation and poor circulation, injuries and infections often lead to severe foot ulceration, GANGRENE and AMPUTATION.
  
• Diabetic Glomerulosclerosis [M0006161]
  
• Diabetic Ketoacidosis [M0025687]
  A life-threatening complication of diabetes mellitus, primarily of TYPE 1 DIABETES MELLITUS with severe INSULIN deficiency and extreme HYPERGLYCEMIA. It is characterized by excessive LIPOLYSIS, oxidation of FATTY ACIDS, production of KETONE BODIES, a sweet smell to the breath (KETOSIS;) DEHYDRATION; and depressed consciousness leading to COMA.
  
• Diabetic Mononeuropathy [M0335863]
  
• Diabetic Nephropathies [M0006160]
  KIDNEY injuries associated with diabetes mellitus and affecting KIDNEY GLOMERULUS; ARTERIOLES; KIDNEY TUBULES; and the interstitium. Clinical signs include persistent PROTEINURIA, from microalbuminuria progressing to ALBUMINURIA of greater than 300 mg/24 h, leading to reduced GLOMERULAR FILTRATION RATE and END-STAGE RENAL DISEASE.
  
• Diabetic Neuralgia [M0335859]
  
• Diabetic Neuropathies [M0006162]
  Peripheral, autonomic, and cranial nerve disorders that are associated with DIABETES MELLITUS. These conditions usually result from diabetic microvascular injury involving small blood vessels that supply nerves (VASA NERVORUM). Relatively common conditions which may be associated with diabetic neuropathy include third nerve palsy (see OCULOMOTOR NERVE DISEASES); MONONEUROPATHY; mononeuropathy multiplex; diabetic amyotrophy; a painful POLYNEUROPATHY; autonomic neuropathy; and thoracoabdominal neuropathy. (From Adams et al., Principles of Neurology, 6th ed, p1325)
  
• Diabetic Polyneuropathy [M0335860]
  
• Diabetic Retinopathy [M0006163]
  Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.
  
• Diaper Rash [M0006208]
  A type of irritant dermatitis localized to the area in contact with a diaper and occurring most often as a reaction to prolonged contact with urine, feces, or retained soap or detergent.
  
• Diaphragmatic Eventration [M0006210]
  A congenital abnormality characterized by the elevation of the DIAPHRAGM dome. It is the result of a thinned diaphragmatic muscle and injured PHRENIC NERVE, allowing the intra-abdominal viscera to push the diaphragm upward against the LUNG.
  
• Diastema [M0006216]
  An abnormal opening or fissure between two adjacent teeth.
  
• Dicrocoeliasis [M0006296]
  Infection with flukes of the genus Dicrocoelium.
  
• Dictyocaulus Infections [M0006310]
  Infection with nematodes of the genus DICTYOCAULUS. In deer, cattle, sheep, and horses the bronchi are the site of infestation.
  
• Dientamoebiasis [M0006322]
  Gastrointestinal infection with PROTOZOA of the genus DIENTAMOEBA.
  
• Diffuse Cerebral Sclerosis of Schilder [M0003893]
  A rare central nervous system demyelinating condition affecting children and young adults. Pathologic findings include a large, sharply defined, asymmetric focus of myelin destruction that may involve an entire lobe or cerebral hemisphere. The clinical course tends to be progressive and includes dementia, cortical blindness, cortical deafness, spastic hemiplegia, and pseudobulbar palsy. Concentric sclerosis of Balo is differentiated from diffuse cerebral sclerosis of Schilder by the pathologic finding of alternating bands of destruction and preservation of myelin in concentric rings. Alpers' Syndrome refers to a heterogeneous group of diseases that feature progressive cerebral deterioration and liver disease. (From Adams et al., Principles of Neurology, 6th ed, p914; Dev Neurosci 1991;13(4-5):267-73)
  
• DiGeorge Syndrome [M0006369]
  Congenital syndrome characterized by a spectrum of malformations including the absence of the THYMUS and PARATHYROID GLANDS resulting in T-cell immunodeficiency and HYPOCALCEMIA. Other features include defects in the outflow tract of the HEART and craniofacial anomalies (velocardiofacial syndrome). Most cases result from a deletion of chromosome 21q11.2 or mutation in the TBX1 gene.
  
• Digestive System Abnormalities [M0006373]
  Congenital structural abnormalities of the DIGESTIVE SYSTEM.
  
• Digestive System Diseases [M0006374]
  Diseases in any part of the GASTROINTESTINAL TRACT or the accessory organs (LIVER; BILIARY TRACT; PANCREAS).
  
• Dioctophyma renale Infections [M0026093]
  
• Dipetalonema Infections [M0006505]
  Infections with nematodes of the genus DIPETALONEMA.
  
• Diphtheria [M0006520]
  A localized infection of mucous membranes or skin caused by toxigenic strains of CORYNEBACTERIUM DIPHTHERIAE. It is characterized by the presence of a pseudomembrane at the site of infection. DIPHTHERIA TOXIN, produced by C. diphtheriae, can cause myocarditis, polyneuritis, and other systemic toxic effects.
  
• Diphyllobothriasis [M0006524]
  Infection with tapeworms of the genus Diphyllobothrium.
  
• Diplopia [M0006527]
  A visual symptom in which a single object is perceived by the visual cortex as two objects rather than one. Disorders associated with this condition include REFRACTIVE ERRORS; STRABISMUS; OCULOMOTOR NERVE DISEASES; TROCHLEAR NERVE DISEASES; ABDUCENS NERVE DISEASES; and diseases of the BRAIN STEM and OCCIPITAL LOBE.
  
• Diplopia, Vertical [M0392830]
  
• Dipylidiasis [M0003959]
  
• Direct Hyperbilirubinemia, Neonatal [M0480990]
  
• Dirofilariasis [M0006554]
  Infection with nematodes of the genus DIROFILARIA, usually in animals, especially dogs, but occasionally in man.
  
• Discitis [M0023556]
  Inflammation of an intervertebral disk or disk space which may lead to disk erosion. Until recently, discitis has been defined as a nonbacterial inflammation and has been attributed to aseptic processes (e.g., chemical reaction to an injected substance). However, recent studies provide evidence that infection may be the initial cause, but perhaps not the promoter, of most cases of discitis. Discitis has been diagnosed in patients following discography, myelography, lumbar puncture, paravertebral injection, and obstetrical epidural anesthesia. Discitis following chemonucleolysis (especially with chymopapain) is attributed to chemical reaction by some and to introduction of microorganisms by others.
  
• Discrete Subaortic Stenosis [M0001558]
  An anatomic alteration in the mitral valve apparatus and interventricular septum leading to obstruction of left ventricular outflow. (from Eur J Cardiothorac Surg 1998;14(3):296-303)
  
• Disease [M0006564]
  A definite pathologic process with a characteristic set of signs and symptoms. It may affect the whole body or any of its parts, and its etiology, pathology, and prognosis may be known or unknown.
  
• Disease Attributes [M0328641]
  Clinical characteristics of disease or illness.
  
• Diseases in Twins [M0006571]
  Disorders affecting TWINS, one or both, at any age.
  
• Disk, Herniated [M0011561]
  
• Disorders of Environmental Origin [M0011360]
  Disorders representing collectively the results of assault by external forces, rather than by organic or physiologic dysfunction or by pathogens.
  
• Disorders of Excessive Somnolence [M0010855]
  Disorders characterized by hypersomnolence during normal waking hours that may impair cognitive functioning. Subtypes include primary hypersomnia disorders (e.g., IDIOPATHIC HYPERSOMNOLENCE; NARCOLEPSY; and KLEINE-LEVIN SYNDROME) and secondary hypersomnia disorders where excessive somnolence can be attributed to a known cause (e.g., drug affect, MENTAL DISORDERS, and SLEEP APNEA SYNDROME). (From J Neurol Sci 1998 Jan 8;153(2):192-202; Thorpy, Principles and Practice of Sleep Medicine, 2nd ed, p320)
  
• Disseminated Intravascular Coagulation [M0006587]
  A disorder characterized by reduction in the elements involved in blood coagulation due to their utilization in widespread blood clotting within the vessels. The activation of the clotting mechanism may arise from any of a number of disorders. In the late stages, it is marked by profuse hemorrhaging. (Dorland, 27th ed)
  
• Dissociated Nystagmus [M0333564]
  
• Distal Myopathies [M0335585]
  A heterogeneous group of genetic disorders characterized by progressive MUSCULAR ATROPHY and MUSCLE WEAKNESS beginning in the hands, the legs, or the feet. Most are adult-onset autosomal dominant forms. Others are autosomal recessive.
  
• Distal Renal Tubular Acidosis [M0491194]
  
• Distal Spinal Muscular Atrophy [M0335740]
  
• Distemper [M0006595]
  A name for several highly contagious viral diseases of animals, especially canine distemper. In dogs, it is caused by the canine distemper virus (DISTEMPER VIRUS, CANINE). It is characterized by a diphasic fever, leukopenia, gastrointestinal and respiratory inflammation and sometimes, neurologic complications. In cats it is known as FELINE PANLEUKOPENIA.
  
• Diurnal Enuresis [M0491959]
  Involuntary discharge of URINE during the daytime while one is awake.
  
• Diverticulitis [M0006630]
  Inflammation of a DIVERTICULUM or diverticula.
  
• Diverticulitis, Colonic [M0006631]
  Inflammation of the COLONIC DIVERTICULA, generally with abscess formation and subsequent perforation.
  
• Diverticulosis [M0356298]
  
• Diverticulosis, Colonic [M0006633]
  A pathological condition characterized by the presence of a number of COLONIC DIVERTICULA in the COLON. Its pathogenesis is multifactorial, including colon aging, motor dysfunction, increases in intraluminal pressure, and lack of dietary fibers.
  
• Diverticulosis, Esophageal [M0356303]
  A pathological condition characterized by the presence of a number of ESOPHAGEAL DIVERTICULA in the ESOPHAGUS.
  
• Diverticulosis, Stomach [M0356305]
  A pathological condition characterized by the presence of a number of GASTRIC DIVERTICULA in the STOMACH.
  
• DNA Repair-Deficiency Disorders [M0470997]
  Disorders resulting from defective DNA REPAIR processes or the associated cellular responses to DNA DAMAGE.
  
• DNA Virus Infections [M0006675]
  
• Dog Diseases [M0006703]
  Diseases of the domestic dog (Canis familiaris). This term does not include diseases of wild dogs, WOLVES; FOXES; and other Canidae for which the heading CARNIVORA is used.
  
• Double Nuchal Cord [M0494861]
  
• Dourine [M0006777]
  A disease of horses and donkeys caused by Trypanosoma equiperdum. The disease occurs in Africa, the Americas, and Asia.
  
• Dracunculiasis [M0006796]
  Infection with nematodes of the genus Dracunculus. One or more worms may be seen at a time, with the legs and feet being the most commonly infected areas. Symptoms include pruritus, nausea, vomiting, diarrhea, or asthmatic attacks.
  
• Drug Eruptions [M0006049]
  Adverse cutaneous reactions caused by ingestion, parenteral use, or local application of a drug. These may assume various morphologic patterns and produce various types of lesions.
  
• Drug Hypersensitivity [M0006829]
  Immunologically mediated adverse reactions to medicinal substances used legally or illegally.
  
• Dry Eye Syndromes [M0023637]
  Corneal and conjunctival dryness due to deficient tear production, predominantly in menopausal and post-menopausal women. Filamentary keratitis or erosion of the conjunctival and corneal epithelium may be caused by these disorders. Sensation of the presence of a foreign body in the eye and burning of the eyes may occur.
  
• Dry Socket [M0006862]
  A condition sometimes occurring after tooth extraction, particularly after traumatic extraction, resulting in a dry appearance of the exposed bone in the socket, due to disintegration or loss of the blood clot. It is basically a focal osteomyelitis without suppuration and is accompanied by severe pain (alveolalgia) and foul odor. (Dorland, 28th ed)
  
• Duane Retraction Syndrome [M0006873]
  A syndrome characterized by marked limitation of abduction of the eye, variable limitation of adduction and retraction of the globe, and narrowing of the palpebral fissure on attempted adduction. The condition is caused by aberrant innervation of the lateral rectus by fibers of the oculomotor nerve. There are three subtypes: type 1 (associated with loss of abduction), type 2 (associated with loss of adduction), and type 3 (loss of abduction and adduction). Two loci for Duane retraction syndrome have been located, one at chromosome 8q13 (DURS1) and another at chromosome 2q31(DURS2). It is usually caused by congenital hypoplasia of the abducens nerve or nucleus, but may rarely represent an acquired syndrome. (Adams et al., Principles of Neurology, 6th ed, p271; Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p691)
  
• Duane Retraction Syndrome, Type 1 [M0384916]
  
• Duane Retraction Syndrome, Type 2 [M0384915]
  
• Duane Retraction Syndrome, Type 3 [M0384914]
  
• Dumping Syndrome [M0006880]
  Gastrointestinal symptoms resulting from an absent or nonfunctioning pylorus.
  
• Duodenal Diseases [M0006881]
  Pathological conditions in the DUODENUM region of the small intestine (INTESTINE, SMALL).
  
• Duodenal Obstruction [M0006883]
  Hindrance of the passage of luminal contents in the DUODENUM. Duodenal obstruction can be partial or complete, and caused by intrinsic or extrinsic factors. Simple obstruction is associated with diminished or stopped flow of luminal contents. Strangulating obstruction is associated with impaired blood flow to the duodenum in addition to obstructed flow of luminal contents.
  
• Duodenal Ulcer [M0006885]
  A PEPTIC ULCER located in the DUODENUM.
  
• Duodenitis [M0006886]
  Inflammation of the DUODENUM section of the small intestine (INTESTINE, SMALL). Erosive duodenitis may cause bleeding in the UPPER GI TRACT and PEPTIC ULCER.
  
• Duodenogastric Reflux [M0006887]
  Retrograde flow of duodenal contents (BILE ACIDS; PANCREATIC JUICE) into the STOMACH.
  
• Dupuytren's Contracture [M0006891]
  A fibromatosis of the palmar fascia characterized by thickening and contracture of the fibrous bands on the palmar surfaces of the hand and fingers. It arises most commonly in men between the ages of 30 and 50.
  
• Dwarfism [M0006897]
  A genetic or pathological condition that is characterized by short stature and undersize. Abnormal skeletal growth usually results in an adult who is significantly below the average height.
  
• Dwarfism, Pituitary [M0006899]
  A form of dwarfism caused by complete or partial GROWTH HORMONE deficiency, resulting from either the lack of GROWTH HORMONE-RELEASING FACTOR from the HYPOTHALAMUS or from the mutations in the growth hormone gene (GH1) in the PITUITARY GLAND. It is also known as Type I pituitary dwarfism. Human hypophysial dwarf is caused by a deficiency of HUMAN GROWTH HORMONE during development.
  
• Dysarthria, Pseudobulbar [M0336490]
  
• Dysautonomia [M0002015]
  
• Dysautonomia, Familial [M0006912]
  An autosomal disorder of the peripheral and autonomic nervous systems limited to individuals of Ashkenazic Jewish descent. Clinical manifestations are present at birth and include diminished lacrimation, defective thermoregulation, orthostatic hypotension (HYPOTENSION, ORTHOSTATIC), fixed pupils, excessive SWEATING, loss of pain and temperature sensation, and absent reflexes. Pathologic features include reduced numbers of small diameter peripheral nerve fibers and autonomic ganglion neurons. (From Adams et al., Principles of Neurology, 6th ed, p1348; Nat Genet 1993;4(2):160-4)
  
• Dyschondroplasias [M0015521]
  
• Dysentery [M0006913]
  Acute inflammation of the intestine associated with infectious DIARRHEA of various etiologies, generally acquired by eating contaminated food containing TOXINS, BIOLOGICAL derived from BACTERIA; PROTOZOA; or other microorganisms. Dysentery is characterized initially by watery FECES then by bloody mucoid stools. It is often associated with ABDOMINAL PAIN; FEVER; and DEHYDRATION.
  
• Dysentery, Amebic [M0006914]
  DYSENTERY caused by intestinal PROTOZOA infection, chiefly with ENTAMOEBA HISTOLYTICA. This condition may be associated with amebic infection of the LIVER and other distant sites.
  
• Dysentery, Bacillary [M0006916]
  DYSENTERY caused by gram-negative rod-shaped enteric bacteria (ENTEROBACTERIACEAE), most often by the genus SHIGELLA. Shigella dysentery, Shigellosis, is classified into subgroups according to syndrome severity and the infectious species. Group A: SHIGELLA DYSENTERIAE (severest); Group B: SHIGELLA FLEXNERI; Group C: SHIGELLA BOYDII; and Group D: SHIGELLA SONNEI (mildest).
  
• Dysentery, Shigella boydii [M0444409]
  
• Dysentery, Shigella dysenteriae [M0444407]
  
• Dysentery, Shigella flexneri [M0444408]
  
• Dysentery, Shigella sonnei [M0444410]
  
• Dysgammaglobulinemia [M0006917]
  An immunologic deficiency state characterized by selective deficiencies of one or more, but not all, classes of immunoglobulins.
  
• Dyskeratosis Congenita [M0029508]
  A predominantly X-linked recessive syndrome characterized by a triad of reticular skin pigmentation, nail dystrophy and leukoplakia of mucous membranes. Oral and dental abnormalities may also be present. Complications are a predisposition to malignancy and bone marrow involvement with pancytopenia. (from Int J Paediatr Dent 2000 Dec;10(4):328-34) The X-linked form is also known as Zinsser-Cole-Engman syndrome and involves the gene which encodes a highly conserved protein called dyskerin.
  
• Dyskinesia, Drug-Induced [M0006920]
  Abnormal movements, including HYPERKINESIS; HYPOKINESIA; TREMOR; and DYSTONIA, associated with the use of certain medications or drugs. Muscles of the face, trunk, neck, and extremities are most commonly affected. Tardive dyskinesia refers to abnormal hyperkinetic movements of the muscles of the face, tongue, and neck associated with the use of neuroleptic agents (see ANTIPSYCHOTIC AGENTS). (Adams et al., Principles of Neurology, 6th ed, p1199)
  
• Dyskinesia, Medication-Induced [M0335655]
  
• Dyskinesias, Paroxysmal [M0334647]
  
• Dyslipidemias [M0010831]
  Abnormalities in the serum levels of LIPIDS, including overproduction or deficiency. Abnormal serum lipid profiles may include high total CHOLESTEROL, high TRIGLYCERIDES, low HIGH DENSITY LIPOPROTEIN CHOLESTEROL, and elevated LOW DENSITY LIPOPROTEIN CHOLESTEROL.
  
• Dyslipoproteinemias [M0486912]
  
• Dysostoses [M0006925]
  Defective bone formation involving individual bones, singly or in combination.
  
• Dyspareunia [M0006926]
  Recurrent genital pain occurring during, before, or after SEXUAL INTERCOURSE in either the male or the female.
  
• Dyssomnias [M0328379]
  A broad category of sleep disorders characterized by either hypersomnolence or insomnia. The three major subcategories include intrinsic (i.e., arising from within the body) (SLEEP DISORDERS, INTRINSIC), extrinsic (secondary to environmental conditions or various pathologic conditions), and disturbances of circadian rhythm. (From Thorpy, Sleep Disorders Medicine, 1994, p187)
  
• Dystocia [M0006934]
  Slow or difficult OBSTETRIC LABOR or CHILDBIRTH.
  
• Dystonia Musculorum Deformans [M0006936]
  A condition characterized by focal DYSTONIA that progresses to involuntary spasmodic contractions of the muscles of the legs, trunk, arms, and face. The hands are often spared, however, sustained axial and limb contractions may lead to a state where the body is grossly contorted. Onset is usually in the first or second decade. Familial patterns of inheritance, primarily autosomal dominant with incomplete penetrance, have been identified. (Adams et al., Principles of Neurology, 6th ed, p1078)
  
• Dystonia, Primary [M0334830]
  
• Dystonia, Secondary [M0334831]
  
• Dystonias, Sporadic [M0334832]
  
• Dystonic Disorders [M0328380]
  Acquired and inherited conditions that feature DYSTONIA as a primary manifestation of disease. These disorders are generally divided into generalized dystonias (e.g., dystonia musculorum deformans) and focal dystonias (e.g., writer's cramp). They are also classified by patterns of inheritance and by age of onset.
  
• Ear Diseases [M0006941]
  Diseases of the ear, general or unspecified.
  
• Early Childhood Epilepsy, Myoclonic [M0334942]
  
• Early Post-Traumatic Seizures [M0335112]
  
• Early-Onset Globoid Cell Leukodystrophy [M0335502]
  
• East Coast Fever [M0021277]
  
• Echinococcosis [M0006960]
  An infection caused by the infestation of the larval form of tapeworms of the genus Echinococcus. The liver, lungs, and kidney are the most common areas of infestation.
  
• Echinococcosis, Hepatic [M0006961]
  Liver disease caused by infections with parasitic tapeworms of the genus ECHINOCOCCUS, such as Echinococcus granulosus or Echinococcus multilocularis. Ingested Echinococcus ova burrow into the intestinal mucosa. The larval migration to the liver via the PORTAL VEIN leads to watery vesicles (HYDATID CYST).
  
• Echinococcosis, Pulmonary [M0006962]
  Helminth infection of the lung caused by Echinococcus granulosus or Echinococcus multilocularis.
  
• Echinostomiasis [M0006969]
  Infection by flukes of the genus Echinostoma.
  
• Echovirus Infections [M0006981]
  Infectious disease processes, including meningitis, diarrhea, and respiratory disorders, caused by echoviruses.
  
• Eclampsia [M0006985]
  Onset of HYPERREFLEXIA; SEIZURES; or COMA in a previously diagnosed pre-eclamptic patient (PRE-ECLAMPSIA).
  
• Ecthyma [M0007029]
  An ulcerative pyoderma usually caused by group A beta-hemolytic streptococcal infection at the site of minor trauma. (Dorland, 27th ed)
  
• Ecthyma, Contagious [M0007030]
  An infectious dermatitis of sheep and goats, affecting primarily the muzzle and lips. It is caused by a poxvirus and may be transmitted to man.
  
• Ectodermal Dysplasia [M0007032]
  A group of hereditary disorders involving tissues and structures derived from the embryonic ectoderm. They are characterized by the presence of abnormalities at birth and involvement of both the epidermis and skin appendages. They are generally nonprogressive and diffuse. Various forms exist, including anhidrotic and hidrotic dysplasias, FOCAL DERMAL HYPOPLASIA, and aplasia cutis congenita.
  
• Ectodermal Dysplasia 1, Anhidrotic [M0007033]
  An X-linked form of ectodermal dysplasia which results from mutations of the gene encoding ECTODYSPLASIN.
  
• Ectodermal Dysplasia 3, Anhidrotic [M0492747]
  An autosomal dominant form of ectodermal dysplasia which is due to mutations in the gene for the EDAR RECEPTOR.
  
• Ectodermal Dysplasia, Hypohidrotic, Autosomal Recessive [M0492750]
  An autosomal recessive form of ectodermal dysplasia which is due to mutations in the gene for the EDAR RECEPTOR or EDAR-ASSOCIATED DEATH DOMAIN PROTEIN.
  
• Ectoparasitic Infestations [M0007037]
  Infestations by PARASITES which live on, or burrow into, the surface of their host's EPIDERMIS. Most ectoparasites are ARTHROPODS.
  
• Ectopia Cordis [M0009949]
  
• Ectromelia, Infectious [M0007045]
  A viral infection of mice, causing edema and necrosis followed by limb loss.
  
• Ectropion [M0007046]
  The turning outward (eversion) of the edge of the eyelid, resulting in the exposure of the palpebral conjunctiva. (Dorland, 27th ed)
  
• Eczema [M0007049]
  A pruritic papulovesicular dermatitis occurring as a reaction to many endogenous and exogenous agents (Dorland, 27th ed).
  
• Eczema Herpeticum [M0336786]
  
• Eczema Vaccinatum [M0336785]
  
• Eczema, Dyshidrotic [M0017279]
  A recurrent eczematous reaction characterized by the development of vesicular eruptions on the palms and soles, particularly along the sides and between the digits. It is accompanied by pruritus, a burning sensation, and hyperhidrosis. The disease is self-limiting, lasting only a few weeks. (Dorland, 27th ed)
  
• Eczema, Infantile [M0006051]
  
• Edema Disease of Swine [M0007052]
  An acute disease of young pigs that is usually associated with weaning. It is characterized clinically by paresis and subcutaneous edema.
  
• Edema, Cardiac [M0007053]
  A manifestation of congestive heart failure caused by increased venous and capillary pressures and often associated with the retention of sodium by the kidneys. (Dorland, 27th ed)
  
• Egg Hypersensitivity [M0351829]
  Allergic reaction to eggs that is triggered by the immune system.
  
• Ehlers-Danlos Syndrome [M0007138]
  A heterogeneous group of inherited COLLAGEN DISEASES. The most common manifestations of Ehlers-Danlos Syndrome are hyperextensible skin and joints, skin fragility and reduced wound healing capability.
  
• Ehrlichiosis [M0025676]
  A tick-borne disease characterized by FEVER; HEADACHE; myalgias; ANOREXIA; and occasionally RASH. It is caused by several bacterial species and can produce disease in DOGS; CATTLE; SHEEP; GOATS; HORSES; and humans. The primary species causing human disease are EHRLICHIA CHAFFEENSIS; ANAPLASMA PHAGOCYTOPHILUM; and Ehrlichia ewingii.
  
• Elaeophoriasis [M0008467]
  
• Electron Transport Chain Deficiencies, Mitochondrial [M0387124]
  
• Elephantiasis [M0007229]
  Hypertrophy and thickening of the tissues from any cause. Elephantiasis caused by filarial infection is ELEPHANTIASIS, FILARIAL. (From Dorland, 27th ed)
  
• Elephantiasis, Filarial [M0007230]
  Parasitic infestation of the human lymphatic system by WUCHERERIA BANCROFTI or BRUGIA MALAYI. It is also called lymphatic filariasis.
  
• Elliptocytosis, Hereditary [M0007240]
  An intrinsic defect of erythrocytes inherited as an autosomal dominant trait. The erythrocytes assume an oval or elliptical shape.
  
• Ellis-Van Creveld Syndrome [M0007241]
  Dwarfism occurring in association with defective development of skin, hair, and teeth, polydactyly, and defect of the cardiac septum. (Dorland, 27th ed)
  
• Embolic Infarction, Middle Cerebral Artery [M0335395]
  
• Embolic Infarction, Posterior Cerebral Artery [M0335404]
  
• Embolism [M0007248]
  Blocking of a blood vessel by a blood clot or foreign matter that has been transported from a distant site by the blood stream.
  
• Embolism and Thrombosis [M0025559]
  A collective term for diseases characterized by the formation, development, or presence of a thrombus (THROMBOSIS) and the blocking of a vessel by the thrombus brought to its site by the blood current (EMBOLISM). (From Dorland, 28th ed)
  
• Embolism, Air [M0007250]
  Embolism due to air bubbles entering the blood vessels after trauma, surgical procedures, or changes in atmospheric pressure.
  
• Embolism, Amniotic Fluid [M0007251]
  Blocking of maternal circulation by AMNIOTIC FLUID that is forced into uterine VEINS by strong UTERINE CONTRACTION near the end of pregnancy. It is characterized by the sudden onset of severe respiratory distress and HYPOTENSION that can lead to maternal DEATH.
  
• Embolism, Cholesterol [M0026764]
  An embolism of lipid debris from an ulcerated atheromatous deposit, generally from a large artery to small arterial branches. It is usually small and rarely causes infarction. (Stedman, 25th ed)
  
• Embolism, Fat [M0007252]
  Embolism caused by fat entering the circulation. It is often seen after fractures of large bones or after corticosteroid administration.
  
• Embolism, Paradoxical [M0028766]
  Blockage of a systemic artery by a thrombus originating in a systemic vein, which has passed through a defect that permits direct communication between the right and the left side of the heart, notably an open foramen ovale. It is also called crossed embolism. (Dorland, 28th ed)
  
• Embryopathies [M0008396]
  
• Emphysematous Cholecystitis [M0439585]
  A variant of acute cholecystitis with inflammation of the GALLBLADDER that is characterized by the pockets of gas in the gallbladder wall. It is due to secondary infection caused by gas-forming organisms, and has a high risk of perforation.
  
• Empty Sella Syndrome [M0007326]
  A condition when the SELLA TURCICA is not filled with pituitary tissue. The pituitary gland is either compressed, atrophied, or removed. There are two types: (1) primary empty sella is due a defect in the sella diaphragm leading to arachnoid herniation into the sellar space; (2) secondary empty sella is associated with the removal or treatment of PITUITARY NEOPLASMS.
  
• Empty Sella Syndrome, Primary [M0334834]
  
• Empty Sella Syndrome, Secondary [M0334835]
  
• Empyema, Gallbladder [M0004233]
  Presence of pus in the GALLBLADDER.
  
• Empyema, Pleural [M0025467]
  Suppurative inflammation of the pleural space.
  
• Empyema, Subdural [M0020655]
  An intracranial or rarely intraspinal suppurative process invading the space between the inner surface of the DURA MATER and the outer surface of the ARACHNOID. Bacteria and other pathogenic organisms may gain entrance to the subdural space from the FRONTAL SINUS; ETHMOID SINUS; middle ear (EAR, MIDDLE); MASTOID; or as the result of CRANIOCEREBRAL TRAUMA or NEUROSURGICAL PROCEDURES. This condition may be associated with intracranial sinus thrombosis (SINUS THROMBOSIS, INTRACRANIAL). Circumscribed collections of purulent material in the subdural space are referred to as subdural abscesses. (From Adams et al., Principles of Neurology, 6th ed, p709)
  
• Empyema, Tuberculous [M0007328]
  Empyema due to MYCOBACTERIUM TUBERCULOSIS.
  
• Encephalitis [M0007337]
  Inflammation of the BRAIN due to infection, autoimmune processes, toxins, and other conditions. Viral infections (see ENCEPHALITIS, VIRAL) are a relatively frequent cause of this condition.
  
• Encephalitis, Acute Necrotizing [M0007375]
  
• Encephalitis, Arbovirus [M0007356]
  Infections of the brain caused by arthropod-borne viruses (i.e., arboviruses) primarily from the families TOGAVIRIDAE; FLAVIVIRIDAE; BUNYAVIRIDAE; REOVIRIDAE; and RHABDOVIRIDAE. Life cycles of these viruses are characterized by ZOONOSES, with birds and lower mammals serving as intermediate hosts. The virus is transmitted to humans by the bite of mosquitoes (CULICIDAE) or TICKS. Clinical manifestations include fever, headache, alterations of mentation, focal neurologic deficits, and COMA. (From Clin Microbiol Rev 1994 Jan;7(1):89-116; Walton, Brain's Diseases of the Nervous System, 10th ed, p321)
  
• Encephalitis, California [M0007355]
  A viral infection of the brain caused by serotypes of California encephalitis virus (ENCEPHALITIS VIRUS, CALIFORNIA) transmitted to humans by the mosquito AEDES triseriatus. The majority of cases are caused by the LA CROSSE VIRUS. This condition is endemic to the midwestern United States and primarily affects children between 5-10 years of age. Clinical manifestations include FEVER; VOMITING; HEADACHE; and abdominal pain followed by SEIZURES, altered mentation, and focal neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13)
  
• Encephalitis, Central European [M0007360]
  
• Encephalitis, European Tick-Borne [M0334866]
  
• Encephalitis, Far Eastern Russian [M0007362]
  
• Encephalitis, Herpes Simplex [M0328381]
  An acute (or rarely chronic) inflammatory process of the brain caused by SIMPLEXVIRUS infections which may be fatal. The majority of infections are caused by human herpesvirus 1 (HERPESVIRUS 1, HUMAN) and less often by human herpesvirus 2 (HERPESVIRUS 2, HUMAN). Clinical manifestations include FEVER; HEADACHE; SEIZURES; HALLUCINATIONS; behavioral alterations; APHASIA; hemiparesis; and COMA. Pathologically, the condition is marked by a hemorrhagic necrosis involving the medial and inferior TEMPORAL LOBE and orbital regions of the FRONTAL LOBE. (From Adams et al., Principles of Neurology, 6th ed, pp751-4)
  
• Encephalitis, Japanese [M0007357]
  A mosquito-borne encephalitis caused by the Japanese B encephalitis virus (ENCEPHALITIS VIRUS, JAPANESE) occurring throughout Eastern Asia and Australia. The majority of infections occur in children and are subclinical or have features limited to transient fever and gastrointestinal symptoms. Inflammation of the brain, spinal cord, and meninges may occur and lead to transient or permanent neurologic deficits (including a POLIOMYELITIS-like presentation); SEIZURES; COMA; and death. (From Adams et al., Principles of Neurology, 6th ed, p751; Lancet 1998 Apr 11;351(9109):1094-7)
  
• Encephalitis, Louping Ill [M0334867]
  
• Encephalitis, Polio [M0335888]
  
• Encephalitis, Post-Vaccinal [M0334281]
  
• Encephalitis, Russian Spring-Summer [M0334868]
  
• Encephalitis, St. Louis [M0007359]
  A viral encephalitis caused by the St. Louis encephalitis virus (ENCEPHALITIS VIRUS, ST. LOUIS), a FLAVIVIRUS. It is transmitted to humans and other vertebrates primarily by mosquitoes of the genus CULEX. The primary animal vectors are wild birds and the disorder is endemic to the midwestern and southeastern United States. Infections may be limited to an influenza-like illness or present as an ASEPTIC MENINGITIS or ENCEPHALITIS. Clinical manifestations of the encephalitic presentation may include SEIZURES, lethargy, MYOCLONUS, focal neurologic signs, COMA, and DEATH. (From Adams et al., Principles of Neurology, 6th ed, p750)
  
• Encephalitis, Tick-Borne [M0007361]
  Encephalitis caused by neurotropic viruses that are transmitted via the bite of TICKS. In Europe, the diseases are caused by ENCEPHALITIS VIRUSES, TICK-BORNE, which give rise to Russian spring-summer encephalitis, central European encephalitis, louping ill encephalitis, and related disorders. Powassan encephalitis occurs in North America and Russia and is caused by the Powassan virus. ASEPTIC MENINGITIS and rarely encephalitis may complicate COLORADO TICK FEVER which is endemic to mountainous regions of the western United States. (From Joynt, Clinical Neurology, 1996, Ch26, pp14-5)
  
• Encephalitis, Varicella Zoster [M0328382]
  Inflammation of brain tissue caused by infection with the varicella-zoster virus (HERPESVIRUS 3, HUMAN). This condition is associated with immunocompromised states, including the ACQUIRED IMMUNODEFICIENCY SYNDROME. Pathologically, the virus tends to induce a vasculopathy and infect oligodendrocytes and ependymal cells, leading to CEREBRAL INFARCTION, multifocal regions of demyelination, and periventricular necrosis. Manifestations of varicella encephalitis usually occur 5-7 days after onset of HERPES ZOSTER and include HEADACHE; VOMITING; lethargy; focal neurologic deficits; FEVER; and COMA. (From Joynt, Clinical Neurology, 1996, Ch 26, pp29-32; Hum Pathol 1996 Sep;27(9):927-38)
  
• Encephalitis, Viral [M0028131]
  Inflammation of brain parenchymal tissue as a result of viral infection. Encephalitis may occur as primary or secondary manifestation of TOGAVIRIDAE INFECTIONS; HERPESVIRIDAE INFECTIONS; ADENOVIRIDAE INFECTIONS; FLAVIVIRIDAE INFECTIONS; BUNYAVIRIDAE INFECTIONS; PICORNAVIRIDAE INFECTIONS; PARAMYXOVIRIDAE INFECTIONS; ORTHOMYXOVIRIDAE INFECTIONS; RETROVIRIDAE INFECTIONS; and ARENAVIRIDAE INFECTIONS.
  
• Encephalitis, West Nile Fever [M0336328]
  
• Encephalitozoonosis [M0025701]
  Infection with FUNGI of the genus ENCEPHALITOZOON. Lesions commonly occur in the BRAIN and KIDNEY tubules. Other sites of infection in MAMMALS are the LIVER; ADRENAL GLANDS; OPTIC NERVES; RETINA; and MYOCARDIUM.
  
• Encephalomalacia [M0007367]
  Softening or loss of brain tissue following CEREBRAL INFARCTION; cerebral ischemia (see BRAIN ISCHEMIA), infection, CRANIOCEREBRAL TRAUMA, or other injury. The term is often used during gross pathologic inspection to describe blurred cortical margins and decreased consistency of brain tissue following infarction. Multicystic encephalomalacia refers to the formation of multiple cystic cavities of various sizes in the cerebral cortex of neonates and infants following injury, most notably perinatal hypoxia-ischemic events. (From Davis et al., Textbook of Neuropathology, 2nd ed, p665; J Neuropathol Exp Neurol, 1995 Mar;54(2):268-75)
  
• Encephalomyelitis [M0007368]
  A general term indicating inflammation of the BRAIN and SPINAL CORD, often used to indicate an infectious process, but also applicable to a variety of autoimmune and toxic-metabolic conditions. There is significant overlap regarding the usage of this term and ENCEPHALITIS in the literature.
  
• Encephalomyelitis, Acute Disseminated [M0007358]
  An acute or subacute inflammatory process of the CENTRAL NERVOUS SYSTEM characterized histologically by multiple foci of perivascular demyelination. Symptom onset usually occurs several days after an acute viral infection or immunization, but it may coincide with the onset of infection or rarely no antecedent event can be identified. Clinical manifestations include CONFUSION, somnolence, FEVER, nuchal rigidity, and involuntary movements. The illness may progress to COMA and eventually be fatal. (Adams et al., Principles of Neurology, 6th ed, p921)
  
• Encephalomyelitis, Eastern Equine [M0328383]
  A form of arboviral encephalitis (primarily affecting equines) endemic to eastern regions of North America. The causative organism (ENCEPHALOMYELITIS VIRUS, EASTERN EQUINE) may be transmitted to humans via the bite of AEDES mosquitoes. Clinical manifestations include the acute onset of fever, HEADACHE, altered mentation, and SEIZURES followed by coma. The condition is fatal in up to 50% of cases. Recovery may be marked by residual neurologic deficits and EPILEPSY. (From Joynt, Clinical Neurology, 1996, Ch26, pp9-10)
  
• Encephalomyelitis, Enzootic Porcine [M0007371]
  A picornavirus infection producing symptoms similar to poliomyelitis in pigs.
  
• Encephalomyelitis, Equine [M0007373]
  A group of ALPHAVIRUS INFECTIONS which affect horses and man, transmitted via the bites of mosquitoes. Disorders in this category are endemic to regions of South America and North America. In humans, clinical manifestations vary with the type of infection, and range from a mild influenza-like syndrome to a fulminant encephalitis. (From Joynt, Clinical Neurology, 1996, Ch26, pp8-10)
  
• Encephalomyelitis, Inflammatory [M0334930]
  
• Encephalomyelitis, Postexanthem [M0334283]
  
• Encephalomyelitis, Venezuelan Equine [M0007377]
  A form of arboviral encephalitis endemic to Central America and the northern latitudes of South America. The causative organism (ENCEPHALITIS VIRUS, VENEZUELAN EQUINE) is transmitted to humans and horses via the bite of several mosquito species. Human viral infection may be asymptomatic or remain restricted to a mild influenza-like illness. Encephalitis, usually not severe, occurs in a small percentage of cases and may rarely feature SEIZURES and COMA. (From Joynt, Clinical Neurology, 1996, Ch26, pp9-10)
  
• Encephalomyelitis, Western Equine [M0328384]
  A form of arboviral encephalitis (which primarily affects horses) endemic to western and central regions of NORTH AMERICA. The causative organism (ENCEPHALOMYELITIS VIRUS, WESTERN EQUINE) may be transferred to humans via the bite of mosquitoes (CULEX tarsalis and others). Clinical manifestations include headache and influenza-like symptoms followed by alterations in mentation, SEIZURES, and COMA. DEATH occurs in a minority of cases. Survivors may recover fully or be left with residual neurologic dysfunction, including PARKINSONISM, POSTENCEPHALITIC. (From Joynt, Clinical Neurology, 1996, Ch26, pp8-9)
  
• Encephalopathy, Bovine Spongiform [M0025363]
  A transmissible spongiform encephalopathy of cattle associated with abnormal prion proteins in the brain. Affected animals develop excitability and salivation followed by ATAXIA. This disorder has been associated with consumption of SCRAPIE infected ruminant derived protein. This condition may be transmitted to humans, where it is referred to as variant or new variant CREUTZFELDT-JAKOB SYNDROME. (Vet Rec 1998 Jul 25;143(41):101-5)
  
• Encephalopathy, Lyme Disease [M0335551]
  
• Encephalopathy, Subacute Necrotizing, Infantile [M0335493]
  
• Encephalopathy, Subacute Necrotizing, Juvenile [M0335494]
  
• Enchondromatosis [M0007380]
  Benign growths of cartilage in the metaphyses of several bones.
  
• Endarteritis [M0007386]
  Inflammation of the tunica intima of an artery. (Dorland, 27th ed)
  
• Endemic Cretinism [M0470648]
  
• Endemic Diseases [M0028808]
  The constant presence of diseases or infectious agents within a given geographic area or population group. It may also refer to the usual prevalence of a given disease with such area or group. It includes holoendemic and hyperendemic diseases. A holoendemic disease is one for which a high prevalent level of infection begins early in life and affects most of the child population, leading to a state of equilibrium such that the adult population shows evidence of the disease much less commonly than do children (malaria in many communities is a holoendemic disease). A hyperendemic disease is one that is constantly present at a high incidence and/or prevalence rate and affects all groups equally. (Last, A Dictionary of Epidemiology, 3d ed, p53, 78, 80)
  
• Endocardial Fibroelastosis [M0007391]
  A condition characterized by the thickening of ENDOCARDIUM due to proliferation of fibrous and elastic tissue, usually in the left ventricle leading to impaired cardiac function (CARDIOMYOPATHY, RESTRICTIVE). It is most commonly seen in young children and rarely in adults. It is often associated with congenital heart anomalies (HEART DEFECTS,CONGENITAL;) INFECTION; or gene mutation. Defects in the tafazzin protein, encoded by TAZ gene, result in a form of autosomal dominant familial endocardial fibroelastosis.
  
• Endocarditis [M0007392]
  Exudative and proliferative inflammatory alterations of the endocardium, characterized by the presence of vegetations on the surface of the endocardium or in the endocardium itself, and most commonly involving a heart valve, but sometimes affecting the inner lining of the cardiac chambers or the endocardium elsewhere. It may occur as a primary disorder or as a complication of or in association with another disease. (Dorland, 27th ed)
  
• Endocarditis, Bacterial [M0007393]
  
• Endocarditis, Subacute Bacterial [M0007394]
  Infection of the endocardium caused by species of STREPTOCOCCUS. This condition does not produce metastatic foci and if untreated may take up to a year to be fatal.
  
• Endocrine Breast Diseases [M0458719]
  Breast diseases which are hormone-dependent or responsive to endocrine signals.
  
• Endocrine System Diseases [M0007396]
  Pathological processes of the ENDOCRINE GLANDS, and diseases resulting from abnormal level of available HORMONES.
  
• Endogenous Hyperinsulinism [M0446721]
  
• Endolymphatic Hydrops [M0027370]
  An accumulation of endolymph in the inner ear resulting in deafness and tinnitus, and sometimes vertigo (MENIERE'S DISEASE). Induced experimentally, it often serves as an animal model for Meniere's disease. (From Dorland, 27th ed.)
  
• Endometrial Diseases [M0496916]
  
• Endometrial Hyperplasia [M0007412]
  Benign proliferation of the ENDOMETRIUM in the UTERUS. Endometrial hyperplasia is classified by its cytology and glandular tissue. There are simple, complex (adenomatous without atypia), and atypical hyperplasia representing also the ascending risk of becoming malignant.
  
• Endometrioma [M0406918]
  An enlarged area of ENDOMETRIOSIS that resembles a tumor. It is usually found in the OVARY. When it is filled with old blood, it is known as a chocolate cyst.
  
• Endometriosis [M0007413]
  A condition in which functional endometrial tissue is present outside the UTERUS. It is often confined to the PELVIS involving the OVARY, the ligaments, cul-de-sac, and the uterovesical peritoneum.
  
• Endometritis [M0007414]
  Inflammation of the ENDOMETRIUM, usually caused by intrauterine infections. Endometritis is the most common cause of postpartum fever.
  
• Endomyocardial Fibrosis [M0007420]
  A condition characterized by the thickening of the ventricular ENDOCARDIUM and subendocardium (MYOCARDIUM), seen mostly in children and young adults in the TROPICAL CLIMATE. The fibrous tissue extends from the apex toward and often involves the HEART VALVES causing restrictive blood flow into the respective ventricles (CARDIOMYOPATHY, RESTRICTIVE).
  
• Endomyometritis [M0401966]
  Inflammation of both the ENDOMETRIUM and the MYOMETRIUM, usually caused by infections after a CESAREAN SECTION.
  
• Endophthalmitis [M0015321]
  Suppurative inflammation of the tissues of the internal structures of the eye; not all layers of the uvea are affected. Fungi, necrosis of intraocular tumors, and retained intraocular foreign bodies often cause a purulent endophthalmitis.
  
• Enophthalmos [M0024257]
  Recession of the eyeball into the orbit.
  
• Enoplida Infections [M0026094]
  Infections with nematodes of the order ENOPLIDA.
  
• Entamoebiasis [M0007460]
  Infection with amoebae of the genus ENTAMOEBA. Infection with E. histolytica causes DYSENTERY, AMEBIC and LIVER ABSCESS, AMEBIC.
  
• Entamoebiasis, Hepatic [M0453773]
  
• Entamoebiasis, Intestinal [M0006915]
  
• Enteritis [M0007466]
  Inflammation of any segment of the SMALL INTESTINE.
  
• Enteritis, Granulomatous [M0393458]
  
• Enteritis, Pseudomembranous [M0443803]
  
• Enteritis, Transmissible, of Turkeys [M0007468]
  An acute, highly contagious virus disease of turkeys characterized by chilling, anorexia, decreased water intake, diarrhea, dehydration and weight loss. The infectious agent is a CORONAVIRUS.
  
• Enterobacteriaceae Infections [M0007472]
  Infections with bacteria of the family ENTEROBACTERIACEAE.
  
• Enterobiasis [M0026142]
  Infection with nematodes of the genus ENTEROBIUS; E. vermicularis, the pinworm of man, causes a crawling sensation and pruritus. This condition results in scratching the area, occasionally causing scarification.
  
• Enterocele [M0010260]
  An intestinal HERNIA.
  
• Enterocolitis [M0007478]
  Inflammation of the MUCOSA of both the SMALL INTESTINE and the LARGE INTESTINE. Etiology includes ISCHEMIA, infections, allergic, and immune responses.
  
• Enterocolitis, Necrotizing [M0029980]
  ENTEROCOLITIS with extensive ulceration (ULCER) and NECROSIS. It is observed primarily in LOW BIRTH WEIGHT INFANT.
  
• Enterocolitis, Neutropenic [M0445241]
  A syndrome characterized by inflammation in the ILEUM, the CECUM, and the ASCENDING COLON. It is observed in cancer patients with CHEMOTHERAPY-induced NEUTROPENIA or in other immunocompromised individuals (IMMUNOCOMPROMISED HOST).
  
• Enterocolitis, Pseudomembranous [M0007479]
  An acute inflammation of the INTESTINAL MUCOSA that is characterized by the presence of pseudomembranes or plaques in the SMALL INTESTINE (pseudomembranous enteritis) and the LARGE INTESTINE (pseudomembranous colitis). It is commonly associated with antibiotic therapy and CLOSTRIDIUM DIFFICILE colonization.
  
• Enterotoxemia [M0007486]
  Disease caused by the liberation of exotoxins of CLOSTRIDIUM PERFRINGENS in the intestines of sheep, goats, cattle, foals, and piglets. Type B enterotoxemia in lambs is lamb dysentery; type C enterotoxemia in mature sheep produces "struck", and in calves, lambs and piglets it produces hemorrhagic enterotoxemia; type D enterotoxemia in sheep and goats is pulpy-kidney disease or overeating disease.
  
• Enterovirus Infections [M0007488]
  
• Enthesopathy [M0019015]
  
• Entomophthoramycosis [M0029828]
  
• Entrapment Neuropathies [M0336248]
  
• Entropion [M0007496]
  The turning inward (inversion) of the edge of the eyelid, with the tarsal cartilage turned inward toward the eyeball. (Dorland, 27th ed)
  
• Enuresis [M0007497]
  Involuntary discharge of URINE after expected age of completed development of urinary control. This can happen during the daytime (DIURNAL ENURESIS) while one is awake or during sleep (NOCTURNAL ENURESIS). Enuresis can be in children or in adults (as persistent primary enuresis and secondary adult-onset enuresis).
  
• Environmental Illness [M0028231]
  A polysymptomatic condition believed by clinical ecologists to result from immune dysregulation induced by common foods, allergens, and chemicals, resulting in various physical and mental disorders. The medical community has remained largely skeptical of the existence of this "disease", given the plethora of symptoms attributed to environmental illness, the lack of reproducible laboratory abnormalities, and the use of unproven therapies to treat the condition. (From Segen, Dictionary of Modern Medicine, 1992)
  
• Environmental Sleep Disorder [M0334691]
  
• Eosinophilia [M0007532]
  Abnormal increase in eosinophils in the blood, tissues or organs.
  
• Eosinophilia, Tropical [M0018130]
  
• Eosinophilia-Myalgia Syndrome [M0025320]
  A complex systemic syndrome with inflammatory and autoimmune components that affect the skin, fascia, muscle, nerve, blood vessels, lung, and heart. Diagnostic features generally include EOSINOPHILIA, myalgia severe enough to limit usual activities of daily living, and the absence of coexisting infectious, autoimmune or other conditions that may induce eosinophilia. Biopsy of affected tissue reveals a microangiopathy associated with diffuse inflammation involving connective tissue. (From Spitzer et al., J Rheumatol Suppl 1996 Oct;46:73-9; Blackburn WD, Semin Arthritis Rheum 1997 Jun;26(6):788-93)
  
• Eosinophilia-Myalgia Syndrome, L-Tryptophan-Related [M0335638]
  
• Eperythrozoonosis [M0007538]
  
• Ephemeral Fever [M0007542]
  An Ephemerovirus infection of cattle caused by bovine ephemeral fever virus (EPHEMERAL FEVER VIRUS, BOVINE). It is characterized by respiratory symptoms, increased oropharyngeal secretions and lacrimation, joint pains, tremor, and stiffness.
  
• Epidermal Necrolysis, Toxic [M0007553]
  An exfoliative disease of skin seen primarily in adults and characterized by flaccid bullae and spreading erythema so that the skin has the appearance of being scalded. It results primarily from a toxic reaction to various drugs, but occasionally occurs as a result of infection, neoplastic conditions, or other exposure.
  
• Epidermitis, Exudative, of Swine [M0007555]
  An acute generalized dermatitis of pigs which occurs from 5 to 35 days of age, characterized by sudden onset, with morbidity of 10 to 90% and mortality of 5 to 90%. The lesions are caused by Staphylococcus hyos but the bacterial agent is unable to penetrate the intact skin. Abrasions on the feet and legs or lacerations on the body frequently precede infection. In acute cases, a vesicular-type virus may be the predisposing factor. The causative organism is inhibited by most antibiotics. (Merck Veterinary Manual, 5th ed)
  
• Epidermolysis Bullosa [M0007557]
  Group of genetically determined disorders characterized by the blistering of skin and mucosae. There are four major forms: acquired, simple, junctional, and dystrophic. Each of the latter three has several varieties.
  
• Epidermolysis Bullosa Acquisita [M0024599]
  Form of epidermolysis bullosa characterized by trauma-induced, subepidermal blistering with no family history of the disease. Direct immunofluorescence shows IMMUNOGLOBULIN G deposited at the dermo-epidermal junction.
  
• Epidermolysis Bullosa Dystrophica [M0024601]
  Form of epidermolysis bullosa characterized by atrophy of blistered areas, severe scarring, and nail changes. It is most often present at birth or in early infancy and occurs in both autosomal dominant and recessive forms. All forms of dystrophic epidermolysis bullosa result from mutations in COLLAGEN TYPE VII, a major component fibrils of BASEMENT MEMBRANE and EPIDERMIS.
  
• Epidermolysis Bullosa Herpetiformis Dowling-Meara [M0024606]
  
• Epidermolysis Bullosa Letalis [M0024605]
  
• Epidermolysis Bullosa Progressiva [M0024603]
  
• Epidermolysis Bullosa Simplex [M0024607]
  A form of epidermolysis bullosa characterized by serous bullae that heal without scarring. Mutations in the genes that encode KERATIN-5 and KERATIN-14 have been associated with several subtypes of epidermolysis bullosa simplex.
  
• Epidermolysis Bullosa Simplex Kobner [M0024608]
  
• Epidermolysis Bullosa, Junctional [M0024604]
  Form of epidermolysis bullosa having onset at birth or during the neonatal period and transmitted through autosomal recessive inheritance. It is characterized by generalized blister formation, extensive denudation, and separation and cleavage of the basal cell plasma membranes from the basement membrane.
  
• Epidermophytosis [M0021561]
  
• Epididymitis [M0007560]
  Inflammation of the EPIDIDYMIS. Its clinical features include enlarged epididymis, a swollen SCROTUM; PAIN; PYURIA; and FEVER. It is usually related to infections in the URINARY TRACT, which likely spread to the EPIDIDYMIS through either the VAS DEFERENS or the lymphatics of the SPERMATIC CORD.
  
• Epidural Abscess [M0328385]
  Circumscribed collections of suppurative material occurring in the spinal or intracranial EPIDURAL SPACE. The majority of epidural abscesses occur in the spinal canal and are associated with OSTEOMYELITIS of a vertebral body; ANALGESIA, EPIDURAL; and other conditions. Clinical manifestations include local and radicular pain, weakness, sensory loss, URINARY INCONTINENCE, and FECAL INCONTINENCE. Cranial epidural abscesses are usually associated with OSTEOMYELITIS of a cranial bone, SINUSITIS, or OTITIS MEDIA. (From Adams et al., Principles of Neurology, 6th ed, p710 and pp1240-1; J Neurol Neurosurg Psychiatry 1998 Aug;65(2):209-12)
  
• Epidural Abscess, Spinal [M0334924]
  
• Epiglottitis [M0007563]
  Inflammation of the epiglottis.
  
• Epilepsia Partialis Continua [M0025882]
  A variant of epilepsy characterized by continuous focal jerking of a body part over a period of hours, days, or even years without spreading to other body regions. Contractions may be aggravated by movement and are reduced, but not abolished during sleep. ELECTROENCEPHALOGRAPHY demonstrates epileptiform (spike and wave) discharges over the hemisphere opposite to the affected limb in most instances. The repetitive movements may originate from the CEREBRAL CORTEX or from subcortical structures (e.g., BRAIN STEM; BASAL GANGLIA). This condition is associated with Russian Spring and Summer encephalitis (see ENCEPHALITIS, TICK BORNE); Rasmussen syndrome (see ENCEPHALITIS); MULTIPLE SCLEROSIS; DIABETES MELLITUS; BRAIN NEOPLASMS; and CEREBROVASCULAR DISORDERS. (From Brain, 1996 April;119(pt2):393-407; Epilepsia 1993;34;Suppl 1:S29-S36; and Adams et al., Principles of Neurology, 6th ed, p319)
  
• Epilepsies, Myoclonic [M0328686]
  A clinically diverse group of epilepsy syndromes characterized either by myoclonic seizures or by myoclonus in association with other seizure types. Myoclonic epilepsy syndromes are divided into three subtypes based on etiology: familial, cryptogenic, and symptomatic (i.e., occurring secondary to known disease processes such as infections, hypoxic-ischemic injuries, trauma, etc.).
  
• Epilepsies, Partial [M0007566]
  Conditions characterized by recurrent paroxysmal neuronal discharges which arise from a focal region of the brain. Partial seizures are divided into simple and complex, depending on whether consciousness is unaltered (simple partial seizure) or disturbed (complex partial seizure). Both types may feature a wide variety of motor, sensory, and autonomic symptoms. Partial seizures may be classified by associated clinical features or anatomic location of the seizure focus. A secondary generalized seizure refers to a partial seizure that spreads to involve the brain diffusely. (From Adams et al., Principles of Neurology, 6th ed, pp317)
  
• Epilepsy [M0007564]
  A disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. Epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (From Adams et al., Principles of Neurology, 6th ed, p313)
  
• Epilepsy, Absence [M0007577]
  A childhood seizure disorder characterized by rhythmic electrical brain discharges of generalized onset. Clinical features include a sudden cessation of ongoing activity usually without loss of postural tone. Rhythmic blinking of the eyelids or lip smacking frequently accompanies the SEIZURES. The usual duration is 5-10 seconds, and multiple episodes may occur daily. Juvenile absence epilepsy is characterized by the juvenile onset of absence seizures and an increased incidence of myoclonus and tonic-clonic seizures. (Menkes, Textbook of Child Neurology, 5th ed, p736)
  
• Epilepsy, Absence, Atypical [M0334967]
  
• Epilepsy, Akinetic [M0335038]
  
• Epilepsy, Anterior Fronto-Polar [M0335009]
  
• Epilepsy, Atonic [M0007571]
  
• Epilepsy, Benign Neonatal [M0328386]
  A condition marked by recurrent seizures that occur during the first 4-6 weeks of life despite an otherwise benign neonatal course. Autosomal dominant familial and sporadic forms have been identified. Seizures generally consist of brief episodes of tonic posturing and other movements, apnea, eye deviations, and blood pressure fluctuations. These tend to remit after the 6th week of life. The risk of developing epilepsy at an older age is moderately increased in the familial form of this disorder. (Neurologia 1996 Feb;11(2):51-5)
  
• Epilepsy, Benign Psychomotor, Childhood [M0335125]
  
• Epilepsy, Cingulate [M0335011]
  
• Epilepsy, Complex Partial [M0025874]
  A disorder characterized by recurrent partial seizures marked by impairment of cognition. During the seizure the individual may experience a wide variety of psychic phenomenon including formed hallucinations, illusions, deja vu, intense emotional feelings, confusion, and spatial disorientation. Focal motor activity, sensory alterations and AUTOMATISM may also occur. Complex partial seizures often originate from foci in one or both temporal lobes. The etiology may be idiopathic (cryptogenic partial complex epilepsy) or occur as a secondary manifestation of a focal cortical lesion (symptomatic partial complex epilepsy). (From Adams et al., Principles of Neurology, 6th ed, pp317-8)
  
• Epilepsy, Cryptogenic [M0007565]
  
• Epilepsy, Frontal Lobe [M0025878]
  A localization-related (focal) form of epilepsy characterized by seizures which arise in the frontal lobe. A variety of clinical syndromes exist depending on the exact location of the seizure focus. Simple or complex motor movements may occur, and most commonly involve the face and upper extremities. Seizures in the anterior frontal regions may be associated with head and eye turning, typically away from the side of origin of the seizure. Frontal lobe seizures may be idiopathic (cryptogenic) or caused by an identifiable disease process such as traumatic injuries, neoplasms, or other macroscopic or microscopic lesions of the frontal lobes (symptomatic frontal lobe seizures). (From Adams et al., Principles of Neurology, 6th ed, pp318-9)
  
• Epilepsy, Generalized [M0007570]
  Recurrent conditions characterized by epileptic seizures which arise diffusely and simultaneously from both hemispheres of the brain. Classification is generally based upon motor manifestations of the seizure (e.g., convulsive, nonconvulsive, akinetic, atonic, etc.) or etiology (e.g., idiopathic, cryptogenic, and symptomatic). (From Mayo Clin Proc, 1996 Apr;71(4):405-14)
  
• Epilepsy, Lateral Temporal [M0335126]
  
• Epilepsy, Myoclonic, Infantile [M0334946]
  
• Epilepsy, Myoclonic, Infantile, Severe [M0334943]
  
• Epilepsy, Opercular [M0335012]
  
• Epilepsy, Orbito-Frontal [M0335013]
  
• Epilepsy, Partial, Motor [M0328389]
  A disorder characterized by recurrent localized paroxysmal discharges of cerebral neurons that give rise to seizures that have motor manifestations. The majority of partial motor seizures originate in the FRONTAL LOBE (see also EPILEPSY, FRONTAL LOBE). Motor seizures may manifest as tonic or clonic movements involving the face, one limb or one side of the body. A variety of more complex patterns of movement, including abnormal posturing of extremities, may also occur.
  
• Epilepsy, Partial, Sensory [M0328391]
  A disorder characterized by recurrent focal onset seizures which have sensory (i.e., olfactory, visual, tactile, gustatory, or auditory) manifestations. Partial seizures that feature alterations of consciousness are referred to as complex partial seizures (EPILEPSY, COMPLEX PARTIAL).
  
• Epilepsy, Reflex [M0328392]
  A subtype of epilepsy characterized by seizures that are consistently provoked by a certain specific stimulus. Auditory, visual, and somatosensory stimuli as well as the acts of writing, reading, eating, and decision making are examples of events or activities that may induce seizure activity in affected individuals. (From Neurol Clin 1994 Feb;12(1):57-8)
  
• Epilepsy, Rolandic [M0028742]
  An autosomal dominant inherited partial epilepsy syndrome with onset between age 3 and 13 years. Seizures are characterized by PARESTHESIA and tonic or clonic activity of the lower face associated with drooling and dysarthria. The episodes tend to occur at night and may become secondarily generalized. In most cases, affected children are neurologically and developmentally normal. The electroencephalogram shows characteristic high-voltage sharp waves over the central temporal regions, which are more prominent during drowsiness and sleep. In general, seizures do not continue beyond mid-adolescence. (From Epilepsia 1998 39;Suppl 4:S32-S41)
  
• Epilepsy, Simple Partial [M0007569]
  
• Epilepsy, Supplementary Motor [M0335014]
  
• Epilepsy, Symptomatic, Partial Complex [M0334995]
  
• Epilepsy, Temporal Lobe [M0007578]
  A localization-related (focal) form of epilepsy characterized by recurrent seizures that arise from foci within the temporal lobe, most commonly from its mesial aspect. A wide variety of psychic phenomena may be associated, including illusions, hallucinations, dyscognitive states, and affective experiences. The majority of complex partial seizures (see EPILEPSY, COMPLEX PARTIAL) originate from the temporal lobes. Temporal lobe seizures may be classified by etiology as cryptogenic, familial, or symptomatic (i.e., related to an identified disease process or lesion). (From Adams et al., Principles of Neurology, 6th ed, p321)
  
• Epilepsy, Tonic [M0007572]
  
• Epilepsy, Tonic-Clonic [M0007573]
  A generalized seizure disorder characterized by recurrent major motor seizures. The initial brief tonic phase is marked by trunk flexion followed by diffuse extension of the trunk and extremities. The clonic phase features rhythmic flexor contractions of the trunk and limbs, pupillary dilation, elevations of blood pressure and pulse, urinary incontinence, and tongue biting. This is followed by a profound state of depressed consciousness (post-ictal state) which gradually improves over minutes to hours. The disorder may be cryptogenic, familial, or symptomatic (caused by an identified disease process). (From Adams et al., Principles of Neurology, 6th ed, p329)
  
• Epilepsy, Tonic-Clonic, Familial [M0335130]
  
• Epilepsy, Tonic-Clonic, Symptomatic [M0335131]
  
• Epilepsy, Uncinate [M0007579]
  
• Epiphora [M0012136]
  
• Epiphyses, Slipped [M0007593]
  
• Episcleritis [M0023771]
  
• Episodic Cluster Headache [M0334706]
  
• Episodic Paroxysmal Hemicrania [M0480083]
  
• Epstein-Barr Virus Infections [M0029738]
  Infection with human herpesvirus 4 (HERPESVIRUS 4, HUMAN); which may facilitate the development of various lymphoproliferative disorders. These include BURKITT LYMPHOMA (African type), INFECTIOUS MONONUCLEOSIS, and oral hairy leukoplakia (LEUKOPLAKIA, HAIRY).
  
• Epulides [M0009235]
  
• Epulis, Giant Cell [M0009607]
  
• Equine Infectious Anemia [M0007620]
  Viral disease of horses caused by the equine infectious anemia virus (EIAV; INFECTIOUS ANEMIA VIRUS, EQUINE). It is characterized by intermittent fever, weakness, and anemia. Chronic infection consists of acute episodes with remissions.
  
• Erdheim-Chester Disease [M0396932]
  A rare form of non-Langerhans-cell histiocytosis (HISTIOCYTOSIS, NON-LANGERHANS-CELL) with onset in middle age. The systemic disease is characterized by infiltration of lipid-laden macrophages, multinucleated giant cells, an inflammatory infiltrate of lymphocytes and histiocytes in the bone marrow, and a generalized sclerosis of the long bones.
  
• Erectile Dysfunction [M0011178]
  
• Erosive Duodenitis [M0444529]
  
• Erysipelas [M0007675]
  An acute infection of the skin caused by species of STREPTOCOCCUS. This disease most frequently affects infants, young children, and the elderly. Characteristics include pink-to-red lesions that spread rapidly and are warm to the touch. The commonest site of involvement is the face.
  
• Erysipeloid [M0007676]
  An infection caused by Erysipelothrix rhusiopathiae that is almost wholly restricted to persons who in their occupation handle infected fish, shellfish, poultry, or meat. Three forms of this condition exist: a mild localized form manifested by local swelling and redness of the skin; a diffuse form that might present with fever; and a rare systemic form associated with endocarditis.
  
• Erysipelothrix Infections [M0007678]
  Infections with bacteria of the genus ERYSIPELOTHRIX.
  
• Erythema Chronicum Migrans [M0024184]
  A deep type of gyrate erythema that follows a bite by an ixodid tick; it is a stage-1 manifestation of LYME DISEASE. The site of the bite is characterized by a red papule that expands peripherally as a nonscaling, palpable band that clears centrally. This condition is often associated with systemic symptoms such as chills, fever, headache, malaise, nausea, vomiting, fatigue, backache, and stiff neck.
  
• Erythema Induratum [M0007680]
  A type of panniculitis characterized histologically by the presence of granulomas, vasculitis, and necrosis. It is traditionally considered to be the tuberculous counterpart of nodular vasculitis, but is now known to occur without tuberculous precedent. It is seen most commonly in adolescent and menopausal women, is initiated or exacerbated by cold weather, and typically presents as one or more recurrent erythrocyanotic nodules or plaques on the calves. The nodules may progress to form indurations, ulcerations, and scars.
  
• Erythema Infectiosum [M0025479]
  Contagious infection with human B19 Parvovirus most commonly seen in school age children and characterized by fever, headache, and rashes of the face, trunk, and extremities. It is often confused with rubella.
  
• Erythema Multiforme [M0007681]
  A skin and mucous membrane disease characterized by an eruption of macules, papules, nodules, vesicles, and/or bullae with characteristic "bull's-eye" lesions usually occurring on the dorsal aspect of the hands and forearms.
  
• Erythema Nodosum [M0007682]
  An erythematous eruption commonly associated with drug reactions or infection and characterized by inflammatory nodules that are usually tender, multiple, and bilateral. These nodules are located predominantly on the shins with less common occurrence on the thighs and forearms. They undergo characteristic color changes ending in temporary bruise-like areas. This condition usually subsides in 3-6 weeks without scarring or atrophy.
  
• Erythematotelangiectatic Rosacea [M0461563]
  
• Erythrasma [M0007683]
  A chronic bacterial infection of major folds of the skin, caused by Corynebacterium minutissimum.
  
• Erythroblastosis, Fetal [M0007688]
  A condition characterized by the abnormal presence of ERYTHROBLASTS in the circulation of the FETUS or NEWBORNS. It is a disorder due to BLOOD GROUP INCOMPATIBILITY, such as the maternal alloimmunization by fetal antigen RH FACTORS leading to HEMOLYSIS of ERYTHROCYTES, hemolytic anemia (ANEMIA, HEMOLYTIC), general edema (HYDROPS FETALIS), and SEVERE JAUNDICE IN NEWBORN.
  
• Erythrocytosis [M0017167]
  
• Erythroderma, Maculopapular [M0015907]
  
• Erythromelalgia [M0007714]
  Disease marked by paroxysmal, bilateral vasodilatation, particularly of the extremities, with burning pain, and increased skin temperature and redness.
  
• Escherichia coli Infections [M0007733]
  Infections with bacteria of the species ESCHERICHIA COLI.
  
• Esophageal Achalasia [M0007740]
  A motility disorder of the ESOPHAGUS in which the LOWER ESOPHAGEAL SPHINCTER (near the CARDIA) fails to relax resulting in functional obstruction of the esophagus, and DYSPHAGIA. Achalasia is characterized by a grossly contorted and dilated esophagus (megaesophagus).
  
• Esophageal Atresia [M0007745]
  Congenital abnormality characterized by the lack of full development of the ESOPHAGUS that commonly occurs with TRACHEOESOPHAGEAL FISTULA. Symptoms include excessive SALIVATION; GAGGING; CYANOSIS; and DYSPNEA.
  
• Esophageal Diseases [M0007747]
  Pathological processes in the ESOPHAGUS.
  
• Esophageal Dysphagia [M0453215]
  
• Esophageal Motility Disorders [M0023297]
  Disorders affecting the motor function of the UPPER ESOPHAGEAL SPHINCTER; LOWER ESOPHAGEAL SPHINCTER; the ESOPHAGUS body, or a combination of these parts. The failure of the sphincters to maintain a tonic pressure may result in gastric reflux of food and acid into the esophagus (GASTROESOPHAGEAL REFLUX). Other disorders include hypermotility (spastic disorders) and markedly increased amplitude in contraction (nutcracker esophagus).
  
• Esophageal Perforation [M0007751]
  An opening or hole in the ESOPHAGUS that is caused by TRAUMA, injury, or pathological process.
  
• Esophageal Spasm, Diffuse [M0023299]
  A hypermotility disorder of the ESOPHAGUS that is characterized by spastic non-peristaltic responses to SWALLOWING; CHEST PAIN; and DYSPHAGIA.
  
• Esophageal Stenosis [M0007752]
  A stricture of the ESOPHAGUS. Most are acquired but can be congenital.
  
• Esophageal Varices [M0007743]
  
• Esophagitis [M0007753]
  INFLAMMATION, acute or chronic, of the ESOPHAGUS caused by BACTERIA, chemicals, or TRAUMA.
  
• Esophagitis, Peptic [M0007754]
  INFLAMMATION of the ESOPHAGUS that is caused by the reflux of GASTRIC JUICE with contents of the STOMACH and DUODENUM.
  
• Esophoria [M0337470]
  
• Esotropia [M0007762]
  A form of ocular misalignment characterized by an excessive convergence of the visual axes, resulting in a "cross-eye" appearance. An example of this condition occurs when paralysis of the lateral rectus muscle causes an abnormal inward deviation of one eye on attempted gaze.
  
• Essential Polyarteritis [M0016294]
  
• Essential Tremor [M0328393]
  A relatively common disorder characterized by a fairly specific pattern of tremors which are most prominent in the upper extremities and neck, inducing titubations of the head. The tremor is usually mild, but when severe may be disabling. An autosomal dominant pattern of inheritance may occur in some families (i.e., familial tremor). (Mov Disord 1988;13(1):5-10)
  
• Etat Marbre [M0335699]
  
• Ethmoid Sinusitis [M0023881]
  Inflammation of the ethmoid sinus. It may present itself as an acute (associated with viral rhinitis) or chronic (associated with allergic or hyperplastic sinusitis) condition.
  
• Eunuchism [M0007946]
  The state of being a eunuch, a male without TESTES or whose testes failed to develop. It is characterized by the lack of mature male GERM CELLS and TESTICULAR HORMONES.
  
• Eunuchoidism [M0472203]
  Eunuch-like state in which the male individual has non-functional TESTES.
  
• Euthyroid Sick Syndromes [M0007966]
  Conditions of abnormal THYROID HORMONES release in patients with apparently normal THYROID GLAND during severe systemic illness, physical TRAUMA, and psychiatric disturbances. It can be caused by the loss of endogenous hypothalamic input or by exogenous drug effects. The most common abnormality results in low T3 THYROID HORMONE with progressive decrease in THYROXINE; (T4) and TSH. Elevated T4 with normal T3 may be seen in diseases in which THYROXINE-BINDING GLOBULIN synthesis and release are increased.
  
• Exanthema [M0007993]
  Diseases in which skin eruptions or rashes are a prominent manifestation. Classically, six such diseases were described with similar rashes; they were numbered in the order in which they were reported. Only the fourth (Duke's disease), fifth (ERYTHEMA INFECTIOSUM), and sixth (EXANTHEMA SUBITUM) numeric designations survive as occasional synonyms in current terminology.
  
• Exanthema Subitum [M0007994]
  An acute, short-lived, viral disease of infants and young children characterized by a high fever at onset that drops to normal after 3-4 days and the concomitant appearance of a macular or maculopapular rash that appears first on the trunk and then spreads to other areas. It is the sixth of the classical exanthematous diseases and is caused by HHV-6; (HERPESVIRUS 6, HUMAN). (From Dorland, 27th ed)
  
• Exfoliation Syndrome [M0027032]
  The deposition of flaky, translucent fibrillar material most conspicuous on the anterior lens capsule and pupillary margin but also in both surfaces of the iris, the zonules, trabecular meshwork, ciliary body, corneal endothelium, and orbital blood vessels. It sometimes forms a membrane on the anterior iris surface. Exfoliation refers to the shedding of pigment by the iris. (Newell, Ophthalmology, 7th ed, p380)
  
• Exocrine Pancreatic Insufficiency [M0015801]
  A malabsorption condition resulting from greater than 10% reduction in the secretion of pancreatic digestive enzymes (LIPASE; PROTEASES; and AMYLASE) by the EXOCRINE PANCREAS into the DUODENUM. This condition is often associated with CYSTIC FIBROSIS and with chronic PANCREATITIS.
  
• Exogenous Hyperinsulinism [M0446722]
  
• Exophoria [M0336198]
  
• Exophthalmos [M0008034]
  Abnormal protrusion of both eyes; may be caused by endocrine gland malfunction, malignancy, injury, or paralysis of the extrinsic muscles of the eye.
  
• Exotropia [M0008040]
  A form of ocular misalignment where the visual axes diverge inappropriately. For example, medial rectus muscle weakness may produce this condition as the affected eye will deviate laterally upon attempted forward gaze. An exotropia occurs due to the relatively unopposed force exerted on the eye by the lateral rectus muscle, which pulls the eye in an outward direction.
  
• External Carotid Artery Diseases [M0003541]
  
• External Carotid Artery Stenosis [M0334352]
  
• External Carotid Artery Thrombosis [M0334342]
  
• External Nerve Compression Syndromes [M0336250]
  
• Extrapontine Myelinolysis [M0335746]
  
• Extrapyramidal Disorders [M0002199]
  
• Eye Abnormalities [M0008084]
  Congenital absence of or defects in structures of the eye; may also be hereditary.
  
• Eye Diseases [M0008088]
  
• Eye Diseases, Hereditary [M0024182]
  Transmission of gene defects or chromosomal aberrations/abnormalities which are expressed in extreme variation in the structure or function of the eye. These may be evident at birth, but may be manifested later with progression of the disorder.
  
• Eye Infections [M0024227]
  Infection, moderate to severe, caused by bacteria, fungi, or viruses, which occurs either on the external surface of the eye or intraocularly with probable inflammation, visual impairment, or blindness.
  
• Eye Infections, Bacterial [M0024228]
  Infections in the inner or external eye caused by microorganisms belonging to several families of bacteria. Some of the more common genera found are Haemophilus, Neisseria, Staphylococcus, Streptococcus, and Chlamydia.
  
• Eye Infections, Fungal [M0024239]
  Infection by a variety of fungi, usually through four possible mechanisms: superficial infection producing conjunctivitis, keratitis, or lacrimal obstruction; extension of infection from neighboring structures - skin, paranasal sinuses, nasopharynx; direct introduction during surgery or accidental penetrating trauma; or via the blood or lymphatic routes in patients with underlying mycoses.
  
• Eye Infections, Parasitic [M0024240]
  Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.
  
• Eye Infections, Viral [M0024246]
  Infections of the eye caused by minute intracellular agents. These infections may lead to severe inflammation in various parts of the eye - conjunctiva, iris, eyelids, etc. Several viruses have been identified as the causative agents. Among these are Herpesvirus, Adenovirus, Poxvirus, and Myxovirus.
  
• Eyelid Diseases [M0008105]
  
• Fabry Disease [M0001191]
  An X-linked inherited metabolic disease caused by a deficiency of lysosomal ALPHA-GALACTOSIDASE A. It is characterized by intralysosomal accumulation of globotriaosylceramide and other GLYCOSPHINGOLIPIDS in blood vessels throughout the body leading to multi-system complications including renal, cardiac, cerebrovascular, and skin disorders.
  
• Facial Dermatoses [M0008112]
  
• Facial Hemiatrophy [M0008116]
  A syndrome characterized by slowly progressive unilateral atrophy of facial subcutaneous fat, muscle tissue, skin, cartilage, and bone. The condition typically progresses over a period of 2-10 years and then stabilizes.
  
• Facial Myokymia [M0335903]
  
• Facial Nerve Diseases [M0008122]
  Diseases of the facial nerve or nuclei. Pontine disorders may affect the facial nuclei or nerve fascicle. The nerve may be involved intracranially, along its course through the petrous portion of the temporal bone, or along its extracranial course. Clinical manifestations include facial muscle weakness, loss of taste from the anterior tongue, hyperacusis, and decreased lacrimation.
  
• Facial Nerve Motor Disorders [M0336032]
  
• Facial Nerve Sensory Disorders [M0336033]
  
• Facial Neuralgia [M0008123]
  Neuralgic syndromes and other conditions which feature chronic or recurrent FACIAL PAIN as the primary manifestation of disease. Disorders of the trigeminal and facial nerves are frequently associated with these conditions.
  
• Facial Neuritis [M0336034]
  
• Factor V Deficiency [M0008143]
  A deficiency of blood coagulation factor V (known as proaccelerin or accelerator globulin or labile factor) leading to a rare hemorrhagic tendency known as Owren's disease or parahemophilia. It varies greatly in severity. Factor V deficiency is an autosomal recessive trait. (Dorland, 27th ed)
  
• Factor VII Deficiency [M0008145]
  An autosomal recessive characteristic or a coagulation disorder acquired in association with VITAMIN K DEFICIENCY. FACTOR VII is a Vitamin K dependent glycoprotein essential to the extrinsic pathway of coagulation.
  
• Factor X Deficiency [M0008155]
  Blood coagulation disorder usually inherited as an autosomal recessive trait, though it can be acquired. It is characterized by defective activity in both the intrinsic and extrinsic pathways, impaired thromboplastin time, and impaired prothrombin consumption.
  
• Factor XI Deficiency [M0008157]
  A deficiency of blood coagulation factor XI (known as plasma thromboplastin antecedent or PTA or antihemophilic factor C) resulting in a systemic blood-clotting defect called hemophilia C or Rosenthal's syndrome, that may resemble classical hemophilia. (Dorland, 27th ed)
  
• Factor XII Deficiency [M0008159]
  An absence or reduced level of blood coagulation factor XII. It normally occurs in the absence of patient or family history of hemorrhagic disorders and is marked by prolonged clotting time.
  
• Factor XIII Deficiency [M0008162]
  A deficiency of blood coagulation FACTOR XIII or fibrin stabilizing factor (FSF) that prevents blood clot formation and results in a clinical hemorrhagic diathesis.
  
• Failure to Thrive [M0008170]
  A condition in which an infant or child's weight gain and growth are far below usual levels for age.
  
• Fallopian Tube Diseases [M0008171]
  Diseases involving the FALLOPIAN TUBES including neoplasms (FALLOPIAN TUBE NEOPLASMS); SALPINGITIS; tubo-ovarian abscess; and blockage.
  
• Familial Amyloid Neuropathy, Finnish Type [M0335927]
  
• Familial Amyloid Neuropathy, Portuguese Type [M0335929]
  
• Familial Amyloid Polyneuropathy, Appalachian Type [M0335919]
  
• Familial Amyloid Polyneuropathy, Jewish Type [M0335928]
  
• Familial Amyloid Polyneuropathy, Type IV [M0335930]
  
• Familial Amyloid Polyneuropathy, Type V [M0335920]
  
• Familial Amyloid Polyneuropathy, Type VI [M0393103]
  
• Familial Dystonia [M0332739]
  
• Familial Dystonia, Idiopathic [M0334833]
  
• Familial Facial Neuropathy [M0336035]
  
• Familial Hemiplegic Migraine [M0334696]
  
• Familial Hemophagocytic Lymphocytosis [M0480276]
  Rare form of hemophagocytic lymphohistiocytosis with multiorgan involvement seen in infants and young children
  
• Familial Juvenile Parkinsonism [M0335826]
  
• Familial Mediterranean Fever [M0016320]
  An autosomal recessive inherited disease characterized by episodic FEVER; severe ABDOMINAL PAIN; PLEURISY; ARTHRITIS; and a characteristic ankle RASH. Disease flare-ups tend to last 3 days, and individuals are asymptomatic between attacks. ORCHITIS; benign recurrent MENINGITIS; HEADACHE; and AMYLOID nephropathy may also occur. (From Medicine (Baltimore) 1998 Jul;77(4):268-97)
  
• Familial Motor Neuron Disease [M0337053]
  
• Familial Olivopontocerebellar Atrophy [M0332844]
  
• Familial Partial Lipodystrophy, Type 1 [M0487303]
  
• Familial Partial Lipodystrophy, Type 2 [M0487302]
  This type can be caused by mutation in the gene encoding LAMIN TYPE A.
  
• Familial Partial Lipodystrophy, Type 3 [M0487304]
  This type can be caused by mutation in the gene encoding PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR GAMMA.
  
• Familial Progressive Myoclonic Epilepsy [M0335760]
  
• Familial Tremor [M0335132]
  
• Fanconi Anemia [M0008227]
  Congenital disorder affecting all bone marrow elements, resulting in ANEMIA; LEUKOPENIA; and THROMBOPENIA, and associated with cardiac, renal, and limb malformations as well as dermal pigmentary changes. Spontaneous CHROMOSOME BREAKAGE is a feature of this disease along with predisposition to LEUKEMIA. There are at least 7 complementation groups in Fanconi anemia: FANCA, FANCB, FANCC, FANCD1, FANCD2, FANCE, FANCF, FANCG, and FANCL. (from Online Mendelian Inheritance in Man, http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=227650, August 20, 2004)
  
• Fanconi Syndrome [M0008225]
  A hereditary or acquired form of generalized dysfunction of the PROXIMAL KIDNEY TUBULE without primary involvement of the KIDNEY GLOMERULUS. It is usually characterized by the tubular wasting of nutrients and salts (GLUCOSE; AMINO ACIDS; PHOSPHATES; and BICARBONATES) resulting in HYPOKALEMIA; ACIDOSIS; HYPERCALCIURIA; and PROTEINURIA.
  
• Farmer's Lung [M0008232]
  Systemic and pulmonary reactions resulting from inhalation of dust from moldy hay, threshing dust, or moldy straw, by persons who have become hypersensitive to antigens in the dust. It is most often associated with inhalation of spores of Micromonospora faeni or Thermoactinomyces vulgaris. (From Dorland, 27th ed)
  
• Fascicular Block [M0003028]
  
• Fasciitis [M0008239]
  Inflammation of the fascia. There are three major types: 1, Eosinophilic fasciitis, an inflammatory reaction with eosinophilia, producing hard thickened skin with an orange-peel configuration suggestive of scleroderma and considered by some a variant of scleroderma; 2, Necrotizing fasciitis (FASCIITIS, NECROTIZING), a serious fulminating infection (usually by a beta hemolytic streptococcus) causing extensive necrosis of superficial fascia; 3, Nodular/Pseudosarcomatous /Proliferative fasciitis, characterized by a rapid growth of fibroblasts with mononuclear inflammatory cells and proliferating capillaries in soft tissue, often the forearm; it is not malignant but is sometimes mistaken for fibrosarcoma.
  
• Fasciitis, Necrotizing [M0028525]
  A fulminating group A streptococcal infection beginning with severe or extensive cellulitis that spreads to involve the superficial and deep fascia, producing thrombosis of the subcutaneous vessels and gangrene of the underlying tissues. A cutaneous lesion usually serves as a portal of entry for the infection, but sometimes no such lesion is found. (Dorland, 28th ed)
  
• Fasciitis, Plantar [M0411529]
  Inflammation of the thick tissue on the bottom of the foot (plantar fascia) causing HEEL pain. The plantar fascia (also called plantar aponeurosis) are bands of fibrous tissue extending from the calcaneal tuberosity to the TOES. The etiology of plantar fasciitis remains controversial but is likely to involve a biomechanical imbalance. Though often presenting along with HEEL SPUR, they do not appear to be causally related.
  
• Fascioliasis [M0008242]
  Liver disease caused by infections with parasitic flukes of the genus FASCIOLA, such as FASCIOLA HEPATICA.
  
• Fascioloidiasis [M0008246]
  Infection of cattle and other herbivores with the giant liver fluke Fascioloides magna. It is characterized by extensive destruction of the liver parenchyma.
  
• Fasciolopsiasis [M0021866]
  
• Fasting Hypoglycemia [M0446503]
  HYPOGLYCEMIA expressed in the postabsorptive state, after prolonged FASTING, or an overnight fast.
  
• Fatigable Positional Nystagmus [M0333565]
  
• Fatigue Syndrome, Chronic [M0024027]
  A syndrome characterized by persistent or recurrent fatigue, diffuse musculoskeletal pain, sleep disturbances, and subjective cognitive impairment of 6 months duration or longer. Symptoms are not caused by ongoing exertion; are not relieved by rest; and result in a substantial reduction of previous levels of occupational, educational, social, or personal activities. Minor alterations of immune, neuroendocrine, and autonomic function may be associated with this syndrome. There is also considerable overlap between this condition and FIBROMYALGIA. (From Semin Neurol 1998;18(2):237-42; Ann Intern Med 1994 Dec 15;121(12): 953-9)
  
• Fatty Liver [M0008275]
  Lipid infiltration of the hepatic parenchymal cells resulting in a yellow-colored liver. The abnormal lipid accumulation is usually in the form of TRIGLYCERIDES, either as a single large droplet or multiple small droplets. Fatty liver is caused by an imbalance in the metabolism of FATTY ACIDS.
  
• Fatty Liver, Alcoholic [M0008276]
  Lipid infiltration of the hepatic parenchymal cells that is due to ALCOHOL ABUSE. The fatty changes in the alcoholic fatty liver may be reversible, depending on the amounts of TRIGLYCERIDES accumulated.
  
• Favism [M0008277]
  Hemolytic anemia due to the ingestion of fava beans or after inhalation of pollen from the Vicia fava plant by persons with glucose-6-phosphate dehydrogenase deficient erythrocytes.
  
• Favre-Racouchot Syndrome [M0008113]
  
• Fazio-Londe Syndrome [M0337042]
  
• Fecal Incontinence [M0008281]
  Failure of voluntary control of the anal sphincters, with involuntary passage of feces and flatus.
  
• Feline Acquired Immunodeficiency Syndrome [M0024698]
  Acquired defect of cellular immunity that occurs in cats infected with feline immunodeficiency virus (FIV) and in some cats infected with feline leukemia virus (FeLV).
  
• Feline Infectious Peritonitis [M0025557]
  Common coronavirus infection of cats caused by the feline infectious peritonitis virus (CORONAVIRUS, FELINE). The disease is characterized by a long incubation period, fever, depression, loss of appetite, wasting, and progressive abdominal enlargement. Infection of cells of the monocyte-macrophage lineage appears to be essential in FIP pathogenesis.
  
• Feline Panleukopenia [M0008298]
  A highly contagious DNA virus infection of the cat family, characterized by fever, enteritis and bone marrow changes. It is also called feline ataxia, feline agranulocytosis, feline infectious enteritis, cat fever, cat plague, and show fever. It is caused by FELINE PANLEUKOPENIA VIRUS or the closely related MINK ENTERITIS VIRUS or CANINE PARVOVIRUS.
  
• Felty's Syndrome [M0008306]
  A combination of rheumatoid arthritis, splenomegaly, leukopenia, pigmented spots on lower extremities, and other evidence of hypersplenism (anemia and thrombocytopenia). (From Dorland, 27th ed)
  
• Female Athlete Triad Syndrome [M0495788]
  A condition of competitive female athletes in which there are interrelated problems of EATING DISORDERS; AMENORRHEA; and OSTEOPOROSIS.
  
• Female Pseudo-Turner Syndrome [M0446934]
  
• Female Pseudohermaphroditism [M0472584]
  
• Female Urogenital Diseases [M0489295]
  Pathological processes of the female URINARY TRACT and the reproductive system (GENITALIA, FEMALE).
  
• Female Urogenital Diseases and Pregnancy Complications [M0008309]
  Pathological processes of the female URINARY TRACT, the reproductive system (GENITALIA, FEMALE), and disorders related to PREGNANCY.
  
• Feminization [M0008310]
  Development of female secondary SEX CHARACTERISTICS in the MALE. It is due to the effects of estrogenic metabolites of precursors from endogenous or exogenous sources, such as ADRENAL GLANDS or therapeutic drugs.
  
• Femoral Neuritis [M0392802]
  
• Femoral Neuropathy [M0328396]
  Disease involving the femoral nerve. The femoral nerve may be injured by ISCHEMIA (e.g., in association with DIABETIC NEUROPATHIES), nerve compression, trauma, COLLAGEN DISEASES, and other disease processes. Clinical features include MUSCLE WEAKNESS or PARALYSIS of hip flexion and knee extension, ATROPHY of the QUADRICEPS MUSCLE, reduced or absent patellar reflex, and impaired sensation over the anterior and medial thigh.
  
• Femur Head Necrosis [M0008320]
  Aseptic or avascular necrosis of the femoral head. The major types are idiopathic (primary), as a complication of fractures or dislocations, and LEGG-PERTHES DISEASE.
  
• Fetal Alcohol Syndrome [M0008388]
  A condition occurring in FETUS or NEWBORN due to in utero ETHANOL exposure when mother consumed alcohol during PREGNANCY. It is characterized by a cluster of irreversible BIRTH DEFECTS including abnormalities in physical, mental, and behavior development (such as FETAL GROWTH RETARDATION; MENTAL RETARDATION; ATTENTION DEFICIT AND DISRUPTIVE BEHAVIOR DISORDERS) with varied degree of severity in an individual.
  
• Fetal Anoxia [M0008389]
  
• Fetal Diseases [M0008397]
  Pathophysiological conditions of the FETUS in the UTERUS. Some fetal diseases may be treated with FETAL THERAPIES.
  
• Fetal Hypoxia [M0483549]
  Deficient oxygenation of FETAL BLOOD.
  
• Fetal Macrosomia [M0008403]
  A condition of fetal overgrowth leading to a large-for-gestational-age FETUS. It is defined as BIRTH WEIGHT greater than 4,000 grams or above the 90th percentile for population and sex-specific growth curves. It is commonly seen in GESTATIONAL DIABETES; PROLONGED PREGNANCY; and pregnancies complicated by pre-existing diabetes mellitus.
  
• Fetal Malnutrition [M0460577]
  
• Fetal Membranes, Premature Rupture [M0008405]
  Spontaneous tearing of the membranes surrounding the FETUS any time before the onset of OBSTETRIC LABOR. Preterm PROM is membrane rupture before 37 weeks of GESTATION.
  
• Fetal Nutrition Disorders [M0460578]
  Disorders caused by nutritional imbalance, either overnutrition or undernutrition, in the FETUS in utero.
  
• Fetal Resorption [M0008411]
  The disintegration and assimilation of the dead FETUS in the UTERUS at any stage after the completion of organogenesis which, in humans, is after the 9th week of GESTATION. It does not include embryo resorption (see EMBRYO LOSS).
  
• Fetomaternal Transfusion [M0008416]
  Transplacental passage of fetal blood into the circulation of the maternal organism. (Dorland, 27th ed)
  
• Fibrocystic Breast Disease [M0008440]
  A common and benign breast disease characterized by varying degree of fibrocystic changes in the breast tissue. There are three major patterns of morphological changes, including FIBROSIS, formation of CYSTS, and proliferation of glandular tissue (adenosis). The fibrocystic breast has a dense irregular lumpy bumpy consistency.
  
• Fibrodysplasia Ossificans Progressiva [M0014369]
  
• Fibromuscular Dysplasia [M0008449]
  An idiopathic, segmental, nonatheromatous disease of the musculature of arterial walls, leading to stenosis of small and medium-sized arteries. Most commonly affected are the renal arteries; involvement of the axillary, iliac, basilar, carotid, hepatic and intracranial arteries have been reported.
  
• Fibromyalgia [M0008454]
  A common nonarticular rheumatic syndrome characterized by myalgia and multiple points of focal muscle tenderness to palpation (trigger points). Muscle pain is typically aggravated by inactivity or exposure to cold. This condition is often associated with general symptoms, such as sleep disturbances, fatigue, stiffness, HEADACHES, and occasionally DEPRESSION. There is significant overlap between fibromyalgia and the chronic fatigue syndrome (FATIGUE SYNDROME, CHRONIC). Fibromyalgia may arise as a primary or secondary disease process. It is most frequent in females aged 20 to 50 years. (From Adams et al., Principles of Neurology, 6th ed, p1494-95)
  
• Fibromyalgia, Primary [M0335635]
  
• Fibromyalgia, Secondary [M0335636]
  
• Fibrosis, Liver [M0012637]
  
• Fibrous Dysplasia of Bone [M0008455]
  A disease of bone marked by thinning of the cortex and replacement of bone marrow by gritty fibrous tissue containing bony spicules, producing pain, disability, and gradually increasing deformity. Only one bone may be involved (FIBROUS DYSPLASIA, MONOSTOTIC) or several (FIBROUS DYSPLASIA, POLYOSTOTIC). (From Dorland, 28th ed)
  
• Fibrous Dysplasia, Polyostotic [M0008457]
  FIBROUS DYSPLASIA OF BONE affecting several or many bones. When associated with melanotic pigmentation of the skin and endocrine disorders, it is known as Albright's syndrome. (From Dorland, 28th ed)
  
• Fibular Neuropathy [M0336017]
  
• Filariasis [M0008468]
  Infections with nematodes of the superfamily FILARIOIDEA. The presence of living worms in the body is mainly asymptomatic but the death of adult worms leads to granulomatous inflammation and permanent fibrosis. Organisms of the genus Elaeophora infect wild elk and domestic sheep causing ischemic necrosis of the brain, blindness, and dermatosis of the face.
  
• Filoviridae Infections [M0028016]
  Infections with viruses of the family FILOVIRIDAE. The infections in humans consist of a variety of clinically similar viral hemorrhagic fevers but the natural reservoir host is unknown.
  
• Fish Diseases [M0008515]
  Diseases of freshwater, marine, hatchery or aquarium fish. This term includes diseases of both teleosts (true fish) and elasmobranchs (sharks, rays and skates).
  
• Fish-Eye Disease [M0487136]
  
• Flail Chest [M0008534]
  A complication of multiple rib fractures, rib and sternum fractures, or thoracic surgery. A portion of the chest wall becomes isolated from the thoracic cage and exhibits paradoxical respiration.
  
• Flaviviridae Infections [M0027405]
  Infections with viruses of the family FLAVIVIRIDAE.
  
• Flavivirus Infections [M0027404]
  Infections with viruses of the genus FLAVIVIRUS, family FLAVIVIRIDAE.
  
• Flavobacteriaceae Infections [M0449412]
  Infections with bacteria of the family FLAVOBACTERIACEAE.
  
• Flexibacteraceae Infections [M0449413]
  Infections with bacteria of the family FLEXIBACTERACEAE.
  
• Fluorosis, Dental [M0014119]
  A chronic endemic form of hypoplasia of the dental enamel caused by drinking water with a high fluorine content during the time of tooth formation, and characterized by defective calcification that gives a white chalky appearance to the enamel, which gradually undergoes brown discoloration. (Jablonski's Dictionary of Dentistry, 1992, p286)
  
• Focal Clonic Seizures [M0335062]
  
• Focal Dermal Hypoplasia [M0008655]
  A genetic skin disease characterized by hypoplasia of the dermis, herniations of fat, and hand anomalies. It is found exclusively in females and transmitted as an X-linked dominant trait.
  
• Focal Dystonia [M0334821]
  
• Focal Epithelial Hyperplasia [M0026635]
  Hyperplasia of the mucous membrane of the lips, tongue, and less commonly, the buccal mucosa, floor of the mouth, and palate, presenting soft, painless, round to oval sessile papules about 1 to 4 mm in diameter. The condition usually occurs in children and young adults and has familial predilection, lasting for several months, sometimes years, before running its course. A viral etiology is suspected, the isolated organism being usually the human papillomavirus. (Jablonski, Illustrated Dictionary of Dentistry; Belshe, Textbook of Human Virology, 2d ed, p954)
  
• Focal Infection [M0008656]
  
• Focal Nodular Hyperplasia [M0328479]
  Solitary or multiple benign hepatic vascular tumors, usually occurring in women of 20-50 years of age. The nodule, poorly encapsulated, consists of a central stellate fibrous scar and normal liver elements such as HEPATOCYTES, small BILE DUCTS, and KUPFFER CELLS among the intervening fibrous septa. The pale colored central scar represents large blood vessels with hyperplastic fibromuscular layer and narrowing lumen.
  
• Focal Sensory Seizure [M0335096]
  
• Focal Tonic Seizures [M0335066]
  
• Foley-Denny-Brown Syndrome [M0337845]
  
• Folic Acid Deficiency [M0008663]
  A nutritional condition produced by a deficiency of FOLIC ACID in the diet. Many plant and animal tissues contain folic acid, abundant in green leafy vegetables, yeast, liver, and mushrooms but destroyed by long-term cooking. Alcohol interferes with its intermediate metabolism and absorption. Folic acid deficiency may develop in long-term anticonvulsant therapy or with use of oral contraceptives. This deficiency causes anemia, macrocytic anemia, and megaloblastic anemia. It is indistinguishable from vitamin B 12 deficiency in peripheral blood and bone marrow findings, but the neurologic lesions seen in B 12 deficiency do not occur. (Merck Manual, 16th ed)
  
• Folliculitis [M0008668]
  Inflammation of follicles, primarily hair follicles.
  
• Food Hypersensitivity [M0008686]
  Gastrointestinal disturbances, skin eruptions, or shock due to allergic reactions to allergens in food.
  
• Foot Deformities, Congenital [M0008721]
  Alterations or deviations from normal shape or size which result in a disfigurement of the foot occurring at or before birth.
  
• Foot Dermatoses [M0008722]
  Skin diseases of the foot, general or unspecified.
  
• Foot Diseases [M0008723]
  Anatomical and functional disorders affecting the foot.
  
• Foot Rot [M0008724]
  A disease of the horny parts and of the adjacent soft structures of the feet of cattle, swine, and sheep. It is usually caused by Corynebacterium pyogenes or Bacteroides nodosus (see DICHELOBACTER NODOSUS). It is also known as interdigital necrobacillosis. (From Black's Veterinary Dictionary, 18th ed)
  
• Foot Ulcer [M0025219]
  Lesion on the surface of the skin of the foot, usually accompanied by inflammation. The lesion may become infected or necrotic and is frequently associated with diabetes or leprosy.
  
• Foot Ulcer, Diabetic [M0480794]
  
• Foot-and-Mouth Disease [M0008725]
  
• Foramen Ovale, Patent [M0009965]
  
• Foster-Kennedy Syndrome [M0336203]
  
• Fournier Gangrene [M0028303]
  An acute necrotic infection of the SCROTUM; PENIS; or PERINEUM. It is characterized by scrotum pain and redness with rapid progression to gangrene and sloughing of tissue. Fournier gangrene is usually secondary to perirectal or periurethral infections associated with local trauma, operative procedures, or urinary tract disease.
  
• Fourth Cranial Nerve Palsy [M0336338]
  
• Foville Syndrome [M0334263]
  
• Fowlpox [M0008794]
  A poxvirus infection of poultry and other birds characterized by the formation of wart-like nodules on the skin and diphtheritic necrotic masses (cankers) in the upper digestive and respiratory tracts.
  
• Fox-Fordyce Disease [M0008797]
  Chronic pruritic disease, usually in women, characterized by small follicular papular eruptions in apocrine areas. It is caused by obstruction and rupture of intraepidermal apocrine ducts. (From Dorland, 27th ed)
  
• Fractures, Spontaneous [M0008809]
  Fractures occurring as a result of disease of a bone or from some undiscoverable cause, and not due to trauma. (Dorland, 27th ed)
  
• Frasier Syndrome [M0391904]
  A syndrome characterized by CHRONIC KIDNEY FAILURE and GONADAL DYSGENESIS in phenotypic females with karyotype of 46,XY or 46,XX. It is caused by donor splice-site mutations of Wilms tumor suppressor gene (GENES, WILMS TUMOR) on chromosome 11.
  
• Freckles [M0013315]
  
• Freemartinism [M0008832]
  A condition occurring in the female offspring of dizygotic twins (TWIN, DIZYGOTIC) in a mixed-sex pregnancy, usually in CATTLE. Freemartinism can occur in other mammals. When placental fusion between the male and the female FETUSES permits the exchange of fetal cells and fetal hormones, TESTICULAR HORMONES from the male fetus can androgenize the female fetus producing a sterile XX/XY chimeric "female"(CHIMERISM).
  
• Friedreich Ataxia [M0008844]
  An autosomal recessive disease, usually of childhood onset, characterized pathologically by degeneration of the spinocerebellar tracts, posterior columns, and to a lesser extent the corticospinal tracts. Clinical manifestations include GAIT ATAXIA, pes cavus, speech impairment, lateral curvature of spine, rhythmic head tremor, kyphoscoliosis, congestive heart failure (secondary to a cardiomyopathy), and lower extremity weakness. Most forms of this condition are associated with a mutation in a gene on chromosome 9, at band q13, which codes for the mitochondrial protein frataxin. (From Adams et al., Principles of Neurology, 6th ed, p1081; N Engl J Med 1996 Oct 17;335(16):1169-75) The severity of Friedreich ataxia associated with expansion of GAA repeats in the first intron of the frataxin gene correlates with the number of trinucleotide repeats. (From Durr et al, N Engl J Med 1996 Oct 17;335(16):1169-75)
  
• Froehlich's Syndrome [M0010934]
  
• Frontal Epilepsy, Benign, Childhood [M0335008]
  
• Frontal Sinusitis [M0023882]
  Inflammation of the frontal sinus; in most cases the infection is caused by the bacteria STREPTOCOCCUS PNEUMONIAE and HAEMOPHILUS INFLUENZAE. This condition may be acute or chronic.
  
• Fructose Intolerance [M0008856]
  An autosomal recessive fructose metabolism disorder due to deficient fructose-1-phosphate aldolase (EC 2.1.2.13) activity, resulting in accumulation of fructose-1-phosphate. The accumulated fructose-1-phosphate inhibits glycogenolysis and gluconeogenesis, causing severe hypoglycemia following ingestion of fructose. Prolonged fructose ingestion in infants leads ultimately to hepatic failure and death. Patients develop a strong distaste for sweet food, and avoid a chronic course of the disease by remaining on a fructose- and sucrose-free diet.
  
• Fructose Metabolism, Inborn Errors [M0023586]
  Inherited abnormalities of fructose metabolism, which include three known autosomal recessive types: hepatic fructokinase deficiency (essential fructosuria), hereditary fructose intolerance, and hereditary fructose-1,6-diphosphatase deficiency. Essential fructosuria is a benign asymptomatic metabolic disorder caused by deficiency in fructokinase, leading to decreased conversion of fructose to fructose-1-phosphate and alimentary hyperfructosemia, but with no clinical dysfunction; may produce a false-positive diabetes test.
  
• Fructose-1,6-Diphosphatase Deficiency [M0023587]
  An autosomal recessive fructose metabolism disorder due to absent or deficient fructose-1,6-diphosphatase activity. Gluconeogenesis is impaired, resulting in accumulation of gluconeogenic precursors (e.g., amino acids, lactate, ketones) and manifested as hypoglycemia, ketosis, and lactic acidosis. Episodes in the newborn infant are often lethal. Later episodes are often brought on by fasting and febrile infections. As patients age through early childhood, tolerance to fasting improves and development becomes normal.
  
• Fuchs' Endothelial Dystrophy [M0008872]
  Disorder caused by loss of endothelium of the central cornea. It is characterized by hyaline endothelial outgrowths on Descemet's membrane, epithelial blisters, reduced vision, and pain.
  
• Fucosidosis [M0008875]
  An autosomal recessive lysosomal storage disease caused by a deficiency of ALPHA-L-FUCOSIDASE activity resulting in an accumulation of fucose containing SPHINGOLIPIDS; GLYCOPROTEINS, and mucopolysaccharides (GLYCOSAMINOGLYCANS) in lysosomes. The infantile form (type I) features psychomotor deterioration, MUSCLE SPASTICITY, coarse facial features, growth retardation, skeletal abnormalities, visceromegaly, SEIZURES, recurrent infections, and MACROGLOSSIA, with death occurring in the first decade of life. Juvenile fucosidosis (type II) is the more common variant and features a slowly progressive decline in neurologic function and angiokeratoma corporis diffusum. Type II survival may be through the fourth decade of life. (From Menkes, Textbook of Child Neurology, 5th ed, p87; Am J Med Genet 1991 Jan;38(1):111-31)
  
• Fucosidosis Type I [M0335151]
  
• Fucosidosis Type II [M0335152]
  
• Fulminant Hepatic Failure with Cerebral Edema [M0335277]
  
• Functional Gastrointestinal Disorders [M0443706]
  Chronic or recurrent gastrointestinal disorders without an identifiable structural or biochemical explanation by the routine diagnostic tests. Functional gastrointestinal disorders are classified according to the presumed site of the disorder, such as IRRITABLE BOWEL SYNDROME, non-ulcer DYSPEPSIA, and non-cardiac CHEST PAIN.
  
• Fungemia [M0025155]
  The presence of fungi circulating in the blood. Opportunistic fungal sepsis is seen most often in immunosuppressed patients with severe neutropenia or in postoperative patients with intravenous catheters and usually follows prolonged antibiotic therapy.
  
• Funisitis [M0481193]
  Inflammation of the fetal UMBILICAL CORD.
  
• Furunculosis [M0008903]
  A persistent skin infection marked by the presence of furuncles, often chronic and recurrent. In humans, the causative agent is various species of STAPHYLOCOCCUS. In salmonid fish (SALMONIDS), the pathogen is AEROMONAS SALMONICIDA.
  
• Fusobacteriaceae Infections [M0449411]
  Infections with bacteria of the family Fusobacteriaceae, in the order Fusobacterales, phylum FUSOBACTERIA.
  
• Fusobacterium Infections [M0008917]
  Infections with bacteria of the genus FUSOBACTERIUM.
  
• Gait Disorder, Sensorimotor [M0337770]
  
• Gait Disorders, Neurologic [M0328402]
  Gait abnormalities that are a manifestation of nervous system dysfunction. These conditions may be caused by a wide variety of disorders which affect motor control, sensory feedback, and muscle strength including: CENTRAL NERVOUS SYSTEM DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; or MUSCULAR DISEASES.
  
• Galactokinase Deficiency Disease [M0335204]
  
• Galactorrhea [M0008935]
  Excessive or inappropriate LACTATION in females or males, and not necessarily related to PREGNANCY. Galactorrhea can occur either unilaterally or bilaterally, and be profuse or sparse. Its most common cause is HYPERPROLACTINEMIA.
  
• Galactose-1-Phosphate Uridyl-Transferase Deficiency Disease [M0335205]
  
• Galactosemias [M0008941]
  A group of inherited enzyme deficiencies which feature elevations of GALACTOSE in the blood. This condition may be associated with deficiencies of GALACTOKINASE; UDPGLUCOSE-HEXOSE-1-PHOSPHATE URIDYLYLTRANSFERASE; or UDPGLUCOSE 4-EPIMERASE. The classic form is caused by UDPglucose-Hexose-1-Phosphate Uridylyltransferase deficiency, and presents in infancy with FAILURE TO THRIVE; VOMITING; and INTRACRANIAL HYPERTENSION. Affected individuals also may develop MENTAL RETARDATION; JAUNDICE; hepatosplenomegaly; ovarian failure (OVARIAN FAILURE, PREMATURE); and cataracts. (From Menkes, Textbook of Child Neurology, 5th ed, pp61-3)
  
• Gallbladder Diseases [M0008958]
  Diseases of the GALLBLADDER. They generally involve the impairment of BILE flow, GALLSTONES in the BILIARY TRACT, infections, neoplasms, or other diseases.
  
• Gallbladder Dyskinesia [M0455050]
  
• gamma-Chain Disease [M0009992]
  
• Gangliosidoses [M0008988]
  A group of autosomal recessive lysosomal storage disorders marked by the accumulation of GANGLIOSIDES. They are caused by impaired enzymes or defective cofactors required for normal ganglioside degradation in the LYSOSOMES. Gangliosidoses are classified by the specific ganglioside accumulated in the defective degradation pathway.
  
• Gangliosidoses, GM2 [M0328040]
  A group of recessively inherited diseases characterized by the intralysosomal accumulation of G(M2) GANGLIOSIDE in the neuronal cells. Subtypes include mutations of enzymes in the BETA-N-ACETYLHEXOSAMINIDASE system or G(M2) ACTIVATOR PROTEIN leading to disruption of normal degradation of GANGLIOSIDES, a subclass of ACIDIC GLYCOSPHINGOLIPIDS.
  
• Gangliosidosis, Generalized GM1, Type 1 [M0335232]
  
• Gangliosidosis, Generalized GM1, Type 2 [M0335233]
  
• Gangliosidosis, Generalized GM1, Type 3 [M0335231]
  
• Gangliosidosis, GM1 [M0025239]
  An autosomal recessive neurodegenerative disorder caused by the absence or deficiency of BETA-GALACTOSIDASE. It is characterized by intralysosomal accumulation of G(M1) GANGLIOSIDE and oligosaccharides, primarily in neurons of the central nervous system. The infantile form is characterized by MUSCLE HYPOTONIA, poor psychomotor development, HIRSUTISM, hepatosplenomegaly, and facial abnormalities. The juvenile form features HYPERACUSIS; SEIZURES; and psychomotor retardation. The adult form features progressive DEMENTIA; ATAXIA; and MUSCLE SPASTICITY. (From Menkes, Textbook of Child Neurology, 5th ed, pp96-7)
  
• Gangrene [M0008989]
  Death and putrefaction of tissue usually due to a loss of blood supply.
  
• Gangrene, Dental Pulp [M0005934]
  
• Gargoylism, Hurler Syndrome [M0012561]
  
• Gas Gangrene [M0008993]
  A severe condition resulting from bacteria invading healthy muscle from adjacent traumatized muscle or soft tissue. The infection originates in a wound contaminated with bacteria of the genus CLOSTRIDIUM. C. perfringens accounts for the majority of cases (over eighty percent), while C. noyvi, C. septicum, and C. histolyticum cause most of the other cases.
  
• Gastric Antral Vascular Ectasia [M0029917]
  A distinct vascular lesion in the PYLORIC ANTRUM that is characterized by tortuous dilated blood vessels (ectasia) radiating outward from the PYLORUS. The vessel pattern resembles the stripes on the surface of a watermelon. This lesion causes both acute and chronic GASTROINTESTINAL HEMORRHAGE.
  
• Gastric Dilatation [M0020541]
  Abnormal distention of the STOMACH due to accumulation of gastric contents that may reach 10 to 15 liters. Gastric dilatation may be the result of GASTRIC OUTLET OBSTRUCTION; ILEUS; GASTROPARESIS; or denervation.
  
• Gastric Outlet Obstruction [M0026129]
  The hindering of output from the STOMACH into the SMALL INTESTINE. This obstruction may be of mechanical or functional origin such as EDEMA from PEPTIC ULCER; NEOPLASMS; FOREIGN BODIES; or AGING.
  
• Gastric Varix [M0007744]
  
• Gastritis [M0009015]
  Inflammation of the GASTRIC MUCOSA, a lesion observed in a number of unrelated disorders.
  
• Gastritis, Atrophic [M0009016]
  GASTRITIS with atrophy of the GASTRIC MUCOSA, the GASTRIC PARIETAL CELLS, and the mucosal glands leading to ACHLORHYDRIA. Atrophic gastritis usually progresses from chronic gastritis.
  
• Gastritis, Hypertrophic [M0009017]
  GASTRITIS with HYPERTROPHY of the GASTRIC MUCOSA. It is characterized by giant gastric folds, diminished acid secretion, excessive MUCUS secretion, and HYPOPROTEINEMIA. Symptoms include VOMITING; DIARRHEA; and WEIGHT LOSS.
  
• Gastroenteritis [M0009018]
  INFLAMMATION of any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM. Causes of gastroenteritis are many including genetic, infection, HYPERSENSITIVITY, drug effects, and CANCER.
  
• Gastroenteritis, Transmissible, of Swine [M0009020]
  A condition of chronic gastroenteritis in adult pigs and fatal gastroenteritis in piglets caused by a CORONAVIRUS.
  
• Gastroesophageal Reflux [M0009024]
  Retrograde flow of gastric juice (GASTRIC ACID) and/or duodenal contents (BILE ACIDS; PANCREATIC JUICE) into the distal ESOPHAGUS, commonly due to incompetence of the LOWER ESOPHAGEAL SPHINCTER. Gastric regurgitation is an extension of this process with retrograde flow into the PHARYNX or MOUTH.
  
• Gastrointestinal Diseases [M0009033]
  Diseases in any segment of the GASTROINTESTINAL TRACT from ESOPHAGUS to RECTUM.
  
• Gastroparesis [M0027865]
  Chronic delayed gastric emptying. Gastroparesis may be caused by motor dysfunction or paralysis of STOMACH muscles or may be associated with other systemic diseases such as DIABETES MELLITUS.
  
• Gastroschisis [M0029878]
  A congenital defect with major fissure in the ABDOMINAL WALL lateral to, but not at, the UMBILICUS. This results in the extrusion of VISCERA. Unlike OMPHALOCELE, herniated structures in gastroschisis are not covered by a sac or PERITONEUM.
  
• Gaucher Disease [M0009048]
  An autosomal recessive disorder caused by a deficiency of acid beta-glucosidase (GLUCOSYLCERAMIDASE) leading to intralysosomal accumulation of glycosylceramide mainly in cells of the RETICULOENDOTHELIAL SYSTEM. The characteristic Gaucher cells, glycosphingolipid-filled HISTIOCYTES, displace normal cells in BONE MARROW and visceral organs causing skeletal deterioration, hepatosplenomegaly, and organ dysfunction. There are several subtypes based on the presence and severity of neurological involvement.
  
• Gaucher Disease, Type 1 [M0335236]
  This type afflicts both children and adults who show no neurological effect. It is more prevalent in people of Ashkenazi Jewish ancestry.
  
• Gaucher Disease, Type 2 [M0335237]
  This type usually shows severe neurological effect in the first year of life.
  
• Gaucher Disease, Type 3 [M0335238]
  This type shows moderate to severe neurological effect in childhood.
  
• Gelastic Epilepsy [M0334948]
  
• General Adaptation Syndrome [M0009072]
  The sum of all nonspecific systemic reactions of the body to long-continued exposure to systemic stress.
  
• General Paralysis [M0014772]
  
• Generalized Nonconvulsive Seizure Disorder [M0335030]
  
• Genetic Diseases, Inborn [M0385531]
  Diseases that are caused by genetic mutations present during embryo or fetal development, although they may be observed later in life. The mutations may be inherited from a parent's genome or they may be acquired in utero.
  
• Genetic Diseases, X-Linked [M0420489]
  Genetic diseases that are linked to gene mutations on the X CHROMOSOME in humans (X CHROMOSOME, HUMAN) or the X CHROMOSOME in other species. Included here are animal models of human X-linked diseases.
  
• Genetic Diseases, Y-Linked [M0473013]
  Genetic diseases that are linked to mutant ALLELES on the Y CHROMOSOME in humans (Y CHROMOSOME, HUMAN) or the Y chromosome in other species. Included here are animal models of human Y-linked diseases.
  
• Geniculate Ganglionitis [M0336031]
  
• Genital Diseases, Female [M0009154]
  Pathological processes involving the female reproductive tract (GENITALIA, FEMALE).
  
• Genital Diseases, Male [M0009155]
  Pathological processes involving the male reproductive tract (GENITALIA, MALE).
  
• Genital Infantilism [M0472166]
  
• Geotrichosis [M0009187]
  Infection due to the fungus Geotrichum.
  
• Gerstmann Syndrome [M0009211]
  A disorder of cognition characterized by the tetrad of finger agnosia, dysgraphia, dyscalculia, and right-left disorientation. The syndrome may be developmental or acquired. Acquired Gerstmann syndrome is associated with lesions in the dominant (usually left) PARIETAL LOBE which involve the angular gyrus or subjacent white matter. (From Adams et al., Principles of Neurology, 6th ed, p457)
  
• Gerstmann-Straussler-Scheinker Disease [M0024593]
  An autosomal dominant familial prion disease with a wide spectrum of clinical presentations including ATAXIA, spastic paraparesis, extrapyramidal signs, and DEMENTIA. Clinical onset is in the third to sixth decade of life and the mean duration of illness prior to death is five years. Several kindreds with variable clinical and pathologic features have been described. Pathologic features include cerebral prion protein amyloidosis, and spongiform or neurofibrillary degeneration. (From Brain Pathol 1998 Jul;8(3):499-513; Brain Pathol 1995 Jan;5(1):61-75)
  
• Gianotti-Crosti Syndrome [M0000258]
  
• Giant Intracranial Aneurysm [M0335410]
  
• Giant Lymph Node Hyperplasia [M0009222]
  Large benign, hyperplastic lymph nodes. The more common hyaline vascular subtype is characterized by small hyaline vascular follicles and interfollicular capillary proliferations. Plasma cells are often present and represent another subtype with the plasma cells containing IgM and IMMUNOGLOBULIN A.
  
• Giardiasis [M0009224]
  An infection of the SMALL INTESTINE caused by the flagellated protozoan GIARDIA LAMBLIA. It is spread via contaminated food and water and by direct person-to-person contact.
  
• Gigantism [M0009228]
  The condition of accelerated and excessive GROWTH in children or adolescents who are exposed to excess HUMAN GROWTH HORMONE before the closure of EPIPHYSES. It is usually caused by somatotroph hyperplasia or a GROWTH HORMONE-SECRETING PITUITARY ADENOMA. These patients are of abnormally tall stature, more than 3 standard deviations above normal mean height for age.
  
• Gilbert Disease [M0009229]
  A benign familial disorder, transmitted as an autosomal dominant trait. It is characterized by low-grade chronic hyperbilirubinemia with considerable daily fluctuations of the bilirubin level.
  
• Gingival Diseases [M0009233]
  
• Gingival Hyperplasia [M0009238]
  Non-inflammatory enlargement of the gingivae produced by factors other than local irritation. It is characteristically due to an increase in the number of cells. (From Jablonski's Dictionary of Dentistry, 1992, p400)
  
• Gingival Hypertrophy [M0009239]
  Abnormal enlargement or overgrowth of the gingivae brought about by enlargement of existing cells.
  
• Gingival Overgrowth [M0028618]
  Excessive growth of the gingiva either by an increase in the size of the constituent cells (GINGIVAL HYPERTROPHY) or by an increase in their number (GINGIVAL HYPERPLASIA). (From Jablonski's Dictionary of Dentistry, 1992, p574)
  
• Gingival Recession [M0009243]
  The exposure of root surface by an apical shift in the position of the gingiva.
  
• Gingivitis [M0009245]
  
• Gingivitis, Necrotizing Ulcerative [M0009246]
  An acute or chronic GINGIVITIS characterized by redness and swelling, NECROSIS extending from the interdental papillae along the gingival margins, PAIN; HEMORRHAGE, necrotic odor, and often a pseudomembrane. The condition may extend to the ORAL MUCOSA; TONGUE; PALATE; or PHARYNX. The etiology is somewhat unclear, but may involve a complex of FUSOBACTERIUM NUCLEATUM along with spirochetes BORRELIA or TREPONEMA.
  
• Gingivosis [M0009234]
  
• Gingivostomatitis, Herpetic [M0020555]
  
• Gitelman Syndrome [M0494801]
  An inherited renal disorder characterized by defective NaCl reabsorption in the convoluted DISTAL KIDNEY TUBULE leading to HYPOKALEMIA. In contrast with BARTTER SYNDROME, Gitelman syndrome includes hypomagnesemia and normocalcemic hypocalciuria and is caused by mutations in the thiazide-sensitive SODIUM CHLORIDE COTRANSPORTER.
  
• Glanders [M0009255]
  A contagious disease of horses that can be transmitted to humans. It is caused by BURKHOLDERIA MALLEI and characterized by ulceration of the respiratory mucosa and an eruption of nodules on the skin.
  
• Glaucoma [M0009260]
  An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)
  
• Glaucoma, Angle-Closure [M0024213]
  A form of glaucoma in which the intraocular pressure increases because the angle of the anterior chamber is blocked and the aqueous humor cannot drain from the anterior chamber.
  
• Glaucoma, Neovascular [M0023640]
  A form of secondary glaucoma which develops as a consequence of another ocular disease and is attributed to the forming of new vessels in the angle of the anterior chamber.
  
• Glaucoma, Open-Angle [M0009261]
  Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
  
• Glaucoma, Suspect [M0015212]
  
• Glenohumeral Subluxation [M0495741]
  
• Glomerular Necrosis [M0490226]
  
• Glomerulonephritis [M0009300]
  Inflammation of the renal glomeruli (KIDNEY GLOMERULUS) that can be classified by the type of glomerular injuries including antibody deposition, complement activation, cellular proliferation, and glomerulosclerosis. These structural and functional abnormalities usually lead to HEMATURIA; PROTEINURIA; HYPERTENSION; and RENAL INSUFFICIENCY.
  
• Glomerulonephritis, IGA [M0009301]
  A chronic form of glomerulonephritis characterized by deposits of predominantly IMMUNOGLOBULIN A in the mesangial area (GLOMERULAR MESANGIUM). Deposits of COMPLEMENT C3 and IMMUNOGLOBULIN G are also often found. Clinical features may progress from asymptomatic HEMATURIA to END-STAGE KIDNEY DISEASE.
  
• Glomerulonephritis, Membranoproliferative [M0023780]
  Chronic glomerulonephritis characterized histologically by proliferation of MESANGIAL CELLS, increase in the MESANGIAL EXTRACELLULAR MATRIX, and a thickening of the glomerular capillary walls. This may appear as a primary disorder or secondary to other diseases including infections and autoimmune disease SYSTEMIC LUPUS ERYTHEMATOSUS. Various subtypes are classified by their abnormal ultrastructures and immune deposits. Hypocomplementemia is a characteristic feature of all types of MPGN.
  
• Glomerulonephritis, Membranous [M0023781]
  A type of glomerulonephritis that is characterized by the accumulation of immune deposits (COMPLEMENT MEMBRANE ATTACK COMPLEX) on the outer aspect of the GLOMERULAR BASEMENT MEMBRANE. It progresses from subepithelial dense deposits, to basement membrane reaction and eventual thickening of the basement membrane.
  
• Glomerulonephritis, Minimal Change [M0491069]
  
• Glomerulosclerosis, Focal Segmental [M0009302]
  A clinicopathological syndrome or diagnostic term for a type of glomerular injury that has multiple causes, primary or secondary. Clinical features include PROTEINURIA, reduced GLOMERULAR FILTRATION RATE, and EDEMA. Kidney biopsy initially indicates focal segmental glomerular consolidation (hyalinosis) or scarring which can progress to globally sclerotic glomeruli leading to eventual KIDNEY FAILURE.
  
• Glossitis [M0009309]
  Inflammation of the tongue.
  
• Glossitis, Benign Migratory [M0009310]
  An idiopathic disorder characterized by the loss of filiform papillae leaving reddened areas of circinate macules bound by a white band. The lesions heal, then others erupt.
  
• Glossopharyngeal Motor Neuropathy [M0392793]
  
• Glossopharyngeal Nerve Diseases [M0328066]
  Diseases of the ninth cranial (glossopharyngeal) nerve or its nuclei in the medulla. The nerve may be injured by diseases affecting the lower brain stem, floor of the posterior fossa, jugular foramen, or the nerve's extracranial course. Clinical manifestations include loss of sensation from the pharynx, decreased salivation, and syncope. Glossopharyngeal neuralgia refers to a condition that features recurrent unilateral sharp pain in the tongue, angle of the jaw, external auditory meatus and throat that may be associated with SYNCOPE. Episodes may be triggered by cough, sneeze, swallowing, or pressure on the tragus of the ear. (Adams et al., Principles of Neurology, 6th ed, p1390)
  
• Glossopharyngeal Nerve Sensory Neuropathy [M0392792]
  
• Glossopharyngeal Nerve Taste Disorder [M0336132]
  
• Glossopharyngeal Neuralgia [M0336131]
  
• Glucose Intolerance [M0027356]
  A pathological state in which BLOOD GLUCOSE level is less than approximately 140 mg/100 ml of PLASMA at fasting, and above approximately 200 mg/100 ml plasma at 30-, 60-, or 90-minute during a GLUCOSE TOLERANCE TEST. This condition is seen frequently in DIABETES MELLITUS, but also occurs with other diseases and MALNUTRITION.
  
• Glucose Metabolism Disorders [M0446458]
  Pathological conditions in which the BLOOD GLUCOSE cannot be maintained within the normal range, such as in HYPOGLYCEMIA and HYPERGLYCEMIA. Etiology of these disorders varies. Plasma glucose concentration is critical to survival for it is the predominant fuel for the CENTRAL NERVOUS SYSTEM.
  
• Glucosephosphate Dehydrogenase Deficiency [M0009353]
  A disease-producing enzyme deficiency subject to many variants, some of which cause a deficiency of enzyme activity in erythrocytes, leading to hemolytic anemia.
  
• Glycogen Storage Disease [M0009469]
  A group of inherited metabolic disorders involving the enzymes responsible for the synthesis and degradation of glycogen. In some patients, prominent liver involvement is presented. In others, more generalized storage of glycogen occurs, sometimes with prominent cardiac involvement.
  
• Glycogen Storage Disease Type I [M0009351]
  An autosomal recessive disease in which gene expression of glucose-6-phosphatase is absent, resulting in hypoglycemia due to lack of glucose production. Accumulation of glycogen in liver and kidney leads to organomegaly, particularly massive hepatomegaly. Increased concentrations of lactic acid and hyperlipidemia appear in the plasma. Clinical gout often appears in early childhood.
  
• Glycogen Storage Disease Type II [M0009470]
  An autosomal recessively inherited glycogen storage disease caused by GLUCAN 1,4-ALPHA-GLUCOSIDASE deficiency. Large amounts of GLYCOGEN accumulate in the LYSOSOMES of skeletal muscle (MUSCLE, SKELETAL); HEART; LIVER; SPINAL CORD; and BRAIN. Three forms have been described: infantile, childhood, and adult. The infantile form is fatal in infancy and presents with hypotonia and a hypertrophic cardiomyopathy (CARDIOMYOPATHY, HYPERTROPHIC). The childhood form usually presents in the second year of life with proximal weakness and respiratory symptoms. The adult form consists of a slowly progressive proximal myopathy. (From Muscle Nerve 1995;3:S61-9; Menkes, Textbook of Child Neurology, 5th ed, pp73-4)
  
• Glycogen Storage Disease Type II, Infantile [M0335241]
  
• Glycogen Storage Disease Type II, Juvenile [M0335242]
  
• Glycogen Storage Disease Type IIb [M0483279]
  An X-linked dominant multisystem disorder resulting in cardiomyopathy, myopathy and MENTAL RETARDATION. It is caused by mutation in the gene encoding LYSOSOMAL-ASSOCIATED MEMBRANE PROTEIN 2.
  
• Glycogen Storage Disease Type III [M0009471]
  An autosomal recessive metabolic disorder due to deficient expression of amylo-1,6-glucosidase (one part of the glycogen debranching enzyme system). The clinical course of the disease is similar to that of glycogen storage disease type I, but milder. Massive hepatomegaly, which is present in young children, diminishes and occasionally disappears with age. Levels of glycogen with short outer branches are elevated in muscle, liver, and erythrocytes. Six subgroups have been identified, with subgroups Type IIIa and Type IIIb being the most prevalent.
  
• Glycogen Storage Disease Type IV [M0009472]
  An autosomal recessive metabolic disorder due to a deficiency in expression of GLYCOGEN BRANCHING ENZYME 1 (alpha-1,4-glucan-6-alpha-glucosyltransferase), resulting in an accumulation of abnormal GLYCOGEN with long outer branches. Clinical features are MUSCLE HYPOTONIA and CIRRHOSIS. Death from liver disease usually occurs before age 2.
  
• Glycogen Storage Disease Type V [M0009473]
  Glycogenosis due to muscle phosphorylase deficiency. Characterized by painful cramps following sustained exercise.
  
• Glycogen Storage Disease Type VI [M0009474]
  A hepatic GLYCOGEN STORAGE DISEASE in which there is an apparent deficiency of hepatic phosphorylase (GLYCOGEN PHOSPHORYLASE, LIVER FORM) activity.
  
• Glycogen Storage Disease Type VII [M0009475]
  An autosomal recessive glycogen storage disease in which there is deficient expression of 6-phosphofructose 1-kinase in muscle (PHOSPHOFRUCTOKINASE-1, MUSCLE TYPE) resulting in abnormal deposition of glycogen in muscle tissue. These patients have severe congenital muscular dystrophy and are exercise intolerant.
  
• Glycogen Storage Disease Type VIII [M0009476]
  An x-linked recessive hepatic glycogen storage disease resulting from lack of expression of phosphorylase-b-kinase activity. Symptoms are relatively mild; hepatomegaly, increased liver glycogen, and decreased leukocyte phosphorylase are present. Liver shrinkage occurs in response to glucagon.
  
• Glycosuria [M0009502]
  The appearance of an abnormally large amount of GLUCOSE in the urine, such as more than 500 mg/day in adults. It can be due to HYPERGLYCEMIA or genetic defects in renal reabsorption (RENAL GLYCOSURIA).
  
• Glycosuria, Renal [M0009503]
  An autosomal inherited disorder due to defective reabsorption of GLUCOSE by the PROXIMAL RENAL TUBULES. The urinary loss of glucose can reach beyond 50 g/day. It is attributed to the mutations in the SODIUM-GLUCOSE TRANSPORTER 2 encoded by the SLC5A2 gene.
  
• Goat Diseases [M0023872]
  Diseases of the domestic or wild goat of the genus Capra.
  
• Goiter [M0009516]
  Enlargement of the THYROID GLAND that may increase from about 20 grams to hundreds of grams in human adults. Goiter is observed in individuals with normal thyroid function (euthyroidism), thyroid deficiency (HYPOTHYROIDISM), or hormone overproduction (HYPERTHYROIDISM). Goiter may be congenital or acquired, sporadic or endemic (GOITER, ENDEMIC).
  
• Goiter, Endemic [M0009517]
  A form of IODINE deficiency disorders characterized by an enlargement of the THYROID GLAND in a significantly large fraction of a POPULATION GROUP. Endemic goiter is common in mountainous and iodine-deficient areas of the world where the DIET contains insufficient amount of iodine.
  
• Goiter, Intrathoracic [M0009520]
  A goiter that grows behind the STERNUM and CLAVICLE.
  
• Goiter, Nodular [M0009518]
  An enlarged THYROID GLAND containing multiple nodules (THYROID NODULE), usually resulting from recurrent thyroid HYPERPLASIA and involution over many years to produce the irregular enlargement. Multinodular goiters may be nontoxic or may induce THYROTOXICOSIS.
  
• Goiter, Substernal [M0009519]
  An enlarged THYROID GLAND with at least 50% of the gland situated behind the STERNUM. It is an unusual presentation of an intrathoracic goiter. Substernal goiters frequently cause compression on the TRACHEA leading to deviation, narrowing, and respiratory symptoms.
  
• Goldenhar Syndrome [M0009531]
  Mandibulofacial dysostosis with congenital eyelid dermoids.
  
• Gonadal Disorders [M0009536]
  Pathological processes of the OVARIES or the TESTES.
  
• Gonadal Dysgenesis [M0009537]
  A number of syndromes with defective gonadal developments such as streak gonads and dysgenetic testes. The spectrum of gonadal and sexual abnormalities is reflected in their varied sex chromosome (SEX CHROMOSOMES) constitution as shown by the karyotypes of 45,X monosomy (TURNER SYNDROME); 46,XX (GONADAL DYSGENESIS, 46XX); 46,XY (GONADAL DYSGENESIS, 46,XY); and sex chromosome MOSAICISM; (GONADAL DYSGENESIS, MIXED). Their phenotypes range from female, through ambiguous, to male. This concept includes gonadal agenesis.
  
• Gonadal Dysgenesis, 45,X [M0022171]
  
• Gonadal Dysgenesis, 46,XX [M0368823]
  The 46,XX gonadal dysgenesis may be sporadic or familial. Familial XX gonadal dysgenesis is transmitted as an autosomal recessive trait and its locus was mapped to chromosome 2. Mutation in the gene for the FSH receptor (RECEPTORS, FSH) was detected. Sporadic XX gonadal dysgenesis is heterogeneous and has been associated with trisomy-13 and trisomy-18. These phenotypic females are characterized by a normal stature, sexual infantilism, bilateral streak gonads, amenorrhea, elevated plasma LUTEINIZING HORMONE and FSH concentration. The syndrome is sometimes called "pure gonadal dysgenesis," but this designation may also refer to gonadal dysgenesis with a 46,XY karyotype (GONADAL DYSGENESIS, 46,XY).
  
• Gonadal Dysgenesis, 46,XY [M0009539]
  This type of gonadal defect is characterized by a female phenotype, normal to tall stature, bilateral streak or dysgenetic gonads, and a 46,XY karyotype. This XY gonadal dysgenesis is a heterogenous condition with variant forms resulting from a structural abnormality on Y chromosome, a mutation in SRY gene or a mutation in autosomal genes. The syndrome is sometimes called "pure gonadal dysgenesis," but this designation may also refer to gonadal dysgenesis with a 46,XX karyotype (GONADAL DYSGENESIS, 46,XX).
  
• Gonadal Dysgenesis, Mixed [M0009538]
  A type of defective gonadal development in patients with a wide spectrum of chromosomal mosaic variants. Their karyotypes are of partial sex chromosome monosomy resulting from an absence or an abnormal second sex chromosome (X or Y). Karyotypes include 45,X/46,XX; 45,X/46,XX/47,XXX; 46,XXp-; 45,X/46,XY; 45,X/47,XYY; 46,XYpi; etc. The spectrum of phenotypes may range from phenotypic female through pseudohermaphrodite to phenotypic male, depending on the ratio in each gonad of 45,X primordial germ cells to those with normal 46,XX or 46,XY constitution.
  
• Gonadotropin-Resistant Ovary Syndrome [M0025371]
  A form of ovarian failure, caused by resistance to GONADOTROPINS stimulation. It may be caused by defects in the receptors for FOLLICLE STIMULATING HORMONE or LUTEINIZING HORMONE. It may be due to factors interfering with the actions of gonadotropins, such as antibodies blocking the ligand-receptor interaction.
  
• Gonorrhea [M0009553]
  Acute infectious disease characterized by primary invasion of the urogenital tract. The etiologic agent, NEISSERIA GONORRHOEAE, was isolated by Neisser in 1879.
  
• Gout [M0009557]
  Hereditary metabolic disorder characterized by recurrent acute arthritis, hyperuricemia and deposition of sodium urate in and around the joints, sometimes with formation of uric acid calculi.
  
• Graft vs Host Disease [M0009578]
  The clinical entity characterized by anorexia, diarrhea, loss of hair, leukopenia, thrombocytopenia, growth retardation, and eventual death brought about by the GRAFT VS HOST REACTION.
  
• Gram-Negative Bacterial Infections [M0025725]
  Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.
  
• Gram-Positive Bacterial Infections [M0025728]
  Infections caused by bacteria that retain the crystal violet stain (positive) when treated by the gram-staining method.
  
• Grand Mal Status Epilepticus [M0336170]
  
• Granular Dystrophy, Corneal [M0005179]
  
• Granuloma Annulare [M0025146]
  Benign granulomatous disease of unknown etiology characterized by a ring of localized or disseminated papules or nodules on the skin and palisading histiocytes surrounding necrobiotic tissue resulting from altered collagen structures.
  
• Granuloma Gangraenescens [M0009612]
  
• Granuloma Inguinale [M0009606]
  Anogenital ulcers caused by Calymmatobacterium granulomatis as distinguished from lymphogranuloma inguinale (see LYMPHOGRANULOMA VENEREUM) caused by CHLAMYDIA TRACHOMATIS. Diagnosis is made by demonstration of typical intracellular Donovan bodies in crushed-tissue smears.
  
• Granuloma, Giant Cell Reparative [M0009609]
  
• Granuloma, Lethal Midline [M0009611]
  A non-neoplastic disease of unknown etiology beginning with inflammation, ulceration, and perforation of nose and palate and progressing to gradual destruction of midline facial structures.
  
• Granuloma, Plasma Cell, Pulmonary [M0025468]
  A pseudotumor of the lung composed of inflammatory cells and showing complete maturity of fibroblastic components with a striking lack of mitosis. It is also called postinflammatory pseudotumor and pseudoneoplastic pneumonitis. (Surg Gynecol Obstet 1983 Jan;156(1):89-96)
  
• Granuloma, Pyogenic [M0026877]
  A disorder of the skin, the oral mucosa, and the gingiva, that usually presents as a solitary polypoid capillary hemangioma often resulting from trauma. It is manifested as an inflammatory response with similar characteristics to those of a granuloma.
  
• Granulomatosis, Orofacial [M0479965]
  A condition characterized by persistent or recurrent labial enlargement, ORAL ULCER, and other orofacial manifestations in the absence of identifiable CROHN DISEASE; or SARCOIDOSIS. There is no consensus on whether orofacial granulomatosis is a distinct clinical disorder or an initial presentation of Crohn disease.
  
• Granulomatous Angiitis [M0335300]
  
• Granulomatous Cheilitis [M0393307]
  
• Granulomatous Disease, Chronic [M0009615]
  A recessive X-linked defect of leukocyte function in which phagocytic cells ingest but fail to digest bacteria, resulting in recurring bacterial infections with granuloma formation.
  
• Granulomatous Rosacea [M0461567]
  A variant of rosacea.
  
• Granulomous Cerebral Cryptococcosis [M0335658]
  
• Graves Disease [M0009624]
  A common form of hyperthyroidism with a diffuse hyperplastic GOITER. It is an autoimmune disorder that produces antibodies against the THYROID STIMULATING HORMONE RECEPTOR. These autoantibodies activate the TSH receptor, thereby stimulating the THYROID GLAND and hypersecretion of THYROID HORMONES. These autoantibodies can also affect the eyes (GRAVES OPHTHALMOPATHY) and the skin (Graves dermopathy).
  
• Graves Ophthalmopathy [M0009625]
  An autoimmune disorder of the EYE, occurring in patients with Graves disease. Subtypes include congestive (inflammation of the orbital connective tissue), myopathic (swelling and dysfunction of the extraocular muscles), and mixed congestive-myopathic ophthalmopathy.
  
• Groenouw's Dystrophies [M0005180]
  
• Gronblad-Strandberg Syndrome [M0017969]
  
• Guillain-Barre Syndrome [M0017242]
  An acute inflammatory autoimmune neuritis caused by T cell- mediated cellular immune response directed towards peripheral myelin. Demyelination occurs in peripheral nerves and nerve roots. The process is often preceded by a viral or bacterial infection, surgery, immunization, lymphoma, or exposure to toxins. Common clinical manifestations include progressive weakness, loss of sensation, and loss of deep tendon reflexes. Weakness of respiratory muscles and autonomic dysfunction may occur. (From Adams et al., Principles of Neurology, 6th ed, pp1312-1314)
  
• Gustatory Partial Seizure [M0335084]
  
• Guyon Syndrome [M0336235]
  
• Gynatresia [M0009714]
  Absence of a normal opening in the lumen of the female genital tract, from the FALLOPIAN TUBES to the VAGINA. This anomaly may be congenital or acquired due to injuries, diseases, or adhesions.
  
• Gynecomastia [M0009717]
  Enlargement of the BREAST in the males, caused by an excess of ESTROGENS. Physiological gynecomastia is normally observed in NEWBORNS; ADOLESCENT; and AGING males.
  
• Gyrate Atrophy [M0024200]
  Progressive, autosomal recessive, diffuse atrophy of the choroid, pigment epithelium, and sensory retina that begins in childhood.
  
• Habermann's Disease [M0026576]
  
• Habronemiasis [M0026108]
  
• Haemobartonellosis [M0001082]
  
• Haemonchiasis [M0009736]
  Infection with nematodes of the genus HAEMONCHUS, characterized by digestive abnormalities and anemia similar to that from hookworm infestation.
  
• Haemophilus Infections [M0009740]
  Infections with bacteria of the genus HAEMOPHILUS.
  
• Haemophilus influenzae Meningitis Type B [M0335664]
  
• Hair Diseases [M0009750]
  Diseases affecting the orderly growth and persistence of hair.
  
• Hajdu-Cheney Syndrome [M0015540]
  Rare, autosomal dominant syndrome characterized by ACRO-OSTEOLYSIS, generalized OSTEOPOROSIS, and skull deformations.
  
• Hallervorden-Spatz Syndrome [M0009761]
  A rare autosomal recessive degenerative disorder which usually presents in late childhood or adolescence. Clinical manifestations include progressive MUSCLE SPASTICITY; hyperreflexia; MUSCLE RIGIDITY; DYSTONIA; DYSARTHRIA; and intellectual deterioration which progresses to severe dementia over several years. Pathologic examination reveals neuronal atrophy in the globus pallidus and iron deposition in blood vessels and perivascular spaces. (From Adams et al., Principles of Neurology, 6th ed, p972; Davis & Robertson, Textbook of Neuropathology, 2nd ed, pp972-929)
  
• Hallopeau-Siemens Disease [M0024602]
  
• Hamartoma [M0009774]
  A focal malformation resembling a neoplasm, composed of an overgrowth of mature cells and tissues that normally occur in the affected area.
  
• Hand Dermatoses [M0009782]
  
• Hand, Foot and Mouth Disease [M0009785]
  A mild, highly infectious viral disease of children, characterized by vesicular lesions in the mouth and on the hands and feet. It is caused by coxsackieviruses A.
  
• Hand-Arm Vibration Syndrome [M0492992]
  An occupational disorder resulting from prolonged exposure to vibration, affecting the fingers, hands, and forearms. It occurs in workers who regularly use vibrating tools such as jackhammers, power chain saws, riveters, etc. Symptoms include episodic finger blanching, NUMBNESS, tingling, and loss of nerve sensitivity.
  
• Hantavirus Infections [M0028114]
  Infections with viruses of the genus HANTAVIRUS. This is associated with at least four clinical syndromes: HEMORRHAGIC FEVER WITH RENAL SYNDROME caused by viruses of the Hantaan group; a milder form of HFRS caused by SEOUL VIRUS; nephropathia epidemica caused by PUUMALA VIRUS; and HANTAVIRUS PULMONARY SYNDROME caused by SIN NOMBRE VIRUS.
  
• Hantavirus Pulmonary Syndrome [M0028154]
  Acute respiratory illness in humans caused by the Muerto Canyon virus whose primary rodent reservoir is the deer mouse Peromyscus maniculatus. First identified in the southwestern United States, this syndrome is characterized most commonly by fever, myalgias, headache, cough, and rapid respiratory failure.
  
• Harlequin Fetus [M0026533]
  
• Hartnup Disease [M0009808]
  An autosomal recessive disorder due to defective absorption of NEUTRAL AMINO ACIDS by both the intestine and the PROXIMAL RENAL TUBULES. The abnormal urinary loss of TRYPTOPHAN, a precursor of NIACIN, leads to a NICOTINAMIDE deficiency, PELLAGRA-like light-sensitive rash, CEREBELLAR ATAXIA, emotional instability, and aminoaciduria. Mutations involve the neurotransmitter transporter gene SLC6A19.
  
• Hashimoto Disease [M0472027]
  Chronic autoimmune thyroiditis, characterized by the presence of high serum thyroid AUTOANTIBODIES; GOITER; and HYPOTHYROIDISM.
  
• Hashish Abuse [M0003277]
  
• Headache Disorders [M0328324]
  Various conditions with the symptom of HEADACHE. Headache disorders are classified into major groups, such as PRIMARY HEADACHE DISORDERS (based on characteristics of their headache symptoms) and SECONDARY HEADACHE DISORDERS (based on their etiologies). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
  
• Headache Disorders, Primary [M0480011]
  Conditions in which the primary symptom is HEADACHE and the headache cannot be attributed to any known causes.
  
• Headache Disorders, Secondary [M0480012]
  Conditions with HEADACHE symptom that can be attributed to a variety of causes including BRAIN VASCULAR DISORDERS; WOUNDS AND INJURIES; INFECTION; drug use or its withdrawal.
  
• Headache, Intractable [M0335253]
  
• Hearing Disorders [M0009926]
  Conditions that impair the transmission of auditory impulses and information from the level of the ear to the temporal cortices, including the sensorineural pathways.
  
• Hearing Loss, Bilateral [M0009927]
  Partial hearing loss in both ears.
  
• Hearing Loss, Central [M0009928]
  Hearing loss due to disease of the AUDITORY PATHWAYS (in the CENTRAL NERVOUS SYSTEM) which originate in the COCHLEAR NUCLEI of the PONS and then ascend bilaterally to the MIDBRAIN, the THALAMUS, and then the AUDITORY CORTEX in the TEMPORAL LOBE. Bilateral lesions of the auditory pathways are usually required to cause central hearing loss. Cortical deafness refers to loss of hearing due to bilateral auditory cortex lesions. Unilateral BRAIN STEM lesions involving the cochlear nuclei may result in unilateral hearing loss.
  
• Hearing Loss, Cochlear [M0452653]
  
• Hearing Loss, Conductive [M0009929]
  Hearing loss due to interference with the mechanical reception or amplification of sound to the COCHLEA. The interference is in the outer or middle ear involving the EAR CANAL; TYMPANIC MEMBRANE; or EAR OSSICLES.
  
• Hearing Loss, Extreme [M0005695]
  
• Hearing Loss, High-Frequency [M0009931]
  Hearing loss in frequencies above 1000 hertz.
  
• Hearing Loss, Mixed Conductive-Sensorineural [M0452654]
  Hearing loss due to damage or impairment of both the conductive elements (HEARING LOSS, CONDUCTIVE) and the sensorineural elements (HEARING LOSS, SENSORINEURAL) of the ear.
  
• Hearing Loss, Sensorineural [M0009934]
  Hearing loss resulting from damage to the COCHLEA and the sensorineural elements which lie internally beyond the oval and round windows. These elements include the AUDITORY NERVE and its connections in the BRAINSTEM.
  
• Hearing Loss, Sudden [M0413169]
  Sensorineural hearing loss which develops suddenly over a period of hours or a few days. It varies in severity from mild to total deafness. Sudden deafness can be due to head trauma, vascular diseases, infections, or can appear without obvious cause or warning.
  
• Hearing Loss, Unilateral [M0452651]
  Partial or complete hearing loss in one ear.
  
• Heart Aneurysm [M0009937]
  An aneurysmal dilatation of a portion of the wall of the ventricle, usually the left, or, rarely, a saccular protrusion through it (false aneurysm of the heart). It is usually consequent to myocardial infarction but other causes such as bacterial endocarditis or trauma have been described. (Dorland, 28th ed)
  
• Heart Block [M0009945]
  Impairment of conduction in heart excitation. It is often applied specifically to atrioventricular heart block. (Dorland, 27th ed)
  
• Heart Defects, Congenital [M0009950]
  Imperfections or malformations of the heart, existing at birth.
  
• Heart Diseases [M0009951]
  
• Heart Failure, Congestive [M0009953]
  A complication of HEART DISEASES. Defective cardiac filling and/or impaired contraction and emptying, resulting in the heart's inability to pump a sufficient amount of blood to meet the needs of the body tissues or to be able to do so only with an elevated filling pressure. (from Braunwald, Heart Disease, 5th ed)
  
• Heart Rupture [M0009962]
  Laceration or tearing of the walls of the heart, of the interatrial or interventricular septum, of the papillary muscles or chordae tendineae, or of any of the valves of the heart. Rupture may be due to a variety of pathological entities, however, the majority are secondary to myocardial infarction (HEART RUPTURE, POST-INFARCTION).
  
• Heart Rupture, Post-Infarction [M0009963]
  Rupture of the heart after myocardial infarction.
  
• Heart Septal Defects [M0009964]
  Defects in the cardiac septa, resulting in abnormal communications between the opposite chambers of the heart.
  
• Heart Septal Defects, Ventricular [M0009967]
  Congenital defects in the septum between the cardiac ventricles, most often due to failure of the bulbar septum to completely close the interventricular foramen.
  
• Heart Valve Diseases [M0009972]
  Diseases caused by or resulting in abnormal functioning of heart valves.
  
• Heart Valve Prolapse [M0024629]
  Displacement of the valves of the heart.
  
• Heartwater Disease [M0009981]
  A tick-borne septicemic disease of domestic and wild ruminants caused by EHRLICHIA RUMINANTIUM.
  
• Heavy Chain Disease [M0009991]
  A disorder of immunoglobulin synthesis in which large quantities of abnormal heavy chains are excreted in the urine. The amino acid sequences of the N-(amino-) terminal regions of these chains are normal, but they have a deletion extending from part of the variable domain through the first domain of the constant region, so that they cannot form cross-links to the light chains. The defect arises through faulty coupling of the variable (V) and constant (C) region genes.
  
• Heel Spur [M0411531]
  A bony outgrowth on the lower surface of the CALCANEUS. Though often presenting along with plantar fasciitis (FASCIITIS, PLANTAR), they are not considered causally related.
  
• Heel Spur Syndrome [M0411530]
  
• Helicobacter Infections [M0025165]
  Infections with organisms of the genus HELICOBACTER, particularly, in humans, HELICOBACTER PYLORI. The clinical manifestations are focused in the stomach, usually the gastric mucosa and antrum, and the upper duodenum. This infection plays a major role in the pathogenesis of type B gastritis and peptic ulcer disease.
  
• HELLP Syndrome [M0026355]
  A syndrome of HEMOLYSIS, elevated liver ENZYMES, and low blood platelets count (THROMBOCYTOPENIA). HELLP syndrome is observed in pregnant women with PRE-ECLAMPSIA or ECLAMPSIA who also exhibit LIVER damage and abnormalities in BLOOD COAGULATION.
  
• Helminthiasis [M0010007]
  Infestation with parasitic worms of the helminth class.
  
• Helminthiasis, Animal [M0010009]
  Infestation of animals with parasitic worms of the helminth class. The infestation may be experimental or veterinary.
  
• Hematologic Diseases [M0010044]
  Disorders of the blood and blood forming tissues.
  
• Hematometra [M0010051]
  Blood-filled UTERUS.
  
• Hematomyelia [M0336127]
  
• Hemeralopia [M0022770]
  
• Hemic and Lymphatic Diseases [M0010072]
  Hematologic diseases and diseases of the lymphatic system collectively. Hemic diseases include disorders involving the formed elements (e.g., ERYTHROCYTE AGGREGATION, INTRAVASCULAR) and chemical components (e.g., BLOOD PROTEIN DISORDERS); lymphatic diseases include disorders relating to lymph, lymph nodes, and lymphocytes.
  
• Hemicrania Migraine [M0335691]
  
• Hemimotor Seizure Disorder [M0335061]
  
• Hemiparesis [M0010082]
  
• Hemochromatosis [M0010098]
  A disorder due to the deposition of hemosiderin in the parenchymal cells, causing tissue damage and dysfunction of the liver, pancreas, heart, and pituitary. Full development of the disease in women is restricted by menstruation, pregnancy, and lower dietary intake of iron. Acquired hemochromatosis may be the result of blood transfusions, excessive dietary iron, or secondary to other disease. Idiopathic or genetic hemochromatosis is an autosomal recessive disorder of metabolism associated with a gene tightly linked to the A locus of the HLA complex on chromosome 6. (From Dorland, 27th ed)
  
• Hemoglobin C Disease [M0010119]
  A disease characterized by compensated hemolysis with a normal hemoglobin level or a mild to moderate anemia. There may be intermittent abdominal discomfort, splenomegaly, and slight jaundice.
  
• Hemoglobin F Disease [M0025961]
  
• Hemoglobin SC Disease [M0010124]
  One of the sickle cell disorders characterized by the presence of both hemoglobin S and hemoglobin C. It is similar to, but less severe than sickle cell anemia.
  
• Hemoglobinopathies [M0010129]
  A group of inherited disorders characterized by structural alterations within the hemoglobin molecule.
  
• Hemoglobinuria [M0010135]
  The presence of free HEMOGLOBIN in the URINE, indicating hemolysis of ERYTHROCYTES within the vascular system. After saturating the hemoglobin-binding proteins (HAPTOGLOBINS), free hemoglobin begins to appear in the urine.
  
• Hemoglobinuria, Paroxysmal [M0010136]
  A condition characterized by the recurrence of HEMOGLOBINURIA caused by intravascular HEMOLYSIS. In cases occurring upon cold exposure (paroxysmal cold hemoglobinuria), usually after infections, there is a circulating antibody which is also a cold hemolysin. In cases occurring during or after sleep (paroxysmal nocturnal hemoglobinuria), the clonal hematopoietic stem cells exhibit a global deficiency of cell membrane proteins.
  
• Hemolytic-Uremic Syndrome [M0010145]
  A syndrome that is associated with microvascular diseases of the KIDNEY, such as RENAL CORTICAL NECROSIS. It is characterized by hemolytic anemia (ANEMIA, HEMOLYTIC); THROMBOCYTOPENIA; and ACUTE RENAL FAILURE.
  
• Hemopericardium [M0016297]
  
• Hemophilia A [M0010149]
  The classic hemophilia resulting from a deficiency of factor VIII. It is an inherited disorder of blood coagulation characterized by a permanent tendency to hemorrhage.
  
• Hemophilia B [M0004363]
  A deficiency of blood coagulation factor IX inherited as an X-linked disorder. (Also known as Christmas Disease, after the first patient studied in detail, not the holy day.) Historical and clinical features resemble those in classic hemophilia (HEMOPHILIA A), but patients present with fewer symptoms. Severity of bleeding is usually similar in members of a single family. Many patients are asymptomatic until the hemostatic system is stressed by surgery or trauma. Treatment is similar to that for hemophilia A. (From Cecil Textbook of Medicine, 19th ed, p1008)
  
• Hemorrhagic Bacteremia [M0010175]
  
• Hemorrhagic Disease of Newborn [M0010158]
  A self-limited hemorrhagic disorder of the first days of life, caused by a deficiency of the vitamin K-dependent blood coagulation factors II, VII, IX, and X. (Dorland, 27th ed)
  
• Hemorrhagic Disorders [M0010157]
  Spontaneous or near spontaneous bleeding caused by a defect in clotting mechanisms (BLOOD COAGULATION DISORDERS) or another abnormality causing a structural flaw in the blood vessels (VASCULAR HEMOSTATIC DISORDERS).
  
• Hemorrhagic Fever with Renal Syndrome [M0010172]
  An acute febrile disease occurring predominately in Asia. It is characterized by fever, prostration, vomiting, hemorrhagic phenonema, shock, and renal failure. It is caused by any one of several closely related species of the genus Hantavirus. The most severe form is caused by HANTAAN VIRUS whose natural host is the rodent Apodemus agrarius. Milder forms are caused by SEOUL VIRUS and transmitted by the rodents Rattus rattus and R. norvegicus, and the PUUMALA VIRUS with transmission by Clethrionomys galreolus.
  
• Hemorrhagic Fever, American [M0010168]
  Diseases caused by American hemorrhagic fever viruses (ARENAVIRUSES, NEW WORLD).
  
• Hemorrhagic Fever, Argentinian [M0010169]
  
• Hemorrhagic Fever, Bolivian [M0010170]
  
• Hemorrhagic Fever, Crimean [M0010171]
  A severe, often fatal disease in humans caused by the Crimean-Congo hemorrhagic fever virus (HEMORRHAGIC FEVER VIRUS, CRIMEAN-CONGO).
  
• Hemorrhagic Fever, Ebola [M0028540]
  A highly fatal, acute hemorrhagic fever, clinically very similar to MARBURG VIRUS DISEASE, caused by EBOLAVIRUS, first occurring in the Sudan and adjacent northwestern (what was then) Zaire.
  
• Hemorrhagic Fever, Omsk [M0010173]
  Infection with the Omsk hemorrhagic fever virus, a Flavivirus.
  
• Hemorrhagic Fevers, Viral [M0010174]
  A group of viral diseases of diverse etiology but having many similar clinical characteristics; increased capillary permeability, leukopenia, and thrombocytopenia are common to all. Hemorrhagic fevers are characterized by sudden onset, fever, headache, generalized myalgia, backache, conjunctivitis, and severe prostration, followed by various hemorrhagic symptoms. Hemorrhagic fever with kidney involvement is HEMORRHAGIC FEVER WITH RENAL SYNDROME.
  
• Hemorrhagic Septicemia [M0010176]
  Any of several bacterial diseases, usually caused by PASTEURELLA MULTOCIDA, marked by the presence of hemorrhagic areas in the subcutaneous tissues, serous membranes, muscles, lymph glands, and throughout the internal organs. The diseases primarily affect animals and rarely humans.
  
• Hemorrhagic Septicemia, Viral [M0399083]
  A systemic infection of various salmonid and a few nonsalmonid fishes caused by Viral hemorrhagic septicemia virus (see NOVIRHABDOVIRUS),
  
• Hemorrhagic Syndrome, Bovine [M0386706]
  Clinically severe acute disease of cattle caused by noncytopathic forms of Bovine viral diarrhea virus 2 (DIARRHEA VIRUS 2, BOVINE VIRAL). Outbreaks are characterized by high morbidity and high mortality.
  
• Hemorrhoids [M0010177]
  Varicosities of the hemorrhoidal venous plexuses.
  
• Hemosiderosis [M0010179]
  Conditions in which there is a generalized increase in the iron stores of body tissues, particularly of liver and the reticuloendothelial system, without demonstrable tissue damage. The name refers to the presence of stainable iron in the tissue in the form of hemosiderin.
  
• Hemospermia [M0480845]
  Blood in the SEMEN, usually due to INFLAMMATION of the PROSTATE, the SEMINAL VESICLES, or both.
  
• Henipavirus Infections [M0448322]
  Infections with viruses of the genus HENIPAVIRUS, family PARAMYXOVIRIDAE.
  
• Henoch Purpura [M0018184]
  
• Hepadnaviridae Infections [M0027580]
  Virus diseases caused by the HEPADNAVIRIDAE.
  
• Hepatic Coma [M0010199]
  
• Hepatic Encephalopathy [M0010200]
  A syndrome characterized by central nervous system dysfunction in association with LIVER FAILURE, including portal-systemic shunts. Clinical features include lethargy and CONFUSION (frequently progressing to COMA); ASTERIXIS; NYSTAGMUS, PATHOLOGIC; brisk oculovestibular reflexes; decorticate and decerebrate posturing; MUSCLE SPASTICITY; and bilateral extensor plantar reflexes (see REFLEX, BABINSKI). ELECTROENCEPHALOGRAPHY may demonstrate triphasic waves. (From Adams et al., Principles of Neurology, 6th ed, pp1117-20; Plum & Posner, Diagnosis of Stupor and Coma, 3rd ed, p222-5)
  
• Hepatic Form of Wilson Disease [M0332756]
  
• Hepatic Stupor [M0335276]
  
• Hepatic Vein Thrombosis [M0010202]
  An acute or subacute blockage of the HEPATIC VEINS, usually extrahepatic and caused by blood clots (THROMBUS) or fibrous webs. Parenchymal FIBROSIS is uncommon.
  
• Hepatic Veno-Occlusive Disease [M0010204]
  Liver disease that is caused by injuries to the ENDOTHELIAL CELLS of the vessels and subendothelial EDEMA, but not by THROMBOSIS. Extracellular matrix, rich in FIBRONECTINS, is usually deposited around the HEPATIC VEINS leading to venous outflow occlusion and sinusoidal obstruction.
  
• Hepatitis [M0010205]
  INFLAMMATION of the LIVER.
  
• Hepatitis A [M0010206]
  INFLAMMATION of the LIVER in humans caused by a member of the HEPATOVIRUS genus, HUMAN HEPATITIS A VIRUS. It can be transmitted through fecal contamination of food or water.
  
• Hepatitis B [M0010210]
  INFLAMMATION of the LIVER in humans caused by a member of the ORTHOHEPADNAVIRUS genus, HEPATITIS B VIRUS. It is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.
  
• Hepatitis B, Chronic [M0029244]
  INFLAMMATION of the LIVER in humans caused by HEPATITIS B VIRUS lasting six months or more. It is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.
  
• Hepatitis C [M0010234]
  INFLAMMATION of the LIVER in humans caused by HEPATITIS C VIRUS, a single-stranded RNA virus. Its incubation period is 30-90 days. Hepatitis C is transmitted primarily by contaminated blood parenterally, and is often associated with transfusion and intravenous drug abuse. However, in a significant number of cases, the source of hepatitis C infection is unknown.
  
• Hepatitis C, Chronic [M0029252]
  INFLAMMATION of the LIVER in humans that is caused by HEPATITIS C VIRUS lasting six months or more. Chronic hepatitis C can lead to LIVER CIRRHOSIS.
  
• Hepatitis D [M0005790]
  INFLAMMATION of the LIVER in humans caused by HEPATITIS DELTA VIRUS, a defective RNA virus that can only infect HEPATITIS B patients. For its viral coating, hepatitis delta virus requires the HEPATITIS B SURFACE ANTIGENS produced by these patients. Hepatitis D can occur either concomitantly with (coinfection) or subsequent to (superinfection) hepatitis B infection. Similar to hepatitis B, it is primarily transmitted by parenteral exposure, such as transfusion of contaminated blood or blood products, but can also be transmitted via sexual or intimate personal contact.
  
• Hepatitis D, Chronic [M0029255]
  INFLAMMATION of the LIVER in humans caused by HEPATITIS DELTA VIRUS in conjunction with HEPATITIS B VIRUS and lasting six months or more.
  
• Hepatitis E [M0025508]
  Acute INFLAMMATION of the LIVER in humans; caused by HEPATITIS E VIRUS, a non-enveloped single-stranded RNA virus. Similar to HEPATITIS A, its incubation period is 15-60 days and is enterically transmitted, usually by fecal-oral transmission.
  
• Hepatitis, Alcoholic [M0010224]
  INFLAMMATION of the LIVER due to ALCOHOL ABUSE. It is characterized by NECROSIS of HEPATOCYTES, infiltration by NEUTROPHILS, and deposit of Mallory hyaline bodies. Depending on its severity, the inflammatory lesion may be reversible or progress to LIVER CIRRHOSIS.
  
• Hepatitis, Animal [M0010226]
  INFLAMMATION of the LIVER in non-human animals.
  
• Hepatitis, Autoimmune [M0029243]
  A chronic self-perpetuating hepatocellular INFLAMMATION of unknown cause, usually with HYPERGAMMAGLOBULINEMIA and serum AUTOANTIBODIES.
  
• Hepatitis, Chronic [M0010227]
  INFLAMMATION of the LIVER with ongoing hepatocellular injury for 6 months or more, characterized by NECROSIS of HEPATOCYTES and inflammatory cell (LEUKOCYTES) infiltration. Chronic hepatitis can be caused by viruses, medications, autoimmune diseases, and other unknown factors.
  
• Hepatitis, Chronic Active [M0010228]
  An aggressive form of chronic hepatitis involving extensive liver damage and cell injury beyond the portal tract.
  
• Hepatitis, Chronic Persistent [M0454313]
  A mild form of chronic hepatitis causing limited damage to the liver.
  
• Hepatitis, Chronic, Drug-Induced [M0029256]
  INFLAMMATION of the LIVER, lasting six months or more, and caused by an adverse drug effect. The adverse effect may result from a direct toxic effect of a drug or metabolite, or an idiosyncratic response to a drug or metabolite. The clinical and histological changes can mimic viral or autoimmune hepatitis.
  
• Hepatitis, Drug-Induced [M0454320]
  
• Hepatitis, Infectious Canine [M0010230]
  A contagious disease caused by canine adenovirus (ADENOVIRUSES, CANINE) infecting the LIVER, the EYE, the KIDNEY, and other organs in dogs, other canids, and bears. Symptoms include FEVER; EDEMA; VOMITING; and DIARRHEA.
  
• Hepatitis, Toxic [M0010231]
  INFLAMMATION of the LIVER due to hepatocellular toxicity, caused by drug metabolites and chemicals from the environment.
  
• Hepatitis, Viral, Animal [M0010232]
  INFLAMMATION of the LIVER in animals due to viral infection.
  
• Hepatitis, Viral, Human [M0010233]
  INFLAMMATION of the LIVER in humans due to infection by VIRUSES. There are several significant types of human viral hepatitis with infection caused by enteric-transmission (HEPATITIS A; HEPATITIS E) or blood transfusion (HEPATITIS B; HEPATITIS C; and HEPATITIS D).
  
• Hepatolenticular Degeneration [M0010235]
  A rare autosomal recessive disease characterized by the deposition of copper in the BRAIN; LIVER; CORNEA; and other organs. It is caused by defects in the ATP7B gene encoding copper-transporting ATPase 2 (EC 3.6.3.4), also known as the Wilson disease protein. The overload of copper inevitably leads to progressive liver and neurological dysfunction such as LIVER CIRRHOSIS; TREMOR; ATAXIA and intellectual deterioration. Hepatic dysfunction may precede neurologic dysfunction by several years.
  
• Hepatopulmonary Syndrome [M0029773]
  A syndrome characterized by the clinical triad of advanced chronic liver disease, pulmonary vascular dilatations, and reduced arterial oxygenation (HYPOXEMIA) in the absence of intrinsic cardiopulmonary disease. This syndrome is common in the patients with LIVER CIRRHOSIS or portal hypertension (HYPERTENSION, PORTAL).
  
• Hepatorenal Syndrome [M0010238]
  Functional KIDNEY FAILURE in patients with liver disease, usually LIVER CIRRHOSIS or portal hypertension (HYPERTENSION, PORTAL), and in the absence of intrinsic renal disease or kidney abnormality. It is characterized by intense renal vasculature constriction, reduced renal blood flow, OLIGURIA, and sodium retention.
  
• Hereditary Autosomal Dominant Spastic Paraplegia [M0336734]
  
• Hereditary Central Nervous System Demyelinating Diseases [M0328329]
  Inherited conditions characterized by a loss of myelin in the central nervous system.
  
• Hereditary Cerebral Amyloid Angiopathy, Dutch Type [M0334469]
  
• Hereditary Cerebral Amyloid Angiopathy, Icelandic Type [M0334470]
  
• Hereditary Chorea [M0334648]
  
• Hereditary Diseases [M0010254]
  Diseases caused by genetic mutations that are inherited from a parent's genome.
  
• Hereditary Motor and Sensory Neuropathies [M0023767]
  A group of slowly progressive inherited disorders affecting motor and sensory peripheral nerves. Subtypes include HMSNs I-VII. HMSN I and II both refer to CHARCOT-MARIE-TOOTH DISEASE. HMSN III refers to hypertrophic neuropathy of infancy. HMSN IV refers to REFSUM DISEASE. HMSN V refers to a condition marked by a hereditary motor and sensory neuropathy associated with spastic paraplegia (see SPASTIC PARAPLEGIA, HEREDITARY). HMSN VI refers to HMSN associated with an inherited optic atrophy (OPTIC ATROPHIES, HEREDITARY), and HMSN VII refers to HMSN associated with retinitis pigmentosa. (From Adams et al., Principles of Neurology, 6th ed, p1343)
  
• Hereditary Opalescent Dentin [M0005959]
  
• Hereditary Periodic Fever Syndromes [M0335133]
  
• Hereditary Sensory and Autonomic Neuropathies [M0014743]
  A group of inherited disorders characterized by degeneration of dorsal root and autonomic ganglion cells, and clinically by loss of sensation and autonomic dysfunction. There are five subtypes. Type I features autosomal dominant inheritance and distal sensory involvement. Type II is characterized by autosomal inheritance and distal and proximal sensory loss. Type III is DYSAUTONOMIA, FAMILIAL. Type IV features insensitivity to pain, heat intolerance, and mental deficiency. Type V is characterized by a selective loss of pain with intact light touch and vibratory sensation. (From Joynt, Clinical Neurology, 1995, Ch51, pp142-4)
  
• Hereditary Sensory Radicular Neuropathy [M0014744]
  
• Hereditary Type I Motor and Sensory Neuropathy [M0336505]
  
• Hereditary X-Linked Recessive Spastic Paraplegia [M0336728]
  
• Hereditary, Type VII, Motor and Sensory Neuropathy [M0336471]
  
• Heredodegenerative Disorders, Nervous System [M0328330]
  Inherited disorders characterized by progressive atrophy and dysfunction of anatomically or physiologically related neurologic systems.
  
• Hermanski-Pudlak Syndrome [M0024620]
  Syndrome characterized by the triad of oculocutaneous albinism (ALBINISM, OCULOCUTANEOUS); PLATELET STORAGE POOL DEFICIENCY; and lysosomal accumulation of ceroid lipofuscin.
  
• Hermaphroditism [M0010258]
  A state of intersex or sexual ambiguity, involving the GENOTYPE, the GONADS, the reproductive tract, and/or the external GENITALIA or PHENOTYPE. This concept covers TRUE HERMAPHRODITISM and PSEUDOHERMAPHRODITISM. True hermaphrodites are rare and they possess gonadal tissues of both SEXES, tissues from the OVARY and the TESTIS. Pseudohermaphrodites possess gonadal tissue of one sex but exhibit external phenotype of the opposite sex.
  
• Hermaphroditism, True [M0472577]
  A rare condition of sexual ambiguity in which the individual possesses gonadal tissues of both SEXES, tissues from the OVARY and the TESTIS. There can be a testis on one side and an ovary on the other (lateral), or there may be combined ovarian and testicular tissue (ovotestes) on each side (bilateral). Most common karyotype is 46,XX. Others include 46,XY and 45,X/XY.
  
• Hernia, Abdominal [M0454342]
  A protrusion of abdominal structures through the retaining ABDOMINAL WALL. It involves two parts: an opening in the abdominal wall, and a hernia sac consisting of PERITONEUM and abdominal contents. Abdominal hernias include groin hernia (HERNIA, FEMORAL; HERNIA, INGUINAL) and VENTRAL HERNIA.
  
• Hernia, Diaphragmatic [M0010261]
  Protrusion of abdominal structures into the THORAX as a result of congenital or traumatic defects in the respiratory DIAPHRAGM.
  
• Hernia, Femoral [M0010263]
  A groin hernia occurring inferior to the inguinal ligament and medial to the FEMORAL VEIN and FEMORAL ARTERY. The femoral hernia sac has a small neck but may enlarge considerably when it enters the subcutaneous tissue of the thigh. It is caused by defects in the ABDOMINAL WALL.
  
• Hernia, Hiatal [M0010264]
  STOMACH herniation located at or near the diaphragmatic opening for the ESOPHAGUS, esophageal hiatus. When the ESOPHAGOGASTRIC JUNCTION is above the DIAPHRAGM, it is called a SLIDING HIATAL HERNIA. When the ESOPHAGOGASTRIC JUNCTION is below the DIAPHRAGM, it is called a PARAESOPHAGEAL HIATAL HERNIA.
  
• Hernia, Inguinal [M0010267]
  An abdominal hernia with an external bulge in the GROIN region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the ABDOMINAL WALL (transversalis fascia) in Hesselbach's triangle. The former type is commonly seen in children and young adults; the latter in adults.
  
• Hernia, Umbilical [M0010269]
  A HERNIA due to an imperfect closure or weakness of the umbilical ring. It appears as a skin-covered protrusion at the UMBILICUS during crying, coughing, or straining. The hernia generally consists of OMENTUM or SMALL INTESTINE. The vast majority of umbilical hernias are congenital but can be acquired due to severe abdominal distention.
  
• Hernia, Ventral [M0010271]
  A hernia caused by weakness of the anterior ABDOMINAL WALL due to midline defects, previous incisions, or increased intra-abdominal pressure. Ventral hernias include UMBILICAL HERNIA, incisional, epigastric, and spigelian hernias.
  
• Herpangina [M0010275]
  
• Herpes Genitalis [M0010276]
  Infection of the genitals (GENITALIA) with HERPES SIMPLEX VIRUS in either the males or the females.
  
• Herpes Labialis [M0010278]
  Herpes simplex, caused by type 1 virus, primarily spread by oral secretions and usually occurring as a concomitant of fever. It may also develop in the absence of fever or prior illness. It commonly involves the facial region, especially the lips and the nares. (Dorland, 27th ed.)
  
• Herpes Simplex [M0010279]
  A group of acute infections caused by herpes simplex virus type 1 or type 2 that is characterized by the development of one or more small fluid-filled vesicles with a raised erythematous base on the skin or mucous membrane. It occurs as a primary infection or recurs due to a reactivation of a latent infection. (Dorland, 27th ed.)
  
• Herpes Zoster [M0010280]
  An acute infectious, usually self-limited, disease believed to represent activation of latent varicella-zoster virus (HERPESVIRUS 3, HUMAN) in those who have been rendered partially immune after a previous attack of CHICKENPOX. It involves the SENSORY GANGLIA and their areas of innervation and is characterized by severe neuralgic pain along the distribution of the affected nerve and crops of clustered vesicles over the area. (From Dorland, 27th ed)
  
• Herpes Zoster Ophthalmicus [M0010281]
  Virus infection of the Gasserian ganglion and its nerve branches characterized by pain and vesicular eruptions with much swelling. Ocular involvement is usually heralded by a vesicle on the tip of the nose. This area is innervated by the nasociliary nerve.
  
• Herpes Zoster Oticus [M0025433]
  A syndrome characterized by facial palsy in association with a herpetic eruption of the external auditory meatus. This may occasionally be associated with tinnitus, vertigo, deafness, severe otalgia, and inflammation of the pinna. The condition is caused by reactivation of a latent HERPESVIRUS 3, HUMAN infection which causes inflammation of the facial and vestibular nerves, and may occasionally involve additional cranial nerves. (From Adams et al., Principles of Neurology, 6th ed, p757)
  
• Herpesviridae Infections [M0010285]
  Virus diseases caused by the HERPESVIRIDAE.
  
• Herpetic Acute Necrotizing Encephalitis [M0334886]
  
• Herpetic Facial Paralysis [M0336045]
  
• Heubner Artery Infarction [M0335393]
  
• Heymann Nephritis [M0490941]
  An experimental rat model of human membranous nephropathy characterized by complement activation and formation of subepithelial immune deposits in the glomerular capillary wall.
  
• Hibernation, Myocardial [M0026744]
  
• Hidradenitis [M0025287]
  The inflammation of a sweat gland (usually of the apocrine type). The condition can be idiopathic or occur as a result of or in association with another underlying condition. Neutrophilic eccrine hidradenitis is a relatively rare variant that has been reported in patients undergoing chemotherapy, usually for non-Hodgkin lymphomas or leukemic conditions.
  
• Hidradenitis Suppurativa [M0026548]
  A chronic suppurative and cicatricial disease of the apocrine glands occurring chiefly in the axillae in women and in the groin and anal regions in men. It is characterized by poral occlusion with secondary bacterial infection, evolving into abscesses which eventually rupture. As the disease becomes chronic, ulcers appear, sinus tracts enlarge, fistulas develop, and fibrosis and scarring become evident. Hormonal mechanisms are expected in its pathogenesis.
  
• Hidrotic Ectodermal Dysplasia [M0007034]
  
• High Pressure Neurological Syndrome [M0010353]
  A syndrome related to increased atmospheric pressure and characterized by tremors, nausea, dizziness, decreased motor and mental performance, and SEIZURES. This condition may occur in those who dive deeply (c. 1000 ft) usually while breathing a mixture of oxygen and helium. The condition is associated with a neuroexcitatory effect of helium.
  
• High T4 Syndrome [M0007967]
  
• Hip Contracture [M0010362]
  Permanent fixation of the hip in primary positions, with limited passive or active motion at the hip joint. Locomotion is difficult and pain is sometimes present when the hip is in motion. It may be caused by trauma, infection, or poliomyelitis. (From Current Medical Information & Technology, 5th ed)
  
• Hip Dislocation, Congenital [M0010364]
  Congenital dislocation of the hip generally includes subluxation of the femoral head, acetabular dysplasia, and complete dislocation of the femoral head from the true acetabulum. This condition occurs in approximately 1 in 1000 live births and is more common in females than in males.
  
• Hip Dysplasia, Canine [M0010365]
  A hereditary disease of the hip joints in dogs. Signs of the disease may be evident any time after 4 weeks of age.
  
• Hippel-Lindau Disease [M0010373]
  An autosomal dominant disorder associated with various neoplasms including central nervous system (most often cerebellar) and retinal HEMANGIOBLASTOMA, endolymphatic sac tumors, renal cell carcinoma (see CARCINOMA, RENAL CELL), renal and pancreatic cysts, HEMANGIOMA of the spinal cord, and PHEOCHROMOCYTOMA. The most common presenting manifestations are neurologic deficits associated with intracranial hemangioblastomas which may HEMORRHAGE, causing ataxia, INTRACRANIAL HYPERTENSION, and other signs of neurologic dysfunction. (From Neurochirurgie 1998 Nov;44(4):258-66)
  
• Histiocytic Necrotizing Lymphadenitis [M0029754]
  Development of lesions in the lymph node characterized by infiltration of the cortex or paracortex by large collections of proliferating histiocytes and complete or, more often, incomplete necrosis of lymphoid tissue.
  
• Histiocytosis [M0023956]
  General term for the abnormal appearance of histiocytes in the blood. Based on the pathological features of the cells involved rather than on clinical findings, the histiocytic diseases are subdivided into three groups: HISTIOCYTOSIS, LANGERHANS CELL; HISTIOCYTOSIS, NON-LANGERHANS CELL; and HISTIOCYTIC DISORDERS, MALIGNANT.
  
• Histiocytosis, Langerhans-Cell [M0010406]
  Group of disorders characterized by monoclonal proliferation of CD1+ HISTIOCYTES. The demonstration of the LANGERHANS CELLS Birbeck granules is the gold standard of the phenotype. EOSINOPHILIC GRANULOMA makes up 60-80% of all the cases.
  
• Histiocytosis, Non-Langerhans-Cell [M0023959]
  Group of disorders which feature accumulations of active HISTIOCYTES and LYMPHOCYTES, but where the histiocytes are not LANGERHANS CELLS. The group includes HEMOPHAGOCYTIC LYMPHOHISTIOCYTOSIS; SINUS HISTIOCYTOSIS; xanthogranuloma; reticulohistiocytoma; JUVENILE XANTHOGRANULOMA; xanthoma disseminatum; as well as the lipid storage diseases (SEA-BLUE HISTIOCYTE SYNDROME; and NIEMANN-PICK DISEASES).
  
• Histiocytosis, Sinus [M0023963]
  Benign, non-Langerhans-cell, histiocytic proliferative disorder that primarily affects the lymph nodes. It is often referred to as sinus histiocytosis with massive lymphadenopathy.
  
• Histomoniasis [M0017925]
  
• Histoplasmosis [M0010434]
  Infection resulting from inhalation or ingestion of spores of the fungus of the genus HISTOPLASMA, species H. capsulatum. It is worldwide in distribution and particularly common in the midwestern United States. (From Dorland, 27th ed)
  
• HIV Encephalopathy [M0023888]
  
• HIV Enteropathy [M0028443]
  A syndrome characterized by chronic, well-established DIARRHEA (greater than one month in duration) without an identified infectious cause after thorough evaluation, in an HIV-positive individual. It is thought to be due to direct or indirect effects of HIV on the enteric mucosa. HIV enteropathy is a diagnosis of exclusion and can be made only after other forms of diarrheal illness have been ruled out. (Harrison's Principles of Internal Medicine, 13th ed, pp1607-8; Haubrich et al., Bockus Gastroenterology, 5th ed, p1155)
  
• HIV Infections [M0023997]
  Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).
  
• HIV Wasting Syndrome [M0028660]
  Involuntary weight loss of greater than 10 percent associated with intermittent or constant fever and chronic diarrhea or fatigue for more than 30 days in the absence of a defined cause other than HIV infection. A constant feature is major muscle wasting with scattered myofiber degeneration. A variety of etiologies, which vary among patients, contributes to this syndrome. (From Harrison's Principles of Internal Medicine, 13th ed, p1611).
  
• HIV-1-Associated Cognitive Motor Complex [M0023889]
  
• HIV-Associated Lipodystrophy Syndrome [M0419385]
  Defective metabolism leading to fat maldistribution in patients infected with HIV. The etiology appears to be multifactorial and probably involves some combination of infection-induced alterations in metabolism, direct effects of antiretroviral therapy, and patient-related factors.
  
• HIV-Associated Vasculitis of the Central Nervous System [M0333925]
  
• HMN (Hereditary Motor Neuropathy) Proximal Type I [M0336135]
  
• HMSN Type II [M0023765]
  
• HMSN Type III [M0023764]
  
• Holocarboxylase Synthetase Deficiency [M0381890]
  The neonatal form of MULTIPLE CARBOXYLASE DEFICIENCY that is caused by a defect or deficiency in holocarboxylase synthetase. HLCS is the enzyme that covalently links biotin to the biotin dependent carboxylases (propionyl-CoA-carboxylase, pyruvate carboxylase, and beta-methylcrotonyl-CoA carboxylase).
  
• Homocystinuria [M0010516]
  An autosomal recessive inborn error of methionine metabolism usually caused by a deficiency of CYSTATHIONINE BETA-SYNTHASE and associated with elevations of homocysteine in plasma and urine. Clinical features include a tall, slender habitus, SCOLIOSIS, arachnodactyly, MUSCLE WEAKNESS, genu varis, thin blond hair, malar flush, lens dislocations, an increased incidence of MENTAL RETARDATION, and a tendency to develop fibrosis of arteries, frequently complicated by CEREBROVASCULAR ACCIDENTS and MYOCARDIAL INFARCTION. (From Adams et al., Principles of Neurology, 6th ed, p979)
  
• Hookworm Infections [M0010535]
  Infection of humans or animals with hookworms other than those caused by the genus Ancylostoma or Necator, for which the specific terms ANCYLOSTOMIASIS and NECATORIASIS are available.
  
• Hordeolum [M0010536]
  Purulent infection of one of the sebaceous glands of Zeis along the eyelid margin (external) or of the meibomian gland on the conjunctival side of the eyelid (internal).
  
• Horizontal Nystagmus [M0333556]
  
• Horner Syndrome [M0010542]
  A syndrome associated with defective sympathetic innervation to one side of the face, including the eye. Clinical features include MIOSIS; mild BLEPHAROPTOSIS; and hemifacial ANHIDROSIS (decreased sweating)(see HYPOHIDROSIS). Lesions of the BRAIN STEM; cervical SPINAL CORD; first thoracic nerve root; apex of the LUNG; CAROTID ARTERY; CAVERNOUS SINUS; and apex of the ORBIT may cause this condition. (From Miller et al., Clinical Neuro-Ophthalmology, 4th ed, pp500-11)
  
• Horner Syndrome, Acquired [M0333517]
  
• Horner Syndrome, Central [M0333518]
  
• Horner's Syndrome, Pupil [M0333519]
  
• Horse Diseases [M0010544]
  Diseases of domestic and wild horses of the species Equus caballus.
  
• HSAN Type IV [M0014741]
  
• HSAN Type V [M0014742]
  
• HSN Type I [M0014739]
  
• HSN Type II [M0014740]
  
• HTLV Infections [M0010637]
  
• HTLV-I Infections [M0023852]
  
• HTLV-II Infections [M0023853]
  
• Human Transmissible Spongiform Encephalopathies, Inherited [M0335897]
  
• Hunermann-Conradi Syndrome [M0004309]
  
• Huntington Disease [M0010660]
  A familial disorder inherited as an autosomal dominant trait and characterized by the onset of progressive CHOREA and DEMENTIA in the fourth or fifth decade of life. Common initial manifestations include paranoia; poor impulse control; DEPRESSION; HALLUCINATIONS; and DELUSIONS. Eventually intellectual impairment; loss of fine motor control; ATHETOSIS; and diffuse chorea involving axial and limb musculature develops, leading to a vegetative state within 10-15 years of disease onset. The juvenile variant has a more fulminant course including SEIZURES; ATAXIA; dementia; and chorea. (From Adams et al., Principles of Neurology, 6th ed, pp1060-4)
  
• Huntington Disease, Late Onset [M0332778]
  
• Hurler-Scheie Syndrome [M0012560]
  
• Hyalinosis, Segmental Glomerular [M0009303]
  Segmental glomerular degeneration with a glassy appearance (hyalinosis) caused by the accumulation of plasma proteins in the glomeruli.
  
• Hydrarthrosis [M0010682]
  Accumulation of watery fluid in the cavity of a joint. (Dorland, 27th ed)
  
• Hydroa Vacciniforme [M0010686]
  A vesicular and bullous eruption having a tendency to recur in summer during childhood and commonly appearing on sun-exposed skin. The lesions are surrounded by an erythematous zone and resemble a vaccination. (From Dorland, 27th ed)
  
• Hydrocephalus [M0010699]
  Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, INTRACRANIAL HYPERTENSION; HEADACHE; lethargy; URINARY INCONTINENCE; and ATAXIA (and in infants macrocephaly). This condition may be caused by obstruction of cerebrospinal fluid pathways due to neurologic abnormalities, INTRACRANIAL HEMORRHAGES; CENTRAL NERVOUS SYSTEM INFECTIONS; BRAIN NEOPLASMS; CRANIOCEREBRAL TRAUMA; and other conditions. Impaired resorption of cerebrospinal fluid from the arachnoid villi results in a communicating form of hydrocephalus. Hydrocephalus ex-vacuo refers to ventricular dilation that occurs as a result of brain substance loss from CEREBRAL INFARCTION and other conditions.
  
• Hydrocephalus Ex-Vacuo [M0335284]
  
• Hydrocephalus, Normal Pressure [M0010700]
  A form of compensated hydrocephalus characterized clinically by a slowly progressive gait disorder (see GAIT DISORDERS, NEUROLOGIC), progressive intellectual decline, and URINARY INCONTINENCE. Spinal fluid pressure tends to be in the high normal range. This condition may result from processes which interfere with the absorption of CSF including SUBARACHNOID HEMORRHAGE, chronic MENINGITIS, and other conditions. (From Adams et al., Principles of Neurology, 6th ed, pp631-3)
  
• Hydronephrosis [M0010730]
  Abnormal enlargement or swelling of a KIDNEY due to dilation of the KIDNEY CALICES and the KIDNEY PELVIS. It is often associated with obstruction of the URETER or chronic kidney diseases that prevents normal drainage of urine into the URINARY BLADDER.
  
• Hydrophthalmos [M0010732]
  Congenital open-angle glaucoma that results from dysgenesis of the angle structures accompanied by increased intraocular pressure and enlargement of the eye. Treatment is both medical and surgical.
  
• Hydropneumothorax [M0010733]
  A collection of fluid and gas within the pleural cavity. (Dorland, 27th ed)
  
• Hydrosyringomyelia [M0336216]
  
• Hydrothorax [M0010738]
  A collection of watery fluid in the pleural cavity. (Dorland, 27th ed)
  
• Hymenolepiasis [M0010803]
  Infection with tapeworms of the genus Hymenolepis.
  
• Hyper-IgM Immunodeficiency Syndrome [M0492421]
  A rare inherited immunodeficiency syndrome characterized by normal or elevated serum IMMUNOGLOBULIN M levels with absence of IMMUNOGLOBULIN G; IMMUNOGLOBULIN A; and IMMUNOGLOBULIN E. It results in a profound susceptibility to BACTERIAL INFECTIONS and an increased susceptibility to OPPORTUNISTIC INFECTIONS. Several subtypes of hyper-IgM immunodeficiency syndrome exist depending upon the location of genetic mutation.
  
• Hyper-IgM Immunodeficiency Syndrome, Type 1 [M0492429]
  An X-linked hyper-IgM immunodeficiency subtype resulting from mutation in the gene encoding CD40 LIGAND.
  
• Hyper-IgM Immunodeficiency Syndrome, Type 2 [M0492422]
  Hyper-IgM immunodeficiency subtype resulting from mutation in the gene encoding activation-induced CYTIDINE DEAMINASE.
  
• Hyper-IgM Immunodeficiency Syndrome, Type 3 [M0492427]
  Hyper-IgM immunodeficiency subtype resulting from mutation in the gene encoding CD40 ANTIGEN.
  
• Hyper-IgM Immunodeficiency Syndrome, Type 5 [M0492428]
  
• Hyperaldosteronism [M0010808]
  A condition caused by the overproduction of ALDOSTERONE. It is characterized by sodium retention and potassium excretion with resultant HYPERTENSION and HYPOKALEMIA.
  
• Hyperalgesia [M0010809]
  An increased sensation to painful stimuli that may follow damage to soft tissue containing NOCICEPTORS or injury to a peripheral nerve. Hyperalgesia can occur both at the site of tissue damage (primary hyperalgesia) and in the surrounding undamaged areas (secondary hyperalgesia). (Kandel et al., Principles of Neural Science, 3d ed, p386)
  
• Hyperandrogenism [M0026654]
  A condition caused by the excessive secretion of ANDROGENS from the ADRENAL CORTEX; the OVARIES; or the TESTES. The clinical significance in males is negligible. In women, the common manifestations are HIRSUTISM and VIRILISM as seen in patients with POLYCYSTIC OVARY SYNDROME and ADRENOCORTICAL HYPERFUNCTION.
  
• Hyperargininemia [M0328331]
  A rare autosomal recessive disorder of the urea cycle. It is caused by a deficiency of the hepatic enzyme ARGINASE. Arginine is elevated in the blood and cerebrospinal fluid, and periodic hyperammonemia may occur. Disease onset is usually in infancy or early childhood. Clinical manifestations include seizures, microcephaly, progressive mental impairment, hypotonia, ataxia, spastic diplegia, and quadriparesis. (From Hum Genet 1993 Mar;91(1):1-5; Menkes, Textbook of Child Neurology, 5th ed, p51)
  
• Hyperbilirubinemia, Hereditary [M0010812]
  Inborn errors of bilirubin metabolism resulting in excessive amounts of bilirubin in the circulating blood, either because of increased bilirubin production or because of delayed clearance of bilirubin from the blood.
  
• Hyperbilirubinemia, Neonatal [M0480985]
  Accumulation of BILIRUBIN, a breakdown product of HEME PROTEINS, in the BLOOD during the first weeks of life. This may lead to NEONATAL JAUNDICE. The excess bilirubin may exist in the unconjugated (indirect) or the conjugated (direct) form. The condition may be self-limiting (PHYSIOLOGICAL NEONATAL JAUNDICE) or pathological with toxic levels of bilirubin.
  
• Hypercalcemia [M0010814]
  Abnormally high level of calcium in the blood.
  
• Hypercementosis [M0010817]
  A regressive change of teeth characterized by excessive development of secondary cementum on the tooth surface. It may occur on any part of the root, but the apical two-thirds are most commonly affected. (Dorland, 27th ed)
  
• Hypercholesterolemia [M0010818]
  A condition with abnormally high levels of CHOLESTEROL in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population.
  
• Hyperemia [M0010821]
  The presence of an increased amount of blood in a part or organ. (Stedman, 25th ed)
  
• Hypereosinophilic Syndrome [M0026741]
  A heterogeneous group of disorders with the common feature of prolonged eosinophilia of unknown cause and associated organ system dysfunction, including the heart, central nervous system, kidneys, lungs, gastrointestinal tract, and skin. There is a massive increase in the number of eosinophils in the blood, mimicking leukemia, and extensive eosinophilic infiltration of the various organs. It is often referred to as idiopathic.
  
• Hypergammaglobulinemia [M0010823]
  An excess of GAMMA-GLOBULINS in the serum due to chronic infections or PARAPROTEINEMIAS.
  
• Hyperglycemia [M0010824]
  Abnormally high BLOOD GLUCOSE level, beyond the normal range (roughly 70 to 150 mg/100 ml of PLASMA).
  
• Hyperglycemic Hyperosmolar Nonketotic Coma [M0010825]
  A serious complication of TYPE 2 DIABETES MELLITUS. It is characterized by extreme HYPERGLYCEMIA; DEHYDRATION; serum hyperosmolarity; and depressed consciousness leading to COMA in the absence of KETOSIS and ACIDOSIS.
  
• Hyperglycinemia, Nonketotic [M0328332]
  An autosomal recessive metabolic disorder caused by deficiencies in the mitochondrial GLYCINE cleavage system; an enzyme system with four components: P-, T-, H-, and L-proteins. Deficiency of the P-protein is the most prevalent form. Neonatal and juvenile presentations have been reported. Neonatal onset is more common and may be fatal. Clinical features include SEIZURES; hypotonia; APNEA; and COMA. When the illness presents in childhood there tends to be an associated progressive DEMENTIA accompanied by extrapyramidal signs. (Menkes, Textbook of Child Neurology, 5th ed, p46; Jpn J Hum Genet 1997 Mar;42(1):13-22)
  
• Hyperglycinemia, Nonketotic, Type I [M0335285]
  
• Hyperglycinemia, Nonketotic, Type II [M0335286]
  
• Hyperglycinemia, Nonketotic, Type III [M0335287]
  
• Hypergonadotropic Hypogonadism [M0472163]
  
• Hyperhidrosis [M0010826]
  Excessive sweating. In the localized type, the most frequent sites are the palms, soles, axillae, inguinal folds, and the perineal area. Its chief cause is thought to be emotional. Generalized hyperhidrosis may be induced by a hot, humid environment, by fever, or by vigorous exercise.
  
• Hyperhomocysteinemia [M0029877]
  An inborn error of methionone metabolism which produces an excess of homocysteine in the blood. It is often caused by a deficiency of CYSTATHIONINE BETA-SYNTHASE and is a risk factor for coronary vascular disease.
  
• Hyperinsulinism [M0010827]
  A syndrome with excessively high INSULIN levels in the BLOOD. It may cause HYPOGLYCEMIA. Etiology of hyperinsulinism varies, including hypersecretion of a beta cell tumor (INSULINOMA); autoantibodies against insulin (INSULIN ANTIBODIES); defective insulin receptor (INSULIN RESISTANCE); or overuse of exogenous insulin or HYPOGLYCEMIC AGENTS.
  
• Hyperkeratosis, Epidermolytic [M0026530]
  A form of congenital ichthyosis inherited as an autosomal dominant trait and characterized by ERYTHRODERMA and severe hyperkeratosis. It is manifested at birth by blisters followed by the appearance of thickened, horny, verruciform scales over the entire body, but accentuated in flexural areas. Mutations in the genes that encode KERATIN-1 and KERATIN-10 have been associated with this disorder.
  
• Hyperkinetic Heart Syndrome [M0014702]
  
• Hyperlipidemia, Familial Combined [M0010832]
  A type of familial lipid metabolism disorder characterized by a variable pattern of elevated plasma CHOLESTEROL and/or TRIGLYCERIDES. Multiple genes on different chromosomes may be involved, such as the major late transcription factor (UPSTREAM STIMULATORY FACTORS) on CHROMOSOME 1.
  
• Hyperlipidemias [M0010830]
  Conditions with excess LIPIDS in the blood.
  
• Hyperlipoproteinemia Type I [M0012579]
  An inherited condition due to a deficiency of either LIPOPROTEIN LIPASE or APOLIPOPROTEIN C-II (a lipase-activating protein). The lack of lipase activities results in inability to remove CHYLOMICRONS and TRIGLYCERIDES from the blood which has a creamy top layer after standing.
  
• Hyperlipoproteinemia Type II [M0010819]
  A group of familial disorders characterized by elevated circulating cholesterol contained in either LOW-DENSITY LIPOPROTEINS alone or also in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins).
  
• Hyperlipoproteinemia Type IIa [M0486997]
  Hypercholesterolemia that is caused by mutation in the LOW DENSITY LIPOPROTEIN RECEPTOR gene. This receptor defect prevents LDL binding to the cell membrane and uptake of cholesterol which normally suppresses further cholesterol synthesis.
  
• Hyperlipoproteinemia Type IIb [M0486998]
  Type IIb hyperlipoproteinemia is caused by mutation in the receptor-binding domain of APOLIPOPROTEIN B-100 which is a major component of LOW-DENSITY LIPOPROTEINS and VERY-LOW-DENSITY LIPOPROTEINS resulting in reduced clearance of these lipoproteins. It is characterized by both hypercholesterolemia and HYPERTRIGLYCERIDEMIA (combined hyperlipidemia).
  
• Hyperlipoproteinemia Type III [M0010834]
  An autosomal recessively inherited disorder characterized by the accumulation of intermediate-density lipoprotein (IDL or broad-beta-lipoprotein). IDL has a CHOLESTEROL to TRIGLYCERIDES ratio greater than that of VERY-LOW-DENSITY LIPOPROTEINS. This disorder is due to mutation of APOLIPOPROTEIN E, a receptor-binding component of VLDL and CHYLOMICRONS, resulting in their reduced clearance and high plasma levels of both cholesterol and triglycerides.
  
• Hyperlipoproteinemia Type IV [M0010835]
  A hypertriglyceridemia disorder, often with autosomal dominant inheritance. It is characterized by the persistent elevations of plasma TRIGLYCERIDES, endogenously synthesized and contained predominantly in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins). In contrast, the plasma CHOLESTEROL and PHOSPHOLIPIDS usually remain within normal limits.
  
• Hyperlipoproteinemia Type V [M0010836]
  A severe type of hyperlipidemia, sometimes familial, that it is characterized by the elevation of both plasma CHYLOMICRONS and TRIGLYCERIDES contained in VERY-LOW-DENSITY LIPOPROTEINS. Type V hyperlipoproteinemia is often associated with DIABETES MELLITUS and is not caused by reduced LIPOPROTEIN LIPASE activity as in HYPERLIPOPROTEINEMIA TYPE I .
  
• Hyperlipoproteinemias [M0010833]
  Conditions with abnormally elevated levels of LIPOPROTEINS in the blood. They may be inherited, acquired, primary, or secondary. Hyperlipoproteinemias are classified according to the pattern of lipoproteins on electrophoresis or ultracentrifugation.
  
• Hyperlysinemia, Periodic [M0335294]
  
• Hyperlysinemias [M0328333]
  A group of inherited metabolic disorders which have in common elevations of serum LYSINE levels. Enzyme deficiencies of alpha-aminoadipic semialdehyde dehydrogenase and the SACCHAROPINE DEHYDROGENASES have been associated with hyperlysinemia. Clinical manifestations include mental retardation, recurrent emesis, hypotonia, lethargy, diarrhea, and developmental delay. (From Menkes, Textbook of Child Neurology, 5th ed, p56)
  
• Hypernatremia [M0010837]
  Excessive amount of sodium in the blood. (Dorland, 27th ed)
  
• Hyperopia [M0010838]
  A refractive error in which rays of light entering the eye parallel to the optic axis are brought to a focus behind the retina, as a result of the eyeball being too short from front to back. It is also called farsightedness because the near point is more distant than it is in emmetropia with an equal amplitude of accommodation. (Dorland, 27th ed)
  
• Hyperostosis [M0023928]
  Increase in the mass of bone per unit volume.
  
• Hyperostosis Corticalis Generalisata [M0015522]
  
• Hyperostosis Frontalis Interna [M0010839]
  Thickening of the inner table of the frontal bone, which may be associated with hypertrichosis and obesity. It most commonly affects women near menopause.
  
• Hyperostosis, Cortical, Congenital [M0010841]
  A disease of young infants characterized by soft tissue swellings over the affected bones, fever, and irritability, and marked by periods of remission and exacerbation. (Dorland, 27th ed)
  
• Hyperostosis, Diffuse Idiopathic Skeletal [M0006363]
  A disease of elderly men characterized by large osteophytes that bridge vertebrae and ossification of ligaments and tendon insertions.
  
• Hyperostosis, Sternocostoclavicular [M0023380]
  A rare, benign rheumatologic disorder or syndrome characterized by hyperostosis and soft tissue ossification between the clavicles and the anterior part of the upper ribs. It is often associated with the dermatologic disorder palmoplantar pustulosis, particularly in Japan. Careful diagnosis is required to distinguish it from psoriatic arthritis, OSTEITIS DEFORMANS, and other diseases. Spondylitis of pustulosis palmaris et plantaris is one of the possible causes; also, evidence suggests one origin may be bone infection. Bone imaging is especially useful for diagnosis. It was originally described by Sonozaki in 1974.
  
• Hyperoxaluria [M0010842]
  Excretion of an excessive amount of OXALATES in the urine.
  
• Hyperoxaluria, Primary [M0010843]
  A genetic disorder characterized by excretion of large amounts of OXALATES in urine; NEPHROLITHIASIS; NEPHROCALCINOSIS; early onset of RENAL FAILURE; and often a generalized deposit of CALCIUM OXALATE. There are subtypes classified by the enzyme defects in glyoxylate metabolism.
  
• Hyperparathyroidism [M0010845]
  A condition of abnormally elevated output of PARATHYROID HORMONE (or PTH) triggering responses that increase blood CALCIUM. It is characterized by HYPERCALCEMIA and BONE RESORPTION, eventually leading to bone diseases. PRIMARY HYPERPARATHYROIDISM is caused by parathyroid HYPERPLASIA or PARATHYROID NEOPLASMS. SECONDARY HYPERPARATHYROIDISM is increased PTH secretion in response to HYPOCALCEMIA, usually caused by chronic KIDNEY DISEASES.
  
• Hyperparathyroidism, Primary [M0471516]
  A condition of abnormally elevated output of PARATHYROID HORMONE due to parathyroid HYPERPLASIA or PARATHYROID NEOPLASMS. It is characterized by the combination of HYPERCALCEMIA, phosphaturia, elevated renal 1,25-DIHYDROXYVITAMIN D3 synthesis, and increased BONE RESORPTION.
  
• Hyperparathyroidism, Secondary [M0010846]
  Abnormally elevated PARATHYROID HORMONE secretion as a response to HYPOCALCEMIA. It is caused by chronic KIDNEY FAILURE or other abnormalities in the controls of bone and mineral metabolism, leading to various BONE DISEASES, such as RENAL OSTEODYSTROPHY.
  
• Hyperphenylalaninaemia [M0335856]
  
• Hyperphenylalaninemia, Non-Phenylketonuric [M0335853]
  
• Hyperpipecolic Acidemia [M0028262]
  
• Hyperpituitarism [M0010848]
  Disease of the glandular, anterior portion of the pituitary (PITUITARY GLAND, ANTERIOR) resulting in hypersecretion of ADENOHYPOPHYSEAL HORMONES such as GROWTH HORMONE; PROLACTIN; THYROTROPIN; LUTEINIZING HORMONE; FOLLICLE STIMULATING HORMONE ; and ADRENOCORTICOTROPIC HORMONE. Hyperpituitarism usually is caused by a functional ADENOMA.
  
• Hyperprolactinemia [M0010850]
  Increased levels of PROLACTIN in the BLOOD, which may be associated with AMENORRHEA and GALACTORRHEA. Relatively common etiologies include PROLACTINOMA, medication effect, KIDNEY FAILURE, granulomatous diseases of the PITUITARY GLAND, and disorders which interfere with the hypothalamic inhibition of prolactin release. Ectopic (non-pituitary) production of prolactin may also occur. (From Joynt, Clinical Neurology, 1992, Ch36, pp77-8)
  
• Hypersomnia with Periodic Respiration [M0019961]
  
• Hypersomnia, Post-Traumatic [M0334758]
  
• Hypersomnia, Recurrent [M0334761]
  
• Hypersomnolence Disorders, Primary [M0334762]
  
• Hypersomnolence Disorders, Secondary [M0334763]
  
• Hypersomnolence, Idiopathic [M0328334]
  A sleep disorder of central nervous system origin characterized by prolonged nocturnal sleep and periods of daytime drowsiness. Affected individuals experience difficulty with awakening in the morning and may have associated sleep drunkenness, automatic behaviors, and memory disturbances. This condition differs from narcolepsy in that daytime sleep periods are longer, there is no association with CATAPLEXY, and the multiple sleep latency onset test does not record sleep-onset rapid eye movement sleep. (From Chokroverty, Sleep Disorders Medicine, 1994, pp319-20; Psychiatry Clin Neurosci 1998 Apr:52(2):125-129)
  
• Hypersplenism [M0010857]
  Condition characterized by splenomegaly, some reduction in the number of circulating blood cells in the presence of a normal or hyperactive bone marrow, and the potential for reversal by splenectomy.
  
• Hypertension [M0010859]
  Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.
  
• Hypertension, Goldblatt [M0010867]
  HYPERTENSION due to renal ISCHEMIA. In 1934, Harry Goldblatt described that hypertension can be produced experimentally by using a clamp to obstruct blood flow to one kidney, the Goldblatt phenomenon.
  
• Hypertension, Malignant [M0010861]
  A condition of markedly elevated BLOOD PRESSURE with DIASTOLIC PRESSURE usually greater than 120 mm Hg. Malignant hypertension is characterized by widespread vascular damage, PAPILLEDEMA, retinopathy, HYPERTENSIVE ENCEPHALOPATHY, and renal dysfunction.
  
• Hypertension, Portal [M0010863]
  Abnormal increase of resistance to blood flow within the hepatic PORTAL SYSTEM, frequently seen in LIVER CIRRHOSIS and conditions with obstruction of the PORTAL VEIN.
  
• Hypertension, Pregnancy-Induced [M0452741]
  A condition in pregnant women with elevated systolic (>140 mm Hg) and diastolic (>90 mm Hg) blood pressure on at least two occasions 6 h apart. HYPERTENSION complicates 8-10% of all pregnancies, generally after 20 weeks of gestation. Gestational hypertension can be divided into several broad categories according to the complexity and associated symptoms, such as EDEMA; PROTEINURIA; SEIZURES; abnormalities in BLOOD COAGULATION and liver functions.
  
• Hypertension, Pulmonary [M0010865]
  Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.
  
• Hypertension, Renal [M0010866]
  Persistent high BLOOD PRESSURE due to KIDNEY DISEASES, such as those involving the renal parenchyma, the renal vasculature, or tumors that secrete RENIN.
  
• Hypertension, Renovascular [M0010868]
  Hypertension due to RENAL ARTERY OBSTRUCTION or compression.
  
• Hypertensive Encephalopathy [M0328335]
  Brain dysfunction or damage resulting from sustained MALIGNANT HYPERTENSION. When BLOOD PRESSURE exceeds the limits of cerebral autoregulation, cerebral blood flow is impaired (BRAIN ISCHEMIA). Clinical manifestations include HEADACHE; NAUSEA; VOMITING; SEIZURES; altered mental status (in some cases progressing to COMA); PAPILLEDEMA; and RETINAL HEMORRHAGE.
  
• Hyperthyroidism [M0010871]
  Hypersecretion of THYROID HORMONES from the THYROID GLAND. Elevated levels of thyroid hormones increase BASAL METABOLIC RATE.
  
• Hyperthyroxinemia [M0010872]
  Abnormally elevated THYROXINE level in the BLOOD.
  
• Hyperthyroxinemia, Familial Dysalbuminemic [M0471943]
  An inherited autosomal dominant trait characterized by abnormally elevated levels of total serum THYROXINE; (T4) in euthyroid patients with abnormal SERUM ALBUMIN that binds T4 with enhanced affinity. The serum levels of free T4, free T3, and TSH are normal. It is one of several T4 abnormalities produced by non-thyroid disorder. This condition is due to mutations of the ALB gene on CHROMOSOME 4.
  
• Hypertrichosis [M0010874]
  Excessive hair growth at inappropriate locations, such as on the extremities, the head, and the back. It is caused by genetic or acquired factors, and is an androgen-independent process. This concept does not include HIRSUTISM which is an androgen-dependent excess hair growth in WOMEN and CHILDREN.
  
• Hypertriglyceridemia [M0023401]
  A condition of elevated levels of TRIGLYCERIDES in the blood.
  
• Hypertropia [M0020558]
  
• Hypervitaminosis A [M0010877]
  A symptom complex resulting from ingesting excessive amounts of VITAMIN A.
  
• Hypnic Headache [M0335254]
  A primary headache disorder which occurs exclusively during sleep and regularly awakes patients at a consistent time of night.
  
• Hypoaldosteronism [M0010887]
  A congenital or acquired condition of insufficient production of ALDOSTERONE by the ADRENAL CORTEX leading to diminished aldosterone-mediated synthesis of Na(+)-K(+)-EXCHANGING ATPASE in renal tubular cells. Clinical symptoms include HYPERKALEMIA, sodium-wasting, HYPOTENSION, and sometimes metabolic ACIDOSIS.
  
• Hypoaldosteronism, Hyporeninemic [M0010888]
  A selective aldosterone deficiency resulting from diminished RENIN-generated ANGIOTENSIN II, a key stimulus to aldosterone secretion. Previously, it was called type IV renal tubular acidosis.
  
• Hypoalphalipoproteinemia, Familial [M0487126]
  
• Hypoalphalipoproteinemias [M0487118]
  Conditions with abnormally low levels of ALPHA-LIPOPROTEINS (high-density lipoproteins) in the blood. Hypoalphalipoproteinemia can be associated with mutations in genes encoding APOLIPOPROTEIN A-I; LECITHIN CHOLESTEROL ACYLTRANSFERASE; and ATP-BINDING CASSETTE TRANSPORTERS.
  
• Hypobetalipoproteinemia, Familial, Apolipoprotein B [M0487158]
  An autosomal dominant disorder of lipid metabolism. It is caused by mutations of APOLIPOPROTEINS B, main components of CHYLOMICRONS and BETA-LIPOPROTEINS (low density lipoproteins or LDL). Features include abnormally low LDL, normal triglyceride level, and dietary fat malabsorption.
  
• Hypobetalipoproteinemias [M0010890]
  Conditions with abnormally low levels of BETA-LIPOPROTEINS (low density lipoproteins or LDL) in the blood. It is defined as LDL values equal to or less than the 5th percentile for the population. They include the autosomal dominant form involving mutation of the APOLIPOPROTEINS B gene, and the autosomal recessive form involving mutation of the microsomal triglyceride transfer protein. All are characterized by low LDL and dietary fat malabsorption.
  
• Hypocalcemia [M0010891]
  Reduction of the blood calcium below normal. Manifestations include hyperactive deep tendon reflexes, Chvostek's sign, muscle and abdominal cramps, and carpopedal spasm. (Dorland, 27th ed)
  
• Hypocatalasemia [M0332925]
  
• Hypodermyiasis [M0010897]
  Infestation with larvae of the genus Hypoderma, the warble fly.
  
• Hypogalactia [M0012158]
  A condition of less than normal MILK secretion.
  
• Hypogammaglobulinemia [M0000552]
  
• Hypoglossal Nerve Diseases [M0328336]
  Diseases of the twelfth cranial (hypoglossal) nerve or nuclei. The nuclei and fascicles of the nerve are located in the medulla, and the nerve exits the skull via the hypoglossal foramen and innervates the muscles of the tongue. Lower brain stem diseases, including ischemia and MOTOR NEURON DISEASES may affect the nuclei or nerve fascicles. The nerve may also be injured by diseases of the posterior fossa or skull base. Clinical manifestations include unilateral weakness of tongue musculature and lingual dysarthria, with deviation of the tongue towards the side of weakness upon attempted protrusion.
  
• Hypoglossal Nerve Palsy [M0336165]
  
• Hypoglossal Neuralgia [M0336166]
  
• Hypoglossal Neuropathy [M0336167]
  
• Hypoglycemia [M0010901]
  A syndrome of abnormally low BLOOD GLUCOSE level. Clinical hypoglycemia has diverse etiologies. Severe hypoglycemia eventually lead to glucose deprivation of the CENTRAL NERVOUS SYSTEM resulting in HUNGER; SWEATING; PARESTHESIA; impaired mental function; SEIZURES; COMA; and even DEATH.
  
• Hypogonadism [M0010905]
  Condition resulting from deficient gonadal functions, such as GAMETOGENESIS and the production of GONADAL STEROID HORMONES. It is characterized by delay in GROWTH, germ cell maturation, and development of secondary sex characteristics. Hypogonadism can be due to a deficiency of GONADOTROPINS (hypogonadotropic hypogonadism) or due to primary gonadal failure (hypergonadotropic hypogonadism).
  
• Hypogonadotropic Hypogonadism [M0472162]
  
• Hypohidrosis [M0010908]
  Abnormally diminished or absent perspiration. Both generalized and segmented (reduced or absent sweating in circumscribed locations) forms of the disease are usually associated with other underlying conditions.
  
• Hypokalemia [M0010909]
  Abnormally low potassium concentration in the blood. It may result from potassium loss by renal secretion or by the gastrointestinal route, as by vomiting or diarrhea. It may be manifested clinically by neuromuscular disorders ranging from weakness to paralysis, by electrocardiographic abnormalities (depression of the T wave and elevation of the U wave), by renal disease, and by gastrointestinal disorders. (Dorland, 27th ed)
  
• Hypokalemic Periodic Paralysis [M0328337]
  An autosomal dominant familial disorder characterized by recurrent episodes of skeletal muscle weakness associated with falls in serum potassium levels. The condition usually presents in the first or second decade of life with attacks of trunk and leg paresis during sleep or shortly after awakening. Symptoms may persist for hours to days and generally are precipitated by exercise or a meal high in carbohydrates. (Adams et al., Principles of Neurology, 6th ed, p1483)
  
• Hypolipoproteinemias [M0010910]
  Conditions with abnormally low levels of LIPOPROTEINS in the blood. This may involve any of the lipoprotein subclasses, including ALPHA-LIPOPROTEINS (high-density lipoproteins); BETA-LIPOPROTEINS (low-density lipoproteins); and PREBETA-LIPOPROTEINS (very-low-density lipoproteins).
  
• Hypomenorrhea [M0013401]
  
• Hyponatremia [M0010911]
  Deficiency of sodium in the blood; salt depletion. (Dorland, 27th ed)
  
• Hypoparathyroidism [M0010912]
  A condition caused by a deficiency of PARATHYROID HORMONE (or PTH). It is characterized by HYPOCALCEMIA and hyperphosphatemia. Hypocalcemia leads to TETANY. The acquired form is due to removal or injuries to the PARATHYROID GLANDS. The congenital form is due to mutations of genes, such as TBX1 (DIGEORGE SYNDROME); CASR encoding CALCIUM-SENSING RECEPTOR; or PTH encoding parathyroid hormone.
  
• Hypophosphatasia [M0010915]
  A genetic metabolic disorder resulting from serum and bone alkaline phosphatase deficiency leading to hypercalcemia, ethanolamine phosphatemia, and ethanolamine phosphaturia. Clinical manifestations include severe skeletal defects resembling vitamin D-resistant rickets, failure of the calvarium to calcify, dyspnea, cyanosis, vomiting, constipation, renal calcinosis, failure to thrive, disorders of movement, beading of the costochondral junction, and rachitic bone changes. (From Dorland, 27th ed)
  
• Hypophosphatemia [M0026730]
  A condition of an abnormally low level of PHOSPHATES in the blood. Severe hypophosphatemia (below 1 mg/liter) can affect every organ in the body leading to HEMOLYSIS; LASSITUDE; SEIZURES; and COMA. Chronic hypophosphatemia can lead to MUSCLE WEAKNESS; and bone diseases, such as RICKETS and OSTEOMALACIA.
  
• Hypophosphatemia, Familial [M0010916]
  An inherited condition of abnormally low serum levels of PHOSPHATES (below 1 mg/liter) which can occur in a number of genetic diseases with defective reabsorption of inorganic phosphorus by the PROXIMAL RENAL TUBULES. This leads to phosphaturia, HYPOPHOSPHATEMIA, and disturbances of cellular and organ functions such as those in X-LINKED HYPOPHOSPHATEMIC RICKETS; OSTEOMALACIA; and FANCONI SYNDROME.
  
• Hypophosphatemic Rickets, X-Linked Dominant [M0010917]
  An X-linked disorder characterized by HYPOPHOSPHATEMIA; RICKETS; OSTEOMALACIA; renal defects in phosphate reabsorption and vitamin D metabolism; and growth retardation. This disorder is caused by mutations in PHEX PHOSPHATE REGULATING NEUTRAL ENDOPEPTIDASE.
  
• Hypopigmentation [M0026547]
  A condition caused by a deficiency or a loss of melanin pigmentation in the epidermis, also known as hypomelanosis. Hypopigmentation can be localized or generalized, and may result from genetic defects, trauma, inflammation, or infections.
  
• Hypopituitarism [M0010921]
  Diminution or cessation of secretion of one or more hormones from the anterior pituitary gland (including LH; FOLLICLE STIMULATING HORMONE; SOMATOTROPIN; and CORTICOTROPIN). This may result from surgical or radiation ablation, non-secretory PITUITARY NEOPLASMS, metastatic tumors, infarction, PITUITARY APOPLEXY, infiltrative or granulomatous processes, and other conditions.
  
• Hypoplastic Left Heart Syndrome [M0027929]
  A condition characterized by underdevelopment of the left cardiac chambers, atresia or stenosis of the aorta or mitral valve or both, and hypoplasia of the aorta. These anomalies are a common cause of heart failure in early infancy.
  
• Hypoprebetalipoproteinemia [M0487112]
  A condition with abnormally low levels of or VLDL (PREBETA-LIPOPROTEINS) in the blood.
  
• Hypoprothrombinemias [M0010925]
  Absence or reduced levels of prothrombin in the blood.
  
• Hypotension, Orthostatic [M0010929]
  A drop in blood pressure upon standing or after standing motionless in a static position.
  
• Hypothalamic Diseases [M0010935]
  Neoplastic, inflammatory, infectious, and other diseases of the hypothalamus. Clinical manifestations include appetite disorders; AUTONOMIC NERVOUS SYSTEM DISEASES; SLEEP DISORDERS; behavioral symptoms related to dysfunction of the LIMBIC SYSTEM; and neuroendocrine disorders.
  
• Hypothalamic Dysfunction Syndromes [M0335310]
  
• Hypothalamic Dysinhibition Syndrome [M0335311]
  
• Hypothalamic Overactivity Syndrome [M0335312]
  
• Hypothalamic Pseudopuberty [M0335313]
  
• Hypothalamic-Adenohypophyseal Disorders [M0335316]
  
• Hypothalamic-Neurohypophyseal Disorders [M0335308]
  
• Hypothyroidism [M0010948]
  A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA.
  
• Hypotrichosis [M0010950]
  Presence of less than the normal amount of hair. (Dorland, 27th ed)
  
• Hypoxia-Ischemia, Brain [M0328338]
  A disorder characterized by a reduction in oxygen supply (HYPOXIA) combined with reduced blood flow (ISCHEMIA) to the brain. This condition may result from a localized obstruction of a cerebral artery or from systemic hypoperfusion. Prolonged hypoxia-ischemia is associated with ISCHEMIC ATTACK, TRANSIENT; BRAIN INFARCTION; BRAIN EDEMA; COMA; and other conditions.
  
• Hypoxic-Ischemic Encephalopathy [M0335392]
  
• Iatrogenic Disease [M0010962]
  Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by the patient during the course of treatment.
  
• Ichthyosiform Erythroderma, Congenital [M0024612]
  Designation for several severe forms of ichthyosis, present at birth, that are characterized by hyperkeratotic scaling. Infants may be born encased in a collodion membrane which begins shedding within 24 hours. This is followed in about two weeks by persistent generalized scaling. The forms include bullous (HYPERKERATOSIS, EPIDERMOLYTIC), non-bullous (ICHTHYOSIS, LAMELLAR), wet type, and dry type.
  
• Ichthyosis [M0010978]
  Any of several generalized skin disorders characterized by dryness, roughness, and scaliness, due to hypertrophy of the stratum corneum epidermis. Most are genetic, but some are acquired, developing in association with other systemic disease or genetic syndrome.
  
• Ichthyosis Bullosa of Siemens [M0494619]
  An autosomal dominant form of ichthyosis characterized by generalized reddening of the skin (ERYTHEMA) and widespread blistering. The disease shows similar, but somewhat milder, clinical and histopathological findings to those in HYPERKERATOSIS, EPIDERMOLYTIC and is associated with the gene that encodes KERATIN-2A.
  
• Ichthyosis Vulgaris [M0024611]
  Most common form of ICHTHYOSIS characterized by prominent scaling especially on the exterior surfaces of the extremities. It is inherited as an autosomal dominant trait.
  
• Ichthyosis, Lamellar [M0026532]
  A chronic, congenital ichthyosis inherited as an autosomal recessive trait. Infants are usually born encased in a collodion membrane which sheds within a few weeks. Scaling is generalized and marked with grayish-brown quadrilateral scales, adherent at their centers and free at the edges. In some cases, scales are so thick that they resemble armored plate.
  
• Ichthyosis, X-Linked [M0024615]
  Chronic form of ichthyosis that is inherited as a sex-linked recessive trait carried on the X-chromosome and transmitted to the male offspring. It is characterized by severe scaling, especially on the extremities, and is associated with steroid sulfatase deficiency.
  
• Idiopathic Hypercatabolic Hypoproteinemia [M0017885]
  
• Idiopathic Hypereosinophilic Syndrome [M0026738]
  
• Idiopathic Hypertrophic Subaortic Stenosis [M0003467]
  
• Idiopathic Hypoparathyroidism [M0471567]
  A condition of low or absent PTH level and HYPOCALCEMIA. It usually occurs as part of an autoimmune syndrome.
  
• Idiopathic Inflammatory Myopathies [M0335633]
  
• Idiopathic Membranous Glomerulonephritis [M0023782]
  
• Idiopathic Myoclonic Epilepsy [M0334937]
  
• IgA Deficiency [M0025980]
  A dysgammaglobulinemia characterized by a deficiency of IMMUNOGLOBULIN A.
  
• IgG Deficiency [M0025981]
  A dysgammaglobulinemia characterized by a deficiency of IMMUNOGLOBULIN G.
  
• Ileal Diseases [M0011023]
  Pathological development in the ILEUM including the ILEOCECAL VALVE.
  
• Ileitis [M0011025]
  Inflammation of any segment of the ILEUM and the ILEOCECAL VALVE.
  
• Ileitis, Terminal [M0393457]
  
• Ileocolitis [M0393456]
  
• Ileus [M0449404]
  A condition caused by the lack of intestinal PERISTALSIS or INTESTINAL MOTILITY without any mechanical obstruction. This interference of the flow of INTESTINAL CONTENTS often leads to INTESTINAL OBSTRUCTION. Ileus may be classified into postoperative, inflammatory, metabolic, neurogenic, and drug-induced.
  
• Iliac Aneurysm [M0026606]
  An aneurysm of the common, internal, or external iliac arteries.
  
• Immersion Related Epilepsy [M0335121]
  
• Immune Complex Diseases [M0011066]
  Group of diseases mediated by the deposition of large soluble complexes of antigen and antibody with resultant damage to tissue. Besides SERUM SICKNESS and the ARTHUS REACTION, evidence supports a pathogenic role for immune complexes in many other IMMUNE SYSTEM DISEASES including GLOMERULONEPHRITIS, systemic lupus erythematosus (LUPUS ERYTHEMATOSUS, SYSTEMIC) and POLYARTERITIS NODOSA.
  
• Immune Disorders, Nervous System [M0334183]
  
• Immune System Diseases [M0011156]
  Disorders caused by abnormal or absent immunologic mechanisms, whether humoral, cell-mediated, or both.
  
• Immunoblastic Lymphadenopathy [M0011089]
  A disorder characterized by proliferation of arborizing small vessels, prominent immunoblastic proliferations and amorphous acidophilic interstitial material. Clinical manifestations include fever, sweats, weight loss, generalized lymphadenopathy and frequently hepatosplenomegaly.
  
• Immunologic Deficiency Syndromes [M0011155]
  Syndromes in which there is a deficiency or defect in the mechanisms of immunity, either cellular or humoral.
  
• Immunoproliferative Disorders [M0011164]
  Disorders characterized by abnormal proliferation of primary cells of the immune system or by excessive production of immunoglobulins.
  
• Impetigo [M0011174]
  A common superficial bacterial infection caused by STAPHYLOCOCCUS AUREUS or group A beta-hemolytic streptococci. Characteristics include pustular lesions that rupture and discharge a thin, amber-colored fluid that dries and forms a crust. This condition is commonly located on the face, especially about the mouth and nose.
  
• Impetigo Contagiosa [M0011175]
  
• Impotence [M0011177]
  The inability to perform sexual intercourse due to psychological or organ dysfunction.
  
• Impotence, Arteriogenic [M0028118]
  
• Impotence, Vasculogenic [M0028121]
  Inability to achieve and maintain an erection (ERECTILE DYSFUNCTION) due to defects in the arterial blood flow to the PENIS, defect in venous occlusive function allowing blood drainage (leakage) from the erectile tissue (corpus cavernosum penis), or both.
  
• Impotence, Venogenic [M0028119]
  
• Inadequate Sleep Hygiene [M0334692]
  
• Inappropriate ACTH Secretion Syndrome [M0459577]
  
• Inappropriate ADH Syndrome [M0011185]
  A condition of HYPONATREMIA and renal salt loss attributed to overexpansion of BODY FLUIDS resulting from sustained release of ANTIDIURETIC HORMONES which stimulates renal resorption of water. It is characterized by normal KIDNEY function, high urine OSMOLALITY, low serum osmolality, and neurological dysfunction. Etiologies include ADH-producing neoplasms, injuries or diseases involving the HYPOTHALAMUS, the PITUITARY GLAND, and the LUNG. This syndrome can also be drug-induced.
  
• Inclusion Body Myopathy, Sporadic [M0335634]
  
• Incontinentia Pigmenti [M0011200]
  A genodermatosis occurring mostly in females and characterized by skin changes in three phases - vesiculobullous, verrucous papillomatous, and macular melanodermic. Hyperpigmentation is bizarre and irregular. Sixty percent of patients have abnormalities of eyes, teeth, central nervous system, and skin appendages.
  
• Indirect Hyperbilirubinemia, Neonatal [M0480991]
  
• Indolent Systemic Mastocytosis [M0406103]
  A form of systemic mastocytosis in which patients experience no pain. It is characterized by the multifocal mast cell filtrates, mostly in skin and bone marrow (<20% MAST CELLS). It has a low cytomorphological grade.
  
• Industrial Dermatosis [M0015190]
  
• Infant Gynecomastia [M0458830]
  
• Infant Malnutrition [M0439620]
  Malnutrition, occurring in infants ages 1 month to 24 months, which is due to insufficient intake of food, dietary nutrients, or a pathophysiologic condition which prevents the absorption and utilization of food. Growth and development are markedly affected.
  
• Infant Nutrition Disorders [M0011280]
  Disorders caused by nutritional imbalance, either overnutrition or undernutrition, occurring in infants ages 1 month to 24 months.
  
• Infant Overnutrition [M0440456]
  
• Infant, Newborn, Diseases [M0011286]
  Diseases of newborn infants present at birth (congenital) or developing within the first month of birth. It does not include hereditary diseases not manifesting at birth or within the first 30 days of life nor does it include inborn errors of metabolism. Both HEREDITARY DISEASES and METABOLISM, INBORN ERRORS are available as general concepts.
  
• Infant, Premature, Diseases [M0011290]
  
• Infantile Neuroaxonal Dystrophy [M0028550]
  
• Infantile Neuronal Ceroid Lipfuscinosis [M0337073]
  This type is caused by mutation in the gene (CLN1or PPT1) encoding palmitoyl-protein thioesterase (THIOLESTER HYDROLASES), an enzyme involved in catabolism of lipid-modified proteins.
  
• Infantile Paralysis [M0335885]
  
• Infantile Sandhoff Disease [M0335922]
  
• Infantile Sialic Acid Storage Disease [M0384695]
  
• Infarction, Anterior Cerebral Artery [M0328339]
  An infarction in the vascular distribution of the anterior cerebral artery which supplies the majority of the medial surface of the cerebral hemispheres, and provides branches (including Heubner's artery) to the anterior limb of the internal capsule, head of the CAUDATE NUCLEUS, and anterior GLOBUS PALLIDUS. Clinical manifestations may include contralateral lower extremity weakness and sensory loss. Bilateral anterior cerebral artery infarctions are associated with abulia, PARAPLEGIA, and URINARY INCONTINENCE. (From Adams et al., Principles of Neurology, 6th ed, pp789-93)
  
• Infarction, Lacunar [M0334196]
  
• Infarction, Middle Cerebral Artery [M0328605]
  The formation of an area of coagulation necrosis in the vascular distribution of the middle cerebral artery secondary to ISCHEMIA. Clinical features include contralateral weakness and loss of sensation in the arm and face and a contralateral homonymous hemianopsia. Dominant hemisphere lesions may produce APHASIA, alexia, AGRAPHIA, acalculia, finger agnosia, and right-left confusion. Nondominant hemisphere lesions may produce unilateral neglect, dressing APRAXIA, anosognosia, and constructional apraxia. (From Adams et al., Principles of Neurology, 6th ed, p786)
  
• Infarction, Posterior Cerebral Artery [M0328606]
  Formation of an area of coagulation necrosis induced by ischemia in the vascular distribution of the posterior cerebral artery. This artery supplies portions of the MESENCEPHALON (see also BRAIN STEM INFARCTIONS) and thalamus, inferomedial TEMPORAL LOBE, and medial OCCIPITAL LOBE. Clinical manifestations vary with the size and location of infarction, but include a variety of midbrain and thalamic syndromes, HEMIANOPSIA, and behavioral syndromes related to memory and processing visual information. (From Adams et al., Principles of Neurology, 6th ed, pp793-8)
  
• Infection [M0011294]
  Invasion of the host organism by microorganisms that can cause pathological conditions or diseases.
  
• Infections, Arenavirus [M0001677]
  
• Infections, Bunyavirus [M0003044]
  
• Infections, Calicivirus [M0026173]
  
• Infections, Hospital [M0005343]
  
• Infections, Nematomorpha [M0010008]
  
• Infections, Parvovirus [M0015997]
  
• Infections, Upper Respiratory [M0018920]
  
• Infectious Bovine Rhinotracheitis [M0011297]
  A herpesvirus infection of CATTLE characterized by INFLAMMATION and NECROSIS of the mucous membranes of the upper RESPIRATORY TRACT.
  
• Infectious Encephalitis [M0334838]
  
• Infectious Mononucleosis [M0011300]
  A common, acute infection usually caused by the Epstein-Barr virus (HERPESVIRUS 4, HUMAN). There is an increase in mononuclear white blood cells and other atypical lymphocytes, generalized lymphadenopathy, splenomegaly, and occasionally hepatomegaly with hepatitis.
  
• Infectious Myelitis [M0335749]
  
• Infertility [M0011302]
  Inability to reproduce after a specified period of unprotected intercourse. Reproductive sterility is permanent infertility.
  
• Inflammatory Bowel Diseases [M0023374]
  Chronic, non-specific inflammation of the GASTROINTESTINAL TRACT. Etiology may be genetic or environmental. This term includes CROHN DISEASE and ULCERATIVE COLITIS.
  
• Inflammatory Pseudotumor [M0009614]
  
• Influenza in Birds [M0008793]
  Infection of domestic and wild fowl and other BIRDS with INFLUENZA A VIRUS. Avian influenza usually does not sicken birds, but can be highly pathogenic and fatal in domestic POULTRY.
  
• Influenza, Human [M0011309]
  An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the NASAL MUCOSA; the PHARYNX; and conjunctiva, and by headache and severe, often generalized, myalgia.
  
• Inguinal Hernia, Direct [M0453544]
  
• Inguinal Hernia, Indirect [M0453543]
  
• Insomnia, Fatal Familial [M0025976]
  An autosomal dominant disorder characterized by degeneration of the THALAMUS and progressive insomnia. It is caused by a mutation in the prion protein (PRIONS).
  
• Insufficient Sleep Syndrome [M0334753]
  
• Insulin Coma [M0011427]
  Severe HYPOGLYCEMIA induced by a large dose of exogenous INSULIN resulting in a COMA or profound state of unconsciousness from which the individual cannot be aroused.
  
• Insulin Shock [M0446505]
  Sudden significant drop in BLOOD GLUCOSE or hypoglycemic shock which affects the hemodynamic equilibrium of all vital organs.
  
• Intermediate Maple Syrup Urine Disease [M0335652]
  
• Intermittent Claudication [M0011515]
  A symptom complex characterized by leg pain and weakness brought on by walking, with the disappearance of the symptoms following a brief rest.
  
• Intermittent Esotropia [M0336195]
  
• Intermittent Maple Syrup Urine Disease [M0335653]
  
• Internal Carotid Artery Diseases [M0003542]
  
• Internal Carotid Artery Stenosis [M0334353]
  
• Internal Carotid Artery Thrombosis [M0334343]
  
• Internal Nerve Compression Syndromes [M0336251]
  
• Internuclear Ophthalmoplegia [M0335797]
  
• Intertrigo [M0011557]
  A superficial dermatitis occurring on skin surfaces in contact with each other, such as the axillae, neck creases, intergluteal fold, between the toes, etc. Obesity is a predisposing factor. The condition is caused by moisture and friction and is characterized by erythema, maceration, burning, and exudation.
  
• Intervertebral Disk Displacement [M0011560]
  An intervertebral disk in which the nucleus pulposus has protruded through surrounding fibrocartilage. This occurs most frequently in the lower lumbar region.
  
• Intestinal Atresia [M0011568]
  Congenital obliteration of the lumen of the intestine, with the ILEUM involved in 50% of the cases and the JEJUNUM and DUODENUM following in frequency. It is the most frequent cause of INTESTINAL OBSTRUCTION in NEWBORNS. (From Stedman, 25th ed)
  
• Intestinal Diseases [M0011569]
  Pathological processes in any segment of the INTESTINE from DUODENUM to RECTUM.
  
• Intestinal Diseases, Parasitic [M0011570]
  Infections of the INTESTINES with PARASITES, commonly involving PROTOZOA or PARASITIC WORMS. Infections with roundworms (NEMATODE INFECTIONS) and tapeworms (CESTODE INFECTIONS) are also known as HELMINTHIASIS.
  
• Intestinal Obstruction [M0011575]
  Any impairment, arrest, or reversal of the normal flow of INTESTINAL CONTENTS toward the ANAL CANAL.
  
• Intestinal Perforation [M0011577]
  Opening or penetration through the wall of the INTESTINES.
  
• Intestinal Polyposis [M0445225]
  The growth of INTESTINAL POLYPS. Growth processes include neoplastic (ADENOMA and CARCINOMA) and non-neoplastic (hyperplastic, mucosal, inflammatory, and other polyps).
  
• Intestinal Pseudo-Obstruction [M0011580]
  A type of ILEUS, a functional not mechanical obstruction of the INTESTINES. This syndrome is caused by a large number of disorders involving the smooth muscles (MUSCLE, SMOOTH) or the NERVOUS SYSTEM.
  
• Intestinal Volvulus [M0011576]
  A twisting in the intestine (INTESTINES) that can cause INTESTINAL OBSTRUCTION.
  
• Intracranial Aneurysm [M0003870]
  Congenital or acquired abnormal outpouching of an intracranial blood vessel wall. Saccular (berry) aneurysms are the most common variant, and tend to form at arterial branch points near the base of the brain. Rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE (see also OCULOMOTOR NERVE DISEASES). (From Adams et al., Principles of Neurology, 6th ed, p841)
  
• Intracranial Arterial Diseases [M0328607]
  Conditions which affect the arteries of the brain, meninges, and intracranial portions of the cranial nerves. Relatively common disease processes in this category include: ATHEROSCLEROSIS; emboli; thrombosis (INTRACRANIAL EMBOLISM AND THROMBOSIS); VASCULITIS, CENTRAL NERVOUS SYSTEM; CEREBROVASCULAR TRAUMA; vasospasm (VASOSPASM, INTRACRANIAL); INTRACRANIAL ARTERIOVENOUS MALFORMATIONS; and infections.
  
• Intracranial Arteriosclerosis [M0333616]
  Vascular diseases characterized by thickening, hardening, and remodeling of the walls of intracranial arteries. There are three subtypes: (1) atherosclerosis, marked by fatty depositions in the innermost layer of the arterial walls, (2) Monckeberg's sclerosis, which features calcium deposition in the media and (3) arteriolosclerosis, which refers to sclerosis of small caliber arteries. Clinically, this process may be associated with ISCHEMIC ATTACK, TRANSIENT; BRAIN INFARCTION; INTRACRANIAL EMBOLISM AND THROMBOSIS; or INTRACRANIAL ANEURYSM.
  
• Intracranial Arteriovenous Malformation, Ruptured [M0335451]
  
• Intracranial Atherosclerosis [M0337456]
  
• Intracranial Embolism [M0328608]
  Migration of foreign material to the intracranial components of the nervous system via arterial pathways. Emboli most frequently are of cardiac origin and are associated with ARRHYTHMIA; mural thrombi; ENDOCARDITIS, SUBACUTE BACTERIAL; HEART VALVE DISEASES; and HEART SEPTAL DEFECTS. Noncardiac sources include lesions of the aorta, carotid arteries, vertebral arteries, and intracranial arteries. Emboli may be composed of thrombosed platelets, atherosclerotic debris, fat, air, tumor cells, or infectious materials, and may cause CEREBRAL INFARCTION. (From Adams et al., Principles of Neurology, 6th ed, pp824-6)
  
• Intracranial Embolism and Thrombosis [M0333623]
  Embolism or thrombosis involving blood vessels which supply intracranial structures. Emboli may originate from extracranial or intracranial sources. Thrombosis may occur in arterial or venous structures.
  
• Intracranial Hypertension [M0029084]
  Increased pressure within the cranial vault. This may result from several conditions, including HYDROCEPHALUS; BRAIN EDEMA; intracranial masses; severe systemic HYPERTENSION; PSEUDOTUMOR CEREBRI; and other disorders.
  
• Intracranial Hypotension [M0029083]
  Reduction of CEREBROSPINAL FLUID pressure characterized clinically by HEADACHE which is maximal in an upright posture and occasionally by an abducens nerve palsy (see ABDUCENS NERVE DISEASES), neck stiffness, hearing loss (see DEAFNESS); NAUSEA; and other symptoms. This condition may be spontaneous or secondary to SPINAL PUNCTURE; NEUROSURGICAL PROCEDURES; DEHYDRATION; UREMIA; trauma (see also CRANIOCEREBRAL TRAUMA); and other processes. Chronic hypotension may be associated with subdural hematomas (see HEMATOMA, SUBDURAL) or hygromas. (From Semin Neurol 1996 Mar;16(1):5-10; Adams et al., Principles of Neurology, 6th ed, pp637-8)
  
• Intracranial Hypotension, Essential [M0335455]
  
• Intracranial Hypotension, Secondary [M0335456]
  
• Intracranial Sinus Thrombophlebitis [M0336047]
  
• Intracranial Thrombosis [M0328612]
  Formation of a clot composed of platelets and fibrin within the lumen of an intracranial artery or vein, which may result in CEREBRAL INFARCTION. Arterial thrombosis is associated with INTRACRANIAL ARTERIOSCLEROSIS, but may also result from hypercoagulability states (see THROMBOPHILIA). Cerebral vein thrombosis is frequently complicated by INTRACRANIAL HEMORRHAGES.
  
• Intracranial Toxoplasmosis [M0336245]
  
• Intraosseous Ganglion [M0002773]
  
• Intussusception [M0011617]
  A form of intestinal obstruction caused by the PROLAPSE of a part of the intestine into the adjoining intestinal lumen. There are four types: colic, involving segments of the LARGE INTESTINE; enteric, involving only the SMALL INTESTINE; ileocecal, in which the ILEOCECAL VALVE prolapses into the CECUM, drawing the ILEUM along with it; and ileocolic, in which the ileum prolapses through the ileocecal valve into the COLON.
  
• Iodamoebiasis [M0000880]
  
• Iridocyclitis [M0024287]
  Acute or chronic inflammation of the iris and ciliary body characterized by exudates into the anterior chamber, discoloration of the iris, and constricted, sluggish pupil. Symptoms include radiating pain, photophobia, lacrimation, and interference with vision.
  
• Iris Diseases [M0011716]
  Diseases, dysfunctions, or disorders of or located in the iris.
  
• Iritis [M0011717]
  Inflammation of the iris characterized by circumcorneal injection, aqueous flare, keratotic precipitates, and constricted and sluggish pupil along with discoloration of the iris.
  
• Iron Metabolism Disorders [M0028591]
  Disorders in the processing of iron in the body: its absorption, transport, storage, and utilization. (From Mosby's Medical, Nursing, & Allied Health Dictionary, 4th ed)
  
• Iron Overload [M0028592]
  An excessive accumulation of iron in the body due to a greater than normal absorption of iron from the gastrointestinal tract or from parenteral injection. This may arise from idiopathic hemochromatosis, excessive iron intake, chronic alcoholism, certain types of refractory anemia, or transfusional hemosiderosis. (From Churchill's Illustrated Medical Dictionary, 1989)
  
• Irritable Bowel Syndrome [M0004816]
  A disorder with chronic or recurrent colonic symptoms without a clearcut etiology. This condition is characterized by chronic or recurrent ABDOMINAL PAIN, bloating, MUCUS in FECES, and an erratic disturbance of DEFECATION.
  
• Isaacs Syndrome [M0008237]
  A rare neuromuscular disorder with onset usually in late childhood or early adulthood, characterized by intermittent or continuous widespread involuntary muscle contractions; FASCICULATION; hyporeflexia; MUSCLE CRAMP; MUSCLE WEAKNESS; HYPERHIDROSIS; TACHYCARDIA; and MYOKYMIA. Involvement of pharyngeal or laryngeal muscles may interfere with speech and breathing. The continuous motor activity persists during sleep and general anesthesia (distinguishing this condition from STIFF-PERSON SYNDROME). Familial and acquired (primarily autoimmune) forms have been reported. (From Ann NY Acad Sci 1998 May 13;841:482-496; Adams et al., Principles of Neurology, 6th ed, p1491)
  
• Ischemia [M0011734]
  A hypoperfusion of the BLOOD through an organ or tissue caused by a PATHOLOGIC CONSTRICTION or obstruction of its BLOOD VESSELS, or an absence of BLOOD CIRCULATION.
  
• Ischemic Attack, Transient [M0003887]
  Brief reversible episodes of focal, nonconvulsive ischemic dysfunction of the brain having a duration of less than 24 hours, and usually less than one hour, caused by transient thrombotic or embolic blood vessel occlusion or stenosis. Events may be classified by arterial distribution, temporal pattern, or etiology (e.g., embolic vs. thrombotic). (From Adams et al., Principles of Neurology, 6th ed, pp814-6)
  
• Isosporiasis [M0355659]
  Infection with parasitic protozoa of the genus ISOSPORA, producing intestinal disease. It is caused by ingestion of oocysts and can produce tissue cysts.
  
• Ito Syndrome [M0016851]
  
• Jackknife Seizures [M0020208]
  
• Jacksonian Seizure [M0007567]
  
• Jaundice, Chronic Idiopathic [M0011823]
  A benign, autosomally recessive inherited hyperbilirubinemia characterized by the presence of a dark pigment in the centrilobular region of the liver cells. There is a functional defect in biliary excretion of bilirubin, cholephilic dyes, and porphyrins. Affected persons may be asymptomatic or have vague constitutional or gastrointestinal symptoms. The liver may be slightly enlarged, and oral and intravenous cholangiography fails to visualize the biliary tract.
  
• Jaundice, Hemolytic [M0001126]
  
• Jaw Abnormalities [M0011826]
  Congenital absence of or defects in structures of the jaw.
  
• Jaw Cysts [M0011827]
  Saccular lesions lined with epithelium and contained within pathologically formed cavities in the jaw; also nonepithelial cysts (pseudocysts) as they apply to the jaw, e.g., traumatic or solitary cyst, static bone cavity, and aneurysmal bone cyst. True jaw cysts are classified as odontogenic or nonodontogenic.
  
• Jaw Diseases [M0011828]
  
• Jaw, Edentulous [M0011835]
  The total absence of teeth from either the mandible or the maxilla, but not both. Total absence of teeth from both is MOUTH, EDENTULOUS. Partial absence of teeth in either is JAW, EDENTULOUS, PARTIALLY.
  
• Jaw, Edentulous, Partially [M0011836]
  Absence of teeth from a portion of the mandible and/or maxilla.
  
• Jejunal Diseases [M0011839]
  Pathological development in the JEJUNUM region of the SMALL INTESTINE.
  
• Jerk Nystagmus [M0333557]
  
• Jervell-Lange Nielsen Syndrome [M0012683]
  An autosomal recessive syndrome of abnormal cardioelectrophysiology, combining LONG QT SYNDROME with deafness.
  
• Jet Lag Syndrome [M0328614]
  A chronobiologic disorder resulting from rapid travel across a number of time zones, characterized by insomnia or hypersomnolence, fatigue, behavioral symptoms, headaches, and gastrointestinal disturbances. (From Cooper, Sleep, 1994, pp593-8)
  
• Job's Syndrome [M0011856]
  A disorder of neutrophils characterized by the presence of abnormal or absent chemotactic responses and hyperimmunoglobulinemia E. It is transmitted as an autosomal recessive trait and most cases reported have been in girls.
  
• Joint Diseases [M0011860]
  
• Joint Instability [M0011861]
  Lack of stability of a joint or joint prosthesis. Factors involved are intra-articular disease and integrity of extra-articular structures such as joint capsule, ligaments, and muscles.
  
• Joint Tuberculosis [M0022127]
  
• Juvenile Huntington Disease [M0332772]
  
• Juvenile Neuroaxonal Dystrophy [M0335763]
  
• Juvenile Neuronal Ceroid Lipfuscinosis [M0014731]
  This type is caused by mutation in the CLN3 gene encoding a lysosomal integral membrane protein (Battenin).
  
• Juvenile Paresis [M0335775]
  
• Juvenile Pyruvate Dehydrogenase Complex Deficiency Disease [M0335906]
  
• Juvenile Sandhoff Disease [M0335923]
  
• Juvenile Spinal Muscular Atrophy [M0336134]
  
• Juvenile Temporal Arteritis [M0335460]
  
• Juvenile-Onset Still Disease [M0001749]
  
• Kallmann Syndrome [M0026453]
  A genetically heterogeneous disorder caused by hypothalamic GNRH deficiency and OLFACTORY NERVE defects. It is characterized by congenital HYPOGONADOTROPIC HYPOGONADISM and ANOSMIA, possibly with additional midline defects. It can be transmitted as an X-linked (GENETIC DISEASES, X-LINKED), an autosomal dominant, or an autosomal recessive trait.
  
• Kallmann Syndrome 1 [M0472223]
  Type 1 is the X-linked form with mutations of gene KAL1 which encodes anosmin-1 protein that plays a key role in the migration of GNRH-containing neurons and olfactory nerves to the HYPOTHALAMUS.
  
• Kallmann Syndrome 2 [M0472224]
  Type 2 is an autosomal dominant form with loss-of-function mutations of gene KAL2 which encodes fibroblast growth-factor receptor-1 (FGFR1).
  
• Kaposi Varicelliform Eruption [M0011927]
  A disseminated vesicular-pustular eruption caused by the herpes simplex virus (HERPESVIRUS HOMINIS), the VACCINIA VIRUS, or Varicella zoster (HERPESVIRUS 3, HUMAN). It is usually superimposed on a preexisting, inactive or active, atopic dermatitis (DERMATITIS, ATOPIC).
  
• Kartagener Syndrome [M0011929]
  An autosomal recessive disorder characterized by BRONCHIECTASIS; SINUSITIS; DEXTROCARDIA; and INFERTILITY. In vitro studies of tissues from these patients, have shown various patterns of abnormal ciliary beating. (Online Mendelian Inheritance in Man, http://www.ncbi.nlm.nih.gov/OMIM, MIM # 244400, April 24, 2001)
  
• Kearns-Sayer Syndrome [M0011934]
  A mitochondrial disorder featuring the triad of chronic progressive EXTERNAL OPHTHALMOPLEGIA, cardiomyopathy (CARDIOMYOPATHIES) with conduction block (HEART BLOCK), and RETINITIS PIGMENTOSA. Disease onset is in the first or second decade. Elevated CSF protein, sensorineural deafness, seizures, and pyramidal signs may also be present. Ragged-red fibers are found on muscle biopsy. (Adams et al., Principles of Neurology, 6th ed, p984)
  
• Keloid [M0011936]
  A sharply elevated, irregularly shaped, progressively enlarging scar resulting from formation of excessive amounts of collagen in the dermis during connective tissue repair. It is differentiated from a hypertrophic scar (CICATRIX, HYPERTROPHIC) in that the former does not spread to surrounding tissues.
  
• Keratitis [M0011962]
  Inflammation of the cornea.
  
• Keratitis, Dendritic [M0011963]
  A form of herpetic keratitis characterized by the formation of small vesicles which break down and coalesce to form recurring dendritic ulcers, characteristically irregular, linear, branching, and ending in knoblike extremities. (Dictionary of Visual Science, 3d ed)
  
• Keratitis, Herpetic [M0025643]
  A superficial, epithelial Herpesvirus hominis infection of the cornea, characterized by the presence of small vesicles which may break down and coalesce to form dendritic ulcers (KERATITIS, DENDRITIC). (Dictionary of Visual Science, 3d ed)
  
• Keratoacanthoma [M0011964]
  A benign, non-neoplastic, usually self-limiting epithelial lesion closely resembling squamous cell carcinoma clinically and histopathologically. It occurs in solitary, multiple, and eruptive forms. The solitary and multiple forms occur on sunlight exposed areas and are identical histologically; they affect primarily white males. The eruptive form usually involves both sexes and appears as a generalized papular eruption.
  
• Keratoconjunctivitis [M0011965]
  Simultaneous inflammation of the cornea and conjunctiva.
  
• Keratoconjunctivitis Sicca [M0011966]
  Drying and inflammation of the conjunctiva as a result of insufficient lacrimal secretion. When found in association with XEROSTOMIA and polyarthritis, it is called SJOGREN'S SYNDROME.
  
• Keratoconjunctivitis, Infectious [M0011967]
  Infectious diseases of cattle, sheep, and goats, characterized by blepharospasm, lacrimation, conjunctivitis, and varying degrees of corneal opacity and ulceration. In cattle the causative agent is MORAXELLA (MORAXELLA) BOVIS; in sheep, MYCOPLASMA; RICKETTSIA; CHLAMYDIA; or ACHOLEPLASMA; in goats, RICKETTSIA.
  
• Keratoconjunctivitis, Vernal [M0005020]
  
• Keratoconus [M0011968]
  A noninflammatory, usually bilateral protrusion of the cornea, the apex being displaced downward and nasally. It occurs most commonly in females at about puberty. The cause is unknown but hereditary factors may play a role. The -conus refers to the cone shape of the corneal protrusion. (From Dorland, 27th ed)
  
• Keratocysts [M0015222]
  
• Keratoderma, Palmoplantar [M0011974]
  Group of mostly hereditary disorders characterized by thickening of the palms and soles as a result of excessive keratin formation leading to hypertrophy of the stratum corneum (hyperkeratosis).
  
• Keratoderma, Palmoplantar, Diffuse [M0024171]
  An autosomal dominant disorder characterized by a widely distributed, well-demarcated hyperkeratosis of the palms and soles. There is more than one genotypically distinct form, each of which is clinically similar but histologically distinguishable. Diffuse palmoplantar keratoderma is distinct from palmoplantar keratoderma (KERATODERMA, PALMOPLANTAR), as the former exhibits autosomal dominant inheritance and hyperhidrosis is frequently present.
  
• Keratoderma, Palmoplantar, Epidermolytic [M0494459]
  An autosomal dominant hereditary skin disease characterized by epidermolytic hyperkeratosis that is strictly confined to the palms and soles. It has been associated with mutations in the gene that codes for KERATIN-9.
  
• Keratosis Blennorrhagica [M0011971]
  
• Keratosis Follicularis [M0011973]
  A slowly progressive autosomal dominant disorder of keratinization characterized by pinkish-to-tan papules that coalesce to form plaques. These lesions become darker over time and commonly fuse, forming papillomatous and warty malodorous growths.
  
• Kernicterus [M0011977]
  A term used pathologically to describe BILIRUBIN staining of the BASAL GANGLIA; BRAIN STEM; and CEREBELLUM and clinically to describe a syndrome associated with HYPERBILIRUBINEMIA. Clinical features include athetosis, MUSCLE SPASTICITY or hypotonia, impaired vertical gaze, and DEAFNESS. Nonconjugated bilirubin enters the brain and acts as a neurotoxin, often in association with conditions that impair the BLOOD-BRAIN BARRIER (e.g., SEPSIS). This condition occurs primarily in neonates (INFANT, NEWBORN), but may rarely occur in adults. (Menkes, Textbook of Child Neurology, 5th ed, p613)
  
• Ketosis [M0012000]
  A condition characterized by an abnormally elevated concentration of ketone bodies in the body tissues and fluids. It is a complication of diabetes mellitus and starvation. (Dorland, 27th ed)
  
• Kidney Cortex Necrosis [M0012013]
  Death of cells in the KIDNEY CORTEX, a common final result of various renal injuries including HYPOXIA; ISCHEMIA; and drug toxicity.
  
• Kidney Diseases [M0012014]
  Pathological processes of the KIDNEY or its component tissues.
  
• Kidney Diseases, Cystic [M0483545]
  A heterogeneous group of hereditary and acquired disorders in which the KIDNEY contains one or more CYSTS unilaterally or bilaterally (KIDNEY, CYSTIC).
  
• Kidney Failure [M0025974]
  A severe irreversible decline in the ability of kidneys to remove wastes, concentrate URINE, and maintain ELECTROLYTE BALANCE; BLOOD PRESSURE; and CALCIUM metabolism. Renal failure, either acute (KIDNEY FAILURE, ACUTE) or chronic (KIDNEY FAILURE, CHRONIC), requires HEMODIALYSIS.
  
• Kidney Failure, Acute [M0012015]
  A severe stage of acute renal insufficiency, characterized by the sudden decrease in GLOMERULAR FILTRATION RATE to less than 15 ml per min, sometime to less than 1 to 2 ml per min. It is usually associated with OLIGURIA; EDEMA; and increase in BLOOD UREA NITROGEN and serum CREATININE concentrations.
  
• Kidney Failure, Chronic [M0012016]
  The end-stage of CHRONIC RENAL INSUFFICIENCY. It is characterized by the severe irreversible kidney damage (as measured by the level of PROTEINURIA) and the reduction in GLOMERULAR FILTRATION RATE to less than 15 ml per min (Kidney Foundation: Kidney Disease Outcome Quality Initiative, 2002). These patients generally require HEMODIALYSIS or KIDNEY TRANSPLANTATION.
  
• Kidney Papillary Necrosis [M0012022]
  A complication of kidney diseases characterized by cell death involving KIDNEY PAPILLA in the KIDNEY MEDULLA. Damages to this area may hinder the kidney to concentrate urine resulting in POLYURIA. Sloughed off necrotic tissue may block KIDNEY PELVIS or URETER. Necrosis of multiple renal papillae can lead to KIDNEY FAILURE.
  
• Kidney Tubular Necrosis, Acute [M0012024]
  Acute kidney failure resulting from destruction of EPITHELIAL CELLS of the KIDNEY TUBULES. It is commonly attributed to exposure to toxic agents or renal ISCHEMIA following severe TRAUMA.
  
• Kimura Disease [M0001193]
  
• King's Evil [M0027882]
  The historic designation for scrofula (TUBERCULOSIS, LYMPH NODE). The disease is so called from the belief that it could be healed by the touch of a king. This term is used only for historical articles using the name "king's evil", and is to be differentiated from scrofula as lymph node tuberculosis in modern clinical medicine. (From Webster, 3d ed)
  
• Kinsbourne Syndrome [M0494758]
  
• Klebsiella Infections [M0012059]
  Infections with bacteria of the genus KLEBSIELLA.
  
• Kleine-Levin Syndrome [M0026659]
  A rare condition characterized by recurrent hypersomnias associated with hyperphagia, occurring primarily in males in the second to third decade of life. Clinical features include mental confusion, excessive sleep requirements (approximately 18 hours per day), restlessness, and in some cases hallucinations. Episodes have a duration of days to weeks, and may recur several times per year. This condition may resolve spontaneously over several years. (From Adams, et al., Principles of Neurology, 6th ed, p569)
  
• Klinefelter Syndrome [M0012062]
  A form of male HYPOGONADISM, characterized by the presence of an extra X CHROMOSOME, small TESTES, seminiferous tubule dysgenesis, elevated levels of GONADOTROPINS, low serum TESTOSTERONE, underdeveloped secondary sex characteristics, and male infertility (INFERTILITY, MALE). Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several karyotype variants include 48,XXYY; 48,XXXY; 49,XXXXY, and mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).
  
• Klippel-Trenaunay-Weber Syndrome [M0012064]
  A rare condition usually affecting one extremity, characterized by hypertrophy of the bone and related soft tissues, large cutaneous hemangiomas, persistent nevus flammeus, and skin varices. (Dorland, 27th ed)
  
• Kuru [M0012084]
  A prion disease found exclusively among the Fore linguistic group natives of the highlands of NEW GUINEA. The illness is primarily restricted to adult females and children of both sexes. It is marked by the subacute onset of tremor and ataxia followed by motor weakness and incontinence. Death occurs within 3-6 months of disease onset. The condition is associated with ritual cannibalism, and has become rare since this practice has been discontinued. Pathologic features include a noninflammatory loss of neurons that is most prominent in the cerebellum, glial proliferation, and amyloid plaques. (From Adams et al., Principles of Neurology, 6th ed, p773)
  
• Kwashiorkor [M0012087]
  A syndrome produced by severe protein deficiency, characterized by retarded growth, changes in skin and hair pigment, edema, and pathologic changes in the liver, including fatty infiltration, necrosis, and fibrosis. The word is a local name in Gold Coast, Africa, meaning "displaced child". Although first reported from Africa, kwashiorkor is now known throughout the world, but mainly in the tropics and subtropics. It is considered to be related to marasmus. (From Dorland, 27th ed)
  
• Kyasanur Forest Disease [M0012088]
  Tick-borne flavivirus infection occurring in the Kyasanur Forest in India.
  
• Laboratory Infection [M0012123]
  Accidentally acquired infection in laboratory workers.
  
• Labyrinth Diseases [M0012125]
  
• Labyrinthitis [M0012128]
  Inflammation of the inner ear.
  
• Lacrimal Apparatus Diseases [M0012135]
  Diseases of the lacrimal apparatus.
  
• Lactation Disorders [M0012159]
  Disturbances of MILK secretion in either SEX, not necessarily related to PREGNANCY.
  
• Lactose Intolerance [M0012180]
  The condition resulting from the absence or deficiency of LACTASE in the MUCOSA cells of the GASTROINTESTINAL TRACT, and the inability to break down LACTOSE in milk for ABSORPTION. Bacterial fermentation of the unabsorbed lactose leads to symptoms that range from a mild indigestion (DYSPEPSIA) to severe DIARRHEA. Lactose intolerance may be an inborn error or acquired.
  
• Lacunar Dementia [M0023302]
  
• Lafora Body Disease, Late Onset [M0335477]
  
• Lafora Disease [M0328685]
  A form of stimulus sensitive myoclonic epilepsy inherited as an autosomal recessive condition. The most common presenting feature is a single seizure in the second decade of life. This is followed by progressive myoclonus, myoclonic seizures, tonic-clonic seizures, focal occipital seizures, intellectual decline, and severe motor and coordination impairments. Most affected individuals do not live past the age of 25 years. Concentric amyloid (Lafora) bodies are found in neurons, liver, skin, bone, and muscle (From Menkes, Textbook of Childhood Neurology, 5th ed, pp111-110)
  
• Lambert-Eaton Myasthenic Syndrome [M0023968]
  An autoimmune disease characterized by weakness and fatigability of proximal muscles, particularly of the pelvic girdle, lower extremities, trunk, and shoulder girdle. There is relative sparing of extraocular and bulbar muscles. CARCINOMA, SMALL CELL of the lung is a frequently associated condition, although other malignancies and autoimmune diseases may be associated. Muscular weakness results from impaired impulse transmission at the NEUROMUSCULAR JUNCTION. Presynaptic calcium channel dysfunction leads to a reduced amount of acetylcholine being released in response to stimulation of the nerve. (From Adams et al., Principles of Neurology, 6th ed, pp 1471)
  
• Langer-Giedion Syndrome [M0024244]
  Autosomal dominant disorder characterized by cone-shaped epiphyses in the hands and multiple cartilaginous exostoses. Mental retardation and abnormalities of chromosome 8 are often present. The exostoses in this syndrome appear identical to those of hereditary multiple exostoses (EXOSTOSES, HEREDITARY MULTIPLE).
  
• Larva Migrans [M0012221]
  Infections caused by nematode larvae which never develop into the adult stage and migrate through various body tissues. They commonly infect the skin, eyes, and viscera in man. Ancylostoma brasiliensis causes cutaneous larva migrans. Toxocara causes visceral larva migrans.
  
• Larva Migrans, Visceral [M0012224]
  A condition produced in man by the prolonged migration of animal nematode larvae in extraintestinal tissues other than skin; characterized by persistent hypereosinophilia, hepatomegaly, and frequently pneumonitis, commonly caused by Toxocara canis and Toxocara cati.
  
• Laryngeal Diseases [M0012226]
  Disorders of the larynx, general or unspecified.
  
• Laryngeal Nerve Palsy, Recurrent [M0336419]
  
• Laryngeal Paralysis [M0022825]
  
• Laryngeal Perichondritis [M0012227]
  
• Laryngismus [M0012235]
  Spasm of the larynx.
  
• Laryngitis [M0012236]
  Inflammation of the larynx. This condition presents itself with dryness and soreness of the throat, difficulty in swallowing, cough, and hoarseness.
  
• Laryngostenosis [M0012238]
  Stricture or narrowing of the larynx. This condition may be developmental or acquired; with progressive respiratory difficulty as a symptom.
  
• Lassa Fever [M0012249]
  An acute febrile human disease caused by the LASSA VIRUS.
  
• Late Infantile Neuroaxonal Dystrophy [M0335765]
  
• Late Post-Traumatic Seizures [M0335113]
  
• Late-Infantile Neuronal Ceroid Lipfuscinosis [M0014732]
  This type is caused by mutation in the CLN2 gene encoding tripeptidyl-peptidase I, a lysosomal serine protease.
  
• Late-Onset Disorders [M0026724]
  
• Late-Onset Globoid Cell Leukodystrophy [M0335507]
  
• Lateral Medullary Syndrome [M0022866]
  Infarction of the dorsolateral aspect of the medulla due to occlusion of the vertebral artery and/or the posterior inferior cerebellar artery. Clinical manifestations vary with the size of infarction, but may include loss of pain and temperature sensation in the ipsilateral face and contralateral body below the chin; ipsilateral HORNER SYNDROME; ipsilateral ATAXIA; DYSARTHRIA; VERTIGO; nausea, hiccup; dysphagia; and VOCAL CORD PARALYSIS. (From Adams et al., Principles of Neurology, 6th ed, p801)
  
• Lateral Plantar Neuropathy [M0336188]
  
• Lateral Sclerosis [M0001057]
  
• Lateral Sinus Thrombophlebitis [M0335489]
  
• Lateral Sinus Thrombosis [M0328618]
  Infectious or noninfectious thrombosis of the lateral sinus of the brain. Septic thrombosis may be associated with OTITIS MEDIA or MASTOIDITIS. CRANIOCEREBRAL TRAUMA; BRAIN NEOPLASMS; NEUROSURGICAL PROCEDURES; THROMBOPHILIA; and other conditions may result in non-septic thrombosis. Clinical manifestations include headache, vertigo, and increased intracranial pressure. Extension of the thrombus into adjacent venous structures may result in INTRACRANIAL HEMORRHAGES or SEIZURES. (From Joynt, Clinical Neurology, 1997, Ch23, pp60-8)
  
• Latex Hypersensitivity [M0029966]
  Allergic reaction to products containing processed natural rubber latex such as rubber gloves, condoms, catheters, dental dams, balloons, and sporting equipment. Both T-cell mediated (HYPERSENSITIVITY, DELAYED) and IgE antibody-mediated (HYPERSENSITIVITY, IMMEDIATE) allergic responses are possible. Delayed hypersensitivity results from exposure to antioxidants present in the rubber; immediate hypersensitivity results from exposure to a latex protein.
  
• Laurence-Moon Syndrome [M0012263]
  An autosomal recessive condition characterized by hypogonadism; spinocerebellar degeneration; MENTAL RETARDATION; RETINITIS PIGMENTOSA; and OBESITY. This syndrome was previously referred to as Laurence-Moon-Biedl syndrome until BARDET-BIEDL SYNDROME was identified as a distinct entity. (From N Engl J Med. 1989 Oct 12;321(15):1002-9)
  
• Lawsonia Infections [M0449410]
  
• Lazy Eye [M0332638]
  
• Lead Encephalopathy, Childhood [M0335725]
  
• Lead Polyneuropathy [M0335696]
  
• Lecithin Acyltransferase Deficiency [M0012277]
  An autosomal recessively inherited disorder caused by mutation of LECITHIN CHOLESTEROL ACYLTRANSFERASE that facilitates the esterification of lipoprotein cholesterol and subsequent removal from peripheral tissues to the liver. This defect results in low HDL-cholesterol level in blood and accumulation of free cholesterol in tissue leading to a triad of CORNEAL OPACITY, hemolytic anemia (ANEMIA, HEMOLYTIC), and PROTEINURIA.
  
• Left Middle Cerebral Artery Infarction [M0335398]
  
• Leg Dermatoses [M0012283]
  A nonspecific term used to denote any cutaneous lesion or group of lesions, or eruptions of any type on the leg. (From Stedman, 25th ed)
  
• Leg Length Inequality [M0012285]
  A condition in which one of a pair of legs fails to grow as long as the other, which could result from injury or surgery.
  
• Leg Ulcer [M0012286]
  Ulceration of the skin and underlying structures of the lower extremity. About 90% of the cases are due to venous insufficiency (VARICOSE ULCER), 5% to arterial disease, and the remaining 5% to other causes.
  
• Legg-Perthes Disease [M0012288]
  A particular type of FEMUR HEAD NECROSIS occurring in children, mainly male, with a course of four years or so.
  
• Legionellosis [M0012292]
  Infections with bacteria of the genus LEGIONELLA.
  
• Legionnaires' Disease [M0012293]
  An acute, sometimes fatal, pneumonia-like bacterial infection characterized by high fever, malaise, muscle aches, respiratory disorders and headache. It is named for an outbreak at the 1976 Philadelphia convention of the American Legion.
  
• Leigh Disease [M0012315]
  A group of metabolic disorders primarily of infancy characterized by the subacute onset of psychomotor retardation, hypotonia, ataxia, weakness, vision loss, eye movement abnormalities, seizures, dysphagia, and lactic acidosis. Pathological features include spongy degeneration of the neuropile of the basal ganglia, thalamus, brain stem, and spinal cord. Patterns of inheritance include X-linked recessive, autosomal recessive, and mitochondrial. Leigh disease has been associated with mutations in genes for the PYRUVATE DEHYDROGENASE COMPLEX; CYTOCHROME-C OXIDASE; ATP synthase subunit 6; and subunits of mitochondrial complex I. (From Menkes, Textbook of Child Neurology, 5th ed, p850).
  
• Leishmaniasis [M0012333]
  A disease caused by any of a number of species of protozoa in the genus LEISHMANIA. There are four major clinical types of this infection: cutaneous (Old and New World) (LEISHMANIASIS, CUTANEOUS), diffuse cutaneous (LEISHMANIASIS, DIFFUSE CUTANEOUS), mucocutaneous (LEISHMANIASIS, MUCOCUTANEOUS), and visceral (LEISHMANIASIS, VISCERAL).
  
• Leishmaniasis, Cutaneous [M0025563]
  An endemic disease that is characterized by the development of single or multiple localized lesions on exposed areas of skin that typically ulcerate. The disease has been divided into Old and New World forms. Old World leishmaniasis is separated into three distinct types according to epidemiology and clinical manifestations and is caused by species of the L. tropica and L. aethiopica complexes as well as by species of the L. major genus. New World leishmaniasis, also called American leishmaniasis, occurs in South and Central America and is caused by species of the L. mexicana or L. braziliensis complexes.
  
• Leishmaniasis, Diffuse Cutaneous [M0025566]
  A form of LEISHMANIASIS, CUTANEOUS caused by Leishmania aethiopica in Ethiopia and Kenya, L. pifanoi in Venezuela, L. braziliensis in South America, and L. mexicana in Central America. This disease is characterized by massive dissemination of skin lesions without visceral involvement.
  
• Leishmaniasis, Mucocutaneous [M0012334]
  A disease characterized by the chronic, progressive spread of lesions from New World cutaneous leishmaniasis caused by species of the L. braziliensis complex to the nasal, pharyngeal, and buccal mucosa some time after the appearance of the initial cutaneous lesion. Nasal obstruction and epistaxis are frequent presenting symptoms.
  
• Leishmaniasis, New World [M0025564]
  
• Leishmaniasis, Visceral [M0012335]
  A chronic disease caused by LEISHMANIA DONOVANI and transmitted by the bite of several sandflies of the genera Phlebotomus and Lutzomyia. It is commonly characterized by fever, chills, vomiting, anemia, hepatosplenomegaly, leukopenia, hypergammaglobulinemia, emaciation, and an earth-gray color of the skin. The disease is classified into three main types according to geographic distribution: Indian, Mediterranean (or infantile), and African.
  
• Lens Diseases [M0012346]
  
• Lens Dislocation [M0012347]
  
• Lens Dislocation and Subluxation [M0012348]
  
• Lens Opacities [M0003629]
  
• Lens Subluxation [M0012349]
  Incomplete rupture of the zonule with the displaced lens remaining behind the pupil. In dislocation, or complete rupture, the lens is displaced forward into the anterior chamber or backward into the vitreous body. When congenital, this condition is known as ECTOPIA LENTIS.
  
• Lenticulostriate Diseases, Vascular [M0332693]
  
• Lenticulostriate Disorders [M0332676]
  
• Lentigo [M0012354]
  Small circumscribed melanoses resembling, but differing histologically from, freckles. The concept includes senile lentigo ('liver spots') and nevoid lentigo (nevus spilus, lentigo simplex) and may also occur in association with multiple congenital defects or congenital syndromes (e.g., Peutz-Jeghers syndrome).
  
• Lentivirus Infections [M0024697]
  Virus diseases caused by the Lentivirus genus. They are multi-organ diseases characterized by long incubation periods and persistent infection.
  
• Leontiasis Ossium [M0010840]
  
• LEOPARD Syndrome [M0374986]
  A syndrome characterized by Lentigines (LENTIGO); Electrocardiographic conduction abnormalities; Ocular HYPERTELORISM; PULMONARY STENOSIS; Abnormal genitalia; Retardation of growth; and Deafness (HEARING LOSS, SENSORINEURAL). It is caused by mutations of the PTPN11 gene which codes for non-receptor PROTEIN TYROSINE PHOSPHATASE, type 11. The clinical features of LEOPARD syndrome overlap those of NOONAN SYNDROME, also caused by mutations in PTPN11, as well as those of NEUROFIBROMATOSIS 1. The syndrome has also been associated with mutations in the NF1 gene (GENES, NEUROFIBROMATOSIS 1). (J Med Genet 2002 Aug;39(8):571-4)
  
• Leprosy [M0012361]
  A chronic granulomatous infection caused by MYCOBACTERIUM LEPRAE. The granulomatous lesions are manifested in the skin, the mucous membranes, and the peripheral nerves. Two polar or principal types are lepromatous and tuberculoid.
  
• Leprosy, Borderline [M0023792]
  A form of LEPROSY in which there are clinical manifestations of both principal types (lepromatous and tuberculoid). The disease may shift toward one of these two polar or principal forms.
  
• Leprosy, Cutaneous [M0023794]
  
• Leprosy, Lepromatous [M0023793]
  A chronic communicable infection which is a principal or polar form of LEPROSY. This disorder is caused by MYCOBACTERIUM LEPRAE and produces diffuse granulomatous skin lesions in the form of nodules, macules, or papules. The peripheral nerves are involved symmetrically and neural sequelae occur in the advanced stage.
  
• Leprosy, Macular [M0023796]
  
• Leprosy, Neural [M0023797]
  
• Leprosy, Tuberculoid [M0023795]
  A principal or polar form of LEPROSY in which the skin lesions are few and are sharply demarcated. Peripheral nerve involvement is pronounced and may be severe. Unlike lepromatous leprosy (LEPROSY, LEPROMATOUS), the lepromin test is positive. Tuberculoid leprosy is rarely a source of infection to others.
  
• Leptospirosis [M0012366]
  Infections with bacteria of the genus LEPTOSPIRA.
  
• Leriche's Syndrome [M0012367]
  A syndrome caused by obstruction of the terminal aorta. It usually occurs in males and is characterized by fatigue in the hips, thighs, or calves on exercising, absence of pulsation in the femoral arteries, impotence, and often pallor and coldness of the lower limbs. (From Dorland, 27th ed)
  
• Lesch-Nyhan Syndrome [M0012368]
  An inherited disorder transmitted as a sex-linked trait and caused by a deficiency of an enzyme of purine metabolism; HYPOXANTHINE PHOSPHORIBOSYLTRANSFERASE. Affected individuals are normal in the first year of life and then develop psychomotor retardation, extrapyramidal movement disorders, progressive spasticity, and seizures. Self-destructive behaviors such as biting of fingers and lips are seen frequently. Intellectual impairment may also occur but is typically not severe. Elevation of uric acid in the serum leads to the development of renal calculi and gouty arthritis. (Menkes, Textbook of Child Neurology, 5th ed, pp127)
  
• Lesion of Sciatic Nerve [M0336178]
  
• Lesion, Superficial Radial Nerve [M0336151]
  
• Leukemia, Eosinophilic [M0026739]
  
• Leukemoid Reaction [M0012400]
  A peripheral blood picture resembling that of leukemia or indistinguishable from it on the basis of morphologic appearance alone. (Dorland, 27th ed)
  
• Leukocyte Disorders [M0012409]
  Disordered formation of various types of leukocytes or an abnormal accumulation or deficiency of these cells.
  
• Leukocyte-Adhesion Deficiency Syndrome [M0027596]
  Rare, autosomal recessive disorder caused by deficiency of the beta 2 integrin receptors (RECEPTORS, LEUKOCYTE-ADHESION) comprising the CD11/CD18 family of glycoproteins. The syndrome is characterized by abnormal adhesion-dependent functions, especially defective tissue emigration of neutrophils, leading to recurrent infection.
  
• Leukodystrophy, Globoid Cell [M0012415]
  An autosomal recessive metabolic disorder caused by a deficiency of GALACTOSYLCERAMIDASE leading to intralysosomal accumulation of galactolipids such as GALACTOSYLCERAMIDES and PSYCHOSINE. It is characterized by demyelination associated with large multinucleated globoid cells, predominantly involving the white matter of the central nervous system. The loss of MYELIN disrupts normal conduction of nerve impulses.
  
• Leukodystrophy, Metachromatic [M0012416]
  An autosomal recessive metabolic disease caused by a deficiency of arylsulfatase A (CEREBROSIDE-SULFATASE) leading to intralysosomal accumulation of cerebroside sulfate (SULFOGLYCOSPHINGOLIPIDS) in the nervous system and other organs. Pathological features include diffuse demyelination, and metachromatically-staining granules in many cell types such as the GLIAL CELLS. There are several allelic and nonallelic forms with a variety of neurological symptoms.
  
• Leukodystrophy, Metachromatic, Adult [M0335513]
  
• Leukodystrophy, Metachromatic, Juvenile [M0335514]
  
• Leukoedema, Oral [M0012418]
  A disorder of the buccal mucosa resembling early leukoplakia, characterized by the presence of filmy opalescence of the mucosa in the early stages to a whitish gray cast with a coarsely wrinkled surface in the later stages, associated with intracellular edema of the spinous or malpighian layer. (Dorland, 27th ed)
  
• Leukoencephalitis, Acute Hemorrhagic [M0007374]
  A fulminant and often fatal demyelinating disease of the brain which primarily affects young adults and children. Clinical features include the rapid onset of weakness, SEIZURES, and COMA. It may follow a viral illness or MYCOPLASMA PNEUMONIAE infections but in most instances there is no precipitating event. Pathologic examination reveals marked perivascular demyelination and necrosis of white matter with microhemorrhages. (Adams et al., Principles of Neurology, 6th ed, pp924-5)
  
• Leukoencephalitis, Subacute Hemorrhagic [M0334224]
  
• Leukoencephalopathy, Progressive Multifocal [M0012419]
  An opportunistic viral infection of the central nervous system associated with conditions that impair cell-mediated immunity (e.g., ACQUIRED IMMUNODEFICIENCY SYNDROME and other IMMUNOLOGIC DEFICIENCY SYNDROMES; HEMATOLOGIC NEOPLASMS; IMMUNOSUPPRESSION; and COLLAGEN DISEASES). The causative organism is JC Polyomavirus (JC VIRUS) which primarily affects oligodendrocytes, resulting in multiple areas of demyelination. Clinical manifestations include DEMENTIA; ATAXIA; visual disturbances; and other focal neurologic deficits, generally progressing to a vegetative state within 6 months. (From Joynt, Clinical Neurology, 1996, Ch26, pp36-7)
  
• Leukokeratosis, Hereditary Mucosal [M0494325]
  An autosomal dominant disorder that is manifested by thickened spongiform ORAL MUCOSA with a white opalescent tint. Other MUCOSAL TISSUE may also be involved mucosa found in the VAGINA; RECTUM, and NASAL CAVITY may be similarly involved. This form of LEUKOKERATOSIS can be caused by a mutation in the gene for KERATIN 4 and is not considered a PRENEOPLASTIC CONDITION.
  
• Leukomalacia, Periventricular [M0012420]
  Degeneration of white matter adjacent to the CEREBRAL VENTRICLES following cerebral hypoxia or BRAIN ISCHEMIA in neonates. The condition primarily affects white matter in the perfusion zone between superficial and deep branches of the MIDDLE CEREBRAL ARTERY. Clinical manifestations include VISION DISORDERS; CEREBRAL PALSY; PARAPLEGIA; SEIZURES; and cognitive disorders. (From Adams et al., Principles of Neurology, 6th ed, p1021; Joynt, Clinical Neurology, 1997, Ch4, pp30-1)
  
• Leukorrhea [M0012424]
  A clear or white discharge from the VAGINA, consisting mainly of MUCUS.
  
• Leukostasis [M0028290]
  Abnormal intravascular leukocyte aggregation and clumping often seen in leukemia patients. The brain and lungs are the two most commonly affected organs. This acute syndrome requires aggressive cytoreductive modalities including chemotherapy and/or leukophoresis. It is differentiated from LEUKEMIC INFILTRATION which is a neoplastic process where leukemic cells invade organs.
  
• Lewy Body Disease [M0015964]
  A neurodegenerative disease characterized by dementia, mild parkinsonism, and fluctuations in attention and alertness. The neuropsychiatric manifestations tend to precede the onset of bradykinesia, MUSCLE RIGIDITY, and other extrapyramidal signs. DELUSIONS and visual HALLUCINATIONS are relatively frequent in this condition. Histologic examination reveals LEWY BODIES in the CEREBRAL CORTEX and BRAIN STEM. SENILE PLAQUES and other pathologic features characteristic of ALZHEIMER DISEASE may also be present. (From Neurology 1997;48:376-380; Neurology 1996;47:1113-1124)
  
• Libman-Sacks Disease [M0012758]
  
• Lice Infestations [M0016085]
  Parasitic attack or subsistence on the skin by members of the order Phthiraptera, especially on humans by Pediculus humanus of the family Pediculidae. The hair of the head, eyelashes, and pubis is a frequent site of infestation. (From Dorland, 28th ed; Stedman, 26th ed)
  
• Lichen Nitidus [M0026575]
  A chronic inflammatory disease characterized by shiny, flat-topped, usually flesh-colored micropapules no larger than the head of a pin. Lesions are localized in the early stages, found chiefly on the lower abdomen, penis, and inner surface of the thighs. Distribution may become generalized as the disease progresses.
  
• Lichen Planus [M0012481]
  An inflammatory, pruritic disease of the skin and mucous membranes, which can be either generalized or localized. It is characterized by distinctive purplish, flat-topped papules having a predilection for the trunk and flexor surfaces. The lesions may be discrete or coalesce to form plaques. Histologically, there is a "saw-tooth" pattern of epidermal hyperplasia and vacuolar alteration of the basal layer of the epidermis along with an intense upper dermal inflammatory infiltrate composed predominantly of T-cells. Etiology is unknown.
  
• Lichen Planus, Oral [M0026733]
  Oral lesions accompanying cutaneous lichen planus or often occurring alone. The buccal mucosa, lips, gingivae, floor of the mouth, and palate are usually affected (in a descending order of frequency). Typically, oral lesions consist of radiating white or gray, velvety, threadlike lines, arranged in a reticular pattern, at the intersection of which there may be minute, white, elevated dots or streaks (Wickham's striae). (Jablonski, Illustrated Dictionary of Dentistry)
  
• Lichen Sclerosus et Atrophicus [M0027695]
  A chronic, atrophic skin disease characterized by white, angular, flat, well-defined, indurated papules with an erythematous halo and follicular, black, keratotic plugs. It is the most common cause of VULVAR LICHEN SCLEROSUS in females and balanitis xerotica obliterans in males. It is called also white spot disease and Csillag's disease. (Dorland, 27th ed)
  
• Lichen Simplex Chronicus [M0014704]
  
• Lichenoid Eruptions [M0026574]
  Conditions in which there is histological damage to the lower epidermis along with a grouped chronic inflammatory infiltrate in the papillary dermis disturbing the interface between the epidermis and dermis. LICHEN PLANUS is the prototype of all lichenoid eruptions. (From Rook et al., Textbook of Dermatology, 4th ed, p398)
  
• Limbic Encephalitis [M0328110]
  A paraneoplastic syndrome marked by degeneration of neurons in the medial temporal lobe. Clinical features include behavioral changes, HALLUCINATIONS, loss of short term memory, anosmia, AGEUSIA, and DEMENTIA. Circulating anti-neuronal antibodies (anti-Hu; also called ANNA 1) and small cell lung carcinomas are frequently associated with this condition. (From Pathologe 1997 Sep;18(5):406-10; J Int Neuropsychol Soc 1996 Sep;2(5):460-6; Brain 1997 Jun;120(Pt 6):923-8)
  
• Lingual Goiter [M0452909]
  Pathological enlargement of the LINGUAL THYROID, ectopic thyroid tissue at the base of the TONGUE. It may cause upper AIRWAY OBSTRUCTION; DYSPHAGIA; or HYPOTHYROIDISM symptoms.
  
• Lingual Thyroid [M0452908]
  A condition characterized by the presence of rudimentary THYROID tissue at the base of the TONGUE. It is due to failed embryonic development and migration of thyroid tissue to its normal location. The lingual thyroid usually cannot maintain adequate hormone production thereby resulting in HYPOTHYROIDISM.
  
• Lingual-Facial-Buccal Dyskinesia [M0335656]
  
• Lip Diseases [M0012537]
  
• Lipid Metabolism Disorders [M0486903]
  Pathological conditions resulting from abnormal anabolism or catabolism of lipids in the body.
  
• Lipid Metabolism, Inborn Errors [M0012549]
  
• Lipidoses [M0012566]
  Conditions characterized by abnormal lipid deposition due to disturbance in lipid metabolism, such as hereditary diseases involving lysosomal enzymes required for lipid breakdown. They are classified either by the enzyme defect or by the type of lipid involved.
  
• Lipodystrophy [M0012562]
  A collection of heterogenous conditions resulting from defective LIPID METABOLISM and characterized by ADIPOSE TISSUE atrophy. Often there is redistribution of body fat resulting in peripheral fat wasting and central adiposity. They include generalized, localized, congenital, and acquired lipodystrophy.
  
• Lipodystrophy, Congenital Generalized [M0487299]
  Congenital disorders, usually autosomal recessive, characterized by severe generalized lack of ADIPOSE TISSUE, extreme INSULIN RESISTANCE, and HYPERTRIGLYCERIDEMIA.
  
• Lipodystrophy, Familial Partial [M0462327]
  Inherited conditions characterized by the partial loss of ADIPOSE TISSUE, either confined to the extremities with normal or increased fat deposits on the face, neck and trunk (type 1), or confined to the loss of SUBCUTANEOUS FAT from the limbs and trunk (type 2).
  
• Lipoid Proteinosis of Urbach and Wiethe [M0012568]
  An autosomal recessive disorder characterized by glassy degenerative thickening (hyalinosis) of SKIN; MUCOSA; and certain VISCERA. This disorder is caused by mutation in the extracellular matrix protein 1 gene (ECM1). Clinical features include hoarseness and skin eruption due to widespread deposition of HYALIN.
  
• Lipomatosis [M0012573]
  A disorder characterized by the accumulation of encapsulated or unencapsulated tumor-like fatty tissue resembling LIPOMA.
  
• Lipomatosis, Multiple Symmetrical [M0012574]
  A condition characterized by the growth of unencapsulated masses of ADIPOSE TISSUE symmetrically deposited around the neck, shoulders, or other sites around the body.
  
• Lipomucopolysaccharidosis [M0014164]
  
• Lipoprotein Lipase Deficiency, Familial [M0486995]
  
• Listeria Cerebritis [M0335670]
  
• Listeria Infections [M0012614]
  Infections with bacteria of the genus LISTERIA.
  
• Little Disease [M0003889]
  
• Livedo Reticularis [M0026468]
  
• Liver Abscess [M0012633]
  Solitary or multiple collections of PUS within the liver as a result of infection by bacteria, protozoa, or other agents.
  
• Liver Abscess, Amebic [M0012634]
  Single or multiple areas of PUS due to infection by any ameboid protozoa (AMEBIASIS). A common form is caused by the ingestion of ENTAMOEBA HISTOLYTICA.
  
• Liver Abscess, Pyogenic [M0453772]
  Single or multiple areas of PUS due to bacterial infection within the hepatic parenchyma. It can be caused by a variety of BACTERIA, local or disseminated from infections elsewhere such as in APPENDICITIS; CHOLECYSTITIS; PERITONITIS; and after LIVER TRANSPLANTATION.
  
• Liver Cirrhosis [M0012636]
  Liver disease in which the normal microcirculation, the gross vascular anatomy, and the hepatic architecture have been variably destroyed and altered with fibrous septa surrounding regenerated or regenerating parenchymal nodules.
  
• Liver Cirrhosis, Alcoholic [M0012638]
  FIBROSIS of the hepatic parenchyma due to chronic excess ALCOHOL DRINKING.
  
• Liver Cirrhosis, Biliary [M0012640]
  FIBROSIS of the hepatic parenchyma due to obstruction of BILE flow (CHOLESTASIS) in the intrahepatic or extrahepatic bile ducts (BILE DUCTS, INTRAHEPATIC; BILE DUCTS, EXTRAHEPATIC). Primary biliary cirrhosis involves the destruction of small intra-hepatic bile ducts and bile secretion. Secondary biliary cirrhosis is produced by prolonged obstruction of large intrahepatic or extrahepatic bile ducts from a variety of causes.
  
• Liver Diseases [M0012644]
  Pathological processes of the LIVER.
  
• Liver Diseases, Alcoholic [M0012646]
  Liver diseases associated with ALCOHOLISM. It usually refers to the coexistence of two or more subentities, i.e., ALCOHOLIC FATTY LIVER; ALCOHOLIC HEPATITIS; and ALCOHOLIC CIRRHOSIS.
  
• Liver Diseases, Parasitic [M0012647]
  Liver diseases caused by infections with PARASITES, such as tapeworms (CESTODA) and flukes (TREMATODA).
  
• Liver Failure, Acute [M0026001]
  A form of rapid-onset LIVER FAILURE, also known as fulminant hepatic failure, caused by severe liver injury or massive loss of HEPATOCYTES. It is characterized by sudden development of liver dysfunction and JAUNDICE. Acute liver failure may progress to exhibit cerebral dysfunction even HEPATIC COMA depending on the etiology that includes hepatic ISCHEMIA, drug toxicity, malignant infiltration, and viral hepatitis such as post-transfusion HEPATITIS B and HEPATITIS C.
  
• Lobstein's Disease [M0015533]
  
• Locked-In Syndrome [M0018312]
  
• Locomotor Ataxia [M0336218]
  
• Loeffler Syndrome [M0018133]
  
• Loeffler's Endocarditis [M0026740]
  
• Loiasis [M0012661]
  A parasitic infection caused by the nematode Loa loa. The vector in the transmission of this infection is the horsefly (Tabanus) or the deerfly or mango fly (Chrysops). The larvae may be seen just beneath the skin or passing through the conjunctiva. Eye lesions are not uncommon. The disease is generally mild and painless.
  
• Long QT Syndrome [M0012684]
  A syndrome characterized by history of syncopal episodes and a long QT interval, sometimes leading to sudden death (DEATH, SUDDEN, CARDIAC) due to paroxysmal ventricular arrhythmia. A form associated with autosomal recessive inheritance and congenital deafness is called the JERVELL-LANGE NIELSEN SYNDROME. An autosomal dominant form without deafness is called the ROMANO-WARD SYNDROME.
  
• Louping Ill [M0012706]
  An acute tick-borne arbovirus infection causing meningoencephalomyelitis of sheep.
  
• Low Back Pain, Mechanical [M0336403]
  
• Low T3 Syndrome [M0007970]
  
• Low T3-High T4 Syndrome [M0007969]
  
• Low T3-Low T4 Syndrome [M0007968]
  
• Lower Brachial Plexus Neuropathy [M0335823]
  
• Lown-Ganong-Levine Syndrome [M0012710]
  A form of pre-excitation characterized by a short PR interval associated with a normal QRS complex.
  
• Ludwig's Angina [M0012723]
  Severe cellulitis of the submaxillary space with secondary involvement of the sublingual and submental space. It usually results from infection in the lower molar area or from a penetrating injury to the mouth floor. (From Dorland, 27th ed)
  
• Luft Disease [M0382032]
  
• Lumpy Skin Disease [M0012738]
  A poxvirus infection of cattle characterized by the appearance of nodules on all parts of the skin.
  
• Lung Abscess [M0012742]
  A complication of a localized area of pneumonia or when a neoplasm becomes necrotic and contains purulent material that cannot drain easily from the area because of partial or complete bronchial obstruction. (Harrison's Principles of Internal Medicine, 12th ed, p1068)
  
• Lung Diseases [M0012744]
  
• Lung Diseases, Fungal [M0012745]
  
• Lung Diseases, Interstitial [M0026626]
  A heterogeneous group of noninfectious, nonmalignant disorders of the lower respiratory tract, affecting primarily the alveolar wall structures but also often involving the small airways and blood vessels of the lung parenchyma. "Interstitial" refers to the fact that the interstitium of the alveolar walls is thickened, usually by fibrosis. This group of diseases is usually inflammatory. (Dorland, 27th ed; Wyngarden, Cecil Textbook of Medicine, 19th ed, p396)
  
• Lung Diseases, Obstructive [M0012746]
  Any disorder marked by persistent obstruction of bronchial air flow.
  
• Lung Diseases, Parasitic [M0012748]
  Infections of the lungs with a parasite. They are caused most commonly by nematodes (roundworms).
  
• Lung, Hyperlucent [M0029058]
  Hyperlucency of one lung with decreased size and vascularity of the lung. It is often associated with BRONCHIOLITIS OBLITERANS and with adenovirus infection in childhood.
  
• Lupus [M0012753]
  A form of cutaneous tuberculosis. It is seen predominantly in women and typically involves the nasal, buccal, and conjunctival mucosa.
  
• Lupus Erythematosus, Cutaneous [M0012754]
  A form of lupus erythematosus in which the skin may be the only organ involved or in which skin involvement precedes the spread into other body systems. It has been classified into three forms - acute (= LUPUS ERYTHEMATOSUS, SYSTEMIC with skin lesions), subacute, and chronic (= LUPUS ERYTHEMATOSUS, DISCOID).
  
• Lupus Erythematosus, Discoid [M0012756]
  A chronic form of cutaneous lupus erythematosus (LUPUS ERYTHEMATOSUS, CUTANEOUS) in which the skin lesions mimic those of the systemic form but in which systemic signs are rare. It is characterized by the presence of discoid skin plaques showing varying degrees of edema, erythema, scaliness, follicular plugging, and skin atrophy. Lesions are surrounded by an elevated erythematous border. The condition typically involves the face and scalp, but widespread dissemination may occur.
  
• Lupus Erythematosus, Subacute Cutaneous [M0012755]
  
• Lupus Erythematosus, Systemic [M0012757]
  A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys, and serosal membranes. It is of unknown etiology, but is thought to represent a failure of the regulatory mechanisms of the autoimmune system. The disease is marked by a wide range of system dysfunctions, an elevated erythrocyte sedimentation rate, and the formation of LE cells in the blood or bone marrow.
  
• Lupus Meningoencephalitis [M0335428]
  
• Lupus Nephritis [M0012759]
  Glomerulonephritis associated with autoimmune disease SYSTEMIC LUPUS ERYTHEMATOSUS. Lupus nephritis is histologically classified into 6 classes: class I - normal glomeruli, class II - pure mesangial alterations, class III - focal segmental glomerulonephritis, class IV - diffuse glomerulonephritis, class V - diffuse membranous glomerulonephritis, and class VI - advanced sclerosing glomerulonephritis (The World Health Organization classification 1982).
  
• Lupus Vasculitis, Central Nervous System [M0328118]
  Disorders of the brain and spinal cord that are associated with LUPUS ERYTHEMATOSUS, SYSTEMIC. Clinical manifestations may include neurobehavioral dysfunction; SEIZURES; cranial neuropathies (see CRANIAL NERVE DISEASES); hypothalamic dysfunction; focal motor deficits; MYELITIS, TRANSVERSE, and other disorders. Pathologic features include multiple microinfarctions involving the CEREBRAL CORTEX; DIENCEPHALON; and BRAIN STEM (see also BRAIN INFARCTION). (From Adams et al., Principles of Neurology, 6th ed, pp858-9)
  
• Lutembacher's Syndrome [M0012763]
  A combination of atrial septal defect and mitral stenosis.
  
• Lyme Arthritis [M0012775]
  
• Lyme Disease [M0012774]
  An infectious disease caused by a spirochete, BORRELIA BURGDORFERI, which is transmitted chiefly by Ixodes dammini (see IXODES) and pacificus ticks in the United States and Ixodes ricinis (see IXODES) in Europe. It is a disease with early and late cutaneous manifestations plus involvement of the nervous system, heart, eye, and joints in variable combinations. The disease was formerly known as Lyme arthritis and first discovered at Old Lyme, Connecticut.
  
• Lyme Disease Mononeuritis Multiplex [M0335552]
  
• Lyme Meningoencephalitis [M0335553]
  
• Lyme Meningoradiculitis [M0335554]
  
• Lyme Neuroborreliosis [M0328119]
  Nervous system infections caused by tick-borne spirochetes of the BORRELIA BURGDORFERI GROUP. The disease may affect elements of the central or peripheral nervous system in isolation or in combination. Common clinical manifestations include a lymphocytic meningitis, cranial neuropathy (most often a facial neuropathy), POLYRADICULOPATHY, and a mild loss of memory and other cognitive functions. Less often more extensive inflammation involving the central nervous system (encephalomyelitis) may occur. In the peripheral nervous system, B. burgdorferi infection is associated with mononeuritis multiplex and polyradiculoneuritis. (From J Neurol Sci 1998 Jan 8;153(2):182-91)
  
• Lyme Polyradiculitis [M0335555]
  
• Lyme Polyradiculopathy [M0335556]
  
• Lymphangiectasis [M0012784]
  A transient dilatation of the lymphatic vessels.
  
• Lymphangitis [M0012791]
  
• Lymphatic Diseases [M0012792]
  Diseases of lymph or lymph vessels.
  
• Lymphatism [M0012793]
  
• Lymphedema [M0012800]
  Edema due to obstruction of lymph vessels or disorders of the lymph nodes.
  
• Lymphocele [M0012802]
  Cystic mass containing lymph from diseased lymphatic channels or following surgical trauma or other injury.
  
• Lymphocytic Choriomeningitis [M0012809]
  A form of meningitis caused by LYMPHOCYTIC CHORIOMENINGITIS VIRUS. MICE and other rodents serve as the natural hosts, and infection in humans usually occurs through inhalation or ingestion of infectious particles. Clinical manifestations include an influenza-like syndrome followed by stiff neck, alterations of mentation, ATAXIA, and incontinence. Maternal infections may result in fetal malformations and injury, including neonatal HYDROCEPHALUS, aqueductal stenosis, CHORIORETINITIS, and MICROCEPHALY. (From Joynt, Clinical Neurology, 1996, Ch26, pp1-3)
  
• Lymphocytosis [M0012811]
  Excess of normal lymphocytes in the blood or in any effusion.
  
• Lymphogranuloma Venereum [M0012812]
  Subacute inflammation of the inguinal lymph glands caused by certain immunotypes of CHLAMYDIA TRACHOMATIS. It is a sexually transmitted disease in the U.S. but is more widespread in developing countries. It is distinguished from granuloma venereum (see GRANULOMA INGUINALE), which is caused by Calymmatobacterium granulomatis.
  
• Lymphohistiocytosis, Hemophagocytic [M0023960]
  A group of related disorders characterized by LYMPHOCYTOSIS; HISTIOCYTOSIS; and hemophagocytosis. The two major forms are familial and reactive.
  
• Lymphoma, Lymphocytic, Intermediate [M0332014]
  
• Lymphoma, Mantle-Cell [M0328571]
  A rare form of non-Hodgkin lymphoma having a usually diffuse pattern with both small and medium lymphocytes and small cleaved cells. It accounts for about 5% of adult non-Hodgkin lymphomas in the United States and Europe. The majority of mantle-cell lymphomas are associated with a t(11;14) translocation resulting in overexpression of the cyclin D1 gene (GENES, BCL-1).
  
• Lymphopenia [M0012825]
  Reduction in the number of lymphocytes.
  
• Lymphoproliferative Disorders [M0012826]
  Disorders characterized by proliferation of lymphoid tissue, general or unspecified.
  
• Lysine Alpha-Ketoglutarate Reductase Deficiency Disease [M0335292]
  
• Lysosomal Storage Diseases [M0025150]
  Inborn errors of metabolism characterized by defects in specific lysosomal hydrolases and resulting in intracellular accumulation of unmetabolized substrates.
  
• Lysosomal Storage Diseases, Nervous System [M0328120]
  A group of enzymatic disorders affecting the nervous system and to a variable degree the skeletal system, lymphoreticular system, and other organs. The conditions are marked by an abnormal accumulation of catabolic material within lysosomes.
  
• Machado-Joseph Disease [M0026933]
  A dominantly-inherited ATAXIA first described in people of Azorean and Portuguese descent, and subsequently identified in Brazil, Japan, China, and Australia. This disorder is classified as one of the SPINOCEREBELLAR ATAXIAS (Type 3) and has been associated with a mutation of the MJD1 gene on chromosome 14. Clinical features include progressive ataxia, DYSARTHRIA, postural instability, nystagmus, eyelid retraction, and facial FASCICULATIONS. DYSTONIA is prominent in younger patients (referred to as Type I Machado-Joseph Disease). Type II features ataxia and ocular signs; Type III features MUSCULAR ATROPHY and a sensorimotor neuropathy; and Type IV features extrapyramidal signs combined with a sensorimotor neuropathy. (From Clin Neurosci 1995;3(1):17-22; Ann Neurol 1998 Mar;43(3):288-96)
  
• Machado-Joseph Disease Type I [M0335644]
  
• Machado-Joseph Disease Type II [M0335645]
  
• Machado-Joseph Disease Type III [M0335646]
  
• Machado-Joseph Disease Type IV [M0335647]
  
• Macular Degeneration [M0012875]
  Degenerative changes in the macula lutea of the retina.
  
• Macular Dystrophy, Corneal [M0005181]
  
• Macular Edema, Cystoid [M0012877]
  Fluid accumulation in the outer layer of the MACULA LUTEA at the center of the RETINA. Cystic spaces are formed and may lead to a macular depression or hole.
  
• Macular Holes [M0018948]
  
• Madelung Disease [M0012575]
  Diffuse lipomatosis of the neck. It is also known as fat neck or horsecollar lipomata.
  
• Maduromycosis [M0012879]
  A disease caused by various fungi (Madurella mycetomi) or actinomycetes (Nocardia brasiliensis). It usually affects the foot, hand, and legs with tissues becoming necrosed and swollen after infection.
  
• Maffucci Syndrome [M0007381]
  
• Magnesium Deficiency [M0012886]
  A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. (Harrison's Principles of Internal Medicine, 12th ed, p1936)
  
• Majewski Syndrome [M0019795]
  
• Malabsorption Syndromes [M0012908]
  General term for a group of MALNUTRITION syndromes caused by failure of normal INTESTINAL ABSORPTION of nutrients.
  
• Malaria [M0012910]
  A protozoan disease caused in humans by four species of the PLASMODIUM genus: PLASMODIUM FALCIPARUM; PLASMODIUM VIVAX; PLASMODIUM OVALE; and PLASMODIUM MALARIAE; and transmitted by the bite of an infected female mosquito of the genus ANOPHELES. Malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands. It is characterized by extreme exhaustion associated with paroxysms of high FEVER; SWEATING; shaking CHILLS; and ANEMIA. Malaria in ANIMALS is caused by other species of plasmodia.
  
• Malaria Meningitis [M0335648]
  
• Malaria, Avian [M0012911]
  Any of a group of infections of fowl caused by protozoa of the genera PLASMODIUM, Leucocytozoon, and Haemoproteus. The life cycles of these parasites and the disease produced bears strong resemblance to those observed in human malaria.
  
• Malaria, Cerebral [M0025571]
  A condition characterized by somnolence or coma in the presence of an acute infection with PLASMODIUM FALCIPARUM (and rarely other Plasmodium species). Initial clinical manifestations include HEADACHES; SEIZURES; and alterations of mentation followed by a rapid progression to COMA. Pathologic features include cerebral capillaries filled with parasitized erythrocytes and multiple small foci of cortical and subcortical necrosis. (From Adams et al., Principles of Neurology, 6th ed, p136)
  
• Malaria, Falciparum [M0025570]
  Malaria caused by PLASMODIUM FALCIPARUM. This is the severest form of malaria and is associated with the highest levels of parasites in the blood. This disease is characterized by irregularly recurring febrile paroxysms that in extreme cases occur with acute cerebral, renal, or gastrointestinal manifestations.
  
• Malaria, Vivax [M0025572]
  Malaria caused by PLASMODIUM VIVAX. This form of malaria is less severe than MALARIA, FALCIPARUM, but there is a higher probability for relapses to occur. Febrile paroxysms often occur every other day.
  
• Male Pseudohermaphroditism [M0472585]
  
• Male Urogenital Diseases [M0489510]
  Pathological processes of the male URINARY TRACT and the reproductive system (GENITALIA, MALE).
  
• Malignant Carcinoid Syndrome [M0012930]
  A symptom complex associated with CARCINOID TUMOR and characterized by attacks of severe flushing of the skin, diarrheal watery stools, bronchoconstriction, sudden drops in blood pressure, edema, and ascites. The carcinoid tumors are usually located in the gastrointestinal tract and metastasize to the liver. Symptoms are caused by tumor secretion of serotonin, prostaglandins, and other biologically active substances. Cardiac manifestations constitute CARCINOID HEART DISEASE. (Dorland, 27th ed; Stedman, 25th ed)
  
• Malignant Catarrh [M0012931]
  A herpesvirus infection of cattle characterized by catarrhal inflammation of the upper respiratory and alimentary epithelia, keratoconjunctivitis, encephalitis and lymph node enlargement. Syn: bovine epitheliosis, snotsiekte.
  
• Mallory-Weiss Syndrome [M0012939]
  A condition characterized by mucosal tears at the ESOPHAGOGASTRIC JUNCTION, sometimes with HEMATEMESIS. Typically it is caused by forceful bouts of retching or VOMITING.
  
• Malnutrition [M0015121]
  An imbalanced nutritional status resulted from insufficient intake of nutrients to meet normal physiological requirement.
  
• Malocclusion, Angle Class I [M0012945]
  Malocclusion in which the mandible and maxilla are anteroposteriorly normal as reflected by the relationship of the first permanent molar (i.e., in neutroclusion), but in which individual teeth are abnormally related to each other.
  
• Malocclusion, Angle Class II [M0012946]
  Malocclusion in which the mandible is posterior to the maxilla as reflected by the relationship of the first permanent molar (distoclusion).
  
• Malocclusion, Angle Class III [M0012947]
  Malocclusion in which the mandible is anterior to the maxilla as reflected by the first relationship of the first permanent molar (mesioclusion).
  
• Mandibular Diseases [M0012977]
  
• Mange [M0013931]
  
• Mange, Sarcoptic [M0019457]
  
• Mannosidase Deficiency Diseases [M0446510]
  Diseases caused by the loss of one or more enzymes involved in the hydrolysis of mannoside linkages (MANNOSIDASES). The defects in enzyme activity are primarily associated with genetic mutation of the genes that codes for a particular mannosidase isoenzyme.
  
• Mansonelliasis [M0013012]
  Infection with nematodes of the genus MANSONELLA. Symptoms include pruritus, headache, and articular swelling.
  
• Maple Syrup Urine Disease [M0013019]
  An autosomal recessive inherited disorder with multiple forms of phenotypic expression, caused by a defect in the oxidative decarboxylation of branched-chain amino acids (AMINO ACIDS, BRANCHED-CHAIN). These metabolites accumulate in body fluids and render a "maple syrup" odor. The disease is divided into classic, intermediate, intermittent, and thiamine responsive subtypes. The classic form presents in the first week of life with ketoacidosis, hypoglycemia, emesis, neonatal seizures, and hypertonia. The intermediate and intermittent forms present in childhood or later with acute episodes of ataxia and vomiting. (From Adams et al., Principles of Neurology, 6th ed, p936)
  
• Maple Syrup Urine Disease, Thiamine Responsive [M0335654]
  
• Marburg Virus Disease [M0013025]
  An RNA virus infection of rhesus, vervet, and squirrel monkeys transmissible to man.
  
• Marfan Syndrome [M0013029]
  A hereditary disorder of connective tissue characterized by tall stature, elongated extremities, subluxation of the lens, dilatation of the ascending aorta, and "pigeon breast." It is inherited as an autosomal dominant trait.
  
• Marginal Ulcer [M0016210]
  A well-known complication of GASTROENTEROSTOMY. These ulcers occur at the gastrojejunal anastomosis, mostly on the jejunal side.
  
• Marie Cerebellar Ataxia [M0336209]
  
• Marinesco-Sjogren Syndrome [M0020335]
  
• Mastigophora Infections [M0025562]
  Infections with protozoa of the subphylum MASTIGOPHORA.
  
• Mastitis [M0013095]
  INFLAMMATION of the BREAST, or MAMMARY GLAND.
  
• Mastitis, Bovine [M0013096]
  INFLAMMATION of the UDDER in cows.
  
• Mastocytoma, Benign [M0013097]
  A solitary benign tumor of MAST CELLS with a diameter ranging up to a few centimeters. This unifocal tumor is usually confined to the skin.
  
• Mastocytoma, Cutaneous [M0406147]
  A solitary benign skin tumor of MAST CELLS with a diameter ranging up to 4 cm. It is a rare form of MASTOCYTOSIS that occurs almost exclusively in children.
  
• Mastocytosis [M0013098]
  A heterogenous group of disorders characterized by the abnormal increase of MAST CELLS in only the skin (MASTOCYTOSIS, CUTANEOUS), in extracutaneous tissues involving multiple organs (MASTOCYTOSIS, SYSTEMIC), or in solid tumors (MASTOCYTOMA).
  
• Mastocytosis, Bullous [M0022415]
  A form of cutaneous mastocytosis that is characterized by the large fluid-filled lesions.
  
• Mastocytosis, Cutaneous [M0405914]
  Skin lesions due to abnormal infiltration of MAST CELLS. Cutaneous mastocytosis is confined to the skin without the involvement of other tissues or organs, and is mostly found in children.
  
• Mastocytosis, Diffuse Cutaneous [M0022416]
  A form of cutaneous mastocytosis that is characterized by a diffuse erythrodermic rash rather than the maculopapular infiltrates seen in URTICARIA PIGMENTOSA.
  
• Mastocytosis, Systemic [M0405932]
  A group of disorders caused by the abnormal proliferation of MAST CELLS in a variety of extracutaneous tissues including bone marrow, liver, spleen, lymph nodes, and gastrointestinal tract. Systemic mastocytosis is commonly seen in adults. These diseases are categorized on the basis of clinical features, pathologic findings, and prognosis.
  
• Mastoiditis [M0013100]
  Inflammation of the cavity and air cells in the mastoid part of the temporal bone.
  
• Maxillary Diseases [M0013132]
  
• Maxillary Sinusitis [M0023883]
  Inflammation of the maxillary sinus. In most cases it is the result of infection by the bacteria HAEMOPHILUS INFLUENZAE; STREPTOCOCCUS PNEUMONIAE; and STAPHYLOCOCCUS AUREUS. This condition may be acute or chronic.
  
• May-White Syndrome [M0335758]
  
• Measles [M0013152]
  A highly contagious infectious disease caused by MORBILLIVIRUS, common among children but also seen in the nonimmune of any age, in which the virus enters the respiratory tract via droplet nuclei and multiplies in the epithelial cells, spreading throughout the reticuloendothelial system. (From Dorland, 27th ed)
  
• Mechanical Strabismus [M0337318]
  
• Meckel Diverticulum [M0013177]
  A congenital abnormality characterized by the outpouching or sac formation in the ILEUM. It is a remnant of the embryonic YOLK SAC in which the VITELLINE DUCT failed to close.
  
• Meconium Aspiration Syndrome [M0013186]
  A condition caused by inhalation of MECONIUM into the LUNG of FETUS or NEWBORN, usually due to vigorous respiratory movements during difficult PARTURITION or respiratory system abnormalities. Meconium aspirate may block small airways leading to difficulties in PULMONARY GAS EXCHANGE and ASPIRATION PNEUMONIA.
  
• Medial Neuropathy, Distal [M0336007]
  
• Medial Plantar Nerve Disease [M0336189]
  
• Medial Plantar Neuropathy [M0336187]
  
• Median Neuropathy [M0328122]
  Disease involving the median nerve, from its origin at the BRACHIAL PLEXUS to its termination in the hand. Clinical features include weakness of wrist and finger flexion, forearm pronation, thenar abduction, and loss of sensation over the lateral palm, first three fingers, and radial half of the ring finger. Common sites of injury include the elbow, where the nerve passes through the two heads of the pronator teres muscle (pronator syndrome) and in the carpal tunnel (CARPAL TUNNEL SYNDROME).
  
• Median Neuropathy, Proximal [M0336009]
  
• Mediastinal Cyst [M0013192]
  Cysts of one of the parts of the mediastinum: the superior part, containing the trachea, esophagus, thoracic duct and thymus organs; the inferior middle part, containing the pericardium; the inferior anterior part containing some lymph nodes; and the inferior posterior part, containing the thoracic duct and esophagus.
  
• Mediastinal Diseases [M0013197]
  Disorders of the mediastinum, general or unspecified.
  
• Mediastinitis [M0013200]
  Inflammation of the mediastinum, the area between the pleural sacs.
  
• Medullary Sponge Kidney [M0012032]
  A non-hereditary KIDNEY disorder characterized by the abnormally dilated (ECTASIA) medullary and inner papillary portions of the collecting ducts. These collecting ducts usually contain CYSTS or DIVERTICULA filled with jelly-like material or small calculi (KIDNEY STONES) leading to infections or obstruction. It should be distinguished from congenital or hereditary POLYCYSTIC KIDNEY DISEASES.
  
• Megacolon [M0013292]
  Dilatation of the COLON, often to alarming dimensions. There are various types of megacolon including congenital megacolon in HIRSCHSPRUNG DISEASE, idiopathic megacolon in CONSTIPATION, and TOXIC MEGACOLON.
  
• Megacolon, Toxic [M0013293]
  An acute form of MEGACOLON, severe pathological dilatation of the COLON. It is associated with clinical conditions such as ULCERATIVE COLITIS; CROHN DISEASE; AMEBIC DYSENTERY; or CLOSTRIDIUM ENTEROCOLITIS.
  
• Megaconial Myopathies [M0026158]
  
• Megaesophagus [M0007741]
  
• Meige Syndrome [M0013299]
  A syndrome characterized by orofacial DYSTONIA; including BLEPHAROSPASM; forceful jaw opening; lip retraction; platysma muscle spasm; and tongue protrusion. It primarily affects older adults, with an incidence peak in the seventh decade of life. (From Adams et al., Principles of Neurology, 6th ed, p108)
  
• Melanosis [M0013316]
  Disorders of increased melanin pigmentation that develop without preceding inflammatory disease.
  
• MELAS Syndrome [M0026161]
  A mitochondrial disorder characterized by focal or generalized seizures, episodes of transient or persistent neurologic dysfunction resembling strokes, and ragged-red fibers on muscle biopsy. Affected individuals tend to be normal at birth through early childhood, then experience growth failure, episodic vomiting, and recurrent cerebral insults resulting in visual loss and hemiparesis. The cortical lesions tend to occur in the parietal and occipital lobes and are not associated with vascular occlusion. VASCULAR HEADACHE is frequently associated and the disorder tends to be familial. (From Joynt, Clinical Neurology, 1992, Ch56, p117)
  
• Meleda Disease [M0011975]
  
• Melioidosis [M0013324]
  A disease of humans and animals that resembles GLANDERS. It is caused by BURKHOLDERIA PSEUDOMALLEI and may range from a dormant infection to a condition that causes multiple abscesses, pneumonia, and bacteremia.
  
• Melkersson-Rosenthal Syndrome [M0013326]
  An idiopathic syndrome characterized by one or more of the following; recurrent orofacial swelling, relapsing facial paralysis, and fissured tongue (lingua plicata). The onset is usually in childhood and relapses are common. Cheilitis granulomatosa is a monosymptomatic variant of this condition. (Dermatol Clin 1996 Apr;14(2):371-9; Magalini & Magalini, Dictionary of Medical Syndromes, 4th ed, p531)
  
• Melnick-Needles Syndrome [M0015523]
  
• Melorheostosis [M0013328]
  A form of osteosclerosis or hyperostosis extending in a linear track through one of the long bones of an extremity, and consisting of proliferated ivory-like new bone. "Melo-" is from the Greek, limb and "-rheostosis" refers to streaks (rheo- from the Greek, flow), in the bones. (Dorland, 27th ed)
  
• Membranoproliferative Glomerulonephritis, Type I [M0490965]
  A type of mesangiocapillary glomerulonephritis that is characterized by immune deposits on the endothelial side of the GLOMERULAR BASEMENT MEMBRANE leading to splitting and reduplication of the basement membrane.
  
• Membranoproliferative Glomerulonephritis, Type II [M0490966]
  A type of mesangiocapillary glomerulonephritis that is characterized by the dark bands of electron-dense deposits in the GLOMERULAR BASEMENT MEMBRANE caused by autoantibodies against ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb).
  
• Membranoproliferative Glomerulonephritis, Type III [M0490967]
  A type of mesangiocapillary glomerulonephritis that is characterized by subepithelial immune deposit and may be a variant of type I.
  
• Meniere's Disease [M0013357]
  A disease of the inner ear characterized by vertigo, tinnitus, and fluctuating hearing loss often accompanied by fullness in the affected ear. ENDOLYMPHATIC HYDROPS (swelling of the endolymph-containing structures) is the main pathologic finding.
  
• Meningeal Plague [M0016948]
  
• Meningism [M0013364]
  A condition characterized by neck stiffness, headache, and other symptoms suggestive of meningeal irritation, but without actual inflammation of the meninges (MENINGITIS). Spinal fluid pressure may be elevated but spinal fluid is normal. (DeJong, The Neurologic Examination, 4th ed, p673)
  
• Meningitis [M0013365]
  Inflammation of the coverings of the brain and/or spinal cord, which consist of the PIA MATER; ARACHNOID; and DURA MATER. Infections (viral, bacterial, and fungal) are the most common causes of this condition, but subarachnoid hemorrhage (HEMORRHAGES, SUBARACHNOID), chemical irritation (chemical MENINGITIS), granulomatous conditions, neoplastic conditions (e.g., carcinomatous meningitis), and other inflammatory conditions may produce this syndrome. (From Joynt, Clinical Neurology, 1994, Ch24, p6)
  
• Meningitis, Aseptic [M0013366]
  A syndrome characterized by headache, neck stiffness, low grade fever, and CSF lymphocytic pleocytosis in the absence of an acute bacterial pathogen. Viral meningitis is the most frequent cause although MYCOPLASMA INFECTIONS; RICKETTSIA INFECTIONS; diagnostic or therapeutic procedures; NEOPLASTIC PROCESSES; septic perimeningeal foci; and other conditions may result in this syndrome. (From Adams et al., Principles of Neurology, 6th ed, p745)
  
• Meningitis, Bacterial [M0025747]
  Bacterial infections of the leptomeninges and subarachnoid space, frequently involving the cerebral cortex, cranial nerves, cerebral blood vessels, spinal cord, and nerve roots. The type of causative organism varies with age and clinical status (e.g., post-operative, immunodeficient, or post-traumatic states). Clinical manifestations include the acute onset of fever, stiff neck, altered mentation, seizures, and focal neurologic deficits. Death may occur within 24 hours of disease onset. Pathologic features include a purulent exudate in the subarachnoid space, and diffuse inflammation of neural and vascular structures. (From Joynt, Clinical Neurology, 1994, Ch24, pp1-5)
  
• Meningitis, Cryptococcal [M0025746]
  Meningeal inflammation produced by CRYPTOCOCCUS NEOFORMANS, an encapsulated yeast that tends to infect individuals with ACQUIRED IMMUNODEFICIENCY SYNDROME and other immunocompromised states. The organism enters the body through the respiratory tract, but symptomatic infections are usually limited to the lungs and nervous system. The organism may also produce parenchymal brain lesions (torulomas). Clinically, the course is subacute and may feature HEADACHE; NAUSEA; PHOTOPHOBIA; focal neurologic deficits; SEIZURES; cranial neuropathies; and HYDROCEPHALUS. (From Adams et al., Principles of Neurology, 6th ed, pp721-2)
  
• Meningitis, Escherichia coli [M0328123]
  A form of gram-negative meningitis that tends to occur in neonates, in association with anatomical abnormalities (which feature communication between the meninges and cutaneous structures) or as OPPORTUNISTIC INFECTIONS in association with IMMUNOLOGIC DEFICIENCY SYNDROMES. In premature neonates the clinical presentation may be limited to ANOREXIA; VOMITING; lethargy; or respiratory distress. Full-term infants may have as additional features FEVER; SEIZURES; and bulging of the anterior fontanelle. (From Menkes, Textbook of Child Neurology, 5th ed, pp398-400)
  
• Meningitis, Fungal [M0025748]
  Meningitis caused by fungal agents which may occur as OPPORTUNISTIC INFECTIONS or arise in immunocompetent hosts.
  
• Meningitis, Haemophilus [M0013367]
  BACTERIAL INFECTIONS of the nervous system caused by HAEMOPHILUS organisms, and marked by prominent inflammation of the meninges. HAEMOPHILUS INFLUENZAE TYPE B is the most common causative organism. The condition primarily affects children under 6 years of age but may occur in adults. Clinical manifestations include fever; nuchal rigidity; PHOTOPHOBIA; SEIZURES; HEARING LOSS, SENSORINEURAL; COMA; and cerebrovascular thrombosis. The organism tends to enter the central nervous system following infections of adjacent structures, including the middle ear (see also OTITIS MEDIA), sinuses, and pharynx. (From Menkes, Textbook of Child Neurology, 5th ed, pp396-7)
  
• Meningitis, Haemophilus aphrophilus [M0335665]
  
• Meningitis, Haemophilus influenzae Type F [M0335666]
  
• Meningitis, Haemophilus parainfluenzae [M0335667]
  
• Meningitis, Listeria [M0013368]
  Inflammation of the meninges caused by LISTERIA MONOCYTOGENES infection, usually occurring in individuals under the age of 3 years or over the age of 50 years. It may occur at any age in individuals with IMMUNOLOGIC DEFICIENCY SYNDROMES. Clinical manifestations include FEVER, altered mentation, HEADACHE, meningeal signs, focal neurologic signs, and SEIZURES. (From Medicine 1998 Sep;77(5):313-36)
  
• Meningitis, Meningococcal [M0013369]
  A fulminant infection of the meninges and subarachnoid fluid by the bacterium NEISSERIA MENINGITIDIS, producing diffuse inflammation and peri-meningeal venous thromboses. Clinical manifestations include FEVER, nuchal rigidity, SEIZURES, severe HEADACHE, petechial rash, stupor, focal neurologic deficits, HYDROCEPHALUS, and COMA. The organism is usually transmitted via nasopharyngeal secretions and is a leading cause of meningitis in children and young adults. Organisms from Neisseria meningitidis serogroups A, B, C, Y, and W-135 have been reported to cause meningitis. (From Adams et al., Principles of Neurology, 6th ed, pp689-701; Curr Opin Pediatr 1998 Feb;10(1):13-8)
  
• Meningitis, Meningococcal, Serogroup A [M0335671]
  
• Meningitis, Meningococcal, Serogroup B [M0335672]
  
• Meningitis, Meningococcal, Serogroup C [M0335673]
  
• Meningitis, Meningococcal, Serogroup W-135 [M0415970]
  
• Meningitis, Meningococcal, Serogroup Y [M0415969]
  
• Meningitis, Pneumococcal [M0013370]
  An acute purulent infection of the meninges and subarachnoid space caused by Streptococcus pneumoniae, most prevalent in children and adults over the age of 60. This illness may be associated with OTITIS MEDIA; MASTOIDITIS; SINUSITIS; RESPIRATORY TRACT INFECTIONS; sickle cell disease (ANEMIA, SICKLE CELL); skull fractures; and other disorders. Clinical manifestations include FEVER; HEADACHE; neck stiffness; and somnolence followed by SEIZURES; focal neurologic deficits (notably DEAFNESS); and COMA. (From Miller et al., Merritt's Textbook of Neurology, 9th ed, p111)
  
• Meningitis, Pneumococcal, Penicillin-Resistant [M0335675]
  
• Meningitis, Pneumococcal, Recurrent [M0335676]
  
• Meningitis, Viral [M0013371]
  Viral infections of the leptomeninges and subarachnoid space. TOGAVIRIDAE INFECTIONS; FLAVIVIRIDAE INFECTIONS; RUBELLA; BUNYAVIRIDAE INFECTIONS; ORBIVIRUS infections; PICORNAVIRIDAE INFECTIONS; ORTHOMYXOVIRIDAE INFECTIONS; RHABDOVIRIDAE INFECTIONS; ARENAVIRIDAE INFECTIONS; HERPESVIRIDAE INFECTIONS; ADENOVIRIDAE INFECTIONS; JC VIRUS infections; and RETROVIRIDAE INFECTIONS may cause this form of meningitis. Clinical manifestations include fever, headache, neck pain, vomiting, PHOTOPHOBIA, and signs of meningeal irritation. (From Joynt, Clinical Neurology, 1996, Ch26, pp1-3)
  
• Meningococcal Infections [M0013373]
  Infections with bacteria of the species NEISSERIA MENINGITIDIS.
  
• Meningococcal Waterhouse-Friderichsen Syndrome [M0460990]
  
• Meningoencephalitis [M0013374]
  An inflammatory process involving the brain (ENCEPHALITIS) and meninges (MENINGITIS), most often produced by pathogenic organisms which invade the central nervous system, and occasionally by toxins, autoimmune disorders, and other conditions.
  
• Meningoencephalitis, Herpes Simplex Virus [M0334889]
  
• Meningoencephalitis, Herpes Zoster [M0334876]
  
• Meningoencephalitis, Listeria [M0335669]
  
• Meningoencephalitis, Protozoal [M0334430]
  
• Meningoencephalitis, St. Louis [M0334842]
  
• Menkes Kinky Hair Syndrome [M0012055]
  An inherited disorder of copper metabolism transmitted as an X-linked trait and characterized by the infantile onset of HYPOTHERMIA, feeding difficulties, hypotonia, SEIZURES, bony deformities, pili torti (twisted hair), and severely impaired intellectual development. Defective copper transport across plasma and endoplasmic reticulum membranes results in copper being unavailable for the synthesis of several copper containing enzymes, including PROTEIN-LYSINE 6-OXIDASE; CERULOPLASMIN; and SUPEROXIDE DISMUTASE. Pathologic changes include defects in arterial elastin, neuronal loss, and gliosis. (From Menkes, Textbook of Child Neurology, 5th ed, p125)
  
• Menopause, Premature [M0013381]
  The premature cessation of menses (MENSTRUATION) when the last menstrual period occurs in a woman under the age of 40. It is due to the depletion of OVARIAN FOLLICLES. Premature MENOPAUSE can be caused by diseases; OVARIECTOMY; RADIATION; chemicals; and chromosomal abnormalities.
  
• Menstruation, Retrograde [M0013403]
  
• Mercurial Neuroanesthenia [M0335770]
  
• Mercury Encephalopathy [M0335766]
  
• Mercury Poisoning [M0013450]
  
• MERRF Syndrome [M0026164]
  A mitochondrial encephalomyopathy characterized clinically by a mixed seizure disorder, myoclonus, progressive ataxia, spasticity, and a mild myopathy. Dysarthria, optic atrophy, growth retardation, deafness, and dementia may also occur. This condition tends to present in childhood and to be transmitted via maternal lineage. Muscle biopsies reveal ragged-red fibers and respiratory chain enzymatic defects. (From Adams et al., Principles of Neurology, 6th ed, p986)
  
• Mesenteric Lymphadenitis [M0013464]
  INFLAMMATION of LYMPH NODES in the MESENTERY.
  
• Mesenteric Panniculitis [M0023787]
  Inflammation of the ADIPOSE TISSUE in the MESENTERY, a form of peritoneal panniculitis, It is characterized by the presence of MULTINUCLEATED GIANT CELLS and lipid-laden MACROPHAGES in the mesentery.
  
• Mesenteric Vascular Occlusion [M0013465]
  Obstruction of the flow in the SPLANCHNIC CIRCULATION by ATHEROSCLEROSIS; EMBOLISM; THROMBOSIS; STENOSIS; TRAUMA; and compression or intrinsic pressure from adjacent tumors. Rare causes are drugs, intestinal parasites, and vascular immunoinflammatory diseases such as PERIARTERITIS NODOSA and THROMBOANGIITIS OBLITERANS. (From Juergens et al., Peripheral Vascular Diseases, 5th ed, pp295-6)
  
• Mesomycetozoea Infections [M0477446]
  Infections by MESOMYCETOZOEA, general or unspecified.
  
• Metabolic Diseases [M0013493]
  Generic term for diseases caused by an abnormal metabolic process. It can be congenital due to inherited enzyme abnormality (METABOLISM, INBORN ERRORS) or acquired due to disease of an endocrine organ or failure of a metabolically important organ such as the liver. (Stedman, 26th ed)
  
• Metabolic Disorder, Central Nervous System, Acquired [M0334181]
  
• Metabolic Syndrome X [M0011433]
  A cluster of metabolic risk factors for CARDIOVASCULAR DISEASES and TYPE 2 DIABETES MELLITUS. The major components of metabolic syndrome X include excess ABDOMINAL FAT; atherogenic DYSLIPIDEMIA; HYPERTENSION; HYPERGLYCEMIA; INSULIN RESISTANCE; a proinflammatory state; and a prothrombotic (THROMBOSIS) state. (from AHA/NHLBI/ADA Conference Proceedings, Circulation 2004; 109:551-556)
  
• Metabolism, Inborn Errors [M0013496]
  Errors in metabolic processes resulting from inborn genetic mutations that are inherited or acquired in utero.
  
• Metachromatic Leukodystrophy, Infant [M0335515]
  
• Metagonimiasis [M0021867]
  
• Metal Metabolism, Inborn Errors [M0013499]
  
• Metatarsalgia [M0411789]
  Pain in the region of the METATARSUS. It can include pain in the METATARSAL BONES; METATARSOPHALANGEAL JOINT; and/or intermetatarsal joints (TARSAL JOINTS).
  
• Methemoglobinemia [M0013565]
  The presence of methemoglobin in the blood, resulting in cyanosis. A small amount of methemoglobin is present in the blood normally, but injury or toxic agents convert a larger proportion of hemoglobin into methemoglobin, which does not function reversibly as an oxygen carrier. Methemoglobinemia may be due to a defect in the enzyme NADH methemoglobin reductase (an autosomal recessive trait) or to an abnormality in hemoglobin M (an autosomal dominant trait). (Dorland, 27th ed)
  
• Microangiopathy, Diabetic [M0006157]
  
• Microcephaly [M0013769]
  Abnormal smallness of the head, usually associated with mental retardation. (Dorland, 27th ed)
  
• Microglandular Adenosis [M0008441]
  A benign lesion of the BREAST, characterized by a proliferation of disorganized small glands lined by EPITHELIAL CELLS without apparent myoepithelial cells. These glands usually have enlarged lumens, and lie in adipose or fibrous tissue.
  
• Microsporidiosis [M0025685]
  Infections with FUNGI of the phylum MICROSPORIDIA.
  
• Microvascular Angina [M0026629]
  ANGINA PECTORIS or angina-like chest pain with a normal coronary arteriogram and positive EXERCISE TEST. The cause of the syndrome is unknown. While its recognition is of clinical importance, its prognosis is excellent. (Braunwald, Heart Disease, 4th ed, p1346; Jablonski Dictionary of Syndromes & Eponymic Diseases, 2d ed). It is different from METABOLIC SYNDROME X, a syndrome characterized by INSULIN RESISTANCE and HYPERINSULINEMIA, that has increased risk for cardiovascular disease.
  
• Middle Brachial Plexus Neuropathy [M0335824]
  
• Middle Cerebral Artery Embolus [M0335396]
  
• Middle Cerebral Artery Occlusion [M0335400]
  
• Middle Cerebral Artery Syndrome [M0335401]
  
• Middle Cerebral Artery Thrombosis [M0335402]
  
• Middle Lobe Syndrome [M0013858]
  Atelectasis of the right middle pulmonary lobe, with chronic pneumonitis. (Dorland, 27th ed)
  
• Migraine Aura without Headache [M0334702]
  
• Migraine Disorders [M0013864]
  A class of disabling primary headache disorders, characterized by recurrent unilateral pulsatile headaches. The two major subtypes are common migraine (without aura) and classic migraine (with aura or neurological symptoms). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
  
• Migraine Variant [M0335692]
  
• Migraine with Acute Onset Aura [M0334699]
  
• Migraine with Aura [M0328363]
  A subtype of migraine disorder, characterized by recurrent attacks of reversible neurological symptoms (aura) that precede or accompany the headache. Aura may include a combination of sensory disturbances, such as blurred VISION; HALLUCINATIONS; VERTIGO; NUMBNESS; and difficulty in concentrating and speaking. Aura is usually followed by features of the COMMON MIGRAINE, such as PHOTOPHOBIA; PHONOPHOBIA; and NAUSEA. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
  
• Migraine with Prolonged Aura [M0334700]
  
• Migraine with Typical Aura [M0480107]
  
• Migraine without Aura [M0328367]
  Recurrent unilateral pulsatile headaches, not preceded or accompanied by an aura, in attacks lasting 4-72 hours. It is characterized by PAIN of moderate to severe intensity; aggravated by physical activity; and associated with NAUSEA and / or PHOTOPHOBIA and PHONOPHOBIA. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
  
• Mikulicz' Disease [M0013865]
  A chronic, benign, and usually painless inflammatory swelling of the lacrimal and salivary glands. It is considered by some to include the glandular enlargement associated with other diseases, such as Sjogren's syndrome, sarcoidosis, lupus erythematosus, etc.
  
• Miliaria [M0013866]
  A syndrome of cutaneous changes associated with sweat retention and extravasation of sweat at different levels in the skin. Miliaria rubra, or prickly heat, results from apocrine duct obstruction. The sweat then seeps into the epidermis, producing pruritic erythematous papulovesicles. (From Dorland, 27th ed)
  
• Miliaria Rubra [M0013867]
  
• Milk Hypersensitivity [M0024863]
  Allergic reaction to milk (usually cow's milk) or milk products. MILK HYPERSENSITIVITY should be differentiated from LACTOSE INTOLERANCE, an intolerance to milk as a result of congenital deficiency of lactase.
  
• Milk-Alkali Syndrome [M0010815]
  
• Milker's Nodes [M0017423]
  
• Millard-Gublar Syndrome [M0334264]
  
• Miller Fisher Syndrome [M0029456]
  A variant of the GUILLAIN-BARRE SYNDROME characterized by the acute onset of oculomotor dysfunction, ataxia, and loss of deep tendon reflexes with relative sparing of strength in the extremities and trunk. The ataxia is produced by peripheral sensory nerve dysfunction and not by cerebellar injury. Facial weakness and sensory loss may also occur. The process is mediated by autoantibodies directed against a component of myelin found in peripheral nerves. (Adams et al., Principles of Neurology, 6th ed, p1313; Neurology 1987 Sep;37(9):1493-8)
  
• Milroy Disease [M0012801]
  
• Minamata Disease [M0335767]
  
• Mineralocorticoid Excess Syndrome, Apparent [M0442605]
  A hereditary disease characterized by childhood onset HYPERTENSION, hypokalemic alkalosis, and low RENIN and ALDOSTERONE secretion. It results from a defect in the activity of the 11-BETA-HYDROXYSTEROID DEHYDROGENASE TYPE 2 enzyme which results in inadequate conversion of CORTISOL to CORTISONE. The build up of unprocessed cortisol to levels that stimulate MINERALOCORTICOID RECEPTORS creates the appearance of having excessive MINERALOCORTICOIDS.
  
• Minimally Conscious State [M0335846]
  
• Mink Viral Enteritis [M0493681]
  A highly contagious parvovirus infection in mink, caused by MINK ENTERITIS VIRUS or the closely related FELINE PANLEUKOPENIA VIRUS or CANINE PARVOVIRUS. Transmission usually occurs by the fecal/oral route.
  
• Miosis, Innervational Defect [M0333516]
  
• Mite Infestations [M0013932]
  Infestations with arthropods of the subclass ACARI, superorder Acariformes.
  
• Mitochondrial Diseases [M0335637]
  Diseases caused by abnormal function of the MITOCHONDRIA. They may be caused by mutations, acquired or inherited, in mitochondrial DNA or in nuclear genes that code for mitochondrial components. They may also be the result of acquired mitochondria dysfunction due to adverse effects of drugs, infections, or other environmental causes.
  
• Mitochondrial Encephalomyopathies [M0026153]
  A heterogenous group of disorders characterized by alterations of mitochondrial metabolism that result in muscle and nervous system dysfunction. These are often multisystemic and vary considerably in age at onset (usually in the first or second decade of life), distribution of affected muscles, severity, and course. (From Adams et al., Principles of Neurology, 6th ed, pp984-5)
  
• Mitochondrial Myopathies [M0026160]
  A group of muscle diseases associated with abnormal mitochondria function.
  
• Mitral Valve Insufficiency [M0013958]
  Backflow of blood from the left ventricle into the left atrium, owing to imperfect functioning of the mitral valve.
  
• Mitral Valve Prolapse [M0013959]
  Abnormal protrusion of one or both of the leaflets of the mitral valve into the left atrium during systole. This may be accompanied by mitral regurgitation, systolic murmur, nonejection click, or cardiac arrhythmia.
  
• Mitral Valve Stenosis [M0013960]
  A rheumatic disease causing diffuse thickening of the mitral valve leaflets by fibrous tissue or calcific deposits. (Harrison's Principles of Internal Medicine, 13th ed, p1052)
  
• Mixed Connective Tissue Disease [M0013961]
  A syndrome with overlapping clinical features of systemic lupus erythematosus, scleroderma, polymyositis, and Raynaud's phenomenon. The disease is differentially characterized by high serum titers of antibodies to ribonuclease-sensitive extractable (saline soluble) nuclear antigen and a "speckled" epidermal nuclear staining pattern on direct immunofluorescence.
  
• Mobius Syndrome [M0008126]
  A syndrome of congenital facial paralysis, frequently associated with abducens palsy and other congenital abnormalities including lingual palsy, clubfeet, brachial disorders, cognitive deficits, and pectoral muscle defects. Pathologic findings are variable and include brain stem nuclear aplasia, facial nerve aplasia, and facial muscle aplasia, consistent with a multifactorial etiology. (Adams et al., Principles of Neurology, 6th ed, p1020)
  
• Mohr Syndrome [M0015437]
  
• Molluscum Contagiosum [M0013995]
  A common, benign, usually self-limited viral infection of the skin and occasionally the conjunctivae by a poxvirus (MOLLUSCUM CONTAGIOSUM VIRUS). (Dorland, 27th ed)
  
• Monieziasis [M0014019]
  Infection of ruminants with tapeworms of the genus Moniezia.
  
• Monkey Diseases [M0014023]
  Diseases of Old World and New World monkeys. This term includes diseases of baboons but not of chimpanzees or gorillas (= APE DISEASES).
  
• Monkeypox [M0450226]
  A viral disease infecting PRIMATES and RODENTS. Its clinical presentation in humans is similar to SMALLPOX including FEVER; HEADACHE; COUGH; and a painful RASH. It is caused by MONKEYPOX VIRUS and is usually transmitted to humans through BITES or via contact with an animal's BLOOD. Interhuman transmission is relatively low (significantly less than smallpox).
  
• Monochromatopsia [M0336564]
  
• Monoclonal Gammopathies, Benign [M0014031]
  Conditions characterized by the presence of a monoclonal serum (or urine) protein without clinical manifestations of plasma cell dyscrasia.
  
• Monocular Esotropia [M0336194]
  
• Monocular Exotropia [M0336200]
  
• Mononegavirales Infections [M0028015]
  Infections with viruses of the order MONONEGAVIRALES. The concept includes FILOVIRIDAE INFECTIONS; PARAMYXOVIRIDAE INFECTIONS; and RHABDOVIRIDAE INFECTIONS.
  
• Mononeuritis [M0335894]
  
• Mononeuritis Multiplex [M0335896]
  
• Mononeuropathies [M0328145]
  Disease or trauma involving a single peripheral nerve in isolation, or out of proportion to evidence of diffuse peripheral nerve dysfunction. Mononeuropathy multiplex refers to a condition characterized by multiple isolated nerve injuries. Mononeuropathies may result from a wide variety of causes, including ISCHEMIA; traumatic injury; compression; CONNECTIVE TISSUE DISEASES; CUMULATIVE TRAUMA DISORDERS; and other conditions.
  
• Mononeuropathy Multiplex [M0335895]
  
• Monoplegic Cerebral Palsy [M0334585]
  
• Moraxella Infections [M0449415]
  
• Morbillivirus Infections [M0027414]
  Infections with viruses of the genus MORBILLIVIRUS, family PARAMYXOVIRIDAE. Infections mainly cause acute disease in their hosts, although in some cases infection is persistent and leads to degenerative conditions.
  
• Morvan Disease [M0336217]
  
• Mosquito-Borne Encephalitis [M0334882]
  
• Motion Sickness [M0014105]
  Disorder caused by motion, as sea sickness, train sickness, car sickness, air sickness, or SPACE MOTION SICKNESS. It may include nausea, vomiting and dizziness.
  
• Motor Disorder, Vagus Nerve [M0336411]
  
• Motor Neuron Disease [M0025158]
  Diseases characterized by a selective degeneration of the motor neurons of the spinal cord, brainstem, or motor cortex. Clinical subtypes are distinguished by the major site of degeneration. In AMYOTROPHIC LATERAL SCLEROSIS there is involvement of upper, lower, and brainstem motor neurons. In progressive muscular atrophy and related syndromes (see MUSCULAR ATROPHY, SPINAL) the motor neurons in the spinal cord are primarily affected. With progressive bulbar palsy (BULBAR PALSY, PROGRESSIVE), the initial degeneration occurs in the brainstem. In primary lateral sclerosis, the cortical neurons are affected in isolation. (Adams et al., Principles of Neurology, 6th ed, p1089)
  
• Motor Neuron Disease, Lower [M0337054]
  
• Motor Neuron Disease, Secondary [M0337057]
  
• Motor Neuron Disease, Upper [M0337056]
  
• Motor Tic Disorders [M0336233]
  
• Mouth Abnormalities [M0014127]
  Congenital absence of or defects in structures of the mouth.
  
• Mouth Diseases [M0014130]
  
• Mouth, Edentulous [M0014137]
  Total lack of teeth through disease or extraction.
  
• Movement Disorders [M0014141]
  Syndromes which feature DYSKINESIAS as a cardinal manifestation of the disease process. Included in this category are degenerative, hereditary, post-infectious, medication-induced, post-inflammatory, and post-traumatic conditions.
  
• Movement Disorders, Rhythmic Nocturnal [M0335196]
  
• Moyamoya Disease [M0014146]
  A chronic cerebral vasculopathy primarily occurring in childhood and characterized by slowly progressive carotid artery narrowing and occlusion at the base of the brain. An extensive network of anastomoses forms between branches of the carotid arteries, resulting in a characteristic angiographic appearance. The condition may be idiopathic (classic moyamoya disease) or occur in association with ANEMIA, SICKLE CELL; DOWN SYNDROME; CRANIOCEREBRAL TRAUMA; RADIOTHERAPY induced arterial injury; NEUROFIBROMATOSIS; and other diseases. Clinical manifestations include hemiparesis, headache, seizures, and delayed mental development. In older individuals, this disease may present as SUBARACHNOID HEMORRHAGE. (From Adams et al., Principles of Neurology, 6th ed, p831; Clin Neurol Neurosurg 1997 Oct;99 Suppl 2:S36-8)
  
• Moyamoya Disease, Classic [M0335700]
  
• Moyamoya Disease, Secondary [M0335701]
  
• MPS III A [M0014169]
  
• MPS III B [M0014170]
  
• MPS III C [M0014171]
  
• MPS III D [M0014172]
  
• MPS IV A [M0014174]
  
• MPS IV B [M0014175]
  
• MPTP-Induced Degeneration of the Striatum [M0332996]
  
• mu-Chain Disease [M0009993]
  
• Mucinoses [M0026583]
  Mucoid states characterized by the elevated deposition and accumulation of mucin (mucopolysaccharides) in dermal tissue. The fibroblasts are responsible for the production of acid mucopolysaccharides (GLYCOSAMINOGLYCANS) in the ground substance of the connective tissue system. When fibroblasts produce abnormally large quantities of mucopolysaccharides as hyaluronic acid, chondroitin sulfate, or heparin, they accumulate in large amounts in the dermis.
  
• Mucinosis, Follicular [M0000761]
  A disease of the pilosebaceous unit, presenting clinically as grouped follicular papules or plaques with associated hair loss. It is caused by mucinous infiltration of tissues, and usually involving the scalp, face, and neck. It may be primary (idiopathic) or secondary to mycosis fungoides or reticulosis.
  
• Mucocutaneous Lymph Node Syndrome [M0014162]
  An acute, febrile, mucocutaneous condition accompanied by swelling of cervical lymph nodes in infants and young children. The principal symptoms are fever, congestion of the ocular conjunctivae, reddening of the lips and oral cavity, protuberance of tongue papillae, and edema or erythema of the extremities.
  
• Mucolipidoses [M0014165]
  A group of inherited metabolic diseases characterized by the accumulation of excessive amounts of acid mucopolysaccharides, sphingolipids, and/or glycolipids in visceral and mesenchymal cells. Abnormal amounts of sphingolipids or glycolipids are present in neural tissue. Mental retardation and skeletal changes, most notably dysostosis multiplex, occur frequently. (From Joynt, Clinical Neurology, 1992, Ch56, pp36-7)
  
• Mucopolysaccharidoses [M0014167]
  Group of lysosomal storage diseases each caused by an inherited deficiency of an enzyme involved in the degradation of glycosaminoglycans (mucopolysaccharides). The diseases are progressive and often display a wide spectrum of clinical severity within one enzyme deficiency.
  
• Mucopolysaccharidosis I [M0012558]
  Systemic lysosomal storage disease caused by a deficiency of alpha-L-iduronidase (IDURONIDASE) and characterized by progressive physical deterioration with urinary excretion of DERMATAN SULFATE and HEPARAN SULFATE. There are three recognized phenotypes representing a spectrum of clinical severity from severe to mild: Hurler's syndrome, Hurler-Scheie syndrome and Scheie's syndrome (formerly mucopolysaccharidosis V). Symptoms may include DWARFISM, hepatosplenomegaly, gargoyle-like facies, corneal clouding, cardiac complications, and noisy breathing. Hunter syndrome (MUCOPOLYSACCHARIDOSIS II) and Hurler syndrome were each originally called "gargoylism" because of the coarseness of the facial features of affected individuals.
  
• Mucopolysaccharidosis II [M0025232]
  Systemic lysosomal storage disease marked by progressive physical deterioration and caused by a deficiency of L-sulfoiduronate sulfatase. This disease differs from MUCOPOLYSACCHARIDOSIS I by slower progression, lack of corneal clouding, and X-linked rather than autosomal recessive inheritance. The mild form produces near-normal intelligence and life span. The severe form usually causes death by age 15.
  
• Mucopolysaccharidosis III [M0014168]
  Mucopolysaccharidosis characterized by heparitin sulfate in the urine, progressive mental retardation, mild dwarfism, and other skeletal disorders. There are four clinically indistinguishable but biochemically distinct forms, each due to a deficiency of a different enzyme.
  
• Mucopolysaccharidosis IV [M0014173]
  Genetic disorder of mucopolysaccharide metabolism characterized by skeletal abnormalities, joint instability, development of cervical myelopathy, and excessive urinary keratan sulfate. There are two biochemically distinct forms, each due to a deficiency of a different enzyme.
  
• Mucopolysaccharidosis VI [M0014176]
  Mucopolysaccharidosis with excessive chondroitin sulfate B in urine, characterized by dwarfism and deafness. It is caused by a deficiency of N-acetylgalactosamine-4-sulfatase (arylsulfatase B).
  
• Mucopolysaccharidosis VII [M0025240]
  Mucopolysaccharidosis characterized by excessive dermatan and heparan sulfates in the urine and Hurler-like features. It is caused by a deficiency of beta-glucuronidase.
  
• Mucormycosis [M0014180]
  Infection in humans and animals caused by any fungus in the order Mucorales (e.g., Absidia, Mucor, Rhizopus etc.) There are many clinical types associated with infection of the central nervous system, lung, gastrointestinal tract, skin, orbit and paranasal sinuses. In humans, it usually occurs as an opportunistic infection in patients with a chronic debilitating disease, particularly uncontrolled diabetes, or who are receiving immunosuppressive agents. (From Dorland, 28th ed)
  
• Mucositis [M0482523]
  An INFLAMMATION of the MUCOSA with burning or tingling sensation. It is characterized by atrophy of the squamous EPITHELIUM, vascular damage, inflammatory infiltration, and ulceration. It usually occurs at the mucous lining of the MOUTH, the GASTROINTESTINAL TRACT or the airway due to chemical irritations, CHEMOTHERAPY, or radiation therapy (RADIOTHERAPY).
  
• Mulibrey Nanism [M0006898]
  Growth failure from birth that is due to mutations in a gene (TRIM37) on chromosome 17q22-q23 which encodes a RING-B-box-coiled-coil protein.
  
• Multicystic Dysplastic Kidney [M0355423]
  A nongenetic defect due to malformation of the KIDNEY which appears as a bunch of grapes with multiple renal cysts but lacking the normal renal bean shape, and the collection drainage system. This condition can be detected in-utero with ULTRASONOGRAPHY.
  
• Multicystic Encephalomalacia [M0334893]
  
• Multidirectional Nystagmus [M0333566]
  
• Multiple Carboxylase Deficiency [M0014194]
  A deficiency in the activities of biotin-dependent enzymes (propionyl-CoA carboxylase, methylcrotonyl-CoA carboxylase, and PYRUVATE CARBOXYLASE) due to one of two defects in BIOTIN metabolism. The neonatal form is due to HOLOCARBOXYLASE SYNTHETASE DEFICIENCY. The late-onset form is due to BIOTINIDASE DEFICIENCY.
  
• Multiple Chemical Sensitivity [M0028112]
  An acquired disorder characterized by recurrent symptoms, referable to multiple organ systems, occurring in response to demonstrable exposure to many chemically unrelated compounds at doses below those established in the general population to cause harmful effects. (Cullen MR. The worker with multiple chemical sensitivities: an overview. Occup Med 1987;2(4):655-61)
  
• Multiple Epiphyseal Dysplasia [M0015524]
  
• Multiple Sclerosis [M0014197]
  An autoimmune disorder mainly affecting young adults and characterized by destruction of myelin in the central nervous system. Pathologic findings include multiple sharply demarcated areas of demyelination throughout the white matter of the central nervous system. Clinical manifestations include visual loss, extra-ocular movement disorders, paresthesias, loss of sensation, weakness, dysarthria, spasticity, ataxia, and bladder dysfunction. The usual pattern is one of recurrent attacks followed by partial recovery (see MULTIPLE SCLEROSIS, RELAPSING-REMITTING), but acute fulminating and chronic progressive forms (see MULTIPLE SCLEROSIS, CHRONIC PROGRESSIVE) also occur. (Adams et al., Principles of Neurology, 6th ed, p903)
  
• Multiple Sclerosis, Acute Fulminating [M0334267]
  
• Multiple Sclerosis, Acute Relapsing [M0334289]
  
• Multiple Sclerosis, Chronic Progressive [M0328148]
  A form of multiple sclerosis characterized by a progressive deterioration in neurologic function which is in contrast to the more typical relapsing remitting form. If the clinical course is free of distinct remissions, it is referred to as primary progressive multiple sclerosis. When the progressive decline is punctuated by acute exacerbations, it is referred to as progressive relapsing multiple sclerosis. The term secondary progressive multiple sclerosis is used when relapsing remitting multiple sclerosis evolves into the chronic progressive form. (From Ann Neurol 1994;36 Suppl:S73-S79; Adams et al., Principles of Neurology, 6th ed, pp903-914)
  
• Multiple Sclerosis, Primary Progressive [M0334286]
  
• Multiple Sclerosis, Progressive Relapsing [M0334284]
  
• Multiple Sclerosis, Relapsing-Remitting [M0328152]
  The most common clinical variant of MULTIPLE SCLEROSIS, characterized by recurrent acute exacerbations of neurologic dysfunction followed by partial or complete recovery. Common clinical manifestations include loss of visual (see OPTIC NEURITIS), motor, sensory, or bladder function. Acute episodes of demyelination may occur at any site in the central nervous system, and commonly involve the optic nerves, spinal cord, brain stem, and cerebellum. (Adams et al., Principles of Neurology, 6th ed, pp903-914)
  
• Multiple Sclerosis, Secondary Progressive [M0334287]
  
• Multiple Sulfatase Deficiency Disease [M0336078]
  An inherited metabolic disorder characterized by the intralysosomal accumulation of sulfur-containing lipids (sulfatides) and MUCOPOLYSACCHARIDES. Excess levels of both substrates are present in urine. This is a disorder of multiple sulfatase (arylsulfatases A, B, and C) deficiency which is caused by the mutation of sulfatase-modifying factor-1. Neurological deterioration is rapid.
  
• Multiple System Atrophy [M0029076]
  A syndrome complex composed of three conditions which represent clinical variants of the same disease process: STRIATONIGRAL DEGENERATION; SHY-DRAGER SYNDROME; and the sporadic form of OLIVOPONTOCEREBELLAR ATROPHIES. Clinical features include autonomic, cerebellar, and basal ganglia dysfunction. Pathologic examination reveals atrophy of the basal ganglia, cerebellum, pons, and medulla, with prominent loss of autonomic neurons in the brain stem and spinal cord. (From Adams et al., Principles of Neurology, 6th ed, p1076; Baillieres Clin Neurol 1997 Apr;6(1):187-204; Med Clin North Am 1999 Mar;83(2):381-92)
  
• Mumps [M0014202]
  An acute infectious disease caused by RUBULAVIRUS, spread by direct contact, airborne droplet nuclei, fomites contaminated by infectious saliva, and perhaps urine, and usually seen in children under the age of 15, although adults may also be affected. (From Dorland, 28th ed)
  
• Muscular Atrophy [M0014249]
  Derangement in size and number of muscle fibers occurring with aging, reduction in blood supply, or following immobilization, prolonged weightlessness, malnutrition, and particularly in denervation.
  
• Muscular Atrophy, Spinal [M0014250]
  A group of disorders marked by progressive degeneration of motor neurons in the spinal cord resulting in weakness and muscular atrophy, usually without evidence of injury to the corticospinal tracts. Diseases in this category include Werdnig-Hoffmann disease and later onset SPINAL MUSCULAR ATROPHIES OF CHILDHOOD, most of which are hereditary. (Adams et al., Principles of Neurology, 6th ed, p1089)
  
• Muscular Atrophy, Spinal, Type II [M0336136]
  
• Muscular Diseases [M0014252]
  Acquired, familial, and congenital disorders of skeletal muscle (MUSCLE, SKELETAL) and smooth muscle (MUSCLE, SMOOTH).
  
• Muscular Disorders, Atrophic [M0328176]
  Disorders characterized by an abnormal reduction in muscle volume due to a decrease in the size or number of muscle fibers. Atrophy may result from diseases intrinsic to muscle tissue (e.g., MUSCULAR DYSTROPHY) or secondary to PERIPHERAL NERVOUS SYSTEM DISEASES that impair innervation to muscle tissue (e.g., MUSCULAR ATROPHY, SPINAL).
  
• Muscular Dystrophies [M0014254]
  A heterogeneous group of inherited MYOPATHIES, characterized by wasting and weakness of the SKELETAL MUSCLE. They are categorized by the sites of MUSCLE WEAKNESS; AGE OF ONSET; and INHERITANCE PATTERNS.
  
• Muscular Dystrophies, Limb-Girdle [M0335588]
  A heterogenous group of inherited muscular dystrophy that can be autosomal dominant or autosomal recessive. There are many forms (called LGMDs) involving genes encoding muscle membrane proteins such as the sarcoglycan (SARCOGLYCANS) complex that interacts with DYSTROPHIN. The disease is characterized by progressing wasting and weakness of the proximal muscles of arms and legs around the HIPS and SHOULDERS (the pelvic and shoulder girdles).
  
• Muscular Dystrophy, Animal [M0014256]
  
• Muscular Dystrophy, Duchenne [M0014253]
  An X-linked recessive muscle disease caused by an inability to synthesize DYSTROPHIN, which is involved with maintaining the integrity of the sarcolemma. Muscle fibers undergo a process that features degeneration and regeneration. Clinical manifestations include proximal weakness in the first few years of life, pseudohypertrophy, cardiomyopathy (see MYOCARDIAL DISEASES), and an increased incidence of impaired mentation. Becker muscular dystrophy is a closely related condition featuring a later onset of disease (usually adolescence) and a slowly progressive course. (Adams et al., Principles of Neurology, 6th ed, p1415)
  
• Muscular Dystrophy, Emery-Dreifuss [M0328183]
  A heterogenous group of inherited muscular dystrophy without the involvement of nervous system. The disease is characterized by MUSCULAR ATROPHY; MUSCLE WEAKNESS; CONTRACTURE of the elbows; ACHILLES TENDON; and posterior cervical muscles; with or without cardiac features. There are several INHERITANCE PATTERNS including X-linked (X CHROMOSOME), autosomal dominant, and autosomal recessive gene mutations.
  
• Muscular Dystrophy, Facioscapulohumeral [M0328187]
  An autosomal dominant degenerative muscle disease characterized by slowly progressive weakness of the muscles of the face, upper-arm, and shoulder girdle. The onset of symptoms usually occurs in the first or second decade of life. Affected individuals usually present with impairment of upper extremity elevation. This tends to be followed by facial weakness, primarily involving the orbicularis oris and orbicularis oculi muscles. (Neuromuscul Disord 1997;7(1):55-62; Adams et al., Principles of Neurology, 6th ed, p1420)
  
• Muscular Dystrophy, Oculopharyngeal [M0335587]
  An autosomal dominant hereditary disease that presents in late in life and is characterized by DYSPHAGIA and progressive ptosis of the eyelids. Mutations in the gene for POLY(A)-BINDING PROTEIN II have been associated with oculopharyngeal muscular dystrophy.
  
• Musculoskeletal Abnormalities [M0014258]
  Congenital structural abnormalities and deformities of the musculoskeletal system.
  
• Musculoskeletal Diseases [M0014259]
  Diseases of the muscles and their associated ligaments and other connective tissue and of the bones and cartilage viewed collectively.
  
• Mutism [M0014276]
  The inability to generate oral-verbal expression, despite normal comprehension of speech. This may be associated with BRAIN DISEASES or MENTAL DISORDERS. Organic mutism may be associated with damage to the FRONTAL LOBE; BRAIN STEM; THALAMUS; and CEREBELLUM. Selective mutism is a psychological condition that usually affects children characterized by continuous refusal to speak in social situations by a child who is able and willing to speak to selected persons. Kussmal aphasia refers to mutism in psychosis. (From Fortschr Neurol Psychiatr 1994; 62(9):337-44)
  
• Myasthenia Gravis [M0014279]
  A disorder of neuromuscular transmission characterized by weakness of cranial and skeletal muscles. Autoantibodies directed against acetylcholine receptors damage the motor endplate portion of the NEUROMUSCULAR JUNCTION, impairing the transmission of impulses to skeletal muscles. Clinical manifestations may include diplopia, ptosis, and weakness of facial, bulbar, respiratory, and proximal limb muscles. The disease may remain limited to the ocular muscles. THYMOMA is commonly associated with this condition. (Adams et al., Principles of Neurology, 6th ed, p1459)
  
• Myasthenia Gravis, Generalized [M0335255]
  
• Myasthenia Gravis, Neonatal [M0328228]
  A disorder of neuromuscular transmission that occurs in a minority of newborns born to women with myasthenia gravis. Clinical features are usually present at birth or develop in the first 3 days of life and consist of hypotonia and impaired respiratory, suck, and swallowing abilities. This condition is associated with the passive transfer of acetylcholine receptor antibodies through the placenta. In the majority of infants the myasthenic weakness resolves (i.e., transient neonatal myasthenia gravis) although this disorder may rarely continue beyond the neonatal period (i.e., persistent neonatal myasthenia gravis). (From Menkes, Textbook of Child Neurology, 5th ed, p823; Neurology 1997 Jan;48(1):50-4)
  
• Myasthenia Gravis, Neonatal, Persistent [M0335262]
  
• Myasthenia Gravis, Neonatal, Transient [M0335263]
  
• Myasthenia Gravis, Ocular [M0335256]
  
• Myasthenic Syndromes, Congenital [M0328231]
  A heterogeneous group of disorders characterized by a congenital defect in neuromuscular transmission at the NEUROMUSCULAR JUNCTION. This includes presynaptic, synaptic, and postsynaptic disorders (that are not of autoimmune origin). The majority of these diseases are caused by mutations of various subunits of the nicotinic acetylcholine receptor (RECEPTORS, NICOTINIC) on the postsynaptic surface of the junction. (From Arch Neurol 1999 Feb;56(2):163-7)
  
• Myasthenic Syndromes, Congenital, Slow Channel [M0337366]
  
• Mycobacterium avium-intracellulare Infection [M0023509]
  A nontuberculous infection when occurring in humans. It is characterized by pulmonary disease, lymphadenitis in children, and systemic disease in AIDS patients. Mycobacterium avium-intracellulare infection of birds and swine results in tuberculosis.
  
• Mycobacterium Infections [M0014287]
  Infections with bacteria of the genus MYCOBACTERIUM.
  
• Mycobacterium Infections, Atypical [M0014288]
  Infections with so called atypical mycobacteria (tuberculoid bacilli): M. kansasii, M. marinum, M. scrofulaceum, M. flavescens, M. gordonae, M. obuense, M. gilvum, M. duvali, M. szulgai, M. intracellulare (see MYCOBACTERIUM AVIUM COMPLEX;), M. xenopi (littorale), M. ulcerans, M. buruli, M. terrae, M. fortuitum (minetti, giae), M. chelonae.
  
• Mycoplasma Infections [M0014307]
  Infections with species of the genus MYCOPLASMA.
  
• Mycoplasmatales Infections [M0014312]
  Infections with bacteria of the order MYCOPLASMATALES.
  
• Mycoses [M0014313]
  
• Mycotic Aneurysm, Intracranial [M0335411]
  
• Myelinolysis, Central Pontine [M0026656]
  A demyelinating condition affecting the PONS and characterized clinically by an acute progressive QUADRIPLEGIA; DYSARTHRIA; DYSPHAGIA; and alterations of consciousness. Pathologic features include prominent demyelination in the central PONS with sparing of axons and neurons. This condition is usually associated with systemic disorders such as HYPONATREMIA; chronic ALCOHOLISM; LIVER FAILURE; severe BURNS; malignant NEOPLASMS; hemorrhagic PANCREATITIS; HEMODIALYSIS; and SEPSIS. The rapid medical correction of hyponatremia has been cited as a cause of this condition. (From Adams et al., Principles of Neurology, 6th ed, pp1125-6)
  
• Myelitis [M0014321]
  Inflammation of the spinal cord. Relatively common etiologies include infections; AUTOIMMUNE DISEASES; SPINAL CORD; and ischemia (see also SPINAL CORD VASCULAR DISEASES). Clinical features generally include weakness, sensory loss, localized pain, incontinence, and other signs of autonomic dysfunction.
  
• Myelitis, Acute Transverse [M0334305]
  
• Myelitis, Necrotizing [M0334306]
  
• Myelitis, Paraneoplastic [M0334307]
  
• Myelitis, Postinfectious [M0334308]
  
• Myelitis, Postvaccinal [M0334309]
  
• Myelitis, Subacute Transverse [M0334358]
  
• Myelitis, Transverse [M0014322]
  Inflammation of a transverse portion of the spinal cord characterized by acute or subacute segmental demyelination or necrosis. The condition may occur sporadically, follow an infection or vaccination, or present as a paraneoplastic syndrome (see also ENCEPHALOMYELITIS, ACUTE DISSEMINATED). Clinical manifestations include motor weakness, sensory loss, and incontinence. (Adams et al., Principles of Neurology, 6th ed, pp1242-6)
  
• Myelofibrosis [M0014325]
  Replacement of the bone marrow by fibrous tissue, occurring in association with a myeloproliferative disorder or secondary to another, unrelated condition. (Dorland, 27th ed)
  
• Myeloid Metaplasia [M0014329]
  The occurrence of myeloid tissue in extramedullary sites. Specifically it is a syndrome characterized by splenomegaly, anemia, the presence of nucleated erythrocytes and immature granulocytes in the circulating blood, and extramedullary hematopoiesis in the liver and spleen. The primary form is also known as agnogenic myeloid metaplasia, myelosclerosis, and myelofibrosis. The secondary or symptomatic form may be associated with various diseases, including carcinomatosis, tuberculosis, leukemia, and polycythemia vera. (Dorland, 27th ed)
  
• Myelopathic Muscular Atrophy [M0014251]
  
• Myelosis, Nonleukemic [M0014328]
  
• Myiasis [M0014334]
  The invasion of living tissues of man and other mammals by dipterous larvae.
  
• Myocardial Infarction [M0014340]
  Gross necrosis of the myocardium, as a result of interruption of the blood supply to the area. (Dorland, 27th ed)
  
• Myocardial Ischemia [M0026104]
  A disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. The decreased blood flow may be due to narrowing of the coronary arteries (CORONARY ARTERIOSCLEROSIS), to obstruction by a thrombus (CORONARY THROMBOSIS), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. Severe interruption of the blood supply to the myocardial tissue may result in necrosis of cardiac muscle (MYOCARDIAL INFARCTION).
  
• Myocardial Preinfarction Syndrome [M0001183]
  
• Myocardial Stunning [M0026743]
  Prolonged dysfunction of the myocardium after a brief episode of severe ischemia, with gradual return of contractile activity. It occurs frequently, both in the experimental laboratory and in clinical medicine. Since stunned myocardium occurs adjacent to necrotic tissue after prolonged coronary occlusion, many myocardial infarcts may be a mixture of necrotic and stunned tissue. (Braunwald, Heart Disease, 1992, p1176)
  
• Myocarditis [M0014343]
  Inflammatory processes of the muscular walls of the heart (MYOCARDIUM) which result in injury to the cardiac muscle cells (MYOCYTES, CARDIAC). Manifestations range from subclinical to sudden death (DEATH, SUDDEN). Myocarditis in association with cardiac dysfunction is classified as inflammatory CARDIOMYOPATHY usually caused by INFECTION, autoimmune diseases, or responses to toxic substances. Myocarditis is also a common cause of DILATED CARDIOMYOPATHY and other cardiomyopathies.
  
• Myocarditis, Chagas [M0453122]
  
• Myoclonic Absence Epilepsy [M0334938]
  
• Myoclonic Astatic Epilepsy [M0334944]
  
• Myoclonic Cerebellar Dyssynergia [M0003859]
  A condition marked by progressive CEREBELLAR ATAXIA combined with MYOCLONUS usually presenting in the third decade of life or later. Additional clinical features may include generalized and focal SEIZURES, spasticity, and DYSKINESIAS. Autosomal recessive and autosomal dominant patterns of inheritance have been reported. Pathologically, the dentate nucleus and brachium conjunctivum of the CEREBELLUM are atrophic, with variable involvement of the spinal cord, cerebellar cortex, and basal ganglia. (From Joynt, Clinical Neurology, 1991, Ch37, pp60-1)
  
• Myoclonic Encephalopathy [M0334939]
  
• Myoclonic Epilepsies, Progressive [M0328687]
  A heterogeneous group of primarily familial disorders characterized by myoclonic seizures, tonic-clonic seizures, ataxia, progressive intellectual deterioration, and neuronal degeneration. These include LAFORA DISEASE; MERRF SYNDROME; NEURONAL CEROID-LIPOFUSCINOSIS; sialidosis (see MUCOLIPIDOSES), and UNVERRICHT-LUNDBORG SYNDROME.
  
• Myoclonic Epilepsy, Juvenile [M0328258]
  A disorder characterized by the onset of myoclonus in adolescence, a marked increase in the incidence of absence seizures (see EPILEPSY, ABSENCE), and generalized major motor seizures (see EPILEPSY, TONIC-CLONIC). The myoclonic episodes tend to occur shortly after awakening. Seizures tend to be aggravated by sleep deprivation and alcohol consumption. Hereditary and sporadic forms have been identified. (From Adams et al., Principles of Neurology, 6th ed, p323)
  
• Myofacial Pain Syndromes [M0336100]
  
• Myofascial Pain Syndromes [M0014349]
  Muscular pain in numerous body regions that can be reproduced by pressure on trigger points, localized hardenings in skeletal muscle tissue. Pain is referred to a location distant from the trigger points. A prime example is the TEMPOROMANDIBULAR JOINT DYSFUNCTION SYNDROME.
  
• Myopathic Ophthalmopathy [M0471766]
  
• Myopathies, Nemaline [M0026760]
  A group of inherited congenital myopathic conditions characterized clinically by weakness, hypotonia, and prominent hypoplasia of proximal muscles including the face. Muscle biopsy reveals large numbers of rod-shaped structures beneath the muscle fiber plasma membrane. This disorder is genetically heterogeneous and may occasionally present in adults. (Adams et al., Principles of Neurology, 6th ed, p1453)
  
• Myopathies, Structural, Congenital [M0328270]
  A heterogeneous group of diseases characterized by the early onset of hypotonia, developmental delay of motor skills, non-progressive weakness. Each of these disorders is associated with a specific histologic muscle fiber abnormality.
  
• Myopathy, Central Core [M0328271]
  An inherited congenital myopathic condition characterized by weakness and hypotonia in infancy and delayed motor development. Muscle biopsy reveals a condensation of myofibrils and myofibrillar material in the central portion of each muscle fiber. (Adams et al., Principles of Neurology, 6th ed, p1452)
  
• Myopia [M0014358]
  A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.
  
• Myopia, Degenerative [M0459480]
  Excessive axial myopia associated with complications (especially posterior staphyloma and CHOROIDAL NEOVASCULARIZATION) that can lead to BLINDNESS.
  
• Myopia, Progressive [M0459481]
  Myopia that increases at an abnormally rapid rate or increases after maturity (Hofstetter et al, Dictionary of Visual Science and Related Clinical Terms, 5th ed).
  
• Myositis [M0014368]
  Inflammation of skeletal muscle (MUSCLE, SKELETAL). Infectious, autoimmune, and paraneoplastic processes represent some of the more common conditions that may be associated with myositis. (From Adams et al., Principles of Neurology, 6th ed., pp 1402-13)
  
• Myositis Ossificans [M0014370]
  A disease characterized by bony deposits or the ossification of muscle tissue.
  
• Myositis, Focal [M0335630]
  
• Myositis, Inclusion Body [M0028350]
  Progressive myopathies characterized by the presence of inclusion bodies on muscle biopsy. Sporadic and hereditary forms have been described. The sporadic form is an acquired, adult-onset inflammatory vacuolar myopathy affecting proximal and distal muscles. Familial forms usually begin in childhood and lack inflammatory changes. Both forms feature intracytoplasmic and intranuclear inclusions in muscle tissue. (Adams et al., Principles of Neurology, 6th ed, pp1409-10)
  
• Myositis, Infectious [M0335632]
  
• Myositis, Proliferative [M0335631]
  
• Myotonia Congenita [M0014373]
  A dominantly inherited muscle disease that begins in early childhood and is characterized by severe myotonia (delayed relaxation of a muscle) after forceful voluntary contractions. Muscular hypertrophy is common and myotonia may impair ambulation and other movements. Myotonia typically becomes less severe with repetitive voluntary contractions of the affected muscles. Generalized myotonia (of Becker) is an autosomal recessive variant of myotonia congenita that may feature more severe myotonia and muscle wasting. (From Adams et al., Principles of Neurology, 6th ed, pp1476-7; Joynt, Clinical Neurology, 1997, Ch53, p18)
  
• Myotonia Fluctuans [M0337319]
  
• Myotonia Levior [M0337013]
  
• Myotonic Disorders [M0328274]
  Diseases characterized by MYOTONIA, which may be inherited or acquired. Myotonia may be restricted to certain muscles (e.g., intrinsic hand muscles) or occur as a generalized condition. These disorders may be associated with abnormal muscle SODIUM CHANNEL and CHLORIDE CHANNELS. MYOTONIC DYSTROPHY and MYOTONIA CONGENITA represent two relatively common forms of this disorder. Proximal myotonic myopathy often presents with myotonia and muscle pain in early adulthood and later in life thigh muscle weakness and cataracts develop. (From Adams et al., Principles of Neurology, 6th ed, p1392)
  
• Myotonic Dystrophy [M0014372]
  An autosomal dominant neuromuscular disorder which usually presents in early adulthood, characterized by progressive muscular atrophy (most frequently involving the hands, forearms, and face), myotonia, frontal baldness, lenticular opacities, and testicular atrophy. Cardiac conduction abnormalities, diaphragmatic weakness, and mild mental retardation may also occur. Congenital myotonic dystrophy is a severe form of this disorder, characterized by neonatal MUSCLE HYPOTONIA, feeding difficulties, respiratory muscle weakness, and an increased incidence of MENTAL RETARDATION. (From Adams et al., Principles of Neurology, 6th ed, pp1423-5; Joynt, Clinical Neurology, 1997, Ch16, pp16-7)
  
• Myotonic Dystrophy, Congenital [M0335623]
  
• Myotonic Myopathy, Proximal [M0337320]
  
• Myxedema [M0014379]
  A condition characterized by a dry, waxy type of swelling (EDEMA) with abnormal deposits of MUCOPOLYSACCHARIDES in the SKIN and other tissues. It is caused by a deficiency of THYROID HORMONES. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.
  
• Myxedema, Congenital [M0470647]
  
• Myxomatosis, Infectious [M0014385]
  
• Naffziger Syndrome [M0336377]
  
• Nagana [M0022073]
  
• Nail Diseases [M0014427]
  Diseases of the nail plate and tissues surrounding it. The concept is limited to primates.
  
• Nail-Patella Syndrome [M0014428]
  A syndrome of multiple abnormalities characterized by the absence or hypoplasia of the PATELLA and congenital nail dystrophy. It is a genetically determined autosomal dominant trait.
  
• Nails, Ingrown [M0014430]
  Excessive lateral nail growth into the nail fold. Because the lateral margin of the nail acts as a foreign body, inflammation and granulation may result. It is caused by improperly fitting shoes and by improper trimming of the nail.
  
• Nails, Malformed [M0014431]
  Deformities in nail structure or appearance, including hypertrophy, splitting, clubbing, furrowing, etc. Genetic diseases such as PACHYONYCHIA CONGENITA can result in malformed nails.
  
• Nairobi Sheep Disease [M0014432]
  An arbovirus infection of sheep and goats transmitted by ticks. It is characterized by high fever and hemorrhagic gastroenteritis.
  
• Narcolepsy [M0014471]
  A condition characterized by recurrent episodes of daytime somnolence and lapses in consciousness (microsomnias) that may be associated with automatic behaviors and AMNESIA. CATAPLEXY; SLEEP PARALYSIS, and hypnagogic HALLUCINATIONS frequently accompany narcolepsy. The pathophysiology of this disorder includes sleep-onset rapid eye movement (REM) sleep, which normally follows stage III or IV sleep. (From Neurology 1998 Feb;50(2 Suppl 1):S2-S7)
  
• Narcolepsy-Cataplexy Syndrome [M0334764]
  
• Narcosis [M0494989]
  A state of depressed CENTRAL NERVOUS SYSTEM marked by stupor or insensibility.
  
• Nasal Obstruction [M0023869]
  Any hindrance to the passage of air into and out of the nose. The obstruction may be in the nasal vestibule, fossae, or other areas of the nasal cavity.
  
• Nasopharyngeal Diseases [M0014492]
  General or unspecified diseases of the nasopharynx.
  
• Nasopharyngitis [M0014494]
  Inflammation of the nasopharynx.
  
• Necatoriasis [M0014540]
  Infection of humans or animals with hookworms of the genus NECATOR. The resulting anemia from this condition is less severe than that from ANCYLOSTOMIASIS.
  
• Necrobacillosis [M0008918]
  
• Necrobiosis Lipoidica [M0014543]
  A degenerative disease of the dermal connective tissue characterized by the development of erythematous papules or nodules in the pretibial area. The papules form plaques covered with telangiectatic vessels. More than half of the affected patients have diabetes.
  
• Necrotizing Arteritis [M0016295]
  
• Necrotizing Hemorrhagic Encephalomyelitis [M0007376]
  
• Necrotizing Scleritis [M0023772]
  
• Neisseriaceae Infections [M0025673]
  Infections with bacteria of the family NEISSERIACEAE.
  
• Nemaline Myopathy, Autosomal Dominant [M0335627]
  
• Nemaline Myopathy, Autosomal Recessive [M0335628]
  
• Nemaline Myopathy, Childhood Onset [M0335625]
  
• Nemaline Myopathy, Late Onset [M0335626]
  
• Nematode Infections [M0014560]
  Infections by nematodes, general or unspecified.
  
• Neonatal Abstinence Syndrome [M0014568]
  Fetal and neonatal addiction and withdrawal as a result of the mother's dependence on drugs during pregnancy. Withdrawal or abstinence symptoms develop shortly after birth. Symptoms exhibited are loud, high-pitched crying, sweating, yawning and gastrointestinal disturbances.
  
• Neonatal Cerebral Leukomalacia [M0335524]
  
• Neonatal Diseases and Abnormalities [M0374592]
  
• Neonatal Sleep Myoclonus, Benign [M0335105]
  
• Nephritis [M0014626]
  Inflammation of any part of the KIDNEY.
  
• Nephritis, Hereditary [M0014627]
  A group of inherited conditions characterized initially by HEMATURIA and slowly progressing to RENAL INSUFFICIENCY. The most common form is the Alport syndrome (hereditary nephritis with HEARING LOSS) which is caused by mutations in genes for TYPE IV COLLAGEN and defective GLOMERULAR BASEMENT MEMBRANE.
  
• Nephritis, Interstitial [M0014628]
  Inflammation of the interstitial tissue of the kidney. This term is generally used for primary inflammation of KIDNEY TUBULES and/or surrounding interstitium. For primary inflammation of glomerular interstitium, see GLOMERULONEPHRITIS. Infiltration of the inflammatory cells into the interstitial compartment results in EDEMA, increased spaces between the tubules, and tubular renal dysfunction.
  
• Nephritis, Tubulointerstitial [M0014629]
  
• Nephrocalcinosis [M0014631]
  A condition characterized by calcification of the renal tissue itself. It is usually seen in distal RENAL TUBULAR ACIDOSIS with calcium deposition in the DISTAL KIDNEY TUBULES and the surrounding interstitium. Nephrocalcinosis causes RENAL INSUFFICIENCY.
  
• Nephrogenic Diabetes Insipidus, Type I [M0471345]
  X-linked congenital nephrogenic diabetes insipidus disorders occurring mostly in males and are caused by one of more than 130 different V2 RECEPTOR mutations.
  
• Nephrogenic Diabetes Insipidus, Type II [M0471346]
  Congenital nephrogenic diabetes insipidus caused by mutations of the aquaporin-2 water channel gene (AOP2) on chromosome 12q13.
  
• Nephrolithiasis [M0476604]
  Formation of stones in the KIDNEY.
  
• Nephropathia Epidemica [M0028113]
  Mild form of HFRS rarely hemorrhagic and seldom fatal. Caused by the PUUMALA VIRUS.
  
• Nephrosclerosis [M0014634]
  Hardening of the KIDNEY due to infiltration by fibrous connective tissue (FIBROSIS), usually caused by renovascular diseases or chronic HYPERTENSION. Nephrosclerosis leads to renal ISCHEMIA.
  
• Nephrosis [M0014635]
  Pathological processes of the KIDNEY without inflammatory or neoplastic components. Nephrosis may be a primary disorder or secondary complication of other diseases. It is characterized by the NEPHROTIC SYNDROME indicating the presence of PROTEINURIA and HYPOALBUMINEMIA with accompanying EDEMA.
  
• Nephrosis, Lipoid [M0014636]
  A kidney disease with no or minimal histological glomerular changes on light microscopy and with no immune deposits. It is characterized by lipid accumulation in the epithelial cells of KIDNEY TUBULES and in the URINE. Patients usually show NEPHROTIC SYNDROME indicating the presence of PROTEINURIA with accompanying EDEMA.
  
• Nephrotic Syndrome [M0014639]
  A condition characterized by severe PROTEINURIA, greater than 3.5 g/day in an average adult. The substantial loss of protein in the urine results in complications such as HYPOPROTEINEMIA; generalized EDEMA; HYPERTENSION; and HYPERLIPIDEMIAS. Diseases associated with nephrotic syndrome generally cause chronic kidney dysfunction.
  
• Nephrotic Syndrome, Minimal Change [M0491068]
  
• Nerve Compression Syndromes [M0014642]
  Mechanical compression of nerves or nerve roots from internal or external causes. These may result in a conduction block to nerve impulses (due to MYELIN SHEATH dysfunction) or axonal loss. The nerve and nerve sheath injuries may be caused by ISCHEMIA; INFLAMMATION; or a direct mechanical effect.
  
• Nerve Entrapments [M0336249]
  
• Nerve Root Compression [M0336805]
  
• Nerve Root Disorder [M0336806]
  
• Nervous System Diseases [M0014667]
  Diseases of the central and peripheral nervous system. This includes disorders of the brain, spinal cord, cranial nerves, peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscle.
  
• Nervous System Diseases, Parasympathetic [M0335517]
  
• Nervous System Diseases, Sympathetic [M0335518]
  
• Nervous System Malformations [M0014666]
  Structural abnormalities of the central or peripheral nervous system resulting primarily from defects of embryogenesis.
  
• Nesidioblastosis [M0015793]
  An inherited autosomal recessive syndrome characterized by the disorganized formation of new islets in the PANCREAS and PERSISTENT HYPERINSULINEMIA HYPOGLYCEMIA OF INFANCY. It is due to focal hyperplasia of pancreatic ISLET CELLS budding off from the ductal structures and forming new islets of Langerhans. Mutations in the islet cells involve the potassium channel gene KCNJ11 or the ATP-binding cassette transporter gene ABCC8, both on CHROMOSOME 11.
  
• Neuralgia, Amyotrophic [M0337610]
  
• Neuralgia, Atypical [M0336274]
  
• Neuralgia, Iliohypogastric Nerve [M0336275]
  
• Neuralgia, Ilioinguinal [M0336276]
  
• Neuralgia, Perineal [M0336277]
  
• Neuralgia, Stump [M0336278]
  
• Neuralgia, Supraorbital [M0336279]
  
• Neuralgia, Vidian [M0336280]
  
• Neuralgia-Neuritis, Sciatic Nerve [M0336179]
  
• Neuritis [M0014693]
  A general term indicating inflammation of a peripheral or cranial nerve. Clinical manifestation may include PAIN; PARESTHESIAS; PARESIS; or HYPESTHESIA.
  
• Neuritis, Motor [M0336395]
  
• Neuritis, Sensory [M0336394]
  
• Neuroaspergillosis [M0328277]
  Infections of the nervous system caused by fungi of the genus ASPERGILLUS, most commonly ASPERGILLUS FUMIGATUS. Aspergillus infections may occur in immunocompetent hosts, but are more prevalent in individuals with IMMUNOLOGIC DEFICIENCY SYNDROMES. The organism may spread to the nervous system from focal infections in the lung, mastoid region, sinuses, inner ear, bones, eyes, gastrointestinal tract, and heart. Sinus infections may be locally invasive and enter the intracranial compartment, producing MENINGITIS, FUNGAL; cranial neuropathies; and abscesses in the frontal lobes of the brain. (From Joynt, Clinical Neurology, 1998, Ch 27, pp62-3)
  
• Neuroaxonal Dystrophies [M0028551]
  A nonspecific term referring both to the pathologic finding of swelling of distal portions of axons in the brain and to disorders which feature this finding. Neuroaxonal dystrophy is seen in various genetic diseases, vitamin deficiencies, and aging. Infantile neuroaxonal dystrophy is an autosomal recessive disease characterized by arrested psychomotor development at 6 months to 2 years of age, ataxia, brain stem dysfunction, and quadriparesis. Juvenile and adult forms also occur. Pathologic findings include brain atrophy and widespread accumulation of axonal spheroids throughout the neuroaxis, peripheral nerves, and dental pulp. (From Davis & Robertson, Textbook of Neuropathology, 2nd ed, p927)
  
• Neurocirculatory Asthenia [M0014701]
  A clinical syndrome characterized by palpitation, SHORTNESS OF BREATH, labored breathing, subjective complaints of effort and discomfort, all following slight EXERTION. Other symptoms may be DIZZINESS, tremulousness, SWEATING, and INSOMNIA. Neurocirculatory asthenia is most typically seen as a form of anxiety disorder.
  
• Neurocysticercosis [M0029731]
  Infection of the brain, spinal cord, or perimeningeal structures with the larval forms of the genus TAENIA (primarily T. solium in humans). Lesions formed by the organism are referred to as cysticerci. The infection may be subacute or chronic, and the severity of symptoms depends on the severity of the host immune response and the location and number of lesions. SEIZURES represent the most common clinical manifestation although focal neurologic deficits may occur. (From Joynt, Clinical Neurology, 1998, Ch27, pp46-50)
  
• Neurodegenerative Diseases [M0029135]
  Hereditary and sporadic conditions which are characterized by progressive nervous system dysfunction. These disorders are often associated with atrophy of the affected central or peripheral nervous system structures.
  
• Neurodermatitis [M0014703]
  An extremely variable eczematous skin disease that is presumed to be a response to prolonged vigorous scratching, rubbing, or pinching to relieve intense pruritus. It varies in intensity, severity, course, and morphologic expression in different individuals. Neurodermatitis is believed by some to be psychogenic. The circumscribed or localized form is often referred to as lichen simplex chronicus.
  
• Neurogenic Thoracic Outlet Syndrome [M0336373]
  
• Neurogenic Urinary Bladder, Atonic [M0337439]
  
• Neurogenic Urinary Bladder, Spastic [M0337440]
  
• Neuroleptic Malignant Syndrome [M0014713]
  A potentially fatal syndrome associated primarily with the use of neuroleptic agents (see ANTIPSYCHOTIC AGENTS) which are in turn associated with dopaminergic receptor blockade (see RECEPTORS, DOPAMINE) in the BASAL GANGLIA and HYPOTHALAMUS, and sympathetic dysregulation. Clinical features include diffuse MUSCLE RIGIDITY; TREMOR; high FEVER; diaphoresis; labile blood pressure; cognitive dysfunction; and autonomic disturbances. Serum CPK level elevation and a leukocytosis may also be present. (From Adams et al., Principles of Neurology, 6th ed, p1199; Psychiatr Serv 1998 Sep;49(9):1163-72)
  
• Neuroleptic-Induced Neuroleptic Malignant Syndrome [M0332878]
  
• Neurologic Syndrome, Thoracic Outlet [M0336374]
  
• Neuromuscular Diseases [M0014726]
  A general term encompassing lower MOTOR NEURON DISEASE; PERIPHERAL NERVOUS SYSTEM DISEASES; and certain MUSCULAR DISEASES. Manifestations include MUSCLE WEAKNESS; FASCICULATION; muscle ATROPHY; SPASM; MYOKYMIA; MUSCLE HYPERTONIA, myalgias, and MUSCLE HYPOTONIA.
  
• Neuromuscular Junction Diseases [M0328288]
  Conditions characterized by impaired transmission of impulses at the NEUROMUSCULAR JUNCTION. This may result from disorders that affect receptor function, pre- or postsynaptic membrane function, or ACETYLCHOLINESTERASE activity. The majority of diseases in this category are associated with autoimmune, toxic, or inherited conditions.
  
• Neuromuscular Junction Toxic Disorders [M0337353]
  
• Neuromyelitis Optica [M0014730]
  A syndrome characterized by acute OPTIC NEURITIS in combination with acute MYELITIS, TRANSVERSE. Demyelinating and/or necrotizing lesions form in one or both optic nerves and in the spinal cord. The onset of optic neuritis and myelitis may be simultaneous or separated by several months. (J Neurol Neurosurg Psychiatry 1996 Apr;60(4):382-387)
  
• Neuronal Ceroid-Lipofuscinoses [M0014734]
  A group of severe neurodegenerative diseases characterized by intracellular accumulation of autofluorescent wax-like lipid materials (CEROID; LIPOFUSCIN) in neurons. There are several subtypes based on mutations of the various genes, time of disease onset, and severity of the neurological defects such as progressive DEMENTIA; SEIZURES; and visual failure.
  
• Neuronopathic Gaucher Disease [M0335234]
  
• Neuropapillitis [M0015361]
  
• Neuropathy, Common Peroneal [M0336014]
  
• Neuropathy, Deep Peroneal [M0336015]
  
• Neuropathy, Superficial Peroneal [M0336016]
  
• Neuropsychiatric Systemic Lupus Erythematosus [M0335427]
  
• Neuroretinitis [M0374913]
  
• Neuroschistosomiasis [M0328302]
  SCHISTOSOMIASIS of the brain, spinal cord, or meninges caused by infections with trematodes of the genus SCHISTOSOMA (primarily SCHISTOSOMA JAPONICUM; SCHISTOSOMA MANSONI; and SCHISTOSOMA HAEMATOBIUM in humans). S. japonicum infections of the nervous system may cause an acute meningoencephalitis or a chronic encephalopathy. S. mansoni and S. haematobium nervous system infections are associated with acute transverse myelitis involving the lower portions of the spinal cord. (From Joynt, Clinical Neurology, 1998, Ch27, pp61-2)
  
• Neurosyphilis [M0014771]
  Infections of the central nervous system caused by TREPONEMA PALLIDUM which present with a variety of clinical syndromes. The initial phase of infection usually causes a mild or asymptomatic meningeal reaction. The meningovascular form may present acutely as BRAIN INFARCTION. The infection may also remain subclinical for several years. Late syndromes include general paresis; TABES DORSALIS; meningeal syphilis; syphilitic OPTIC ATROPHY; and spinal syphilis. General paresis is characterized by progressive DEMENTIA; DYSARTHRIA; TREMOR; MYOCLONUS; SEIZURES; and Argyll-Robertson pupils. (Adams et al., Principles of Neurology, 6th ed, pp722-8)
  
• Neurosyphilis, Asymptomatic [M0335776]
  
• Neurosyphilis, Gummatous [M0335777]
  
• Neurosyphilis, Juvenile [M0335778]
  
• Neurosyphilis, Secondary [M0335781]
  
• Neurosyphilis, Symptomatic [M0335782]
  
• Neurotoxoplasmosis [M0336246]
  
• Neutropenia [M0014782]
  A decrease in the number of neutrophilic leukocytes in the blood. (Dorland, 27th ed)
  
• Neutropenic Typhlitis [M0495708]
  An acute necrotizing inflammation of the CECUM occurring in neutropenic patients.
  
• Neutrophilic Eccrine Hidradenitis [M0025288]
  
• New Variant Creutzfeldt-Jakob Disease [M0011819]
  
• Newcastle Disease [M0014801]
  An acute febrile, contagious, viral disease of birds caused by an AVULAVIRUS called NEWCASTLE DISEASE VIRUS. It is characterized by respiratory and nervous symptoms in fowl and is transmissible to man causing a severe, but transient conjunctivitis.
  
• Nidovirales Infections [M0387005]
  Infections with viruses of the order NIDOVIRALES. The concept includes ARTERIVIRUS INFECTIONS and CORONAVIRIDAE INFECTIONS.
  
• Niemann-Pick Disease, Type A [M0335783]
  The classic infantile form of Niemann-Pick Disease, caused by mutation in SPHINGOMYELIN PHOSPHODIESTERASE. It is characterized by accumulation of SPHINGOMYELINS in the cells of the RETICULOENDOTHELIAL SYSTEM and other cell throughout the body leading to cell death. Clinical signs include JAUNDICE, hepatosplenomegaly, and severe brain damage.
  
• Niemann-Pick Disease, Type B [M0335784]
  An allelic disorder of TYPE A NIEMANN-PICK DISEASE, a late-onset form. It is also caused by mutation in SPHINGOMYELIN PHOSPHODIESTERASE but clinical signs involve only visceral organs (non-neuropathic type).
  
• Niemann-Pick Disease, Type C [M0335789]
  An autosomal recessive lipid storage disorder that is characterized by accumulation of CHOLESTEROL and SPHINGOMYELINS in cells of the VISCERA and the CENTRAL NERVOUS SYSTEM. Type C (or C1) and type D are allelic disorders caused by mutation of gene (NPC1) encoding a protein that mediate intracellular cholesterol transport from lysosomes. Clinical signs include hepatosplenomegaly and chronic neurological symptoms. Type D is a variant in people with a Nova Scotia ancestry.
  
• Niemann-Pick Disease, Type D [M0335790]
  
• Niemann-Pick Disease, Type E [M0335791]
  
• Niemann-Pick Diseases [M0014846]
  A group of autosomal recessive disorders in which harmful quantities of lipids accumulate in the viscera and the central nervous system. They can be caused by deficiencies of enzyme activities (SPHINGOMYELIN PHOSPHODIESTERASE) or defects in intracellular transport, resulting in the accumulation of SPHINGOMYELINS and CHOLESTEROL. There are various subtypes based on their clinical and genetic differences.
  
• Night Blindness [M0015129]
  Failure or imperfection of vision at night or in dim light, with good vision only on bright days. (Dorland, 27th ed)
  
• Nijmegen Breakage Syndrome [M0471083]
  A chromosome instability syndrome resulting from a defective response to DNA double-strand breaks. In addition to characteristic FACIES and MICROCEPHALY, patients have a range of findings including RADIOSENSITIVITY, immunodeficiency, increased cancer risk, and growth retardation. Causative mutations occur in the NBS1 gene, located on human chromosome 8q21. NBS1 codes for nibrin, the key regulator protein of the R/M/N (RAD50/MRE11/NBS1) protein complex which senses and mediates cellular response to DNA DAMAGE caused by IONIZING RADIATION.
  
• Nocardia Infections [M0014935]
  Infections with bacteria of the genus NOCARDIA.
  
• Nocturnal Enuresis [M0007498]
  Involuntary discharge of URINE during sleep at night after expected age of completed development of urinary control.
  
• Nocturnal Leg Cramps [M0335191]
  
• Nocturnal Myoclonus Syndrome [M0328315]
  Excessive periodic leg movements during sleep that cause micro-arousals and interfere with the maintenance of sleep. This condition induces a state of relative sleep deprivation which manifests as excessive daytime hypersomnolence. The movements are characterized by repetitive contractions of the tibialis anterior muscle, extension of the toe, and intermittent flexion of the hip, knee and ankle. (Adams et al., Principles of Neurology, 6th ed, p387)
  
• Nocturnal Paroxysmal Dystonia [M0328316]
  A parasomnia characterized by paroxysmal episodes of choreoathetotic, ballistic, dystonic movements, and semipurposeful activity. The episodes occur during non-rapid eye movement sleep and typically recur several times per night. (Neurology 1992 Jul;42(7 Suppl 6):61-67; Adams et al., Principles of Neurology, 6th ed, p391)
  
• Nocturnal Sleep Head Banging [M0335197]
  
• Nodding Spasm [M0020207]
  
• Nodular Circumscribed Lipomatosis [M0012576]
  
• Nodular Elastoidosis [M0008114]
  
• Noma [M0014943]
  A severe gangrenous process occurring predominantly in debilitated and malnourished children, especially in underdeveloped countries. It typically begins as a small vesicle or ulcer on the gingiva that rapidly becomes necrotic and spreads to produce extensive destruction of the buccal and labial mucosa and tissues of the face, which may result in severe disfigurement and even death. Various bacteria have been implicated in the etiology. (Dorland, 27th ed)
  
• Non-24 Hour Sleep-Wake Disorder [M0334750]
  
• Non-Convulsive Status Epilepticus [M0336171]
  
• Non-Fatigable Positional Nystagmus [M0333591]
  
• Non-Syphilitic Argyll-Robertson Pupil [M0337232]
  
• Nonfamilial Olivopontocerebellar Atrophy [M0332845]
  
• Nonodontogenic Cysts [M0014952]
  Cysts formed from epithelial inclusions in the lines of fusion of the embryonic processes which form the jaws. They include nasopalatine or incisive canal cyst, incisive papilla cyst, globulomaxillary cyst, median palatal cyst, median alveolar cyst, median mandibular cyst, and nasoalveolar cyst.
  
• Nonorganic Insomnia [M0334965]
  
• Noonan Syndrome [M0014957]
  A multifaceted disorder characterized by short stature, webbed neck, ptosis, skeletal malformations, hypertelorism, hormonal imbalance, CRYPTORCHIDISM, multiple cardiac abnormalities (most commonly including PULMONARY VALVE STENOSIS), and some degree of MENTAL RETARDATION. The phenotype bears similarities to that of TURNER SYNDROME that occurs only in females and has its basis in a 45, X karyotype abnormality. However, Noonan syndrome occurs in both males and females with a normal sex chromosome constitution (46,XX and 46,XY). NS1 is due to mutations at chromosome location 12q24.1, in PTPN11, a gene encoding the non-receptor type 11 PROTEIN TYROSINE PHOSPHATASE. LEOPARD SYNDROME, a disorder that has clinical features overlapping those of Noonan Syndrome, is also due to mutations in PTPN11. In addition, there is a syndrome called neurofibromatosis-Noonan syndrome. Both the PTPN11 and NF1 gene products are involved in the SIGNAL TRANSDUCTION pathway of Ras (RAS PROTEINS).
  
• Normokalemic Periodic Paralysis [M0337201]
  
• Nose Diseases [M0015012]
  Disorders of the nose, general or unspecified.
  
• Nuchal Cord [M0494858]
  A complication of pregnancy in which the UMBILICAL CORD wraps around the fetal neck once or multiple times. In some cases, cord entanglement around fetal neck may not affect pregnancy outcome significantly. In others, the nuchal cord may lead to restricted fetal blood flow, oxygen transport, fetal development, fetal movement, and complicated delivery at birth.
  
• Nut Hypersensitivity [M0351847]
  Allergic reaction to tree nuts that is triggered by the immune system.
  
• Nutcracker Esophagus [M0023298]
  
• Nutrition Disorders [M0015120]
  Disorders caused by nutritional imbalance, either overnutrition or undernutrition.
  
• Nutritional and Metabolic Diseases [M0015124]
  A collective term for nutritional disorders resulting from poor absorption or nutritional imbalance, and metabolic disorders resulting from defects in biosynthesis (ANABOLISM) or breakdown (CATABOLISM) of endogenous substances.
  
• Nystagmus, Congenital [M0328317]
  Nystagmus present at birth or caused by lesions sustained in utero or at the time of birth. It is usually pendular, and is associated with ALBINISM and conditions characterized by early loss of central vision. Inheritance patterns may be X-linked, autosomal dominant, or recessive. (Adams et al., Principles of Neurology, 6th ed, p275)
  
• Nystagmus, Pathologic [M0015138]
  Involuntary movements of the eye that are divided into two types, jerk and pendular. Jerk nystagmus has a slow phase in one direction followed by a corrective fast phase in the opposite direction, and is usually caused by central or peripheral vestibular dysfunction. Pendular nystagmus features oscillations that are of equal velocity in both directions and this condition is often associated with visual loss early in life. (Adams et al., Principles of Neurology, 6th ed, p272)
  
• Obesity Hypoventilation Syndrome [M0016835]
  HYPOVENTILATION syndrome in very obese persons with excessive ADIPOSE TISSUE around the ABDOMEN and DIAPHRAGM. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic HYPOXIA; HYPERCAPNIA; POLYCYTHEMIA; and long periods of sleep during day and night (HYPERSOMNOLENCE). It is a condition often related to OBSTRUCTIVE SLEEP APNEA but can occur separately.
  
• Obstetric Labor Complications [M0012106]
  Medical problems associated with OBSTETRIC LABOR, such as BREECH PRESENTATION; PREMATURE OBSTETRIC LABOR; HEMORRHAGE; or others. These complications can affect the well-being of the mother, the FETUS, or both.
  
• Obstetric Labor, Premature [M0012117]
  Onset of OBSTETRIC LABOR before term (TERM BIRTH) but usually after the FETUS has become viable. In humans, it occurs sometime during the 29th through 38th week of PREGNANCY. TOCOLYSIS inhibits premature labor and can prevent the BIRTH of premature infants (INFANT, PREMATURE).
  
• Obstructive Hydrocephalus [M0335282]
  
• Occipital Lobe Epilepsy [M0334952]
  
• Occupational Diseases [M0015191]
  Diseases due to factors involved in one's employment. (From Dorland, 28th ed)
  
• Ocular Hypertension [M0015213]
  A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
  
• Ocular Hypotension [M0024219]
  Abnormally low intraocular pressure often related to chronic inflammation (uveitis).
  
• Ocular Larva Migrans [M0012222]
  
• Ocular Motility Disorders [M0024250]
  Disorders that feature impairment of eye movements as a primary manifestation of disease. These conditions may be divided into infranuclear, nuclear, and supranuclear disorders. Diseases of the eye muscles or oculomotor cranial nerves (III, IV, and VI) are considered infranuclear. Nuclear disorders are caused by disease of the oculomotor, trochlear, or abducens nuclei in the BRAIN STEM. Supranuclear disorders are produced by dysfunction of higher order sensory and motor systems that control eye movements, including neural networks in the CEREBRAL CORTEX; BASAL GANGLIA; CEREBELLUM; and BRAIN STEM. Ocular torticollis refers to a head tilt that is caused by an ocular misalignment. Opsoclonus refers to rapid, conjugate oscillations of the eyes in multiple directions, which may occur as a parainfectious or paraneoplastic condition (e.g., OPSOCLONUS-MYOCLONUS SYNDROME). (Adams et al., Principles of Neurology, 6th ed, p240)
  
• Ocular Rosacea [M0461566]
  
• Ocular Torticollis [M0024251]
  
• Oculocerebrorenal Syndrome [M0015215]
  A sex-linked recessive disorder affecting multiple systems including the EYE, the NERVOUS SYSTEM, and the KIDNEY. Clinical features include congenital CATARACT; MENTAL RETARDATION; and renal tubular dysfunction (FANCONI SYNDROME; RENAL TUBULAR ACIDOSIS; X-LINKED HYPOPHOSPHATEMIA or vitamin-D-resistant rickets) and SCOLIOSIS. This condition is due to a deficiency of phosphatidylinositol 4,5-bisphosphate-5-phosphatase leading to defects in PHOSPHATIDYLINOSITOL metabolism and INOSITOL signaling pathway. (from Menkes, Textbook of Child Neurology, 5th ed, p60; Am J Hum Genet 1997 Jun;60(6):1384-8)
  
• Oculomotor Nerve Diseases [M0024256]
  Diseases of the oculomotor nerve or nucleus that result in weakness or paralysis of the superior rectus, inferior rectus, medial rectus, inferior oblique, or levator palpebrae muscles, or impaired parasympathetic innervation to the pupil. With a complete oculomotor palsy, the eyelid will be paralyzed, the eye will be in an abducted and inferior position, and the pupil will be markedly dilated. Commonly associated conditions include neoplasms, CRANIOCEREBRAL TRAUMA, ischemia (especially in association with DIABETES MELLITUS), and aneurysmal compression. (From Adams et al., Principles of Neurology, 6th ed, p270)
  
• Oculopharyngeal Spinal Muscular Atrophy [M0335731]
  
• Odontogenic Cysts [M0015221]
  Cysts found in the jaws and arising from epithelium involved in tooth formation. They include follicular cysts (e.g., primordial cyst, dentigerous cyst, multilocular cyst), lateral periodontal cysts, and radicular cysts. They may become keratinized (odontogenic keratocysts). Follicular cysts may give rise to ameloblastomas and, in rare cases, undergo malignant transformation.
  
• Oesophagostomiasis [M0015232]
  Infection of the intestinal tract with worms of the genus OESOPHAGOSTOMUM. This condition occurs mainly in animals other than man.
  
• Ogilvie Syndrome [M0443789]
  
• Okihiro Syndrome [M0482231]
  
• Olfaction Disorders [M0333802]
  Loss of or impaired ability to smell. This may be caused by OLFACTORY NERVE DISEASES; PARANASAL SINUS DISEASES; viral RESPIRATORY TRACT INFECTIONS; CRANIOCEREBRAL TRAUMA; SMOKING; and other conditions.
  
• Olfactory Nerve Diseases [M0328318]
  Diseases of the first cranial (olfactory) nerve, which usually feature anosmia or other alterations in the sense of smell and taste. Anosmia may be associated with NEOPLASMS; CENTRAL NERVOUS SYSTEM INFECTIONS; CRANIOCEREBRAL TRAUMA; inherited conditions; toxins; METABOLIC DISEASES; tobacco abuse; and other conditions. (Adams et al., Principles of Neurology, 6th ed, pp229-31)
  
• Olfactory Partial Seizure [M0335085]
  
• Oligohydramnios [M0024596]
  A condition of abnormally low AMNIOTIC FLUID volume. Principal causes include malformations of fetal URINARY TRACT; FETAL GROWTH RETARDATION; GESTATIONAL HYPERTENSION; nicotine poisoning; and PROLONGED PREGNANCY.
  
• Oligospermia [M0015283]
  A condition of suboptimal concentration of SPERMATOZOA in the ejaculated SEMEN to ensure successful FERTILIZATION of an OVUM. In humans, oligospermia is defined as a sperm count below 20 million per milliliter semen.
  
• Olivopontocerebellar Atrophies [M0015287]
  A group of inherited and sporadic disorders which share progressive ataxia in combination with atrophy of the CEREBELLUM; PONS; and inferior olivary nuclei. Additional clinical features may include MUSCLE RIGIDITY; NYSTAGMUS, PATHOLOGIC; RETINAL DEGENERATION; MUSCLE SPASTICITY; DEMENTIA; URINARY INCONTINENCE; and OPHTHALMOPLEGIA. The familial form has an earlier onset (second decade) and may feature spinal cord atrophy. The sporadic form tends to present in the fifth or sixth decade, and is considered a clinical subtype of MULTIPLE SYSTEM ATROPHY. (From Adams et al., Principles of Neurology, 6th ed, p1085)
  
• Olivopontocerebellar Atrophy, Idiopathic [M0332843]
  
• Omental Panniculitis [M0023788]
  
• Omphalocele [M0010270]
  A congenital defect with major fissure in the ABDOMINAL WALL at the UMBILICUS resulting in the extrusion of VISCERA through the UMBILICUS. Unlike GASTROSCHISIS, omphalocele is covered with PERITONEUM but without overlying SKIN.
  
• Onchocerciasis [M0015295]
  Infection with nematodes of the genus ONCHOCERCA. Characteristics include the presence of firm subcutaneous nodules filled with adult worms, PRURITUS, and ocular lesions.
  
• Onchocerciasis, Ocular [M0024245]
  Filarial infection of the eyes transmitted from person to person by bites of Onchocerca volvulus-infected black flies. The microfilariae of Onchocerca are thus deposited beneath the skin. They migrate through various tissues including the eye. Those persons infected have impaired vision and up to 20% are blind. The incidence of eye lesions has been reported to be as high as 30% in Central America and parts of Africa.
  
• Onychomycosis [M0021567]
  A fungal infection of the nail plate, usually caused by a DERMATOPHYTES; YEASTS; or nondermatophyte MOLDS.
  
• Oophoritis [M0015311]
  Inflammation of the OVARY, generally caused by an ascending infection of organisms from the endocervix.
  
• Ophthalmia Neonatorum [M0015322]
  Acute conjunctival inflammation in the newborn, usually caused by maternal gonococcal infection. The causative agent is NEISSERIA GONORRHOEAE. The baby's eyes are contaminated during passage through the birth canal.
  
• Ophthalmia, Sympathetic [M0015323]
  Granulomatous uveitis which follows in one eye after a penetrating injury to the other eye; the secondarily affected eye is called the sympathizing eye, and the injured eye is called the exciting or activating eye.
  
• Ophthalmoplegia, Chronic Progressive External [M0026169]
  A mitochondrial myopathy characterized by slowly progressive paralysis of the levator palpebrae, orbicularis oculi, and extraocular muscles. Ragged-red fibers and atrophy are found on muscle biopsy. Familial and sporadic forms may occur. Disease onset is usually in the first or second decade of life, and the illness slowly progresses until usually all ocular motility is lost. (From Adams et al., Principles of Neurology, 6th ed, p1422)
  
• Opisthorchiasis [M0015338]
  Infection with flukes of the genus Opisthorchis.
  
• Opportunistic Infections [M0015350]
  An infection caused by an organism which becomes pathogenic under certain conditions, e.g., during immunosuppression.
  
• Opsoclonus [M0024252]
  
• Opsoclonus-Myoclonus Syndrome [M0337038]
  A neurological condition that is characterized by uncontrolled rapid irregular movements of the eye (OPSOCLONUS) and the muscle (MYOCLONUS) causing unsteady, trembling gait. It is also known as dancing eyes-dancing feet syndrome and is often associated with neoplasms, viral infections, or autoimmune disorders involving the nervous system.
  
• Optic Atrophy [M0015352]
  Atrophy of the optic disk which may be congenital or acquired. This condition indicates a deficiency in the number of nerve fibers which arise in the RETINA and converge to form the OPTIC DISK; OPTIC NERVE; OPTIC CHIASM; and optic tracts. GLAUCOMA; ISCHEMIA; inflammation, a chronic elevation of intracranial pressure, toxins, optic nerve compression, and inherited conditions (see OPTIC ATROPHIES, HEREDITARY) are relatively common causes of this condition.
  
• Optic Atrophy, Autosomal Dominant [M0333666]
  Dominant optic atrophy is a hereditary optic neuropathy causing decreased visual acuity, color vision deficits, a centrocecal scotoma, and optic nerve pallor (Hum. Genet. 1998; 102: 79-86). Mutations leading to this condition have been mapped to the OPA1 gene at chromosome 3q28-q29. OPA1 codes for a dynamin-related GTPase that localizes to mitochondria.
  
• Optic Atrophy, Hereditary, Leber [M0333667]
  A maternally linked genetic disorder that presents in mid-life as acute or subacute central vision loss leading to central scotoma and blindness. The disease has been associated with missense mutations in the mtDNA, in genes for Complex I, III, and IV polypeptides, that can act autonomously or in association with each other to cause the disease. (from Online Mendelian Inheritance in Man, http://www.ncbi.nlm.nih.gov/Omim/, MIM#535000 (April 17, 2001))
  
• Optic Disk Disorders [M0336204]
  
• Optic Disk Drusen [M0023938]
  Optic disk bodies composed primarily of acid mucopolysaccharides that may produce pseudopapilledema (elevation of the optic disk without associated INTRACRANIAL HYPERTENSION) and visual field deficits. Drusen may also occur in the retina (see RETINAL DRUSEN). (Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p355)
  
• Optic Nerve Diseases [M0015358]
  Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.
  
• Optic Neuritis [M0015359]
  Inflammation of the optic nerve. Commonly associated conditions include autoimmune disorders such as MULTIPLE SCLEROSIS, infections, and granulomatous diseases. Clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (Marcus-Gunn pupil), and in some instances optic disc hyperemia and swelling. Inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis).
  
• Optic Neuropathy, Ischemic [M0028286]
  Ischemic injury to the optic nerve which usually affects the optic disk (optic neuropathy, anterior ischemic) and less frequently the retrobulbar portion of the nerve (optic neuropathy, posterior ischemic). The injury results from occlusion of arterial blood supply which may result from TEMPORAL ARTERITIS; ATHEROSCLEROSIS; COLLAGEN DISEASES; EMBOLISM; DIABETES MELLITUS; and other conditions. The disease primarily occurs in the sixth decade or later and presents with the sudden onset of painless and usually severe monocular visual loss. Anterior ischemic optic neuropathy also features optic disk edema with microhemorrhages. The optic disk appears normal in posterior ischemic optic neuropathy. (Glaser, Neuro-Ophthalmology, 2nd ed, p135)
  
• Oral Dyskinesia [M0392826]
  
• Oral Mucositis [M0484569]
  Inflammation of the ORAL MUCOSA.
  
• Oral Submucous Fibrosis [M0015375]
  
• Oral Ulcer [M0028634]
  A loss of mucous substance of the mouth showing local excavation of the surface, resulting from the sloughing of inflammatory necrotic tissue. It is the result of a variety of causes, e.g., denture irritation, aphthous stomatitis (STOMATITIS, APHTHOUS); NOMA; necrotizing gingivitis (GINGIVITIS, NECROTIZING ULCERATIVE); TOOTHBRUSHING; and various irritants. (From Jablonski, Dictionary of Dentistry, 1992, p842)
  
• Orbital Diseases [M0015377]
  Diseases of the bony orbit and contents except the eyeball.
  
• Orchitis [M0015383]
  Inflammation of a TESTIS. It has many features of EPIDIDYMITIS, such as swollen SCROTUM; PAIN; PYURIA; and FEVER. It is usually related to infections in the URINARY TRACT, which likely spread to the EPIDIDYMIS and then the TESTIS through either the VAS DEFERENS or the lymphatics of the SPERMATIC CORD.
  
• Oriental Sore [M0025565]
  
• Ornithine Carbamoyltransferase Deficiency Disease [M0328321]
  An inherited urea cycle disorder associated with deficiency of the enzyme ORNITHINE CARBAMOYLTRANSFERASE, transmitted as a sex-linked trait and featuring elevations of amino acids and ammonia in the serum. Clinical features, which are more prominent in males, include seizures, behavioral alterations, episodic vomiting, lethargy, and coma. (Menkes, Textbook of Child Neurology, 5th ed, pp49-50)
  
• Orofaciodigital Syndromes [M0015438]
  Two syndromes of oral, facial, and digital malformations. Type I (Papillon-Leage and Psaume syndrome, Gorlin-Psaume syndrome) is inherited as an X-linked dominant trait and is found only in females and XXY males. Type II (Mohr syndrome) is inherited as an autosomal recessive trait.
  
• Oropharyngeal Dysphagia [M0453214]
  
• Oroya Fever [M0002190]
  
• Orphan Diseases [M0409570]
  Rare diseases that have not been well studied.
  
• Orthomyxoviridae Infections [M0015470]
  Virus diseases caused by the ORTHOMYXOVIRIDAE.
  
• Osteitis [M0015506]
  
• Osteitis Deformans [M0015507]
  A disease marked by repeated episodes of increased bone resorption followed by excessive attempts at repair, resulting in weakened, deformed bones of increased mass. The resultant architecture of the bone assumes a mosaic pattern in which the fibers take on a haphazard pattern instead of the normal parallel symmetry.
  
• Osteitis Fibrosa Cystica [M0015508]
  A fibrous degeneration, cyst formation, and the presence of fibrous nodules in bone, usually due to HYPERPARATHYROIDISM.
  
• Osteoarthritis [M0015509]
  A progressive, degenerative joint disease, the most common form of arthritis, especially in older persons. The disease is thought to result not from the aging process but from biochemical changes and biomechanical stresses affecting articular cartilage. In the foreign literature it is often called osteoarthrosis deformans.
  
• Osteoarthritis, Hip [M0023369]
  Noninflammatory degenerative disease of the hip joint which usually appears in late middle or old age. It is characterized by growth or maturational disturbances in the femoral neck and head, as well as acetabular dysplasia. A dominant symptom is pain on weight-bearing or motion.
  
• Osteoarthritis, Knee [M0030009]
  Noninflammatory degenerative disease of the knee joint consisting of three large categories: conditions that block normal synchronous movement, conditions that produce abnormal pathways of motion, and conditions that cause stress concentration resulting in changes to articular cartilage. (Crenshaw, Campbell's Operative Orthopaedics, 8th ed, p2019)
  
• Osteoarthropathy, Primary Hypertrophic [M0015511]
  A conditioned chiefly characterized by thickening of the skin of the head and distal extremities, deep folds and furrows of the skin of the forehead, cheeks, and scalp, seborrhea, hyperhidrosis, periostosis of the long bones, digital clubbing, and spadelike enlargement of the hands and feet. It is more prevalent in the male, and is usually first evident during adolescence. It is believed to be inherited as an autosomal dominant trait. (From Dorland, 27th ed)
  
• Osteoarthropathy, Secondary Hypertrophic [M0015513]
  Symmetrical osteitis of the four limbs, chiefly localized to the phalanges and the terminal epiphyses of the long bones of the forearm and leg, sometimes extending to the proximal ends of the limbs and the flat bones, and accompanied by dorsal kyphosis and joint involvement. It is often secondary to chronic conditions of the lungs and heart. (Dorland, 27th ed)
  
• Osteoarthrosis Deformans [M0015510]
  
• Osteochondritis [M0015518]
  Inflammation of bone and cartilage.
  
• Osteochondritis Dissecans [M0015520]
  A type of osteochondritis in which articular cartilage and associated bone becomes partially or totally detached to form joint loose bodies. Affects mainly the knee, ankle, and elbow joints.
  
• Osteochondrodysplasias [M0015525]
  Abnormal development of cartilage and bone.
  
• Osteochondromatosis, Synovial [M0024255]
  
• Osteochondrosis [M0015519]
  
• Osteogenesis Imperfecta [M0015534]
  Autosomal dominant COLLAGEN DISEASES resulting from defective biosynthesis of COLLAGEN TYPE I and characterized by brittle, osteoporotic, and easily fractured bones. It may also present with blue sclerae, loose joints, and imperfect dentin formation. There are four major types, I-IV.
  
• Osteolysis, Essential [M0015537]
  Syndromes of bone destruction where the cause is not obvious such as neoplasia, infection, or trauma. The destruction follows various patterns: massive (Gorham disease), multicentric (HAJDU-CHENEY SYNDROME), or carpal/tarsal.
  
• Osteolysis, Idiopathic Multicentric [M0015538]
  
• Osteolysis, Massive [M0015539]
  
• Osteomalacia [M0015543]
  A condition marked by softening of the bones (due to impaired mineralization, with excess accumulation of osteoid), with pain, tenderness, muscular weakness, anorexia, and loss of weight, resulting from deficiency of vitamin D and calcium. (Dorland, 27th ed)
  
• Osteomyelitis [M0015544]
  
• Osteopenia [M0002781]
  
• Osteopetrosis [M0015549]
  Excessive formation of dense trabecular bone leading to pathological fractures; OSTEITIS; SPLENOMEGALY with infarct; ANEMIA; and extramedullary hemopoiesis (HEMATOPOIESIS, EXTRAMEDULLARY).
  
• Osteopoikilosis [M0015550]
  An asymptomatic, autosomal dominant trait in which pea-sized sclerotic spots, prominent in the metaphyseal area, are accompanied by unique cutaneous lesions. These are yellowish papules or plaques with increased elastin content. (From Cecil Textbook of Medicine, 19th ed, pp1434-35)
  
• Osteoporosis [M0015552]
  Reduction of bone mass without alteration in the composition of bone, leading to fractures. Primary osteoporosis can be of two major types: postmenopausal osteoporosis (OSTEOPOROSIS, POSTMENOPAUSAL) and age-related or senile osteoporosis.
  
• Osteoporosis, Age-Related [M0015551]
  
• Osteoporosis, Post-Traumatic [M0336965]
  
• Osteoporosis, Postmenopausal [M0024020]
  Metabolic disorder associated with fractures of the femoral neck, vertebrae, and distal forearm. It occurs commonly in women within 15-20 years after menopause, and is caused by factors associated with menopause including estrogen deficiency.
  
• Osteoporosis, Senile [M0015553]
  
• Osteoradionecrosis [M0015554]
  Necrosis of bone following radiation injury.
  
• Osteosclerosis [M0015555]
  An abnormal hardening or increased density of bone tissue.
  
• Ostertagiasis [M0015559]
  A disease of herbivorous mammals, particularly cattle and sheep, caused by stomach worms of the genus OSTERTAGIA.
  
• Otitis [M0015561]
  Inflammation of the ear, which may be marked by pain, fever, abnormalities of hearing, hearing loss, tinnitus, and vertigo. Inflammation of the external ear is OTITIS EXTERNA; of the middle ear, OTITIS MEDIA; of the inner ear, LABYRINTHITIS. (From Dorland, 27th ed)
  
• Otitis Externa [M0015562]
  Inflammation of the external auditory canal. (Dorland, 27th ed)
  
• Otitis Media [M0015563]
  Inflammation of the middle ear.
  
• Otitis Media with Effusion [M0015564]
  Inflammation of the middle ear with a clear pale yellow-colored transudate.
  
• Otitis Media, Serous [M0015565]
  
• Otitis Media, Suppurative [M0015566]
  Inflammation of the middle ear with purulent discharge.
  
• Otorhinolaryngologic Diseases [M0015572]
  General or unspecified diseases of the ear, nose, and throat.
  
• Otosclerosis [M0015574]
  The formation of spongy bone in the labyrinth capsule. The ossicles can become fixed and unable to transmit sound vibrations, thereby causing deafness.
  
• Ovarian Cysts [M0015589]
  General term for CYSTS and cystic diseases of the OVARY.
  
• Ovarian Diseases [M0015590]
  Pathological processes of the OVARY.
  
• Ovarian Failure, Premature [M0025370]
  Cessation of ovarian function after MENARCHE but before the age of 40, without or with OVARIAN FOLLICLE depletion. It is characterized by the presence of OLIGOMENORRHEA or AMENORRHEA, elevated GONADOTROPINS, and low ESTRADIOL levels. It is a state of female HYPERGONADOTROPIC HYPOGONADISM. Etiologies include genetic defects, autoimmune processes, chemotherapy, radiation, and infections.
  
• Ovarian Hyperstimulation Syndrome [M0025157]
  A complication of OVULATION INDUCTION in infertility treatment. It is graded by the severity of symptoms which include OVARY enlargement, multiple OVARIAN FOLLICLES; OVARIAN CYSTS; ASCITES; and generalized EDEMA. The full-blown syndrome may lead to RENAL FAILURE, respiratory distress, and even DEATH. Increased capillary permeability is caused by the vasoactive substances, such as VASCULAR ENDOTHELIAL GROWTH FACTORS, secreted by the overly-stimulated OVARIES.
  
• Overactive Detrusor [M0491957]
  
• Overnutrition [M0440450]
  An imbalanced nutritional status resulted from excessive intake of nutrients. Generally, overnutrition generates an energy imbalance between food consumption and energy expenditure leading to disorders such as OBESITY.
  
• Oxidative Phosphorylation Deficiencies [M0382031]
  
• Oxyuriasis [M0015707]
  Infection with nematodes of the superfamily OXYUROIDEA.
  
• Oxyurida Infections [M0026099]
  Infections with nematodes of the order OXYURIDA.
  
• Ozena [M0019021]
  
• Pachymeningitis [M0335657]
  
• Pachymeningitis, Fungal [M0335663]
  
• Pachyonychia Congenita [M0494472]
  A group of inherited ectodermal dysplasias whose most prominent clinical feature is hypertrophic nail dystrophy resulting in PACHYONYCHIA. Several specific subtypes of pachyonychia congenita have been associated with mutations in genes that encode KERATINS.
  
• Pachyonychia Congenita, Type 1 [M0494506]
  A subtype of pachyonychia congenita that is associated with mutations in the gene for KERATIN-16 and the gene for KERATIN-6A.
  
• Pachyonychia Congenita, Type 2 [M0494507]
  A subtype of pachyonychia congenita that is associated with mutations in the gene for KERATIN-17 and the gene for KERATIN-6B.
  
• Pain Insensitivity, Congenital [M0001066]
  A syndrome characterized by indifference to PAIN despite the ability to distinguish noxious from nonnoxious stimuli. Absent corneal reflexes and MENTAL RETARDATION may be associated. Familial forms with autosomal recessive and autosomal dominant patterns of inheritance have been described. (Adams et al., Principles of Neurology, 6th ed, p1343)
  
• Painful Bladder Syndrome [M0490133]
  
• Pancreatic Cholera [M0006215]
  
• Pancreatic Cyst [M0015792]
  A true cyst of the PANCREAS, distinguished from the much more common PANCREATIC PSEUDOCYST by possessing a lining of mucous EPITHELIUM. Pancreatic cysts are categorized as congenital, retention, neoplastic, parasitic, enterogenous, or dermoid. Congenital cysts occur more frequently as solitary cysts but may be multiple. Retention cysts are gross enlargements of PANCREATIC DUCTS secondary to ductal obstruction. (From Bockus Gastroenterology, 4th ed, p4145)
  
• Pancreatic Cystic Fibrosis [M0455427]
  
• Pancreatic Diseases [M0015794]
  Pathological processes of the PANCREAS.
  
• Pancreatic Pseudocyst [M0015805]
  Cyst-like space not lined by EPITHELIUM and contained within the PANCREAS. Pancreatic pseudocysts account for most of the cystic collections in the pancreas and are often associated with chronic PANCREATITIS.
  
• Pancreatitis [M0015809]
  INFLAMMATION of the PANCREAS. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of CHRONIC PANCREATITIS (International Symposium on Acute Pancreatitis, Atlanta, 1992). The two most common forms of acute pancreatitis are ALCOHOLIC PANCREATITIS and gallstone pancreatitis.
  
• Pancreatitis, Acute Necrotizing [M0028713]
  A severe form of acute INFLAMMATION of the PANCREAS characterized by one or more areas of NECROSIS in the pancreas with varying degree of involvement of the surrounding tissues or organ systems. Massive pancreatic necrosis may lead to DIABETES MELLITUS, and malabsorption.
  
• Pancreatitis, Alcoholic [M0028997]
  Acute or chronic INFLAMMATION of the PANCREAS due to excessive ALCOHOL DRINKING. Alcoholic pancreatitis usually presents as an acute episode but it is a chronic progressive disease in alcoholics.
  
• Pancreatitis, Chronic [M0475626]
  INFLAMMATION of the PANCREAS that is characterized by recurring or persistent ABDOMINAL PAIN with or without STEATORRHEA or DIABETES MELLITUS. It is characterized by the irregular destruction of the pancreatic parenchyma which may be focal, segmental, or diffuse.
  
• Pancytopenia [M0015816]
  Deficiency of all three cell elements of the blood, erythrocytes, leukocytes and platelets.
  
• Panhypopituitarism [M0471151]
  
• Panniculitis [M0023784]
  General term for inflammation of adipose tissue, usually of the skin, characterized by reddened subcutaneous nodules.
  
• Panniculitis, Lupus Erythematosus [M0023786]
  A type of lupus erythematosus characterized by deep dermal or subcutaneous nodules, most often on the head, face, or upper arms. It is generally chronic and occurs most often in women between the ages of 20 and 45.
  
• Panniculitis, Nodular Nonsuppurative [M0015818]
  A form of panniculitis characterized by recurrent episodes of fever accompanied by the eruption of single or multiple erythematous subcutaneous nodules on the lower extremities. They normally resolve, but tend to leave depressions in the skin. The condition is most often seen in women, alone or in association with other disorders.
  
• Panniculitis, Peritoneal [M0023789]
  INFLAMMATION of the underlying layer of ADIPOSE TISSUE (panniculus) of the PERITONEUM, usually of the MESENTERY or the OMENTUM. There are several forms with various names and are usually characterized by infiltration of LYMPHOCYTES and NEUTROPHILS, fat NECROSIS, and FIBROSIS.
  
• Panniculitis, Subacute Nodular Migratory [M0023785]
  
• Panophthalmitis [M0015819]
  Acute suppurative inflammation of the inner eye with necrosis of the sclera (and sometimes the cornea) and extension of the inflammation into the orbit. Pain may be severe and the globe may rupture. In endophthalmitis the globe does not rupture.
  
• Panuveitis [M0024288]
  Inflammation in which both the anterior and posterior segments of the uvea are involved and a specific focus is not apparent. It is often severe and extensive and a serious threat to vision. Causes include systemic diseases such as tuberculosis, sarcoidosis, and syphilis, as well as malignancies. The intermediate segment of the eye is not involved.
  
• Papilledema [M0015834]
  Swelling of the OPTIC DISK, usually in association with increased intracranial pressure, characterized by hyperemia, blurring of the disk margins, microhemorrhages, blind spot enlargement, and engorgement of retinal veins. Chronic papilledema may cause OPTIC ATROPHY and visual loss. (Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p175)
  
• Papilledema Associated with Increased Intracranial Pressure [M0393385]
  
• Papillitis, Optic [M0336265]
  
• Papillomavirus Infections [M0387084]
  Neoplasms of the skin and mucous membranes caused by papillomaviruses. They are usually benign but some have a high risk for malignant progression.
  
• Papillon-Leage and Psaume Syndrome [M0015440]
  
• Papillon-Lefevre Disease [M0015840]
  Rare, autosomal recessive disorder occurring between the first and fifth years of life. It is characterized by palmoplantar keratoderma with periodontitis followed by the premature shedding of both deciduous and permanent teeth.
  
• Papulopustular Rosacea [M0461564]
  
• Paracoccidioidomycosis [M0015861]
  A mycosis affecting the skin, mucous membranes, lymph nodes, and internal organs. It is caused by Paracoccidioides brasiliensis. It is also called paracoccidioidal granuloma. Superficial resemblance of P. brasiliensis to Blastomyces brasiliensis (BLASTOMYCES) may cause misdiagnosis.
  
• Paraesophageal Hiatal Hernia [M0010265]
  A HIATAL HERNIA in which the STOMACH herniation is located alongside the ESOPHAGUS and the ESOPHAGOGASTRIC JUNCTION is in its normal position below the DIAPHRAGM.
  
• Paragonimiasis [M0015871]
  Infection with trematodes of the genus PARAGONIMUS. (Dorland, 27th ed)
  
• Parainfluenza [M0027411]
  
• Parainfluenza Virus Infections [M0027413]
  
• Parakeratosis [M0015875]
  Persistence of the nuclei of the keratinocytes into the stratum corneum of the skin. This is a normal state only in the epithelium of true mucous membranes in the mouth and vagina. (Dorland, 27th ed)
  
• Parakeratosis Variegata [M0015908]
  
• Paralyses, Familial Periodic [M0015880]
  A heterogenous group of inherited disorders characterized by recurring attacks of rapidly progressive flaccid paralysis or myotonia. These conditions have in common a mutation of the gene encoding the alpha subunit of the sodium channel in skeletal muscle. They are frequently associated with fluctuations in serum potassium levels. Periodic paralysis may also occur as a non-familial process secondary to THYROTOXICOSIS and other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1481)
  
• Paralysis [M0015877]
  A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)
  
• Paralysis, Hyperkalemic Periodic [M0328224]
  An autosomal dominant familial disorder which presents in infancy or childhood and is characterized by episodes of weakness associated with hyperkalemia. During attacks, muscles of the lower extremities are initially affected, followed by the lower trunk and arms. Episodes last from 15-60 minutes and typically occur after a period of rest following exercise. A defect in skeletal muscle sodium channels has been identified as the cause of this condition. Normokalemic periodic paralysis is a closely related disorder marked by a lack of alterations in potassium levels during attacks of weakness. (Adams et al., Principles of Neurology, 6th ed, p1481)
  
• Paralysis, Obstetric [M0015881]
  Paralysis of an infant resulting from injury received at birth. (From Dorland, 27th ed)
  
• Paralysis, Unilateral, Vocal Cord [M0336422]
  
• Paralytic Ileus [M0011581]
  
• Parametritis [M0015884]
  Inflammation of the parametrium, the connective tissue of the pelvic floor, extending from the subserous coat of the uterus laterally between the layers of the BROAD LIGAMENT.
  
• Paramyotonia Congenita [M0337321]
  
• Paramyxoviridae Infections [M0027412]
  Infections with viruses of the family PARAMYXOVIRIDAE. This includes MORBILLIVIRUS INFECTIONS; RESPIROVIRUS INFECTIONS; PNEUMOVIRUS INFECTIONS; HENIPAVIRUS INFECTIONS; AVULAVIRUS INFECTIONS; and RUBULAVIRUS INFECTIONS.
  
• Paranasal Sinus Diseases [M0015892]
  Diseases affecting or involving the PARANASAL SINUSES and generally manifesting as inflammation, abscesses, cysts, or tumors.
  
• Paraneoplastic Autonomic Dysfunction [M0337039]
  
• Paraneoplastic Cerebellar Degeneration [M0328227]
  Cerebellar degeneration associated with a remote neoplasm. Clinical manifestations include progressive limb and GAIT ATAXIA; DYSARTHRIA; and NYSTAGMUS, PATHOLOGIC. The histologic type of the associated neoplasm is usually carcinoma or lymphoma. Pathologically the cerebellar cortex and subcortical nuclei demonstrate diffuse degenerative changes. Anti-Purkinje cell antibodies (anti-Yo) are found in the serum of approximately 50% of affected individuals. (Adams et al., Principles of Neurology, 6th ed, p686)
  
• Paraneoplastic Cerebellar Degeneration, Anti-Yo-Associated [M0335813]
  
• Paraneoplastic Encephalomyelitis [M0337040]
  
• Paraneoplastic Endocrine Syndromes [M0014611]
  Syndromes resulting from inappropriate production of HORMONES or hormone-like materials by NEOPLASMS in non-endocrine tissues or not by the usual ENDOCRINE GLANDS. Such hormone outputs are called ectopic hormone (HORMONES, ECTOPIC) secretion.
  
• Paraneoplastic Opsoclonus-Myoclonus Ataxia [M0494757]
  
• Paraneoplastic Polyneuropathy [M0328230]
  A diffuse or multifocal peripheral neuropathy related to the remote effects of a neoplasm, most often carcinoma or lymphoma. Pathologically, there are inflammatory changes in peripheral nerves. The most common clinical presentation is a symmetric distal mixed sensorimotor polyneuropathy. (Adams et al., Principles of Neurology, 6th ed, p1334)
  
• Paraneoplastic Syndromes, Nervous System [M0328233]
  Degenerative or inflammatory conditions affecting the central or peripheral nervous system that develop in association with a systemic neoplasm without direct invasion by tumor. They may be associated with circulating antibodies that react with the affected neural tissue. (Intern Med 1996 Dec;35(12):925-9)
  
• Paraparesis, Tropical Spastic [M0023855]
  A subacute paralytic myeloneuropathy occurring endemically in tropical areas such as the Caribbean, Colombia, India, and Africa, as well as in the southwestern region of Japan; associated with infection by HUMAN T-CELL LEUKEMIA VIRUS I. Clinical manifestations include a slowly progressive spastic weakness of the legs, increased reflexes, Babinski signs, incontinence, and loss of vibratory and position sensation. On pathologic examination inflammatory, demyelination, and necrotic lesions may be found in the spinal cord. (Adams et al., Principles of Neurology, 6th ed, p1239)
  
• Paraphimosis [M0015902]
  A condition in which the FORESKIN, once retracted, cannot return to its original position. If this condition persists, it can lead to painful constriction of GLANS PENIS, swelling, and impaired blood flow to the penis.
  
• Paraplegia, Spastic [M0015904]
  
• Parapsoriasis [M0015909]
  The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. Eruptions are both psoriatic and lichenoid in appearance, but the diseases are distinct from psoriasis, lichen planus, or other recognized dermatoses. Proposed nomenclature divides parapsoriasis into two distinct subgroups, PITYRIASIS LICHENOIDES and parapsoriasis en plaques (small- and large-plaque parapsoriasis).
  
• Parapsoriasis en Plaques [M0015910]
  
• Parasitemia [M0027759]
  The presence of parasites (especially malarial parasites) in the blood. (Dorland, 27th ed)
  
• Parasitic Diseases [M0015919]
  Infections or infestations with parasitic organisms. They are often contracted through contact with an intermediate vector, but may occur as the result of direct exposure.
  
• Parasitic Diseases, Animal [M0015920]
  Infections or infestations with parasitic organisms. The infestation may be experimental or veterinary.
  
• Parasomnias [M0328249]
  Movements or behaviors associated with sleep, sleep stages, or partial arousals from sleep that may impair sleep maintenance. Parasomnias are generally divided into four groups: arousal disorders, sleep-wake transition disorders, parasomnias of REM sleep, and nonspecific parasomnias. (From Thorpy, Sleep Disorders Medicine, 1994, p191)
  
• Parathyroid Diseases [M0015927]
  Pathological processes of the PARATHYROID GLANDS. They usually manifest as hypersecretion or hyposecretion of PARATHYROID HORMONE that regulates the balance of CALCIUM; PHOSPHORUS; and MAGNESIUM in the body.
  
• Paratuberculosis [M0015933]
  An infectious disease caused by MYCOBACTERIUM PARATUBERCULOSIS. Characteristics include chronic debilitation and weight loss.
  
• Paratyphoid Fever [M0015934]
  A prolonged febrile illness commonly caused by several Paratyphi serotypes of SALMONELLA ENTERICA. It is similar to TYPHOID FEVER but less severe.
  
• Parinaud Syndrome [M0335798]
  
• Parkinson Disease [M0015963]
  A progressive, degenerative neurologic disease characterized by a TREMOR that is maximal at rest, retropulsion (i.e. a tendency to fall backwards), rigidity, stooped posture, slowness of voluntary movements, and a masklike facial expression. Pathologic features include loss of melanin containing neurons in the substantia nigra and other pigmented nuclei of the brainstem. LEWY BODIES are present in the substantia nigra and locus coeruleus but may also be found in a related condition (LEWY BODY DISEASE, DIFFUSE) characterized by dementia in combination with varying degrees of parkinsonism. (Adams et al., Principles of Neurology, 6th ed, p1059, pp1067-75)
  
• Parkinson Disease, Postencephalitic [M0015967]
  Parkinsonism following encephalitis, historically seen as a sequella of encephalitis lethargica (Von Economo Encephalitis). The early age of onset, the rapid progression of symptoms followed by stabilization, and the presence of a variety of other neurological disorders (e.g., sociopathic behavior; TICS; MUSCLE SPASMS; oculogyric crises; hyperphagia; and bizarre movements) distinguish this condition from primary PARKINSON DISEASE. Pathologic features include neuronal loss and gliosis concentrated in the MESENCEPHALON; SUBTHALAMUS; and HYPOTHALAMUS. (From Adams et al., Principles of Neurology, 6th ed, p754)
  
• Parkinson Disease, Secondary [M0015968]
  Conditions which feature clinical manifestations resembling primary Parkinson disease that are caused by a known or suspected condition. Examples include parkinsonism caused by vascular injury, drugs, trauma, toxin exposure, neoplasms, infections and degenerative or hereditary conditions. Clinical features may include bradykinesia, rigidity, parkinsonian gait, and masked facies. In general, tremor is less prominent in secondary parkinsonism than in the primary form. (From Joynt, Clinical Neurology, 1998, Ch38, pp39-42)
  
• Parkinson Disease, Secondary Vascular [M0332994]
  
• Parkinsonian Disorders [M0328250]
  A group of disorders which feature impaired motor control characterized by bradykinesia, MUSCLE RIGIDITY; TREMOR; and postural instability. Parkinsonian diseases are generally divided into primary parkinsonism (see PARKINSON DISEASE), secondary parkinsonism (see PARKINSON DISEASE, SECONDARY) and inherited forms. These conditions are associated with dysfunction of dopaminergic or closely related motor integration neuronal pathways in the BASAL GANGLIA.
  
• Parkinsonism, Juvenile [M0332505]
  
• Parkinsonism, Viral Meningoencephalitic [M0333010]
  
• Paronychia [M0015972]
  An inflammatory reaction involving the folds of the skin surrounding the fingernail. It is characterized by acute or chronic purulent, tender, and painful swellings of the tissues around the nail, caused by an abscess of the nail fold. The pathogenic yeast causing paronychia is most frequently Candida albicans. Saprophytic fungi may also be involved. The causative bacteria are usually Staphylococcus, Pseudomonas aeruginosa, or Streptococcus. (Andrews' Diseases of the Skin, 8th ed, p271)
  
• Parotid Diseases [M0015973]
  
• Parotitis [M0015977]
  INFLAMMATION of the PAROTID GLAND.
  
• Paroxysmal Cold Hemoglobinuria [M0010138]
  
• Paroxysmal Hemicrania [M0480082]
  A primary headache disorder that is similar to the CLUSTER HEADACHE with unilateral head pain, but differs by its multiple short severe attacks. It is usually seen in females, and may be responsive to non-steroidal-anti-inflammatory drugs (NSAIDS).
  
• Paroxysmal Nocturnal Hemoglobinuria [M0010137]
  
• Paroxysmal Ocular Dyskinesia [M0335803]
  
• Paroxysmal Reciprocal Tachycardia [M0021002]
  
• Pars Planitis [M0024296]
  Form of granulomatous uveitis occurring in the region of the pars plana. This disorder is a common condition with no detectable focal pathology. It causes fibrovascular proliferation at the inferior ora serrata.
  
• Partial Paralysis (Paresis) Vocal Cords [M0336423]
  
• Partial Third-Nerve Palsy [M0333509]
  
• Parturient Paresis [M0015992]
  A disease of pregnant and lactating cows and ewes leading to generalized paresis and death. The disease, which is characterized by hypocalcemia, occurs at or shortly after parturition in cows and within weeks before or after parturition in ewes.
  
• Parvoviridae Infections [M0015996]
  Virus infections caused by the PARVOVIRIDAE.
  
• Passive Addiction, Neonatal [M0014569]
  
• Pasteurella Infections [M0016001]
  Infections with bacteria of the genus PASTEURELLA.
  
• Pasteurellaceae Infections [M0025674]
  Infections with bacteria of the family PASTEURELLACEAE.
  
• Pasteurellosis, Pneumonic [M0019776]
  Bovine respiratory disease found in animals that have been shipped or exposed to CATTLE recently transported. The major agent responsible for the disease is MANNHEIMIA HAEMOLYTICA and less commonly, PASTEURELLA MULTOCIDA or HAEMOPHILUS SOMNUS. All three agents are normal inhabitants of the bovine nasal pharyngeal mucosa but not the LUNG. They are considered opportunistic pathogens following STRESS and/or a viral infection. The resulting bacterial fibrinous BRONCHOPNEUMONIA is often fatal.
  
• Patellofemoral Pain Syndrome [M0455459]
  A syndrome characterized by retropatellar or peripatellar PAIN resulting from physical and biochemical changes in the patellofemoral joint. The pain is most prominent when ascending or descending stairs, squatting, or sitting with flexed knees. There is a lack of consensus on the etiology and treatment. The syndrome is often confused with (or accompanied by) CHONDROMALACIA PATELLAE, the latter describing a pathological condition of the CARTILAGE and not a syndrome.
  
• Pathology, Brain [M0002879]
  Acute or chronic brain damage or dysfunction.
  
• Peanut Hypersensitivity [M0351836]
  Allergic reaction to peanuts that is triggered by the immune system.
  
• Pelger-Huet Anomaly [M0016097]
  An inherited defect interfering with normal nuclear lobulation of neutrophils and eosinophils. The nuclei appear rodlike, spherical, or dumbbell-shaped and their structure is coarse and lumpy. (From Dorland, 27th ed)
  
• Peliosis Hepatis [M0016098]
  A vascular disease of the LIVER characterized by the occurrence of multiple blood-filled CYSTS or cavities. The cysts are lined with ENDOTHELIAL CELLS; the cavities lined with hepatic parenchymal cells (HEPATOCYTES). Peliosis hepatis has been associated with use of anabolic steroids (ANABOLIC AGENTS) and certain drugs.
  
• Pelizaeus-Merzbacher Disease [M0003895]
  A rare, slowly progressive disorder of myelin formation. Subtypes are referred to as classic, congenital, transitional, and adult forms of this disease. The classic form is X-chromosome linked, has its onset in infancy and is associated with a mutation of the proteolipid protein gene. Clinical manifestations include TREMOR, spasmus nutans, roving eye movements, ATAXIA, spasticity, and NYSTAGMUS, CONGENITAL. Death occurs by the third decade of life. The congenital form has similar characteristics but presents early in infancy and features rapid disease progression. Transitional and adult subtypes have a later onset and less severe symptomatology. Pathologic features include patchy areas of demyelination with preservation of perivascular islands (trigoid appearance). (From Menkes, Textbook of Child Neurology, 5th ed, p190)
  
• Pelizaeus-Merzbacher Disease, Atypical [M0336645]
  
• Pelizaeus-Merzbacher Disease, Transitional [M0336646]
  
• Pellagra [M0016099]
  A disease due to deficiency of NIACIN, a B-complex vitamin, or its precursor TRYPTOPHAN. It is characterized by scaly DERMATITIS which is often associated with DIARRHEA and DEMENTIA (the three D's).
  
• Pelvic Infection [M0000459]
  Infection involving the tissues or organs in the PELVIS.
  
• Pelvic Inflammatory Disease [M0000460]
  A spectrum of inflammation involving the female upper genital tract and the supporting tissues. It is usually caused by an ascending infection of organisms from the endocervix. Infection may be confined to the uterus (ENDOMETRITIS), the FALLOPIAN TUBES; (SALPINGITIS); the ovaries (OOPHORITIS), the supporting ligaments (PARAMETRITIS), or may involve several of the above uterine appendages. Such inflammation can lead to functional impairment and infertility.
  
• Pelvic Pain [M0026763]
  Pain in the pelvic region of genital and non-genital origin and of organic or psychogenic etiology. Frequent causes of pain are distension or contraction of hollow viscera, rapid stretching of the capsule of a solid organ, chemical irritation, tissue ischemia, and neuritis secondary to inflammatory, neoplastic, or fibrotic processes in adjacent organs. (Kase, Weingold & Gershenson: Principles and Practice of Clinical Gynecology, 2d ed, pp479-508)
  
• Pemphigoid Gestationis [M0010277]
  An itching, autoimmune, bullous SKIN disease that occurs during the last two trimesters of PREGNANCY and PUERPERIUM. It also affects non-pregnant females with tissue of PLACENTA origin, such as CHORIOCARCINOMA; or HYDATIDIFORM MOLE. It exhibits antigenic and clinical similarity to bullous pemphigoid (PEMPHIGOID, BULLOUS). This disease does not involve herpes viruses (old name, herpes gestationis).
  
• Pemphigoid, Benign Mucous Membrane [M0016110]
  A chronic blistering disease with predilection for mucous membranes and less frequently the skin, and with a tendency to scarring. It is sometimes called ocular pemphigoid because of conjunctival mucous membrane involvement.
  
• Pemphigoid, Bullous [M0016111]
  A chronic and relatively benign subepidermal blistering disease usually of the elderly and without histopathologic acantholysis.
  
• Pemphigus [M0016112]
  Group of chronic blistering diseases characterized histologically by ACANTHOLYSIS and blister formation within the EPIDERMIS.
  
• Pemphigus Foliaceus [M0479546]
  
• Pemphigus Vulgaris [M0016113]
  
• Pemphigus, Benign Familial [M0025199]
  Rare hereditary disease characterized by recurrent eruptions of vesicles and bullae mainly on the neck, axillae, and groin. It exhibits autosomal dominant inheritance and is unrelated to pemphigus vulgaris though it closely resembles that disease.
  
• Pendular Nystagmus [M0333558]
  
• Penile Diseases [M0016156]
  Pathological processes involving the PENIS or its component tissues.
  
• Penile Induration [M0016159]
  A condition characterized by hardening of the PENIS due to the formation of fibrous plaques on the dorsolateral aspect of the PENIS, usually involving the membrane (tunica albuginea) surrounding the erectile tissue (corpus cavernosum penis). This may eventually cause a painful deformity of the shaft or constriction of the urethra, or both.
  
• Peptic Ulcer [M0016211]
  Ulcer that occurs in the regions of the GASTROINTESTINAL TRACT which come into contact with GASTRIC JUICE containing PEPSIN and GASTRIC ACID. It occurs when there are defects in the MUCOSA barrier. The common forms of peptic ulcers are associated with HELICOBACTER PYLORI and the consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).
  
• Peptic Ulcer Perforation [M0016213]
  Penetration of a PEPTIC ULCER through the wall of DUODENUM or STOMACH allowing the leakage of luminal contents into the PERITONEAL CAVITY.
  
• Periadenitis Mucosa Necrotica Recurrens [M0020552]
  
• Periapical Abscess [M0016283]
  Acute or chronic inflammation of tissues surrounding the apical portion of a tooth, associated with the collection of pus, resulting from infection following pulp infection through a carious lesion or as a result of an injury causing pulp necrosis. (Dorland, 27th ed)
  
• Periapical Diseases [M0016284]
  Diseases of the PERIAPICAL TISSUE surrounding the root of the tooth, which is distinguished from DENTAL PULP DISEASES inside the TOOTH ROOT.
  
• Periapical Granuloma [M0016285]
  Chronic nonsuppurative inflammation of periapical tissue resulting from irritation following pulp disease or endodontic treatment.
  
• Periapical Periodontitis [M0016289]
  Inflammation of the PERIAPICAL TISSUE. It includes general, unspecified, or acute nonsuppurative inflammation. Chronic nonsuppurative inflammation is PERIAPICAL GRANULOMA. Suppurative inflammation is PERIAPICAL ABSCESS.
  
• Periapical Periodontitis, Chronic Nonsuppurative [M0016286]
  
• Periarthritis [M0016296]
  Inflammation of the tissues around a joint. (Dorland, 27th ed)
  
• Pericardial Cyst [M0013193]
  
• Pericardial Effusion [M0016298]
  Presence of fluid within the pericardium.
  
• Pericarditis [M0016303]
  Inflammation of the pericardium. (Dorland, 27th ed)
  
• Pericarditis, Constrictive [M0016304]
  
• Pericarditis, Tuberculous [M0016306]
  INFLAMMATION of the sac surrounding the heart (PERICARDIUM) due to MYCOBACTERIUM TUBERCULOSIS infection. Pericarditis can lead to swelling (PERICARDIAL EFFUSION), compression of the heart (CARDIAC TAMPONADE), and preventing normal beating of the heart.
  
• Pericementitis [M0016340]
  
• Pericoronitis [M0016309]
  Inflammation of the gingiva surrounding the crown of a tooth.
  
• Perimeningeal Infections [M0328254]
  Infectious processes, including abscesses, effusions, and empyemas which occur in the epidural or subdural spaces surrounding the brain and spinal cord.
  
• Perinephritis [M0016314]
  Inflammation of the connective and adipose tissues surrounding the KIDNEY.
  
• Periodic Alternating Nystagmus [M0333559]
  
• Periodontal Abscess [M0016326]
  Localized circumscribed purulent area of inflammation in the periodontal tissue. It is a derivative of marginal periodontitis and commonly associated with suprabony and infrabony pockets and interradicular involvements, in contrast to periapical abscess which is attributable to pulp necrosis.
  
• Periodontal Attachment Loss [M0026691]
  Loss or destruction of periodontal tissue caused by periodontitis or other destructive periodontal diseases or by injury during instrumentation. Attachment refers to the periodontal ligament which attaches to the alveolar bone. It has been hypothesized that treatment of the underlying periodontal disease and the seeding of periodontal ligament cells enable the creating of new attachment.
  
• Periodontal Cyst [M0016327]
  An epithelium-lined sac containing fluid; usually found at the apex of a pulp-involved tooth. The lateral type occurs less frequently along the side of the root.
  
• Periodontal Diseases [M0016328]
  
• Periodontitis [M0016341]
  Inflammatory reaction of the tissues surrounding a tooth (periodontium), usually resulting from the extension of gingival inflammation (gingivitis) into the periodontium. (From Dorland, 27th ed)
  
• Periodontitis, Acute Nonsuppurative [M0016290]
  
• Periodontitis, Apical, Chronic Nonsuppurative [M0016287]
  
• Periodontitis, Juvenile [M0016343]
  Localized periodontitis in teenagers and young adults. The onset is during the circumpubertal period but the diagnosis can be made beyond puberty. Lesions are confined predominantly to the first permanent molars or incisors and the distribution of lesions is usually symmetrical. The gingiva may appear normal. The lesions are highly active immediately following puberty but later destruction may slow or cease spontaneously. The disease is four times more prevalent in females than males and more prevalent in African Americans than in other races or ethnic groups. (From Schluger et al., Periodontal Diseases, 2d ed, p61)
  
• Periodontitis, Prepubertal [M0393389]
  
• Periodontosis [M0016344]
  
• Periostitis [M0016346]
  Inflammation of the periosteum. The condition is generally chronic, and is marked by tenderness and swelling of the bone and an aching pain. Acute periostitis is due to infection, is characterized by diffuse suppuration, severe pain, and constitutional symptoms, and usually results in necrosis. (Dorland, 27th ed)
  
• Peripheral Arterial Diseases [M0490511]
  
• Peripheral Autonomic Nervous System Diseases [M0335519]
  
• Peripheral Nervous System Diseases [M0016347]
  Diseases of the peripheral nerves external to the brain and spinal cord, which includes diseases of the nerve roots, ganglia, plexi, autonomic nerves, sensory nerves, and motor nerves.
  
• Peripheral Nervous System Lyme Disease [M0335549]
  
• Peripheral Vascular Diseases [M0025176]
  General or unspecified diseases of the blood vessels outside the heart. It is for diseases of the peripheral as opposed to the cardiac circulation.
  
• Periphlebitis [M0016607]
  
• Peritoneal Diseases [M0016360]
  Pathological processes involving the PERITONEUM.
  
• Peritonitis [M0016367]
  INFLAMMATION of the PERITONEUM lining the ABDOMINAL CAVITY as the result of infectious, autoimmune, or chemical processes. Primary peritonitis is due to infection of the PERITONEAL CAVITY via hematogenous or lymphatic spread and without intra-abdominal source. Secondary peritonitis arises from the ABDOMINAL CAVITY itself through RUPTURE or ABSCESS of intra-abdominal organs.
  
• Peritonitis, Tuberculous [M0022129]
  A form of PERITONITIS seen in patients with TUBERCULOSIS, characterized by lesion either as a miliary form or as a pelvic mass on the peritoneal surfaces. Most patients have ASCITES, abdominal swelling, ABDOMINAL PAIN, and other systemic symptoms such as FEVER; WEIGHT LOSS; and ANEMIA.
  
• Peritonsillar Abscess [M0000060]
  An abscess in the peritonsillar tissue extending into the tonsil capsule, resulting from suppuration of the tonsil. (Dorland, 27th ed)
  
• Permanent Nystagmus [M0333592]
  
• Permanent Vegetative State [M0335847]
  
• Peroneal Nerve Paralysis [M0336018]
  
• Peroneal Neuropathies [M0328257]
  Disease involving the common PERONEAL NERVE or its branches, the deep and superficial peroneal nerves. Lesions of the deep peroneal nerve are associated with PARALYSIS of dorsiflexion of the ankle and toes and loss of sensation from the web space between the first and second toe. Lesions of the superficial peroneal nerve result in weakness or paralysis of the peroneal muscles (which evert the foot) and loss of sensation over the dorsal and lateral surface of the leg. Traumatic injury to the common peroneal nerve near the head of the FIBULA is a relatively common cause of this condition. (From Joynt, Clinical Neurology, 1995, Ch51, p31)
  
• Peroxisomal Disorders [M0028264]
  A heterogeneous group of inherited metabolic disorders marked by absent or dysfunctional PEROXISOMES. Peroxisomal enzymatic abnormalities may be single or multiple. Biosynthetic peroxisomal pathways are compromised, including the ability to synthesize ether lipids and to oxidize long-chain fatty acid precursors. Diseases in this category include ZELLWEGER SYNDROME; INFANTILE REFSUM DISEASE; rhizomelic chondrodysplasia (CHONDRODYSPLASIA PUNCTATA, RHIZOMELIC); hyperpipecolic acidemia; neonatal adrenoleukodystrophy; and ADRENOLEUKODYSTROPHY (X-linked). Neurologic dysfunction is a prominent feature of most peroxisomal disorders.
  
• Peroxisomal Dysfunction, General [M0335829]
  
• Peroxisomal Dysfunction, Multiple [M0335830]
  
• Peroxisomal Dysfunction, Single [M0335831]
  
• Persian Gulf Syndrome [M0028292]
  Unexplained symptoms reported by veterans of the Persian Gulf War with Iraq in 1991. The symptoms reported include fatigue, skin rash, muscle and joint pain, headaches, loss of memory, shortness of breath, gastrointestinal and respiratory symptoms, and extreme sensitivity to commonly occurring chemicals. (Nature 1994 May 5;369(6475):8)
  
• Persistent Fetal Circulation Syndrome [M0016380]
  A syndrome of persistent PULMONARY HYPERTENSION in the newborn infant (INFANT, NEWBORN) without demonstrable HEART DISEASES. This neonatal condition can be caused by severe pulmonary vasoconstriction (reactive type), hypertrophy of pulmonary arterial muscle (hypertrophic type), or abnormally developed pulmonary arterioles (hypoplastic type). The newborn patient exhibits CYANOSIS and ACIDOSIS due to the persistence of fetal circulatory pattern of right-to-left shunting of blood through a patent ductus arteriosus (DUCTUS ARTERIOSUS, PATENT) and at times a patent foramen ovale (FORAMEN OVALE, PATENT).
  
• Persistent Hyperinsulinemia Hypoglycemia of Infancy [M0446507]
  A form of nontransient HYPOGLYCEMIA, unique to infancy, due to autosomal recessive mutations of the sulfonylurea receptor gene on CHROMOSOME 11. Defects in the sulfonylurea receptors (ATP-BINDING CASSETTE TRANSPORTERS) on the PANCREATIC BETA CELLS prevent negative feedback of GLUCOSE-regulated INSULIN release thus resulting in HYPERINSULINEMIA. Clinical phenotype includes SEIZURES; COMA; and often large BIRTH WEIGHT for GESTATIONAL AGE.
  
• Persistent Vegetative State [M0027694]
  Vegetative state refers to the neurocognitive status of individuals with severe brain damage, in whom physiologic functions (sleep-wake cycles, autonomic control, and breathing) persist, but awareness (including all cognitive function and emotion) is abolished.
  
• Peste-des-Petits-Ruminants [M0383698]
  A highly fatal contagious disease of goats and sheep caused by PESTE-DES-PETITS-RUMINANTS VIRUS. The disease may be acute or subacute and is characterized by stomatitis, conjunctivitis, diarrhea, and pneumonia.
  
• Pestivirus Infections [M0027409]
  Infections with viruses of the genus PESTIVIRUS, family FLAVIVIRIDAE.
  
• Petechiae [M0018177]
  
• Petit Mal Status [M0020464]
  
• Petrous Sinus Thrombophlebitis [M0336049]
  
• Petrous Sinus Thrombosis [M0336048]
  
• Phagocyte Bactericidal Dysfunction [M0016450]
  Disorders in which phagocytic cells cannot kill ingested bacteria; characterized by frequent recurring infection with formulation of granulomas.
  
• Pharyngeal Diseases [M0016479]
  General or unspecified diseases of the pharynx.
  
• Pharyngitis [M0016483]
  Inflammation of the throat.
  
• Pharyngo-Conjunctival Fever [M0000406]
  
• Phenylketonuria I [M0335854]
  
• Phenylketonuria II [M0335852]
  
• Phenylketonuria, Maternal [M0025897]
  A condition occurring in untreated or partially treated females with PHENYLKETONURIA when they become pregnant. This may result in damages to the FETUS, including MICROCEPHALY; MENTAL RETARDATION; congenital heart disease; FETAL GROWTH RETARDATION; and CRANIOFACIAL ABNORMALITIES. (From Am J Med Genet 1997 Mar 3;69(1):89-95)
  
• Phenylketonurias [M0016567]
  A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952).
  
• Phimosis [M0016606]
  A condition in which the FORESKIN cannot be retracted to reveal the GLANS PENIS. It is due to tightness or narrowing of the foreskin opening.
  
• Phlebitis [M0016608]
  Inflammation of a vein.
  
• Phlebotomus Fever [M0015846]
  Influenza-like febrile viral disease caused by several members of the BUNYAVIRIDAE family and transmitted mostly by the bloodsucking sandfly Phlebotomus papatasii.
  
• Phlegmasia Alba Dolens [M0021431]
  
• Phosphaturia [M0010918]
  
• Phosphorus Metabolism Disorders [M0016725]
  Disorders in the processing of phosphorus in the body: its absorption, transport, storage, and utilization.
  
• Photoallergy [M0026486]
  
• Photosensitivity Disorders [M0016756]
  Abnormal responses to sunlight or artificial light due to extreme reactivity of light-absorbing molecules in tissues. It refers almost exclusively to skin photosensitivity, including sunburn, reactions due to repeated prolonged exposure in the absence of photosensitizing factors, and reactions requiring photosensitizing factors such as photosensitizing agents and certain diseases. With restricted reference to skin tissue, it does not include photosensitivity of the eye to light, as in photophobia or photosensitive epilepsy.
  
• Photosensitization [M0016757]
  
• Phototoxicity [M0026523]
  
• Phycomycosis [M0029827]
  
• Phymatous Rosacea [M0461565]
  
• Pick Disease of Heart [M0016305]
  
• Pick Disease of the Brain [M0005800]
  A rare form of DEMENTIA that is sometimes familial. Clinical features include APHASIA; APRAXIA; CONFUSION; ANOMIA; memory loss; and personality deterioration. This pattern is consistent with the pathologic findings of circumscribed atrophy of the poles of the FRONTAL LOBE and TEMPORAL LOBE. Neuronal loss is maximal in the HIPPOCAMPUS, entorhinal cortex, and AMYGDALA. Some ballooned cortical neurons contain argentophylic (Pick) bodies. (From Brain Pathol 1998 Apr;8(2):339-54; Adams et al., Principles of Neurology, 6th ed, pp1057-9)
  
• Picornaviridae Infections [M0016841]
  Virus diseases caused by the PICORNAVIRIDAE.
  
• Piebaldism [M0024621]
  Autosomal dominant, congenital disorder characterized by localized hypomelanosis of the skin and hair. The most familiar feature is a white forelock presenting in 80 to 90 percent of the patients. The underlying defect is possibly related to the differentiation and migration of melanoblasts, as well as to defective development of the neural crest (neurocristopathy). Piebaldism may be closely related to Waardenburg's syndrome.
  
• Piedra [M0016845]
  Either of two diseases resulting from fungal infection of the hair shafts. Black piedra occurs mainly in and on the hairs of the scalp and is caused by Piedraia hortae; white piedra occurs in and on the hairs of the scalp, beard, moustache and genital areas and is caused by Trichosporon beigelii.
  
• Pierre Robin Syndrome [M0016846]
  An autosomal recessive disorder characterized by brachygnathia and cleft palate, often associated with glossoptosis, backward and upward displacement of the larynx, and angulation of the manubrium sterni. Cleft palate makes sucking and swallowing difficult, permitting easy access of fluids into the larynx. It may appear in several syndromes or as an isolated hypoplasia. (Dorland, 27th ed)
  
• Pigeon Breeder's Lung [M0002577]
  
• Pigmentation Disorders [M0016852]
  
• Pinta [M0016879]
  An infectious disease of the skin caused by Treponema carateum that occurs only in the western hemisphere. Age of onset is between 10 and 20 years of age. This condition is characterized by marked changes in the skin color and is believed to be transmitted by direct person-to-person contact.
  
• Piscirickettsiaceae Infections [M0444628]
  Infections with bacteria of the family PISCIRICKETTSIACEAE, causing septicemic disease of salmonid fish (SALMONIDAE). Piscirickettsia-like bacteria are also associated with disease syndromes in non-salmonid fish.
  
• Pituitary ACTH Hypersecretion [M0335445]
  A disease of the PITUITARY GLAND characterized by the excess amount of ADRENOCORTICOTROPIC HORMONE secreted. This leads to hypersecretion of cortisol (HYDROCORTISONE) by the ADRENAL GLANDS resulting in CUSHING SYNDROME.
  
• Pituitary Apoplexy [M0016907]
  The sudden loss of blood supply to the PITUITARY GLAND, leading to tissue NECROSIS and loss of function (PANHYPOPITUITARISM). The most common cause is hemorrhage or INFARCTION of a PITUITARY ADENOMA. It can also result from acute hemorrhage into SELLA TURCICA due to HEAD TRAUMA; INTRACRANIAL HYPERTENSION; or other acute effects of central nervous system hemorrhage. Clinical signs include severe HEADACHE; HYPOTENSION; bilateral visual disturbances; UNCONSCIOUSNESS; and COMA.
  
• Pituitary Diencephalic Syndrome [M0335309]
  
• Pituitary Diseases [M0016908]
  Disorders involving either the ADENOHYPOPHYSIS or the NEUROHYPOPHYSIS. These diseases usually manifest as hypersecretion or hyposecretion of PITUITARY HORMONES. Neoplastic pituitary masses can also cause compression of the OPTIC CHIASM and other adjacent structures.
  
• Pituitary FSH Hypersecretion [M0335446]
  
• Pituitary LH Hypersecretion [M0335447]
  
• Pituitary TSH Hypersecretion [M0335448]
  
• Pityriasis [M0016925]
  A name originally applied to a group of skin diseases characterized by the formation of fine, branny scales, but now used only with a modifier. (Dorland, 27th ed)
  
• Pityriasis Lichenoides [M0026579]
  A subgroup of PARAPSORIASIS itself divided into acute and chronic forms. The acute form is characterized by the abrupt onset of a generalized, reddish-brown, maculopapular eruption. Lesions may be vesicular, hemorrhagic, crusted, or necrotic. Histologically the disease is characterized by epidermal necrolysis. The chronic form shows milder skin changes with necrosis. An important variant of the chronic form is LYMPHOMATOID PAPULOSIS.
  
• Pityriasis Lichenoides Chronica [M0026577]
  
• Pityriasis Lichenoides et Varioliformis Acuta [M0026578]
  
• Pityriasis Rosea [M0026580]
  A mild exanthematous inflammation of unknown etiology. It is characterized by the presence of salmon-colored maculopapular lesions. The most striking feature is the arrangement of the lesions such that the long axis is parallel to the lines of cleavage. The eruptions are usually generalized, affecting chiefly the trunk, and the course is often self-limiting.
  
• Pityriasis Rubra Pilaris [M0016926]
  A chronic skin disease characterized by small follicular papules, disseminated reddish-brown scaly patches, and often, palmoplantar hyperkeratosis. The papules are about the size of a pin and topped by a horny plug.
  
• Placenta Accreta [M0016936]
  Abnormal placentation in which all or parts of the PLACENTA are attached directly to the MYOMETRIUM due to a complete or partial absence of DECIDUA. It is associated with POSTPARTUM HEMORRHAGE because of the failure of placental separation.
  
• Placenta Diseases [M0016937]
  Pathological processes or abnormal functions of the PLACENTA.
  
• Placenta Increta [M0481680]
  Invasion of CHORIONIC VILLI occurs deep into the MYOMETRIUM.
  
• Placenta Percreta [M0481679]
  Invasion of CHORIONIC VILLI occurs through the MYOMETRIUM penetrating the uterine SEROSA.
  
• Placenta Previa [M0016938]
  Abnormal placentation in which the PLACENTA implants in the lower segment of the UTERUS (the zone of dilation) and may cover part or all of the opening of the CERVIX. It is often associated with serious antepartum bleeding and PREMATURE LABOR.
  
• Placenta, Retained [M0027693]
  A placenta that fails to be expelled after BIRTH of the FETUS. A PLACENTA is retained when the UTERUS fails to contract after the delivery of its content, or when the placenta is abnormally attached to the MYOMETRIUM.
  
• Placental Insufficiency [M0016942]
  Failure of the PLACENTA to deliver an adequate supply of nutrients and OXYGEN to the FETUS.
  
• Plague [M0016945]
  An acute infectious disease caused by YERSINIA PESTIS that affects humans, wild rodents, and their ectoparasites. This condition persists due to its firm entrenchment in sylvatic rodent-flea ecosystems throughout the world. Bubonic plague is the most common form.
  
• Plant Diseases [M0016956]
  Diseases of plants.
  
• Plantar Ulcer [M0025220]
  
• Platelet Storage Pool Deficiency [M0017023]
  Disorder characterized by a decrease or lack of platelet dense bodies in which the releasable pool of adenine nucleotides and 5HT are normally stored.
  
• Pleoconial Myopathies [M0026159]
  
• Pleural Diseases [M0017042]
  
• Pleurisy [M0017045]
  INFLAMMATION of PLEURA, the lining of the LUNG. When PARIETAL PLEURA is involved, there is pleuritic CHEST PAIN.
  
• Pleurodynia, Epidemic [M0017047]
  An acute, febrile, infectious disease generally occurring in epidemics. It is usually caused by coxsackieviruses B and sometimes by coxsackieviruses A; echoviruses; or other enteroviruses.
  
• Pleuropneumonia [M0017048]
  Pleurisy complicated with pneumonia. (Dorland, 27th ed)
  
• Pleuropneumonia, Contagious [M0017049]
  A pleuropneumonia of cattle and goats caused by species of MYCOPLASMA.
  
• Plummer-Vinson Syndrome [M0017051]
  A syndrome of DYSPHAGIA with IRON-DEFICIENCY ANEMIA that is due to congenital anomalies in the ESOPHAGUS (such as cervical esophageal webs). It is known as Patterson-Kelly syndrome in the United Kingdom.
  
• Pneumatosis Cystoides Intestinalis [M0017053]
  A condition characterized by the presence of multiple gas-filled cysts in the intestinal wall, the submucosa and/or subserosa of the INTESTINE. The majority of the cysts are found in the JEJUNUM and the ILEUM.
  
• Pneumocephalus [M0017054]
  Presence of air or gas within the intracranial cavity (e.g., epidural space, subdural space, intracerebral, etc.) which may result from traumatic injuries, fistulous tract formation, erosions of the skull from NEOPLASMS or infection, NEUROSURGICAL PROCEDURES, and other conditions.
  
• Pneumocephalus, Epidural [M0335617]
  
• Pneumocephalus, Tension [M0335620]
  
• Pneumocephalus, Traumatic [M0335618]
  
• Pneumococcal Infections [M0017055]
  Infections with bacteria of the species STREPTOCOCCUS PNEUMONIAE.
  
• Pneumoconiosis [M0017057]
  Condition characterized by permanent deposition of substantial amounts of particulate matter in the lungs, usually of occupational or environmental origin, and by the tissue reaction to its presence.
  
• Pneumocystis Infections [M0025462]
  Infections with species in the genus PNEUMOCYSTIS, a fungus causing interstitial plasma cell pneumonia (PNEUMONIA, PNEUMOCYSTIS) and other infections in humans and other MAMMALS. Immunocompromised patients, especially those with AIDS, are particularly susceptible to these infections. Extrapulmonary sites are rare but seen occasionally.
  
• Pneumonia [M0017064]
  Inflammation of the lungs.
  
• Pneumonia of Calves, Enzootic [M0460596]
  Chronic endemic respiratory disease of dairy calves and an important component of bovine respiratory disease complex. It primarily affects calves up to six months of age and the etiology is multifactorial. Stress plus a primary viral infection is followed by a secondary bacterial infection. The latter is most commonly associated with PASTEURELLA MULTOCIDA producing a purulent BRONCHOPNEUMONIA. Sometimes present are MANNHEIMIA HAEMOLYTICA; HAEMOPHILUS SOMNUS and mycoplasma species.
  
• Pneumonia of Swine, Mycoplasmal [M0449119]
  A chronic, clinically mild, infectious pneumonia of PIGS caused by MYCOPLASMA HYOPNEUMONIAE. Ninety percent of swine herds worldwide are infected with this economically costly disease that primarily affects animals aged two to six months old. The disease can be associated with porcine respiratory disease complex. PASTEURELLA MULTOCIDA is often found as a secondary infection.
  
• Pneumonia, Aspiration [M0017066]
  A type of lung inflammation resulting from the aspiration of food, liquid, or gastric contents into the upper RESPIRATORY TRACT.
  
• Pneumonia, Atypical Interstitial, of Cattle [M0017068]
  A cattle disease of uncertain cause, probably an allergic reaction.
  
• Pneumonia, Bacterial [M0027639]
  Pneumonia caused by various species of bacteria. Bacterial pneumonia commonly results from bronchogenic spread of infection following microaspiration of secretions. The largest category of this disease arises from community-acquired pneumonias.
  
• Pneumonia, Eosinophilic [M0018132]
  
• Pneumonia, Lipid [M0017070]
  Pneumonia due to aspiration or inhalation of various oily or fatty substances.
  
• Pneumonia, Mycoplasma [M0017072]
  Interstitial pneumonia caused by extensive infection of the lungs (LUNG) and BRONCHI, particularly the lower lobes of the lungs, by MYCOPLASMA PNEUMONIAE in humans. In SHEEP, it is caused by MYCOPLASMA OVIPNEUMONIAE. In CATTLE, it may be caused by MYCOPLASMA DISPAR.
  
• Pneumonia, Pneumococcal [M0017071]
  A febrile disease caused by STREPTOCOCCUS PNEUMONIAE. This condition is characterized by inflammation of one or more lobes of the lungs and symptoms include chills, fever, rapid breathing, and cough.
  
• Pneumonia, Pneumocystis [M0017073]
  A pulmonary disease in humans occurring in immunodeficient or malnourished patients or infants, characterized by DYSPNEA, tachypnea, and HYPOXEMIA. Pneumocystis pneumonia is a frequently seen opportunistic infection in AIDS. It is caused by the fungus PNEUMOCYSTIS JIROVECI. The disease is also found in other MAMMALS where it is caused by related species of Pneumocystis.
  
• Pneumonia, Progressive Interstitial, of Sheep [M0017074]
  Chronic respiratory disease caused by the VISNA-MAEDI VIRUS. It was formerly believed to be identical with jaagsiekte (PULMONARY ADENOMATOSIS, OVINE) but is now recognized as a separate entity.
  
• Pneumonia, Rickettsial [M0017075]
  Pneumonia caused by infection with bacteria of the family RICKETTSIACEAE.
  
• Pneumonia, Staphylococcal [M0017076]
  Pneumonia caused by STAPHYLOCOCCUS AUREUS. This condition is a frequent complication of viral influenza.
  
• Pneumonia, Ventilator-Associated [M0495804]
  Serious INFLAMMATION of the LUNG in patients who required the use of PULMONARY VENTILATOR. It is usually caused by cross bacterial infections in hospitals (NOSOCOMIAL INFECTIONS).
  
• Pneumonia, Viral [M0017077]
  Pneumonia caused by a virus. (Dorland, 28th ed)
  
• Pneumonic Plague [M0016946]
  
• Pneumonitis, Interstitial [M0026625]
  
• Pneumopericardium [M0017079]
  
• Pneumoperitoneum [M0017080]
  A condition with trapped gas or air in the PERITONEAL CAVITY, usually secondary to perforation of the internal organs such as the LUNG and the GASTROINTESTINAL TRACT, or to recent surgery. Pneumoperitoneum may be purposely introduced to aid radiological examination.
  
• Pneumothorax [M0017083]
  An accumulation of air or gas in the pleural space, which may occur spontaneously or as a result of trauma or a pathological process, or be introduced deliberately ( = PNEUMOTHORAX, ARTIFICIAL). (Dorland, 27th ed)
  
• Pneumovirus Infections [M0027415]
  Infections with viruses of the genus PNEUMOVIRUS, family PARAMYXOVIRIDAE. This includes RESPIRATORY SYNCYTIAL VIRUS INFECTIONS, an important cause of respiratory disease in humans.
  
• POEMS Syndrome [M0025682]
  A multisystemic disorder characterized by a sensorimotor polyneuropathy (POLYNEUROPATHIES), organomegaly, endocrinopathy, monoclonal gammopathy, and pigmentary skin changes. Other clinical features which may be present include EDEMA; CACHEXIA; microangiopathic glomerulopathy; pulmonary hypertension (HYPERTENSION, PULMONARY); cutaneous necrosis; THROMBOCYTOSIS; and POLYCYTHEMIA. This disorder is frequently associated with osteosclerotic myeloma. (From Adams et al., Principles of Neurology, 6th ed, p1335; Rev Med Interne 1997;18(7):553-62)
  
• Poland Syndrome [M0017104]
  A syndrome which is characterized by symbrachydactyly and aplasia of the sternal head of pectoralis major.
  
• Poliomyelitis [M0017112]
  An acute infectious disease of humans, particularly children, caused by any of three serotypes of human poliovirus (POLIOVIRUS). Usually the infection is limited to the gastrointestinal tract and nasopharynx, and is often asymptomatic. The central nervous system, primarily the spinal cord, may be affected, leading to rapidly progressive paralysis, coarse FASCICULATION and hyporeflexia. Motor neurons are primarily affected. Encephalitis may also occur. The virus replicates in the nervous system, and may cause significant neuronal loss, most notably in the spinal cord. A rare related condition, nonpoliovirus poliomyelitis, may result from infections with nonpoliovirus enteroviruses. (From Adams et al., Principles of Neurology, 6th ed, pp764-5)
  
• Poliomyelitis, Bulbar [M0017113]
  A form of paralytic poliomyelitis affecting neurons of the MEDULLA OBLONGATA of the brain stem. Clinical features include impaired respiration, HYPERTENSION, alterations of vasomotor control, and dysphagia. Weakness and atrophy of the limbs and trunk due to spinal cord involvement is usually associated. (From Adams et al., Principles of Neurology, 6th ed, p765)
  
• Poliomyelitis, Nonpoliovirus [M0335886]
  
• Poliomyelitis, Preparalytic [M0335887]
  
• Polyarteritis Nodosa [M0016293]
  A form of necrotizing vasculitis involving small- and medium-sized arteries. The signs and symptoms result from infarction and scarring of the affected organ system.
  
• Polyarthralgia [M0028100]
  
• Polyarthritis [M0001742]
  
• Polychondritis, Relapsing [M0017161]
  An acquired disease of unknown etiology, chronic course, and tendency to recur. It is characterized by inflammation and degeneration of cartilage and can result in deformities such as floppy ear and saddle nose. Loss of cartilage in the respiratory tract can lead to respiratory obstruction.
  
• Polycystic Kidney Diseases [M0012031]
  Hereditary diseases that are characterized by the progressive expansion of a large number of tightly packed CYSTS within the KIDNEYS. They include diseases with autosomal dominant and autosomal recessive inheritance.
  
• Polycystic Kidney, Autosomal Dominant [M0025702]
  Kidney disorders with autosomal dominant inheritance and characterized by multiple CYSTS in both KIDNEYS with progressive deterioration of renal function.
  
• Polycystic Kidney, Autosomal Recessive [M0025899]
  A genetic disorder with autosomal recessive inheritance, characterized by multiple CYSTS in both KIDNEYS and associated LIVER lesions. Serious manifestations are usually present at BIRTH with high PERINATAL MORTALITY.
  
• Polycystic Kidney, Type 1 Autosomal Dominant Disease [M0355414]
  Type 1 ADPKD is linked to gene mutation at the PKD1 locus on the short arm of CHROMOSOME 16.
  
• Polycystic Kidney, Type 2 Autosomal Dominant Disease [M0355417]
  Type 2 ADPKD is linked to gene mutation at the PKD2 locus on the long arm of CHROMOSOME 4.
  
• Polycystic Ovary Syndrome [M0017165]
  A complex disorder characterized by infertility, HIRSUTISM; OBESITY; and various menstrual disturbances such as OLIGOMENORRHEA; AMENORRHEA; ANOVULATION. Polycystic ovary syndrome is usually associated with bilateral enlarged ovaries studded with atretic follicles, not with cysts. The term, polycystic ovary, is misleading.
  
• Polycythemia [M0017166]
  An increase in the total red cell mass of the blood. (Dorland, 27th ed)
  
• Polyendocrinopathies, Autoimmune [M0025689]
  Autoimmune diseases affecting multiple endocrine organs. Type I is characterized by childhood onset and chronic mucocutaneous candidiasis (CANDIDIASIS, CHRONIC MUCOCUTANEOUS), while type II exhibits any combination of adrenal insufficiency (ADDISON'S DISEASE), lymphocytic thyroiditis (THYROIDITIS, AUTOIMMUNE;), HYPOPARATHYROIDISM; and gonadal failure. In both types organ-specific ANTIBODIES against a variety of ENDOCRINE GLANDS have been detected. The type II syndrome differs from type I in that it is associated with HLA-A1 and B8 haplotypes, onset is usually in adulthood, and candidiasis is not present.
  
• Polyglandular Type I Autoimmune Syndrome [M0025691]
  
• Polyglandular Type II Autoimmune Syndrome [M0025692]
  
• Polymenorrhea [M0013404]
  
• Polymyalgia Rheumatica [M0017211]
  A syndrome in the elderly characterized by proximal joint and muscle pain, high erythrocyte sedimentation rate, and a self-limiting course. Pain is usually accompanied by evidence of an inflammatory reaction. Women are affected twice as commonly as men and Caucasians more frequently than other groups. The condition is frequently associated with TEMPORAL ARTERITIS and some theories pose the possibility that the two diseases arise from a single etiology or even that they are the same entity.
  
• Polymyositis [M0026239]
  Diseases characterized by inflammation involving multiple muscles. This may occur as an acute or chronic condition associated with medication toxicity (DRUG TOXICITY); CONNECTIVE TISSUE DISEASES; infections; malignant NEOPLASMS; and other disorders. The term polymyositis is frequently used to refer to a specific clinical entity characterized by subacute or slowly progressing symmetrical weakness primarily affecting the proximal limb and trunk muscles. The illness may occur at any age, but is most frequent in the fourth to sixth decade of life. Weakness of pharyngeal and laryngeal muscles, interstitial lung disease, and inflammation of the myocardium may also occur. Muscle biopsy reveals widespread destruction of segments of muscle fibers and an inflammatory cellular response. (Adams et al., Principles of Neurology, 6th ed, pp1404-9)
  
• Polymyositis Ossificans [M0337304]
  
• Polymyositis, Idiopathic [M0337305]
  
• Polyneuritis [M0017228]
  Inflammation of multiple nerves.
  
• Polyneuropathies [M0333806]
  Diseases of multiple peripheral nerves simultaneously. Polyneuropathies usually are characterized by symmetrical, bilateral distal motor and sensory impairment with a graded increase in severity distally. The pathological processes affecting peripheral nerves include degeneration of the axon, myelin or both. The various forms of polyneuropathy are categorized by the type of nerve affected (e.g., sensory, motor, or autonomic), by the distribution of nerve injury (e.g., distal vs. proximal), by nerve component primarily affected (e.g., demyelinating vs. axonal), by etiology, or by pattern of inheritance.
  
• Polyneuropathy, Acquired [M0336467]
  
• Polyneuropathy, Critical Illness [M0336468]
  
• Polyneuropathy, Familial [M0336469]
  
• Polyneuropathy, Motor [M0336470]
  
• Polyomavirus Infections [M0380372]
  Infections with POLYOMAVIRUS, which are often cultured from the urine of kidney transplant patients. Excretion of BK VIRUS is associated with ureteral strictures and CYSTITIS, and that of JC VIRUS with progressive multifocal leukoencephalopathy (LEUKOENCEPHALOPATHY, PROGRESSIVE MULTIFOCAL).
  
• Polyradiculitis [M0017241]
  
• Polyradiculoneuritis [M0333441]
  
• Polyradiculoneuropathy [M0017243]
  Diseases characterized by injury or dysfunction involving multiple peripheral nerves and nerve roots. The process may primarily affect myelin or nerve axons. Two of the more common demyelinating forms are acute inflammatory polyradiculopathy (GUILLAIN-BARRE SYNDROME) and POLYRADICULONEUROPATHY, CHRONIC INFLAMMATORY DEMYELINATING. Polyradiculoneuritis refers to inflammation of multiple peripheral nerves and spinal nerve roots.
  
• Polyradiculoneuropathy, Chronic Inflammatory Demyelinating [M0328266]
  A slowly progressive autoimmune demyelinating disease of peripheral nerves and nerve roots. Clinical manifestations include weakness and sensory loss in the extremities and enlargement of peripheral nerves. The course may be relapsing-remitting or demonstrate a step-wise progression. Protein is usually elevated in the spinal fluid and cranial nerves are typically spared. GUILLAIN-BARRE SYNDROME features a relatively rapid progression of disease which distinguishes it from this condition. (Adams et al., Principles of Neurology, 6th ed, p1337)
  
• Polyradiculopathy [M0333810]
  Disease or injury involving multiple SPINAL NERVE ROOTS. Polyradiculitis refers to inflammation of multiple spinal nerve roots.
  
• Polyradiculopathy, Abdominal [M0336798]
  
• Popliteal Cyst [M0017285]
  A SYNOVIAL CYST located in the back of the knee, in the popliteal space arising from the semimembranous bursa or the knee joint.
  
• Porcine Postweaning Multisystemic Wasting Syndrome [M0494731]
  A worldwide emerging disease of weaned piglets first recognized in swine herds in western Canada in 1997. This syndrome is characterized by progressive weight loss, rapid (tachypnea) and difficult (dyspnea) breathing, and yellowing of skin. PMWS is caused by PORCINE CIRCOVIRUS infection, specifically type 2 or PCV-2.
  
• Porcine Reproductive and Respiratory Syndrome [M0028764]
  A syndrome characterized by outbreaks of late term abortions, high numbers of stillbirths and mummified or weak newborn piglets, and respiratory disease in young unweaned and weaned pigs. It is caused by PORCINE RESPIRATORY AND REPRODUCTIVE SYNDROME VIRUS. (Radostits et al., Veterinary Medicine, 8th ed, p1048)
  
• Porokeratosis [M0026551]
  A heritable disorder of faulty keratinization characterized by the proliferation of abnormal clones of KERATINOCYTES and lesions showing varying atrophic patches surrounded by an elevated, keratotic border. These keratotic lesions can progress to overt cutaneous neoplasm. Several clinical variants are recognized, including porokeratosis of Mibelli, linear porokeratosis, disseminated superficial actinic porokeratosis, palmoplantar porokeratosis, and punctate porokeratosis.
  
• Porokeratosis, Disseminated Superficial Actinic [M0376740]
  
• Porokeratosis, Linear [M0376741]
  
• Porokeratosis, Mibelli [M0376739]
  The classical form of porokeratosis with isolated lesions.
  
• Porokeratosis, Palmoplantar [M0026550]
  
• Porokeratosis, Punctate [M0376742]
  
• Porphyria Cutanea Tarda [M0026011]
  An autosomal dominant or acquired porphyria due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in the LIVER. It is characterized by photosensitivity and cutaneous lesions with little or no neurologic symptoms. Type I is the acquired form and is strongly associated with liver diseases and hepatic toxicities caused by alcohol or estrogenic steroids. Type II is the familial form.
  
• Porphyria, Acute Intermittent [M0026010]
  An autosomal dominant porphyria that is due to a deficiency of HYDROXYMETHYLBILANE SYNTHASE in the LIVER, the third enzyme in the 8-enzyme biosynthetic pathway of HEME. Clinical features are recurrent and life-threatening neurologic disturbances, ABDOMINAL PAIN, and elevated level of AMINOLEVULINIC ACID and PORPHOBILINOGEN in the urine.
  
• Porphyria, Erythropoietic [M0025969]
  An autosomal recessive porphyria that is due to a deficiency of UROPORPHYRINOGEN III SYNTHASE in the BONE MARROW; also known as congenital erythropoietic porphyria. This disease is characterized by SPLENOMEGALY; ANEMIA; photosensitivity; cutaneous lesions; accumulation of hydroxymethylbilane; and increased excretion of UROPORPHYRINS and COPROPORPHYRINS.
  
• Porphyria, Hepatoerythropoietic [M0026014]
  An autosomal recessive cutaneous porphyria that is due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in both the LIVER and the BONE MARROW. Similar to PORPHYRIA CUTANEA TARDA, this disorder is caused by defects in the fifth enzyme in the 8-enzyme biosynthetic pathway of HEME, but is a homozygous enzyme deficiency with less than 10% of the normal enzyme activity. Cutaneous lesions are severe and mutilating.
  
• Porphyria, Variegate [M0025972]
  An autosomal dominant porphyria that is due to a deficiency of protoporphyrinogen oxidase (EC 1.3.3.4) in the LIVER, the seventh enzyme in the 8-enzyme biosynthetic pathway of HEME. Clinical features include both neurological symptoms and cutaneous lesions. Patients excrete increased levels of porphyrin precursors, COPROPORPHYRINS and protoporphyrinogen.
  
• Porphyrias [M0017334]
  A diverse group of metabolic diseases characterized by errors in the biosynthetic pathway of HEME in the LIVER, the BONE MARROW, or both. They are classified by the deficiency of specific enzymes, the tissue site of enzyme defect, or the clinical features that include neurological (acute) or cutaneous (skin lesions). Porphyrias can be hereditary or acquired as a result of toxicity to the hepatic or erythropoietic marrow tissues.
  
• Porphyrias, Hepatic [M0025973]
  A group of metabolic diseases due to deficiency of one of a number of LIVER enzymes in the biosynthetic pathway of HEME. They are characterized by the accumulation and increased excretion of PORPHYRINS or its precursors. Clinical features include neurological symptoms (PORPHYRIA, ACUTE INTERMITTENT), cutaneous lesions due to photosensitivity (PORPHYRIA CUTANEA TARDA), or both (HEREDITARY COPROPORPHYRIA). Hepatic porphyrias can be hereditary or acquired as a result of toxicity to the hepatic tissues.
  
• Position Sense Disorders [M0336654]
  
• Positive-Pressure Respiration, Intrinsic [M0027702]
  Non-therapeutic positive end-expiratory pressure occurring frequently in patients with severe airway obstruction. It can appear with or without the administration of external positive end-expiratory pressure (POSITIVE-PRESSURE RESPIRATION). It presents an important load on the inspiratory muscles which are operating at a mechanical disadvantage due to hyperinflation. Auto-PEEP may cause profound hypotension that should be treated by intravascular volume expansion, increasing the time for expiration, and/or changing from assist mode to intermittent mandatory ventilation mode. (From Harrison's Principles of Internal Medicine, 12th ed, p1127)
  
• Post-Comatose Unawareness State [M0335849]
  
• Post-Concussion Syndrome [M0415429]
  The organic and psychogenic disturbances observed after closed head injuries (HEAD INJURIES, CLOSED). Post-concussion syndrome includes subjective physical complaints (i.e. headache, dizziness), cognitive, emotional, and behavioral changes. These disturbances can be chronic, permanent, or late emerging.
  
• Post-Lumbar Puncture Headache [M0480098]
  
• Post-Traumatic Headache [M0335247]
  Secondary headache attributed to TRAUMA of the HEAD and/or the NECK.
  
• Post-Traumatic Hydrocephalus [M0335283]
  
• Post-Traumatic Vegetative State [M0335848]
  
• Postcholecystectomy Syndrome [M0026620]
  Abdominal symptoms after removal of the GALLBLADDER. The common postoperative symptoms are often the same as those present before the operation, such as COLIC, bloating, NAUSEA, and VOMITING. There is pain on palpation of the right upper quadrant and sometimes JAUNDICE. The term is often used, inaccurately, to describe such postoperative symptoms not due to gallbladder removal.
  
• Postcholedochoduodenostomy Syndrome [M0026621]
  
• Postcholedochojejunostomy Syndrome [M0026622]
  
• Postcholedochostomy Syndrome [M0026623]
  
• Postcommissurotomy Syndrome [M0017369]
  
• Posterior Cerebral Artery Syndrome [M0335406]
  
• Posterior Cervical Sympathetic Syndrome [M0020329]
  
• Posterior Choroidal Artery Infarction [M0334512]
  
• Posterior Circulation Transient Ischemic Attack [M0335466]
  
• Posterior Ischemic Optic Neuropathy [M0336261]
  
• Posterior Pituitary Diseases [M0335869]
  
• Posterior Spinal Artery Syndrome [M0336128]
  
• Posterior Tibial Tendon Dysfunction [M0411809]
  A condition characterized by a broad range of progressive disorders ranging from TENOSYNOVITIS to tendon rupture with or without hindfoot collapse to a fixed, rigid, FLATFOOT deformity. Pathologic changes can involve associated tendons, ligaments, joint structures of the ANKLE, hindfoot, and midfoot. Posterior tibial tendon dysfunction is the most common cause of acquired flatfoot deformity in adults.
  
• Posterior Tibial Tendon Insufficiency [M0494746]
  
• Posterior Urethral Stricture [M0491663]
  
• Posterior Vitreous Detachment [M0029920]
  
• Postgastrectomy Syndromes [M0017355]
  Sequelae of gastrectomy from the second week after operation on. Include recurrent or anastomotic ulcer, postprandial syndromes (DUMPING SYNDROME and late postprandial hypoglycemia), disordered bowel action, and nutritional deficiencies.
  
• Postinfectious Encephalomyelitis [M0334282]
  
• Postpartum Hypopituitarism [M0010922]
  
• Postpartum Thyroiditis [M0472035]
  Transient autoimmune thyroiditis occurring in the POSTPARTUM PERIOD. It is characterized by the presence of high titers of AUTOANTIBODIES against THYROID PEROXIDASE and THYROGLOBULIN. Clinical signs include the triphasic thyroid hormone pattern: beginning with THYROTOXICOSIS, followed with HYPOTHYROIDISM, then return to euthyroid state by 1 year postpartum.
  
• Postpericardiotomy Syndrome [M0017370]
  A febrile illness associated with pericardial and sometimes pleuropulmonary reaction that often follows extensive pericardiotomy.
  
• Postphlebitic Syndrome [M0017371]
  Post-thrombotic complications, including destruction of the valves of the deep veins and communication veins of the leg, and obliteration of the thrombosed veins rather than recanalization, resulting in chronic venous insufficiency, marked by edema, stasis dermatitis, and ulceration of the leg.
  
• Postphlebitic Ulcer [M0017372]
  
• Postpoliomyelitis Syndrome [M0024855]
  A syndrome characterized by new neuromuscular symptoms that occur at least 15 years after clinical stability has been attained in patients with a prior history of symptomatic poliomyelitis. Clinical features include new muscular weakness and atrophy of the limbs, bulbar innervated musculature, and muscles of respiration, combined with excessive fatigue, joint pain, and reduced stamina. The process is marked by slow progression and periods of stabilization. (From Ann NY Acad Sci 1995 May 25;753:68-80)
  
• Postprandial Hypoglycemia [M0446504]
  HYPOGLYCEMIA expressed after a meal or FOOD INTAKE. It is also called reactive or stimulative hypoglycemia.
  
• Postzoster Arteritis [M0335301]
  
• Potassium Deficiency [M0017378]
  A condition due to decreased dietary intake of potassium, as in starvation or failure to administer in intravenous solutions, or to gastrointestinal loss in diarrhea, chronic laxative abuse, vomiting, gastric suction, or bowel diversion. Severe potassium deficiency may produce muscular weakness and lead to paralysis and respiratory failure. Muscular malfunction may result in hypoventilation, paralytic ileus, hypotension, muscle twitches, tetany, and rhabomyolysis. Nephropathy from potassium deficit impairs the concentrating mechanism, producing polyuria and decreased maximal urinary concentrating ability with secondary polydipsia. (Merck Manual, 16th ed)
  
• Pouchitis [M0028936]
  Acute INFLAMMATION in the INTESTINAL MUCOSA of the continent ileal reservoir (or pouch) in patients who have undergone ILEOSTOMY and restorative proctocolectomy (PROCTOCOLECTOMY, RESTORATIVE).
  
• Poult Enteritis Mortality Syndrome [M0396969]
  An acute, transmissible, infectious disease associated with high MORTALITY and MORBIDITY in young turkeys (poults). It is characterized by DIARRHEA; ANOREXIA; growth depression, and immune dysfunction. The cause is unknown but astroviruses (AVASTROVIRUS) and coronaviruses (CORONAVIRUS, TURKEY) have been isolated from diseased poults and are thought to cause the enteritis and increased susceptibility to bacterial infections.
  
• Poultry Diseases [M0017390]
  Diseases of birds which are raised as a source of meat or eggs for human consumption and are usually found in barnyards, hatcheries, etc. The concept is differentiated from BIRD DISEASES which is for diseases of birds not considered poultry and usually found in zoos, parks, and the wild.
  
• Powassan Encephalitis [M0334865]
  
• Poxviridae Infections [M0017424]
  Virus diseases caused by the POXVIRIDAE.
  
• Prader-Willi Syndrome [M0017431]
  An autosomal dominant disorder caused by deletion of the proximal long arm of the paternal chromosome 15 (15q11-q13) or by inheritance of both of the pair of chromosomes 15 from the mother (UNIPARENTAL DISOMY) which are imprinted (GENETIC IMPRINTING) and hence silenced. Clinical manifestations include MENTAL RETARDATION; MUSCULAR HYPOTONIA; HYPERPHAGIA; OBESITY; short stature; HYPOGONADISM; STRABISMUS; and HYPERSOMNOLENCE. (Menkes, Textbook of Child Neurology, 5th ed, p229)
  
• Pre-Eclampsia [M0017443]
  A complication of PREGNANCY, characterized by a complex of symptoms including maternal HYPERTENSION and PROTEINURIA with or without pathological EDEMA. Symptoms may range between mild and severe. Pre-eclampsia usually occurs after the 20th week of gestation, but may develop before this time in the presence of trophoblastic disease.
  
• Pre-Excitation Syndromes [M0017444]
  Conditions characterized by activation of the whole or some part of the ventricle by the atrial impulse earlier than would be expected if the impulse reached the ventricle by way of the normal specific conduction system only.
  
• Pre-Excitation, Mahaim-Type [M0017445]
  A form of pre-excitation characterized by a normal PR interval and a long QRS interval with a delta wave.
  
• Prediabetic State [M0017457]
  The time period before the development of symptomatic diabetes. For example, certain risk factors can be observed in subjects who subsequently develop INSULIN RESISTANCE as in type 2 diabetes (DIABETES MELLITUS, TYPE 2).
  
• Pregnancy Complications [M0017474]
  Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases.
  
• Pregnancy Complications, Cardiovascular [M0017475]
  The co-occurrence of pregnancy and a cardiovascular disease. The disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.
  
• Pregnancy Complications, Hematologic [M0017476]
  The co-occurrence of pregnancy and a blood disease (HEMATOLOGIC DISEASES) which involves BLOOD CELLS or COAGULATION FACTORS. The hematologic disease may precede or follow FERTILIZATION and it may or may not have a deleterious effect on the pregnant woman or FETUS.
  
• Pregnancy Complications, Infectious [M0017477]
  The co-occurrence of pregnancy and an INFECTION. The infection may precede or follow FERTILIZATION.
  
• Pregnancy Complications, Parasitic [M0023943]
  The co-occurrence of pregnancy and parasitic diseases. The parasitic infection may precede or follow FERTILIZATION.
  
• Pregnancy in Diabetics [M0017481]
  The state of PREGNANCY in women with DIABETES MELLITUS. This does not include either symptomatic diabetes or GLUCOSE INTOLERANCE induced by pregnancy (DIABETES, GESTATIONAL) which resolves at the end of pregnancy.
  
• Pregnancy, Abdominal [M0017497]
  A type of ectopic pregnancy in which the EMBRYO implants in the ABDOMINAL CAVITY instead of in the ENDOMETRIUM of the UTERUS.
  
• Pregnancy, Ectopic [M0017499]
  A potentially life-threatening condition in which the EMBRYO implants outside the cavity of the UTERUS. Most ectopic pregnancies (>96%) occur in the FALLOPIAN TUBES, known as TUBAL PREGNANCY. They can be in other locations, such as UTERINE CERVIX; OVARY; and abdominal cavity (PREGNANCY, ABDOMINAL).
  
• Pregnancy, High-Risk [M0027830]
  Pregnancy in which the mother and/or FETUS are at greater than normal risk of MORBIDITY or MORTALITY. Causes include inadequate PRENATAL CARE, previous obstetrical history (ABORTION, SPONTANEOUS), pre-existing maternal disease, pregnancy-induced disease (GESTATIONAL HYPERTENSION), and MULTIPLE PREGNANCY, as well as advanced maternal age above 35.
  
• Pregnancy, Ovarian [M0017500]
  
• Pregnancy, Prolonged [M0017502]
  A term used to describe pregnancies that exceed the upper limit of a normal gestational period. In humans, a prolonged pregnancy is defined as one that extends beyond 42 weeks (294 days) after the first day of the last menstrual period (MENSTRUATION), or birth with gestational age of 41 weeks or more.
  
• Pregnancy, Tubal [M0017503]
  The most common (>96%) type of ectopic pregnancy in which the extrauterine EMBRYO IMPLANTATION occurs in the FALLOPIAN TUBE, usually in the ampullary region where FERTILIZATION takes place.
  
• Premenstrual Syndrome [M0017534]
  A combination of distressing physical, psychologic, or behavioral changes that occur during the luteal phase of the menstrual cycle. Symptoms of PMS are diverse (such as pain, water-retention, anxiety, cravings, and depression) and they diminish markedly 2 or 3 days after the initiation of menses.
  
• Presbyopia [M0017556]
  The normal decreasing elasticity of the crystalline lens that leads to loss of accommodation.
  
• Pressure Pneumocephalus [M0335619]
  
• Pressure Ulcer [M0005739]
  An ulceration caused by prolonged pressure on the SKIN and TISSUES when one stay in one position for a long period of time, such as lying in bed. The bony areas of the body are the most frequently affected sites which become ischemic (ISCHEMIA) under sustained and constant pressure.
  
• Preterm Premature Rupture of Fetal Membranes [M0481507]
  
• Priapism [M0017569]
  A prolonged painful erection that may lasts hours and is not associated with sexual activity. It is seen in patients with SICKLE CELL ANEMIA, advanced malignancy, spinal trauma; and certain drug treatments.
  
• Primary CNS Vasculitis [M0335302]
  
• Primary Esotropia [M0336196]
  
• Primary Exertional Headache [M0335249]
  
• Primary Exotropia [M0336201]
  
• Primary Peritonitis [M0455598]
  
• Primate Diseases [M0027647]
  Diseases of animals within the order PRIMATES. This term includes diseases of Haplorhini and Strepsirhini.
  
• Prion Diseases [M0025975]
  A group of genetic, infectious, or sporadic degenerative human and animal nervous system disorders associated with abnormal PRIONS. These diseases are characterized by conversion of the normal prion protein to an abnormal configuration via a post-translational process. In humans, these conditions generally feature DEMENTIA; ATAXIA; and a fatal outcome. Pathologic features include a spongiform encephalopathy without evidence of inflammation. The older literature occasionally refers to these as unconventional SLOW VIRUS DISEASES. (From Proc Natl Acad Sci USA 1998 Nov 10;95(23):13363-83)
  
• Proctitis [M0017632]
  INFLAMMATION of the MUCOUS MEMBRANE of the RECTUM, the distal end of the large intestine (INTESTINE, LARGE).
  
• Proctocolitis [M0017633]
  Inflammation of the RECTUM and the distal portion of the COLON.
  
• Proctosigmoiditis [M0017634]
  
• Progeria [M0017668]
  An abnormal congenital condition, associated with defects in the LAMIN TYPE A gene, which is characterized by premature aging in children, where all the changes of cell senescence occur. It is manifested by premature greying; hair loss; hearing loss (DEAFNESS); cataracts (CATARACT); ARTHRITIS; OSTEOPOROSIS; DIABETES MELLITUS; atrophy of subcutaneous fat; skeletal hypoplasia; elevated urinary HYALURONIC ACID; and accelerated ATHEROSCLEROSIS. Many affected individuals develop malignant tumors, especially SARCOMA.
  
• Progressive Muscular Atrophy [M0393323]
  
• Progressive Proximal Myelopathic Muscular Atrophy [M0335741]
  
• Prolonged Post-Traumatic Unawareness [M0335850]
  
• Prostatic Diseases [M0017828]
  Pathological processes involving the PROSTATE or its component tissues.
  
• Prostatic Hypertrophy, Benign [M0017829]
  
• Prostatitis [M0017835]
  Infiltration of inflammatory cells into the parenchyma of PROSTATE. The subtypes are classified by their varied laboratory analysis, clinical presentation and response to treatment.
  
• Protein C Deficiency [M0029882]
  An absence or deficiency in PROTEIN C which leads to impaired regulation of blood coagulation. It is associated with an increased risk of severe or premature thrombosis. (Stedman's Med. Dict., 26th ed.)
  
• Protein Deficiency [M0017855]
  A nutritional condition produced by a deficiency of proteins in the diet, characterized by adaptive enzyme changes in the liver, increase in amino acid synthetases, and diminution of urea formation, thus conserving nitrogen and reducing its loss in the urine. Growth, immune response, repair, and production of enzymes and hormones are all impaired in severe protein deficiency. Protein deficiency may also arise in the face of adequate protein intake if the protein is of poor quality (i.e., the content of one or more amino acids is inadequate and thus becomes the limiting factor in protein utilization). (From Merck Manual, 16th ed; Harrison's Principles of Internal Medicine, 12th ed, p406)
  
• Protein S Deficiency [M0027690]
  An autosomal dominant disorder showing decreased levels of plasma protein S antigen or activity, associated with venous thrombosis and pulmonary embolism. PROTEIN S is a vitamin K-dependent plasma protein that inhibits blood clotting by serving as a cofactor for activated PROTEIN C (also a vitamin K-dependent protein), and the clinical manifestations of its deficiency are virtually identical to those of protein C deficiency. Treatment with heparin for acute thrombotic processes is usually followed by maintenance administration of coumarin drugs for the prevention of recurrent thrombosis. (From Harrison's Principles of Internal Medicine, 12th ed, p1511; Wintrobe's Clinical Hematology, 9th ed, p1523)
  
• Protein-Energy Malnutrition [M0017876]
  The lack of sufficient energy or protein to meet the body's metabolic demands, as a result of either an inadequate dietary intake of protein, intake of poor quality dietary protein, increased demands due to disease, or increased nutrient losses.
  
• Protein-Losing Enteropathies [M0017886]
  Pathological conditions in the INTESTINES that are characterized by the gastrointestinal loss of serum proteins, including SERUM ALBUMIN; IMMUNOGLOBULINS; and at times LYMPHOCYTES. Severe condition can result in HYPOGAMMAGLOBULINEMIA or LYMPHOPENIA. Protein-losing enteropathies are associated with a number of diseases including INTESTINAL LYMPHANGIECTASIA; WHIPPLE'S DISEASE; and NEOPLASMS of the SMALL INTESTINE.
  
• Proteinuria [M0017891]
  The presence of proteins in the urine, an indicator of KIDNEY DISEASES.
  
• Proteus Infections [M0017900]
  Infections with bacteria of the genus PROTEUS.
  
• Protoporphyria, Erythropoietic [M0026013]
  An autosomal dominant porphyria that is due to a deficiency of FERROCHELATASE (heme synthetase) in both the LIVER and the BONE MARROW, the last enzyme in the 8-enzyme biosynthetic pathway of HEME. Clinical features include mainly neurological symptoms, rarely cutaneous lesions, and elevated levels of protoporphyrin and COPROPORPHYRINS in the feces.
  
• Protozoan Infections [M0017926]
  Infections with unicellular organisms of the subkingdom PROTOZOA.
  
• Protozoan Infections, Animal [M0017927]
  Infections with unicellular organisms of the subkingdom PROTOZOA. The infections may be experimental or veterinary.
  
• Proximal Renal Tubular Acidosis [M0491195]
  
• Prurigo [M0017934]
  A name applied to several itchy skin eruptions of unknown cause. The characteristic course is the formation of a dome-shaped papule with a small transient vesicle on top, followed by crusting over or lichenification. (From Dorland, 27th ed)
  
• Pruritus Vulvae [M0017937]
  Intense itching of the external female genitals.
  
• Pseudarthrosis [M0017941]
  A pathologic entity characterized by deossification of a weight-bearing long bone, followed by bending and pathologic fracture, with inability to form normal BONY CALLUS leading to existence of the "false joint" that gives the condition its name. (Dorland, 27th ed)
  
• Pseudoakathisia [M0335531]
  
• Pseudoaneurysm [M0026604]
  
• Pseudobulbar Mutism [M0336491]
  
• Pseudobulbar Palsy [M0328276]
  A syndrome characterized by DYSARTHRIA, dysphagia, dysphonia, impairment of voluntary movements of tongue and facial muscles, and emotional lability. This condition is caused by diseases that affect the motor fibers that travel from the cerebral cortex to the lower BRAIN STEM (i.e., corticobulbar tracts); including MULTIPLE SCLEROSIS; MOTOR NEURON DISEASE; and CEREBROVASCULAR DISORDERS. (From Adams et al., Principles of Neurology, 6th ed, p489)
  
• Pseudogout [M0004306]
  
• Pseudohermaphroditism [M0017947]
  A condition of sexual ambiguity in which the individual (pseudohermaphrodite) possesses gonadal tissue of one SEX but exhibits external PHENOTYPE of the opposite sex. Female pseudohermaphroditism is an individual with XX karyotype, normal development of OVARIES and internal reproductive tract, but with ambiguous or virilized external GENITALIA. Male pseudohermaphroditism is characterized by the presence of a Y CHROMOSOME and TESTES, but the genital tract and external genitalia are ambiguous or completely female.
  
• Pseudohypoaldosteronism [M0017948]
  A heterogeneous group of disorders with common symptoms of apparent HYPOALDOSTERONISM despite the elevated levels of ALDOSTERONE and RENIN. Other clinical symptoms include HYPERKALEMIA with (Type I) or without (Type II) sodium wasting. Pseudohypoaldosteronism can be the result of defective MINERALOCORTICOID RECEPTORS or defects in the epithelial SODIUM CHANNEL. It can also be acquired after KIDNEY TRANSPLANTATION.
  
• Pseudohypoaldosteronism, Type I, Autosomal Dominant [M0461205]
  
• Pseudohypoaldosteronism, Type I, Autosomal Recessive [M0461206]
  
• Pseudohypoaldosteronism, Type II [M0461207]
  
• Pseudohypoparathyroidism [M0017949]
  A hereditary condition clinically resembling HYPOPARATHYROIDISM, but caused by failure of response to rather than deficiency of parathyroid hormones. It is characterized by hypocalcemia and hyperphosphatemia, and is commonly associated with short stature, obesity, short metacarpals, and ectopic calcification. (Dorland, 27th ed)
  
• Pseudolymphoma [M0028754]
  A group of disorders having a benign course but exhibiting clinical and histological features suggestive of malignant lymphoma. Pseudolymphoma is characterized by a benign infiltration of lymphoid cells or histiocytes which microscopically resembles a malignant lymphoma. (From Dorland, 28th ed & Stedman, 26th ed)
  
• Pseudomonas Infections [M0017955]
  Infections with bacteria of the genus PSEUDOMONAS.
  
• Pseudopelade [M0000758]
  
• Pseudopolyarthritis, Rhizomelic [M0017212]
  
• Pseudopseudohypoparathyroidism [M0017963]
  A genetically related form of PSEUDOHYPOPARATHYROIDISM characterized by the same features except for the abnormal response to parathyroid hormone.
  
• Pseudopyogenic Granuloma [M0001194]
  
• Pseudorabies [M0017964]
  A highly contagious herpesvirus infection affecting the central nervous system of swine, cattle, dogs, cats, rats, and other animals.
  
• Pseudotumor Cerebri [M0017966]
  A condition marked by raised intracranial pressure and characterized clinically by HEADACHES; NAUSEA; PAPILLEDEMA, peripheral constriction of the visual fields, transient visual obscurations, and pulsatile TINNITUS. OBESITY is frequently associated with this condition, which primarily affects women between 20 and 44 years of age. Chronic PAPILLEDEMA may lead to optic nerve injury (see OPTIC NERVE DISEASES) and visual loss (see BLINDNESS).
  
• Pseudoxanthoma Elasticum [M0017968]
  A rare, progressive inherited disorder resulting from extensive basophilic degeneration of elastic tissue, usually presenting after puberty and involving the skin, eye, and cardiovascular system. Characteristic manifestations are small, circumscribed yellowish patches at sites of considerable movement of the skin, ANGIOID STREAKS in the retina, and a tendency towards hemorrhage and arterial insufficiency.
  
• Psittacosis [M0015434]
  Infection with CHLAMYDOPHILA PSITTACI (formerly Chlamydia psittaci), transmitted to humans by inhalation of dust-borne contaminated nasal secretions or excreta of infected BIRDS. This infection results in a febrile illness characterized by PNEUMONITIS and systemic manifestations.
  
• Psoas Abscess [M0025386]
  Abscess of the PSOAS MUSCLES resulting usually from disease of the lumbar vertebrae, with the pus descending into the muscle sheath. The infection is most commonly tuberculous or staphylococcal.
  
• Psoriasis [M0017975]
  A common genetically determined, chronic, inflammatory skin disease characterized by rounded erythematous, dry, scaling patches. The lesions have a predilection for nails, scalp, genitalia, extensor surfaces, and the lumbosacral region. Accelerated epidermopoiesis is considered to be the fundamental pathologic feature in psoriasis.
  
• Psychobacter Infections [M0449416]
  
• Psychophysiological Insomnia [M0334969]
  
• Ptosis Sympathetic [M0333520]
  
• Puberty, Delayed [M0018082]
  The lack of development of SEXUAL MATURATION in boys and girls at a chronological age that is 2.5 standard deviations above the mean age at onset of PUBERTY in a population. Delayed puberty can be classified by defects in the hypothalamic LHRH pulse generator, the PITUITARY GLAND, or the GONADS. These patients will undergo spontaneous but delayed puberty whereas patients with SEXUAL INFANTILISM will not.
  
• Puberty, Precocious [M0018083]
  Development of SEXUAL MATURATION in boys and girls at a chronological age that is 2.5 standard deviations below the mean age at onset of PUBERTY in the population. This early maturation of the hypothalamic-pituitary-gonadal axis results in sexual precocity, elevated serum levels of GONADOTROPINS and GONADAL STEROID HORMONES such as ESTRADIOL and TESTOSTERONE.
  
• Puerperal Disorders [M0018113]
  Disorders or diseases associated with PUERPERIUM, the six-to-eight-week period immediately after PARTURITION in humans.
  
• Puerperal Infection [M0018114]
  An infection occurring in PUERPERIUM, the period of 6-8 weeks after giving birth.
  
• Pulmonary Adenomatosis, Ovine [M0018119]
  A contagious, neoplastic, pulmonary disease of sheep characterized by hyperplasia and hypertrophy of pneumocytes and epithelial cells of the lung. It is caused by JAAGSIEKTE SHEEP RETROVIRUS.
  
• Pulmonary Alveolar Proteinosis [M0018120]
  A chronic lung disease characterized by dyspnea, productive cough, chest pain, weakness, weight loss, and hemoptysis, and by the filling of the distal alveoli with a bland, eosinophilic, proteinaceous material that prevents ventilation of affected areas. (Dorland, 28th ed)
  
• Pulmonary Cystic Fibrosis [M0455430]
  
• Pulmonary Disease, Chronic Obstructive [M0384655]
  A disease of chronic diffuse irreversible airflow obstruction. Subcategories of COPD include CHRONIC BRONCHITIS and PULMONARY EMPHYSEMA.
  
• Pulmonary Edema [M0018125]
  
• Pulmonary Embolism [M0018126]
  Embolism in the pulmonary artery or one of its branches.
  
• Pulmonary Emphysema [M0018129]
  A subcategory of CHRONIC OBSTRUCTIVE PULMONARY DISEASE. The disease is characterized by anatomic alterations of the lungs, such as the enlargement of airspaces and destruction of alveolar walls.
  
• Pulmonary Eosinophilia [M0018131]
  A disease characterized by pulmonary infiltrations of eosinophils and blood eosinophilia.
  
• Pulmonary Fibrosis [M0018134]
  Chronic inflammation and progressive fibrosis of the pulmonary alveolar walls, with steadily progressive dyspnea, resulting finally in death from oxygen lack or right heart failure.
  
• Pulmonary Heart Disease [M0018137]
  
• Pulmonary Infarction [M0018127]
  
• Pulmonary Subvalvular Stenosis [M0018139]
  Stenosis of the conus arteriosus (infundibulum) with or without involvement of the pulmonary valve. It is usually associated with a defect in the interventricular septum.
  
• Pulmonary Thromboembolisms [M0018128]
  
• Pulmonary Valve Insufficiency [M0018142]
  Backflow of blood from the pulmonary artery into the right ventricle, owing to imperfect functioning of the pulmonary valve.
  
• Pulmonary Valve Stenosis [M0018143]
  
• Pulmonary Veno-Occlusive Disease [M0018145]
  Obstruction of the small- and medium-sized pulmonary veins by fibrous proliferation of the intima and media or by thrombosis or a combination of both.
  
• Pulmonic Plague [M0016949]
  
• Pulpitis [M0018151]
  Inflammation of the DENTAL PULP, usually due to bacterial infection in dental caries, tooth fracture, or other conditions causing exposure of the pulp to bacterial invasion. Chemical irritants, thermal factors, hyperemic changes, and other factors may also cause pulpitis.
  
• Pupil Disorders [M0333811]
  Conditions which affect the structure or function of the pupil of the eye, including disorders of innervation to the pupillary constrictor or dilator muscles, and disorders of pupillary reflexes.
  
• Pupillary Functions, Abnormal [M0018162]
  Conditions in which the pupil does not react normally to dilation and constriction. Signs of pupillary abnormalities originate from the pupil's shape, position, and response to stimulation.
  
• Pure Autonomic Failure [M0335522]
  
• Purine-Pyrimidine Metabolism, Inborn Errors [M0018168]
  
• Purpura [M0018178]
  Purplish or brownish red discoloration, easily visible through the epidermis, caused by hemorrhage into the tissues.
  
• Purpura Fulminans [M0018182]
  
• Purpura Hemorrhagica [M0018186]
  
• Purpura, Hyperglobulinemic [M0018179]
  Purpura seen in many hematological disorders, characterized by an increase in GAMMA-GLOBULINS.
  
• Purpura, Nonthrombocytopenic [M0018185]
  
• Purpura, Schoenlein-Henoch [M0018180]
  A form of nonthrombocytopenic purpura due to a hypersensitivity vasculitis associated with a variety of clinical symptoms including urticaria and erythema, arthropathy and arthritis, gastrointestinal symptoms, and renal involvement.
  
• Purpura, Thrombocytopenic [M0018187]
  Any form of purpura in which the PLATELET COUNT is decreased. Many forms are thought to be caused by immunological mechanisms.
  
• Purpura, Thrombocytopenic, Idiopathic [M0025253]
  Thrombocytopenia occurring in the absence of toxic exposure or a disease associated with decreased platelets. It is mediated by immune mechanisms, in most cases IMMUNOGLOBULIN G autoantibodies which attach to platelets and subsequently undergo destruction by macrophages. The disease is seen in acute (affecting children) and chronic (adult) forms.
  
• Purpura, Thrombotic Thrombocytopenic [M0018188]
  A disease characterized by thrombocytopenia, hemolytic anemia, bizarre neurological manifestations, azotemia, fever, and thromboses in terminal arterioles and capillaries.
  
• Pustular Dermatosis, Subcorneal [M0019933]
  
• Pustulosis of Palms and Soles [M0017974]
  
• Pyelitis [M0018193]
  Inflammation of the KIDNEY PELVIS and KIDNEY CALICES where urine is collected before discharge, but does not involve the renal parenchyma (the NEPHRONS) where urine is processed.
  
• Pyelocystitis [M0018194]
  Inflammation of the KIDNEY PELVIS and the URINARY BLADDER.
  
• Pyelonephritis [M0018195]
  Inflammation of the KIDNEY involving the renal parenchyma (the NEPHRONS); KIDNEY PELVIS; and KIDNEY CALICES. It is characterized by ABDOMINAL PAIN; FEVER; NAUSEA; VOMITING; and occasionally DIARRHEA.
  
• Pyelonephritis, Acute Necrotizing [M0490807]
  
• Pyelonephritis, Xanthogranulomatous [M0018197]
  A chronic inflammatory condition of the KIDNEY resulting in diffuse renal destruction, a grossly enlarged and nonfunctioning kidney associated with NEPHROLITHIASIS and KIDNEY STONES.
  
• Pyloric Stenosis [M0018199]
  Narrowing of the pyloric canal with varied etiology. A common form is due to muscle hypertrophy (PYLORIC STENOSIS, HYPERTROPHIC) seen in infants.
  
• Pyloric Stenosis, Hypertrophic [M0453566]
  Narrowing of the pyloric canal due to HYPERTROPHY of the surrounding circular muscle. It is usually seen in infants or young children.
  
• Pyoderma [M0018214]
  Any purulent skin disease (Dorland, 27th ed).
  
• Pyoderma Gangrenosum [M0026573]
  An idiopathic, rapidly evolving, and severely debilitating disease occurring most commonly in association with chronic ulcerative colitis. It is characterized by the presence of boggy, purplish ulcers with undermined borders, appearing mostly on the legs. The majority of cases are in people between 40 and 60 years old. Its etiology is unknown.
  
• Pyonephrosis [M0018196]
  Distention of KIDNEY with the presence of PUS and suppurative destruction of the renal parenchyma. It is often associated with renal obstruction and can lead to total or nearly total loss of renal function.
  
• Pyorrhea Alveolaris [M0016329]
  
• Pyridoxine Deficiency [M0018250]
  Deficiency of PYRIDOXINE, one of the VITAMIN B 6 compounds. Although pyridoxine and Vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading (EE Snell; Ann NY Acad Sci, vol 585 pg 1, 1990).
  
• Pyruvate Carboxylase Deficiency Disease [M0023593]
  An autosomal recessive metabolic disorder caused by absent or decreased PYRUVATE CARBOXYLASE activity, the enzyme that regulates gluconeogenesis, lipogenesis, and neurotransmitter synthesis. Clinical manifestations include lactic acidosis, seizures, respiratory distress, marked psychomotor delay, periodic HYPOGLYCEMIA, and hypotonia. The clinical course may be similar to LEIGH DISEASE. (From Am J Hum Genet 1998 Jun;62(6):1312-9)
  
• Pyruvate Dehydrogenase Complex Deficiency Disease [M0023594]
  An inherited metabolic disorder caused by deficient enzyme activity in the PYRUVATE DEHYDROGENASE COMPLEX, resulting in deficiency of acetyl CoA and reduced synthesis of acetylcholine. Two clinical forms are recognized: neonatal and juvenile. The neonatal form is a relatively common cause of lactic acidosis in the first weeks of life and may also feature an erythematous rash. The juvenile form presents with lactic acidosis, alopecia, intermittent ATAXIA; SEIZURES; and an erythematous rash. (From J Inherit Metab Dis 1996;19(4):452-62) Autosomal recessive and X-linked forms are caused by mutations in the genes for the three different enzyme components of this multisubunit pyruvate dehydrogenase complex. One of the mutations at Xp22.2-p22.1 in the gene for the E1 alpha component of the complex leads to LEIGH DISEASE.
  
• Pyruvate Dehydrogenase Complex Deficiency Disease, Neonatal [M0335907]
  
• Pyruvate Metabolism, Inborn Errors [M0023592]
  Hereditary disorders of pyruvate metabolism. They are difficult to diagnose and describe because pyruvate is a key intermediate in glycolysis, gluconeogenesis, and the tricarboxylic acid cycle. Some inherited metabolic disorders may alter pyruvate metabolism indirectly. Disorders in pyruvate metabolism appear to lead to deficiencies in neurotransmitter synthesis and, consequently, to nervous system disorders.
  
• Pyuria [M0018306]
  The presence of white blood cells (LEUKOCYTES) in the urine. It is often associated with bacterial infections of the urinary tract. Pyuria without BACTERIURIA can be caused by TUBERCULOSIS, stones, or cancer.
  
• Q Fever [M0018308]
  An acute infectious disease caused by COXIELLA BURNETII. It is characterized by a sudden onset of FEVER; HEADACHE; malaise; and weakness. In humans, it is commonly contracted by inhalation of infected dusts derived from infected domestic animals (ANIMALS, DOMESTIC).
  
• Quadriparesis [M0336497]
  
• Quadriplegia [M0018313]
  Severe or complete loss of motor function in all four limbs which may result from BRAIN DISEASES; SPINAL CORD DISEASES; PERIPHERAL NERVOUS SYSTEM DISEASES; NEUROMUSCULAR DISEASES; or rarely MUSCULAR DISEASES. The locked-in syndrome is characterized by quadriplegia in combination with cranial muscle paralysis. Consciousness is spared and the only retained voluntary motor activity may be limited eye movements. This condition is usually caused by a lesion in the upper BRAIN STEM which injures the descending cortico-spinal and cortico-bulbar tracts.
  
• Quadruple Nuchal Cord [M0494860]
  
• Rabies [M0018366]
  An acute infectious disease of the central nervous system affecting almost all mammals, including humans. It is caused by a rhabdovirus and usually spread by contamination with virus-laden saliva of bites inflicted by rabid animals. Important animal vectors include the dog, cat, vampire bat, mongoose, skunk, wolf, raccoon, and fox. (From Dorland, 27th ed)
  
• Rachitis [M0019096]
  
• Radial Nerve Lesion [M0336152]
  
• Radial Neuropathy [M0328281]
  Disease involving the RADIAL NERVE. Clinical features include weakness of elbow extension, elbow flexion, supination of the forearm, wrist and finger extension, and thumb abduction. Sensation may be impaired over regions of the dorsal forearm. Common sites of compression or traumatic injury include the AXILLA and radial groove of the HUMERUS.
  
• Radiation Pneumonitis [M0026627]
  Injurious effects of radiotherapy on the lungs. There are three phases in the reaction of the lungs to radiation injury: an acute phase occurring 1 to 2 months after exposure, a subacute phase 2 to 9 months after exposure, and a chronic or fibrotic phase more than 9 months after exposure. In the acute phase there is vascular damage, congestion, edema, and mononuclear cell infiltration; in the subacute phase the alveolar walls are infiltrated with mononuclear inflammatory cells and fibroblasts; in the chronic phase, alveolar fibrosis and capillary sclerosis take place. (Cecil Textbook of Medicine, 19th ed, p2343)
  
• Radiation Recall Dermatitis [M0495729]
  Acute skin manifestations at the site of previous exposure to ionizing radiation. It is triggered by the administration of certain drugs days or years after the initial radiation exposure.
  
• Radiation Sickness [M0018382]
  
• Radiation Syndrome [M0018381]
  
• Radicular Cyst [M0018392]
  Slow-growing fluid-filled epithelial sac at the apex of a tooth with a nonvital pulp or defective root canal filling.
  
• Radiculitis [M0018393]
  
• Radiculopathy [M0333814]
  Disease involving a spinal nerve root (see SPINAL NERVE ROOTS) which may result from compression related to INTERVERTEBRAL DISK DISPLACEMENT; SPINAL CORD INJURIES; SPINAL DISEASES; and other conditions. Clinical manifestations include radicular pain, weakness, and sensory loss referable to structures innervated by the involved nerve root.
  
• Radiculopathy, Cervical [M0336807]
  
• Radiodermatitis [M0018410]
  A cutaneous inflammatory reaction occurring as a result of exposure to ionizing radiation.
  
• Raeder Paratrigeminal Syndrome [M0336270]
  
• Raillietiniasis [M0003960]
  
• Ramsay Hunt Paralysis Syndrome [M0015966]
  
• Ranula [M0018473]
  A form of retention cyst of the floor of the mouth, usually due to obstruction of the ducts of the submaxillary or sublingual glands, presenting a slowly enlarging painless deep burrowing mucocele of one side of the mouth. It is also called sublingual cyst and sublingual ptyalocele.
  
• Rare Diseases [M0407933]
  A large group of diseases which are characterized by a low prevalence in the population. They frequently are associated with problems in diagnosis and treatment.
  
• Rasmussen Syndrome [M0334837]
  
• Rat-Bite Fever [M0018507]
  A syndrome characterized by recurring fever, rash, and arthralgias occurring days to weeks after a rat bite. The causative agents are either Streptobacillus moniliformis or Spirillum minus.
  
• Raynaud Disease [M0018534]
  An idiopathic vascular disorder characterized by bilateral Raynaud phenomenon, the abrupt onset of digital paleness or CYANOSIS in response to cold exposure or STRESS.
  
• Raynaud Phenomenon [M0449202]
  
• Reactive Hemophagocytic Syndrome [M0480275]
  Proliferation of HISTIOCYTES in response to viral, bacterial, fungal, or parasitic infections.
  
• Rebound Nystagmus [M0333593]
  
• Rectal Diseases [M0018654]
  Pathological developments in the RECTUM region of the large intestine (INTESTINE, LARGE).
  
• Rectal Prolapse [M0018658]
  Protrusion of the rectal mucous membrane through the anus. There are various degrees: incomplete with no displacement of the anal sphincter muscle; complete with displacement of the anal sphincter muscle; complete with no displacement of the anal sphincter muscle but with herniation of the bowel; and internal complete with rectosigmoid or upper rectum intussusception into the lower rectum.
  
• Rectocele [M0029757]
  A hernial protrusion of part of the rectum into the vagina. (Dorland, 28th ed)
  
• Rectocolitis, Hemorrhagic [M0443845]
  
• Rectocolitis, Ulcerative [M0443846]
  
• Recurrent Vestibular Neuritis [M0337543]
  
• Red-Cell Aplasia, Pure [M0018667]
  Suppression of erythropoiesis with little or no abnormality of leukocyte or platelet production.
  
• Reflex Epilepsy, Audiogenic [M0335114]
  
• Reflex Epilepsy, Cursive (Running) [M0335115]
  
• Reflex Epilepsy, Eating-Induced [M0335116]
  
• Reflex Epilepsy, Musicogenic [M0335117]
  
• Reflex Epilepsy, Photosensitive [M0335118]
  
• Reflex Epilepsy, Reading [M0335119]
  
• Reflex Epilepsy, Visual Pattern [M0335122]
  
• Reflex Sympathetic Dystrophy [M0018685]
  A syndrome characterized by severe burning pain in an extremity accompanied by sudomotor, vasomotor, and trophic changes in bone without an associated specific nerve injury. This condition is most often precipitated by trauma to soft tissue or nerve complexes. The skin over the affected region is usually erythematous and demonstrates hypersensitivity to tactile stimuli and erythema. (Adams et al., Principles of Neurology, 6th ed, p1360; Pain 1995 Oct;63(1):127-33)
  
• Refractive Errors [M0018702]
  Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
  
• Refsum Disease [M0018709]
  An autosomal recessive familial disorder that usually presents in childhood with POLYNEUROPATHY; SENSORINEURAL HEARING LOSS; ICHTHYOSIS; ATAXIA; RETINITIS PIGMENTOSA; and CARDIOMYOPATHIES. (From Joynt, Clinical Neurology, 1991, Ch37, p58-9; Rev Med Interne 1996;17(5):391-8) This condition can be caused by mutation in the genes encoding peroxisomal phytanoyl-CoA hydroxylase or proteins associated peroxisomal membrane, leading to impaired catabolism of PHYTANIC ACID in PEROXISOMES.
  
• Refsum Disease, Infantile [M0028263]
  An early onset form of phytanic acid storage disease with clinical and biochemical signs different from those of REFSUM DISEASE. Features include MENTAL RETARDATION; SENSORINEURAL HEARING LOSS; OSTEOPOROSIS; and severe liver damage. It can be caused by mutation in a number of genes encoding proteins involving in the biogenesis or assembly of PEROXISOMES.
  
• Refsum Disease, Phytanoyl-CoA Hydroxylase Deficiency [M0490303]
  
• Reifenstein Syndrome [M0369551]
  A disorder also known as partial androgen insensitivity syndrome (PAIS). These patients exhibit partial resistance to androgenic and metabolic effects of TESTOSTERONE.
  
• Reiter Syndrome [M0018743]
  A complex multisystem syndrome due to immune response to a urogenital or enteric infection. It is characterized by a triad of inflammation involving the eye (CONJUNCTIVITIS), the bone (POST-INFECTIOUS ARTHRITIS), and the urethra (URETHRITIS). Mucocutaneous lesions often are present. Most patients possess the HLA-B27 ANTIGEN.
  
• Relapsing Fever [M0018746]
  An acute infection characterized by recurrent episodes of PYREXIA alternating with asymptomatic intervals of apparent recovery. This condition is caused by SPIROCHETES of the genus BORRELIA. It is transmitted by the BITES of either the body louse (PEDICULUS humanus corporis), for which humans are the reservoir, or by soft ticks of the genus ORNITHODOROS, for which rodents and other animals are the principal reservoirs.
  
• REM Sleep Behavior Disorder [M0328285]
  A disorder characterized by episodes of vigorous and often violent motor activity during REM sleep (SLEEP, REM). The affected individual may inflict self injury or harm others, and is difficult to awaken from this condition. Episodes are usually followed by a vivid recollection of a dream that is consistent with the aggressive behavior. This condition primarily affects adult males. (From Adams et al., Principles of Neurology, 6th ed, p393)
  
• REM Sleep Deprivation [M0334754]
  
• REM Sleep Parasomnias [M0328286]
  Abnormal behavioral or physiologic events that are associated with REM sleep, including REM SLEEP BEHAVIOR DISORDER.
  
• REM Sleep-Related Sinus Arrest [M0335127]
  
• Renal Aminoacidurias [M0000934]
  A group of inherited kidney disorders characterized by the abnormally elevated levels of AMINO ACIDS in URINE. Genetic mutations of transport proteins result in the defective reabsorption of free amino acids at the PROXIMAL RENAL TUBULES. Renal aminoaciduria are classified by the specific amino acid or acids involved.
  
• Renal Artery Obstruction [M0018770]
  Narrowing or occlusion of the RENAL ARTERY or arteries. It is due usually to ATHEROSCLEROSIS; FIBROMUSCULAR DYSPLASIA; THROMBOSIS; EMBOLISM, or external pressure. The reduced renal perfusion can lead to renovascular hypertension (HYPERTENSION, RENOVASCULAR).
  
• Renal Artery Stenosis [M0018771]
  
• Renal Insufficiency [M0480487]
  Conditions in which the KIDNEYS perform below the normal level in the ability to remove wastes, concentrate URINE, and maintain ELECTROLYTE BALANCE; BLOOD PRESSURE; and CALCIUM metabolism. Renal insufficiency can be classified by the degree of kidney damage (as measured by the level of PROTEINURIA) and reduction in GLOMERULAR FILTRATION RATE. The most severe form is KIDNEY FAILURE. Renal function may deteriorate slowly (RENAL INSUFFICIENCY, CHRONIC) or precipitously (RENAL INSUFFICIENCY, ACUTE).
  
• Renal Insufficiency, Acute [M0480709]
  Conditions in which the function of KIDNEYS deteriorates suddenly in a matter of days or even hours. It is characterized by the sudden drop in GLOMERULAR FILTRATION RATE; (GMR). The most severe stage is when the GFR drops below 15 ml per min (ACUTE KIDNEY FAILURE).
  
• Renal Insufficiency, Chronic [M0480472]
  Conditions in which the KIDNEYS perform below the normal level for more than three months. Chronic kidney insufficiency is classified by five stages according to the decline in GLOMERULAR FILTRATION RATE and the degree of kidney damage (as measured by the level of PROTEINURIA). The most severe form is the end-stage renal disease (CHRONIC KIDNEY FAILURE). (Kidney Foundation: Kidney Disease Outcome Quality Initiative, 2002)
  
• Renal Osteodystrophy [M0018773]
  Decalcification of bone or abnormal bone development due to chronic KIDNEY DISEASES, in which 1,25-DIHYDROXYVITAMIN D3 synthesis by the kidneys is impaired, leading to reduced negative feedback on PARATHYROID HORMONE. The resulting SECONDARY HYPERPARATHYROIDISM eventually leads to bone disorders.
  
• Renal Rickets [M0018774]
  
• Renal Tubular Acidosis, Type I [M0000216]
  The genetic defect is in the anion exchange protein gene SLC4A1 resulting in impaired excretion of hydrogen ions or renal acids in the distal renal tubules.
  
• Renal Tubular Acidosis, Type II [M0000217]
  The genetic defect is in the sodium bicarbonate cotransporter gene SLC4A4 resulting in impaired reabsorption of bicarbonate ions in the proximal renal tubules and bicarbonate-wasting.
  
• Renal Tubular Transport, Inborn Errors [M0023861]
  Genetic defects in the selective or non-selective transport functions of the KIDNEY TUBULES.
  
• Renal Tubule Necrosis [M0490227]
  
• Reoviridae Infections [M0018792]
  Infections produced by reoviruses, general or unspecified.
  
• Respiration Disorders [M0018879]
  Diseases of the respiratory system in general or unspecified or for a specific respiratory disease not available.
  
• Respiratory Aspiration of Gastric Contents [M0017065]
  
• Respiratory Chain Deficiencies, Mitochondrial [M0382030]
  
• Respiratory Distress Syndrome, Adult [M0018891]
  A syndrome of life-threatening progressive pulmonary insufficiency in the absence of known pulmonary disease, usually following a systemic insult such as SURGERY or major TRAUMA.
  
• Respiratory Distress Syndrome, Newborn [M0018890]
  A condition of the newborn marked by DYSPNEA with CYANOSIS, heralded by such prodromal signs as dilatation of the alae nasi, expiratory grunt, and retraction of the suprasternal notch or costal margins, mostly frequently occurring in premature infants, children of diabetic mothers, and infants delivered by cesarean section, and sometimes with no apparent predisposing cause.
  
• Respiratory Syncytial Virus Infections [M0027589]
  Pneumovirus infections caused by the RESPIRATORY SYNCYTIAL VIRUSES. Humans and cattle are most affected but infections in goats and sheep have been reported.
  
• Respiratory System Abnormalities [M0023964]
  Congenital structural abnormalities of the respiratory system.
  
• Respiratory Tract Diseases [M0018918]
  
• Respiratory Tract Infections [M0018919]
  
• Respirovirus Infections [M0015891]
  Infections with viruses of the genus RESPIROVIRUS, family PARAMYXOVIRIDAE. Host cell infection occurs by adsorption, via HEMAGGLUTININ, to the cell surface.
  
• Restless Legs Syndrome [M0018926]
  A disorder characterized by aching or burning sensations in the lower and rarely the upper extremities that occur prior to sleep or may awaken the patient from sleep. Complying with an irresistible urge to move the affected limbs brings temporary relief. Sleep may become disrupted, resulting in excessive daytime hypersomnolence. This condition may be associated with UREMIA; DIABETES MELLITUS; and rheumatoid arthritis. Restless Legs Syndrome differs from NOCTURNAL MYOCLONUS SYNDROME in that in the latter condition the individual does not report adverse sensory stimuli and it is primarily a sleep-associated movement disorder. (Adams et al., Principles of Neurology, 6th ed, p387; Schweiz Rundsch Med Prax 1997 Apr 30;86(18):732-736)
  
• Retinal Artery Occlusion [M0023643]
  Occlusion or closure of the central retinal artery causing sudden, usually nearly complete, loss of vision in one eye. Occlusion of the branch retinal artery causes sudden visual loss in only a portion of the visual field.
  
• Retinal Degeneration [M0018942]
  A retrogressive pathological change in the retina, focal or generalized, caused by genetic defects, inflammation, trauma, vascular disease, or aging. Degeneration affecting predominantly the macula lutea of the retina is MACULAR DEGENERATION. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p304)
  
• Retinal Detachment [M0018943]
  Separation of the inner layers of the retina (neural retina) from the pigment epithelium. Retinal detachment occurs more commonly in men than in women, in eyes with degenerative myopia, in aging and in aphakia. It may occur after an uncomplicated cataract extraction, but it is seen more often if vitreous humor has been lost during surgery. (Dorland, 27th ed; Newell, Ophthalmology: Principles and Concepts, 7th ed, p310-12).
  
• Retinal Diseases [M0018945]
  
• Retinal Drusen [M0023937]
  Colloid or hyaline bodies lying beneath the retinal pigment epithelium. They may occur either secondary to changes in the choroid that affect the pigment epithelium or as an autosomal dominant disorder of the retinal pigment epithelium.
  
• Retinal Dysplasia [M0024192]
  Congenital, often bilateral, retinal abnormality characterized by the arrangement of outer nuclear retinal cells in a palisading or radiating pattern surrounding a central ocular space. This disorder is sometimes hereditary.
  
• Retinal Edema [M0015835]
  
• Retinal Necrosis Syndrome, Acute [M0024320]
  Mild to fulminant necrotizing vaso-occlusive retinitis associated with a high incidence of retinal detachment and poor vision outcome.
  
• Retinal Perforations [M0018949]
  Perforations through the whole thickness of the retina including the macula as the result of inflammation, trauma, degeneration, etc. The concept includes retinal breaks, tears, dialyses, and holes.
  
• Retinal Pigment Epithelial Detachment [M0018944]
  
• Retinal Vasculitis [M0397081]
  Inflammation of the retinal vasculature with various causes including infectious disease; LUPUS ERYTHEMATOSUS, SYSTEMIC; MULTIPLE SCLEROSIS; BEHCET SYNDROME; and CHORIORETINITIS.
  
• Retinal Vein Occlusion [M0018952]
  Occlusion of the retinal vein. Those at high risk for this condition include patients with hypertension, diabetes mellitus, arteriosclerosis, and other cardiovascular diseases.
  
• Retinal Vein Thrombosis [M0018953]
  
• Retinitis [M0018959]
  Inflammation of the RETINA. It is rarely limited to the retina, but is commonly associated with diseases of the choroid (CHORIORETINITIS) and of the OPTIC DISK (neuroretinitis).
  
• Retinitis Pigmentosa [M0018960]
  Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.
  
• Retinopathy of Prematurity [M0018966]
  A bilateral retinopathy occurring in premature infants treated with excessively high concentrations of oxygen, characterized by vascular dilatation, proliferation, and tortuosity, edema, and retinal detachment, with ultimate conversion of the retina into a fibrous mass that can be seen as a dense retrolental membrane. Usually growth of the eye is arrested and may result in microophthalmia, and blindness may occur. (Dorland, 27th ed)
  
• Retinoschisis [M0430673]
  A vitreoretinal dystrophy characterized by splitting of the neuroretinal layers. It occurs in two forms: degenerative retinoschisis and X chromosome-linked juvenile retinoschisis.
  
• Retinoschisis, Degenerative [M0430674]
  Splitting of the RETINA into two layers at the level of the outer plexiform layer, beginning as a cystic degeneration in the extreme retinal periphery. It usually occurs after 40 years of age and is generally not progressive.
  
• Retinoschisis, Juvenile, X-Linked [M0430675]
  X chromosome recessive disorder, found nearly exclusively in males and becoming apparent around puberty. Characterized initially by a cystlike structure involving the FOVEA CENTRALIS, a peripheral retinoschisis occurs in about half the patients.
  
• Retractile Mesenteritis [M0455666]
  This entity represents the fibrotic stage of MESENTERY inflammation.
  
• Retraction Nystagmus [M0333594]
  
• Retrobulbar Neuritis [M0015360]
  
• Retrocochlear Diseases [M0018969]
  Diseases of the VESTIBULOCOCHLEAR NERVE. Retrocochlear refers to the eighth cranial nerve and cerebellopontine angle as opposed to the cochlea. (Dorland, 28th ed)
  
• Retropharyngeal Abscess [M0026767]
  A soft tissue infection of the throat with entry usually by the pharynx but sometimes as an extension of a lateral neck infection resulting from a neck injury. The major risk is upper airway obstruction caused by pharyngeal swelling. (Daniel R. Masys, from a written communication)
  
• Retroviridae Infections [M0018986]
  Virus diseases caused by the RETROVIRIDAE.
  
• Rett Syndrome [M0023877]
  An inherited neurological developmental disorder that is associated with X-LINKED INHERITANCE and may be lethal in utero to hemizygous males. The affected female is normal until the age of 6-25 months when progressive loss of voluntary control of hand movements and communication skills; ATAXIA; SEIZURES; autistic behavior; intermittent HYPERVENTILATION; and HYPERAMMONEMIA appear. (From Menkes, Textbook of Child Neurology, 5th ed, p199)
  
• Reye Syndrome [M0018992]
  A form of encephalopathy with fatty infiltration of the LIVER, characterized by brain EDEMA and VOMITING that may rapidly progress to SEIZURES; COMA; and DEATH. It is caused by a generalized loss of mitochondrial function leading to disturbances in fatty acid and CARNITINE metabolism.
  
• Reye Syndrome, Adult [M0335908]
  
• Reye-Like Syndrome [M0335909]
  
• Rh Isoimmunization [M0018993]
  The process by which fetal Rh+ erythrocytes enter the circulation of an Rh- mother during delivery, causing her to produce IMMUNOGLOBULIN G antibodies, which can cross the placenta and destroy the erythrocytes of Rh- fetuses in subsequent pregnancies.
  
• Rhabditida Infections [M0026101]
  Infections with nematodes of the order RHABDITIDA.
  
• Rhabdoviridae Infections [M0027586]
  Virus diseases caused by RHABDOVIRIDAE. Important infections include RABIES; EPHEMERAL FEVER; and vesicular stomatitis.
  
• Rheumatic Diseases [M0019014]
  Disorders of connective tissue, especially the joints and related structures, characterized by inflammation, degeneration, or metabolic derangement.
  
• Rheumatic Fever [M0019009]
  A febrile disease occurring as a delayed sequela of infections with group A hemolytic streptococci and characterized by multiple focal inflammatory lesions of the connective tissue structures, especially of the heart, blood vessels, and joints (polyarthritis), and by the presence of Aschoff bodies in the myocardium and skin. (Dorland, 27th ed)
  
• Rheumatic Heart Disease [M0019010]
  The most important manifestation of and sequel to rheumatic fever, i.e., any cardiac involvement in rheumatic fever. (Dorland, 27th ed)
  
• Rheumatoid Purpura [M0018183]
  
• Rhinencephalic Epilepsy [M0334954]
  
• Rhinitis [M0019019]
  Inflammation of the mucous membrane of the nose.
  
• Rhinitis, Allergic, Perennial [M0019020]
  Inflammation of the mucous membrane of the nose similar to that found in hay fever except that symptoms persist throughout the year. The causes are usually air-borne allergens, particularly dusts, feathers, molds, animal fur, etc.
  
• Rhinitis, Allergic, Seasonal [M0009814]
  Allergic rhinitis that occurs at the same time every year. It is characterized by acute CONJUNCTIVITIS with lacrimation and ITCHING, and regarded as an allergic condition triggered by specific ALLERGENS.
  
• Rhinitis, Atrophic [M0019022]
  A chronic form of rhinitis marked by wasting of the mucous membrane and the glands. It is usually associated with crusting and foul-smelling discharges.
  
• Rhinitis, Vasomotor [M0019023]
  A form of rhinitis brought about by changes in vascular tone and permeability. The etiology is obscure.
  
• Rhinophyma [M0019024]
  A manifestation of severe ROSACEA resulting in significant enlargement of the NOSE and occurring primarily in men. It is caused by hypertrophy of the SEBACEOUS GLANDS and surrounding CONNECTIVE TISSUE. The nose is reddened and marked with TELANGIECTASIS.
  
• Rhinoscleroma [M0019026]
  A granulomatous disease affecting the nose and nasopharynx, usually ascribed to KLEBSIELLA RHINOSCLEROMATIS. It occurs in Egypt, eastern Europe, and Central and South America.
  
• Rhinosporidiosis [M0019027]
  Chronic, localized granulomatous infection of mucocutaneous tissues, especially the NOSE, and characterized by HYPERPLASIA and the development of POLYPS. It is found in humans and other animals and is caused by the mesomycetozoean organism RHINOSPORIDIUM SEEBERI.
  
• Riboflavin Deficiency [M0019065]
  A dietary deficiency of riboflavin causing a syndrome chiefly marked by cheilitis, angular stomatitis, glossitis associated with a purplish red or magenta-colored tongue that may show fissures, corneal vascularization, dyssebacia, and anemia. (Dorland, 27th ed)
  
• Rickets [M0019095]
  A condition caused by deficiency of VITAMIN D, especially in infancy and childhood, with disturbance of normal ossification. The disease is marked by bending and distortion of the bones under muscular action, by the formation of nodular enlargements on the ends and sides of the bones, by delayed closure of the fontanels, pain in the muscles, and sweating of the head. Vitamin D and sunlight together with an adequate diet are curative, provided that the parathyroid glands are functioning properly. (Dorland, 27th ed)
  
• Rickets, Hypophosphatemic [M0491403]
  
• Rickettsia Infections [M0019098]
  Infections by the genus RICKETTSIA.
  
• Rickettsiaceae Infections [M0019106]
  Infections with bacteria of the family RICKETTSIACEAE.
  
• Rickettsialpox [M0019107]
  
• Rift Valley Fever [M0019114]
  An acute infection caused by the RIFT VALLEY FEVER VIRUS, an RNA arthropod-borne virus, affecting domestic animals and humans. In animals, symptoms include HEPATITIS; abortion (ABORTION, VETERINARY); and DEATH. In humans, symptoms range from those of a flu-like disease to hemorrhagic fever, ENCEPHALITIS, or BLINDNESS.
  
• Right Middle Cerebral Artery Infarction [M0335403]
  
• Rinderpest [M0019121]
  A viral disease of cloven-hoofed animals caused by MORBILLIVIRUS. It may be acute, subacute, or chronic with the major lesions characterized by inflammation and ulceration of the entire digestive tract.
  
• Ring Constrictions, Intrauterine [M0000998]
  
• RNA Virus Infections [M0019160]
  
• Rocky Mountain Spotted Fever [M0019235]
  An acute febrile illness caused by RICKETTSIA RICKETTSII. It is transmitted to humans by bites of infected ticks and occurs only in North and South America. Characteristics include a sudden onset with headache and chills and fever lasting about two to three weeks. A cutaneous rash commonly appears on the extremities and trunk about the fourth day of illness.
  
• Rodent Diseases [M0019238]
  Diseases of rodents of the order RODENTIA. This term includes diseases of Sciuridae (squirrels), Geomyidae (gophers), Heteromyidae (pouched mice), Castoridae (beavers), Cricetidae (rats and mice), Muridae (Old World rats and mice), Erethizontidae (porcupines), and Caviidae (guinea pigs).
  
• Romano-Ward Syndrome [M0012685]
  An autosomal dominant LONG QT SYNDROME, without deafness.
  
• Root Caries [M0026122]
  Dental caries involving the tooth root, cementum, or cervical area of the tooth.
  
• Root Resorption [M0019265]
  Resorption in which cementum or dentin is lost from the root of a tooth owing to cementoclastic or osteoclastic activity in conditions such as trauma of occlusion or neoplasms. (Dorland, 27th ed)
  
• Rosacea [M0019267]
  A cutaneous disorder primarily of convexities of the central part of the FACE, such as FOREHEAD; CHEEK; NOSE; and CHIN. It is characterized by FLUSHING; ERYTHEMA; EDEMA; RHINOPHYMA; papules; and ocular symptoms. It may occur at any age but typically after age 30. There are various subtypes of rosacea: erythematotelangiectatic, papulopustular, phymatous, and ocular (National Rosacea Society's Expert Committee on the Classification and Staging of Rosacea, J Am Acad Dermatol 2002; 46:584-7).
  
• Roseolovirus Infections [M0028802]
  Infection with ROSEOLOVIRUS, the most common in humans being EXANTHEMA SUBITUM, a benign disease of infants and young children.
  
• Rotary Nystagmus [M0333560]
  
• Rotational Nystagmus [M0333595]
  
• Rotavirus Infections [M0019278]
  Infection with any of the rotaviruses. Specific infections include human infantile diarrhea, neonatal calf diarrhea, and epidemic diarrhea of infant mice.
  
• Rothmund-Thomson Syndrome [M0017095]
  An autosomal recessive syndrome occurring principally in females, characterized by the presence of reticulated, atrophic, hyperpigmented, telangiectatic cutaneous plaques, often accompanied by juvenile cataracts, saddle nose, congenital bone defects, disturbances in the growth of HAIR; NAILS; and TEETH; and HYPOGONADISM.
  
• Rotor Syndrome [M0010813]
  
• Roussy-Levy Syndrome [M0003995]
  
• Royer Syndrome [M0335754]
  An association of DIABETES MELLITUS with Prader-Willi Syndrome.
  
• Rubella [M0019292]
  An acute, usually benign, infectious disease caused by the RUBELLA VIRUS and most often affecting children and nonimmune young adults, in which the virus enters the respiratory tract via droplet nuclei and spreads to the lymphatic system. (From Dorland, 27th edition)
  
• Rubella Syndrome, Congenital [M0019293]
  Transplacental infection of the fetus with rubella usually in the first trimester of pregnancy, as a consequence of maternal infection, resulting in various developmental abnormalities in the newborn infant. They include cardiac and ocular lesions, deafness, microcephaly, mental retardation, and generalized growth retardation. (From Dorland, 27th ed)
  
• Rubivirus Infections [M0027588]
  Virus diseases caused by the RUBIVIRUS genus, of the family TOGAVIRIDAE.
  
• Rubulavirus Infections [M0028804]
  Infections with viruses of the genus RUBULAVIRUS, family PARAMYXOVIRIDAE.
  
• Ruptured Appendicitis [M0443869]
  
• Saccharopine Dehydrogenase Deficiency Disease [M0335293]
  
• Saethre-Chotzen Syndrome [M0000254]
  
• Sagittal Sinus Thrombophlebitis [M0335911]
  
• Sagittal Sinus Thrombosis [M0328287]
  Infectious or noninfectious venous thrombosis of the sagittal sinus. Spontaneous and secondary forms occur. Associated conditions include DEHYDRATION; SEPSIS; THROMBOPHILIA; CRANIOCEREBRAL TRAUMA; and NEUROSURGICAL PROCEDURES. Affected individuals may present with or develop HEADACHE; neck pain; PAPILLEDEMA; SEIZURES; INTRACRANIAL HYPERTENSION; venous CEREBRAL INFARCTION; INTRACRANIAL HEMORRHAGES; hemiparesis; and other focal neurologic deficits. (From Adams et al., Principles of Neurology, 6th ed, p612)
  
• Salaam Attacks [M0020206]
  
• Saldino-Noonan Syndrome [M0019796]
  
• Salivary Gland Diseases [M0019375]
  
• Salla Disease [M0384696]
  
• Salmonella Food Poisoning [M0019391]
  Poisoning caused by ingestion of food harboring species of SALMONELLA. Conditions of raising, shipping, slaughtering, and marketing of domestic animals contribute to the spread of this bacterium in the food supply.
  
• Salmonella Infections [M0019393]
  Infections with bacteria of the genus SALMONELLA.
  
• Salmonella Infections, Animal [M0019394]
  Infections in animals with bacteria of the genus SALMONELLA.
  
• Salpingitis [M0019403]
  Inflammation of the uterine salpinx, the trumpet-shaped FALLOPIAN TUBES, usually caused by ascending infections of organisms from the lower reproductive tract. Salpingitis can lead to tubal scarring, hydrosalpinx, tubal occlusion, INFERTILITY, and ectopic pregnancy (PREGNANCY, ECTOPIC)
  
• Sandhoff Disease [M0019413]
  An autosomal recessive neurodegenerative disorder characterized by an accumulation of G(M2) GANGLIOSIDE in neurons and other tissues. It is caused by mutation in the common beta subunit of HEXOSAMINIDASE A and HEXOSAMINIDASE B. Thus this disease is also known as the O variant since both hexosaminidase A and B are missing. Clinically, it is indistinguishable from TAY-SACHS DISEASE.
  
• Sarcocystosis [M0019448]
  Infection of the striated muscle of mammals by parasites of the genus SARCOCYSTIS. Disease symptoms such as vomiting, diarrhea, muscle weakness, and paralysis are produced by sarcocystin, a toxin produced by the organism.
  
• Sarcodina Infections [M0025567]
  Infections with protozoa of the subphylum SARCODINA.
  
• Sarcoidosis [M0019426]
  An idiopathic systemic inflammatory granulomatous disorder comprised of epithelioid and multinucleated giant cells with little necrosis. It usually invades the lungs with fibrosis and may also involve lymph nodes, skin, liver, spleen, eyes, phalangeal bones, and parotid glands.
  
• Sarcoidosis, Pulmonary [M0026628]
  Sarcoidosis affecting predominantly the lungs, the site most frequently involved and most commonly causing morbidity and mortality in sarcoidosis. Pulmonary sarcoidosis is characterized by sharply circumscribed granulomas in the alveolar, bronchial, and vascular walls, composed of tightly packed cells derived from the mononuclear phagocyte system. The clinical symptoms when present are dyspnea upon exertion, nonproductive cough, and wheezing. (Cecil Textbook of Medicine, 19th ed, p431)
  
• Sarcomastigophora Infections [M0025561]
  Infections with protozoa of the phylum SARCOMASTIGOPHORA.
  
• Saturday Night Palsy [M0336150]
  
• Scabies [M0019458]
  A contagious cutaneous inflammation caused by the bite of the mite SARCOPTES SCABIEI. It is characterized by pruritic papular eruptions and burrows and affects primarily the axillae, elbows, wrists, and genitalia, although it can spread to cover the entire body.
  
• Scalenus Anticus Syndrome [M0021401]
  
• Scalp Dermatoses [M0019465]
  
• Scapuloperoneal Form of Spinal Muscular Atrophy [M0335732]
  
• Scarlet Fever [M0019470]
  Infection with group A streptococci that is characterized by tonsillitis and pharyngitis. An erythematous rash is commonly present.
  
• Schamberg Disease [M0016853]
  
• Scheie Syndrome [M0012559]
  
• Scheuermann's Disease [M0019473]
  Osteochondrosis of the vertebral epiphyses in children.
  
• Schistosomal Myelitis [M0335773]
  
• Schistosomal Myelopathy [M0335771]
  
• Schistosomal Myeloradiculopathy [M0335774]
  
• Schistosomiasis [M0019481]
  Infection with flukes (trematodes) of the genus SCHISTOSOMA. Three species produce the most frequent clinical diseases: SCHISTOSOMA HAEMATOBIUM (endemic in Africa and the Middle East), SCHISTOSOMA MANSONI (in Egypt, northern and southern Africa, some West Indies islands, northern 2/3 of South America), and SCHISTOSOMA JAPONICUM (in Japan, China, the Philippines, Celebes, Thailand, Laos). S. mansoni is often seen in Puerto Ricans living in the United States. (Merck Manual, 15th ed)
  
• Schistosomiasis haematobia [M0019482]
  A human disease caused by the infection of parasitic worms SCHISTOSOMA HAEMATOBIUM. It is endemic in AFRICA and parts of the MIDDLE EAST. Tissue damages most often occur in the URINARY TRACT, specifically the URINARY BLADDER.
  
• Schistosomiasis japonica [M0019483]
  Schistosomiasis caused by Schistosoma japonicum. It is endemic in the Far East and affects the bowel, liver, and spleen,
  
• Schistosomiasis mansoni [M0019484]
  Schistosomiasis caused by Schistosoma mansoni. It is endemic in Africa, the Middle East, South America, and the Caribbean and affects mainly the bowel, spleen, and liver.
  
• Schistosomiasis, Intestinal [M0019485]
  
• Schistosomiasis, Urinary [M0491735]
  
• Schnitzler Syndrome [M0029510]
  An extremely rare condition manifested as monoclonal IMMUNOGLOBULIN M dysproteinemia without features of lymphoproliferative disease, but with chronic urticaria, fever of unknown origin, disabling bone pain, hyperostosis, and increased erythrocyte sedimentation rate.
  
• Schwartz-Jampel Syndrome [M0015526]
  
• Sciatic Nerve Palsy [M0336180]
  
• Sciatic Neuritis [M0336181]
  
• Sciatic Neuropathy [M0328289]
  Disease or damage involving the SCIATIC NERVE, which divides into the PERONEAL NERVE and TIBIAL NERVE (see also PERONEAL NEUROPATHIES and TIBIAL NEUROPATHY). Clinical manifestations may include SCIATICA or pain localized to the hip, PARESIS or PARALYSIS of posterior thigh muscles and muscles innervated by the peroneal and tibial nerves, and sensory loss involving the lateral and posterior thigh, posterior and lateral leg, and sole of the foot. The sciatic nerve may be affected by trauma; ISCHEMIA; COLLAGEN DISEASES; and other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1363)
  
• Scleral Diseases [M0023770]
  General disorders of the sclera or white of the eye. They may include anatomic, embryologic, degenerative, or pigmentation defects.
  
• Scleredema Adultorum [M0019539]
  A diffuse, non-pitting induration of the skin of unknown etiology that occurs most commonly in association with diabetes mellitus, predominantly in females. It typically begins on the face or head and spreads to other areas of the body, sometimes involving noncutaneous tissues. Often it is preceded by any of various infections, notably staphylococcal infections. The condition resolves spontaneously, usually within two years of onset. (From Dorland, 27th ed)
  
• Scleritis [M0023773]
  Refers to any inflammation of the sclera including episcleritis, a benign condition affecting only the episclera, which is generally short-lived and easily treated. Classic scleritis, on the other hand, affects deeper tissue and is characterized by higher rates of visual acuity loss and even mortality, particularly in necrotizing form. Its characteristic symptom is severe and general head pain. Scleritis has also been associated with systemic collagen disease. Etiology is unknown but is thought to involve a local immune response. Treatment is difficult and includes administration of anti-inflammatory and immunosuppressive agents such as corticosteroids. Inflammation of the sclera may also be secondary to inflammation of adjacent tissues, such as the conjunctiva.
  
• Sclerocystic Ovaries [M0422470]
  
• Scleroderma, Diffuse [M0449197]
  A rapid onset form of SYSTEMIC SCLERODERMA with progressive widespread SKIN thickening over the arms, the legs and the trunk, resulting in stiffness and disability.
  
• Scleroderma, Limited [M0449201]
  The least progressive form of SYSTEMIC SCLERODERMA with skin thickening restricted to the FACE; NECK; and areas distal to the elbows and/or knees, sparing the trunk. The CREST SYNDROME is a form of limited scleroderma.
  
• Scleroderma, Localized [M0019542]
  A term used to describe a variety of localized asymmetrical SKIN thickening that is similar to those of SYSTEMIC SCLERODERMA but without the disease features in the multiple internal organs and BLOOD VESSELS. Lesions may be characterized as patches or plaques (morphea), bands (linear), or nodules.
  
• Scleroderma, Systemic [M0019543]
  A chronic multi-system disorder of CONNECTIVE TISSUE. It is characterized by SCLEROSIS in the SKIN, the LUNGS, the HEART, the GASTROINTESTINAL TRACT, the KIDNEYS, and the MUSCULOSKELETAL SYSTEM. Other important features include diseased small BLOOD VESSELS and AUTOANTIBODIES. The disorder is named for its most prominent feature (hard skin), and classified into subsets by the extent of skin thickening: LIMITED SCLERODERMA and DIFFUSE SCLERODERMA.
  
• Scleromyxedema [M0495807]
  A connective tissue disorder characterized by widespread thickening of SKIN with a cobblestone-like appearance. It is caused by proliferation of FIBROBLASTS and deposition of MUCIN in the DERMIS in the absence of thyroid disease. Most scleromyxedema cases are associated with a MONOCLONAL GAMMOPATHY, immunoglobulin IgG-lambda.
  
• Scrapie [M0019564]
  A fatal disease of the nervous system in sheep and goats, characterized by pruritus, debility, and locomotor incoordination. It is caused by proteinaceous infectious particles called PRIONS.
  
• Screw Worm Infection [M0019565]
  Infection with larvae of the blow fly Cochliomyia hominivorax (Callitroga americanum), a common cause of disease in livestock in the southern and southwestern U.S.A.
  
• Scrofula [M0022119]
  
• Scrofuloderma [M0022112]
  
• Scrub Typhus [M0019567]
  An acute infectious disease caused by ORIENTIA TSUTSUGAMUSHI. It is limited to eastern and southeastern Asia, India, northern Australia, and the adjacent islands. Characteristics include the formation of a primary cutaneous lesion at the site of the bite of an infected mite, fever lasting about two weeks, and a maculopapular rash.
  
• Scurvy [M0019569]
  A condition due to deficiency of ASCORBIC ACID (vitamin C) in the diet and marked by weakness, anemia, spongy gums, a tendency to mucocutaneous hemorrhages and a brawny induration of the muscles of the calves and legs. (Dorland, 27th ed)
  
• Sea-Blue Histiocyte Syndrome [M0019573]
  A congenital disease caused by an inborn error involving APOLIPOPROTEIN E leading to abnormal LIPID METABOLISM and the accumulation of GLYCOSPHINGOLIPIDS, particularly SPHINGOMYELINS in the HISTIOCYTES. This disorder is characterized by SPLENOMEGALY and the sea-blue histiocytes in the spleen and bone marrow after May Grunwald staining.
  
• Seasickness [M0014106]
  
• Sebaceous Gland Diseases [M0019581]
  Diseases of the sebaceous glands such as sebaceous hyperplasia and sebaceous cell carcinoma (SEBACEOUS GLAND NEOPLASMS).
  
• Secernentea Infections [M0026095]
  Infections with nematodes of the subclass SECERNENTEA.
  
• Secondary CNS Vasculitis [M0335303]
  
• Secondary Esotropia [M0336197]
  
• Secondary Exotropia [M0336202]
  
• Secondary Peritonitis [M0455599]
  
• Secondary Trigeminal Neuralgia [M0336284]
  
• See-Saw Nystagmus [M0333561]
  
• Segmental Autonomic Dysfunction [M0335521]
  
• Seizure, Febrile, Complex [M0336038]
  
• Seizure, Febrile, Simple [M0336039]
  
• Seizures, Febrile [M0005138]
  Seizures that occur during a febrile episode. It is a common condition, affecting 2-5% of children aged 3 months to five years. An autosomal dominant pattern of inheritance has been identified in some families. The majority are simple febrile seizures (generally defined as generalized onset, single seizures with a duration of less than 30 minutes). Complex febrile seizures are characterized by focal onset, duration greater than 30 minutes, and/or more than one seizure in a 24 hour period. The likelihood of developing epilepsy (i.e., a nonfebrile seizure disorder) following simple febrile seizures is low. Complex febrile seizures are associated with a moderately increased incidence of epilepsy. (From Menkes, Textbook of Child Neurology, 5th ed, p784)
  
• Seizures, Simple Partial, Special Sensory Symptoms [M0335087]
  
• Self Induced Illness [M0012502]
  
• Sensation Disorders [M0019651]
  Disorders of the special senses (i.e., VISION; HEARING; TASTE; and SMELL) or somatosensory system (i.e., afferent components of the PERIPHERAL NERVOUS SYSTEM).
  
• Sensory Disorder, Vagus Nerve [M0336410]
  
• Sensory Disorders [M0336524]
  
• Sensory Epilepsy [M0335083]
  
• Sensory Neuropathy, Hereditary [M0014745]
  
• Sepsis [M0028155]
  Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by HYPOTENSION despite adequate fluid infusion, it is called SEPTIC SHOCK.
  
• Septic Phlebitis, Cavernous Sinus [M0334356]
  
• Septic Phlebitis, Lateral Sinus [M0335488]
  
• Septic Phlebitis, Sagittal Sinus [M0335910]
  
• Septicemia [M0019666]
  Systemic disease associated with the presence of pathogenic microorganisms or their toxins in the blood.
  
• Septo-Optic Dysplasia [M0376630]
  A condition resulting from congenital malformations involving the brain. The syndrome of septo-optic dysplasia combines hypoplasia or agenesis of the SEPTUM PELLUCIDUM and the OPTIC NERVE. The extent of the abnormalities can vary. Septo-optic dysplasia is often associated with abnormalities of the hypothalamic and other diencephalic structures, and HYPOPITUITARISM.
  
• Serratia Infections [M0025671]
  Infections with bacteria of the genus SERRATIA.
  
• Serum Sickness [M0019699]
  Immune complex disease caused by the administration of foreign serum or serum proteins and characterized by fever, lymphadenopathy, arthralgia, and urticaria. When they are complexed to protein carriers, some drugs can also cause serum sickness when they act as haptens inducing antibody responses.
  
• Setariasis [M0019705]
  Infection with nematodes of the genus Setaria. This condition is usually seen in cattle and equines and is of little pathogenic significance, although migration of the worm to the eye may lead to blindness.
  
• Severe Acute Respiratory Syndrome [M0447378]
  A viral disorder characterized by high FEVER, dry COUGH, shortness of breath (DYSPNEA) or breathing difficulties, and atypical PNEUMONIA. A virus in the genus CORONAVIRUS is the suspected agent.
  
• Severe Combined Immunodeficiency [M0025203]
  Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human SCID.
  
• Severe Sepsis [M0494585]
  Sepsis associated with organ dysfunction distant from the site of infection.
  
• Sex Chromosome Aberrations [M0019730]
  Abnormal number or structure of the SEX CHROMOSOMES. Many sex chromosome aberrations, but not all, are the cause of SEX CHROMOSOME DISORDERS.
  
• Sex Chromosome Disorders [M0373370]
  Clinical conditions caused by an abnormal sex chromosome constitution (SEX CHROMOSOME ABERRATIONS) in which there is extra or missing sex chromosome material (either a whole chromosome or a chromosome segment).
  
• Sex Differentiation Disorders [M0019735]
  Abnormalities in development of the GONADS, the genital tracts, and the external GENITALIA. Disorders of sexual differentiation are due to genetic defects or endocrine imbalance. Sex-determining genes (GENE, SRY) dictate the gonadal SEX whereas the fetal TESTICULAR HORMONES determine the somatic sex during SEX DIFFERENTIATION.
  
• Sexual Dysfunction, Physiological [M0019736]
  Physiological disturbances in normal sexual performance in either the male or the female.
  
• Sexual Infantilism [M0010906]
  The permanent lack of SEXUAL DEVELOPMENT in an individual. This defect is usually observed at an age after expected PUBERTY.
  
• Sexually Transmitted Diseases [M0019758]
  Diseases due to or propagated by sexual contact.
  
• Sexually Transmitted Diseases, Bacterial [M0023404]
  Bacterial diseases transmitted or propagated by sexual conduct.
  
• Sexually Transmitted Diseases, Viral [M0023402]
  Viral diseases which are transmitted or propagated by sexual conduct.
  
• Sheep Diseases [M0019767]
  Diseases of domestic and mountain sheep of the genus Ovis.
  
• Shigellosis [M0446975]
  
• Shock, Endotoxic [M0019785]
  
• Shock, Septic [M0019786]
  Sepsis associated with HYPOTENSION or hypoperfusion despite adequate fluid resuscitation. Perfusion abnormalities may include, but are not limited to LACTIC ACIDOSIS; OLIGURIA; or acute alteration in mental status.
  
• Shock, Toxic [M0019788]
  
• Short Bowel Syndrome [M0019794]
  A malabsorption syndrome resulting from extensive operative resection of the SMALL INTESTINE, the absorptive region of the GASTROINTESTINAL TRACT.
  
• Short Rib-Polydactyly Syndrome [M0019797]
  A syndrome inherited as an autosomal recessive trait and incompatible with life. The main features are narrow thorax, short ribs, scapular and pelvic dysplasia, and polydactyly.
  
• Short Sleeper Syndrome [M0334651]
  
• Shoulder Impingement Syndrome [M0029019]
  Compression of the rotator cuff tendons and subacromial bursa between the humeral head and structures that make up the coracoacromial arch and the humeral tuberosities. This condition is associated with subacromial bursitis and rotator cuff (largely supraspinatus) and bicipital tendon inflammation, with or without degenerative changes in the tendon. Pain that is most severe when the arm is abducted in an arc between 40 and 120 degrees, sometimes associated with tears in the rotator cuff, is the chief symptom. (From Jablonski's Dictionary of Syndromes and Eponymic Diseases, 2d ed)
  
• Shwartzman Phenomenon [M0019807]
  A vasculitis, local or systemic, caused by a two-stage reaction in which a first encounter with endotoxin produces intravascular fibrin thrombi whose clearance results in reticuloendothelial blockade which prevents the clearance of thrombi caused by a second encounter with endotoxin, (or a variety of polyanions, glycogen or antigen/antibody complexes) resulting in tissue necrosis and/or hemorrhage. In pregnancy gram-negative septicemia during delivery or abortion may serve as the first or provocative encounter.
  
• Shy-Drager Syndrome [M0019808]
  A progressive neurodegenerative condition of the central and autonomic nervous systems characterized by atrophy of the preganglionic lateral horn neurons of the thoracic spinal cord, which differentiates this condition from other forms of idiopathic orthostatic hypotension (HYPOTENSION, ORTHOSTATIC). This disease is generally considered a clinical variant of MULTIPLE SYSTEM ATROPHY. Affected individuals present in the fifth or sixth decade with orthostasis and bladder dysfunction; and later develop FECAL INCONTINENCE; anhidrosis; ATAXIA; IMPOTENCE; and alterations of tone suggestive of basal ganglia dysfunction. (From Adams et al., Principles of Neurology, 6th ed, p536)
  
• Sialadenitis [M0019811]
  INFLAMMATION of salivary tissue (SALIVARY GLANDS), usually due to INFECTION or injuries.
  
• Sialic Acid Storage Disease [M0384694]
  Autosomal recessive neurodegenerative disorders caused by lysosomal membrane transport defects that result in accumulation of free sialic acid (N-ACETYLNEURAMINIC ACID) within the lysosomes. The two main clinical phenotypes, which are allelic variants of the SLC17A5 gene, are ISSD, a severe infantile form, or Salla disease, a slowly progressive adult form, named for the geographic area in Finland where the kindred first studied resided.
  
• Sialometaplasia, Necrotizing [M0019818]
  A benign, inflammatory, variably ulcerated, occasionally bilateral, self-healing lesion of the minor salivary glands that is often confused clinically and histologically with carcinoma.
  
• Sialorrhea [M0019820]
  Increased salivary flow.
  
• Sicca Syndrome [M0019912]
  
• Sick Building Syndrome [M0028232]
  A group of symptoms that are two- to three-fold more common in those who work in large, energy-efficient buildings, associated with an increased frequency of headaches, lethargy, and dry skin. Clinical manifestations include hypersensitivity pneumonitis (ALVEOLITIS, EXTRINSIC ALLERGIC); allergic rhinitis (RHINITIS, ALLERGIC, PERENNIAL); ASTHMA; infections, skin eruptions, and mucous membrane irritation syndromes. Current usage tends to be less restrictive with regard to the type of building and delineation of complaints. (From Segen, Dictionary of Modern Medicine, 1992)
  
• Sick Headache [M0335693]
  
• Sick Sinus Syndrome [M0019828]
  Dysfunction of the sinoatrial node manifested by persistent sinus bradycardia, sinus arrest, sinoatrial exit block, chronic atrial fibrillation and inability of the heart to resume sinus rhythm following cardioversion for atrial fibrillation.
  
• Sickle Cell Trait [M0019829]
  The condition of being heterozygous for hemoglobin S.
  
• Siderosis [M0019830]
  The deposition of iron in a tissue. In the eye, the iron may be deposited in the stroma adjacent to the DESCEMET MEMBRANE.
  
• Sigmoid Diseases [M0019836]
  Pathological processes in the SIGMOID COLON region of the large intestine (INTESTINE, LARGE).
  
• Silicosis [M0019862]
  Pneumoconiosis due to the inhalation of dust of stone, sand, or flint containing silicon dioxide, with formation of generalized, nodular fibrotic changes in both lungs. (Dorland, 27th ed)
  
• Silicotuberculosis [M0019863]
  Tuberculosis of the silicotic lung.
  
• Silo Filler's Disease [M0019865]
  Pneumonia or bronchiolitis caused by inhalation of nitrogen dioxide released by silage.
  
• Simian Acquired Immunodeficiency Syndrome [M0024592]
  Acquired defect of cellular immunity that occurs naturally in macaques infected with SRV serotypes, experimentally in monkeys inoculated with SRV or MASON-PFIZER MONKEY VIRUS; (MPMV), or in monkeys infected with SIMIAN IMMUNODEFICIENCY VIRUS.
  
• Simple Endometrial Hyperplasia [M0406717]
  A benign form of endometrial hyperplasia with increased number of endometrial glands and thickened endometrium. Simple hyperplasia has little risk of progression to endometrial carcinoma.
  
• Simple Partial Seizures [M0334953]
  
• Simple Partial Status Epilepticus [M0336172]
  
• Single Nuchal Cord [M0494859]
  
• Single Seizure [M0334959]
  
• Single-Gene Defects [M0010256]
  
• Sinoatrial Block [M0019897]
  Disturbance of heart conduction in which the atrial response is delayed or omitted because of partial or complete interference with the propagation of impulses from the sinoatrial node to the atria.
  
• Sinus Thrombosis, Intracranial [M0019900]
  Thrombus formation in an intracranial venous sinus, including the superior sagittal, cavernous, lateral, and petrous sinuses. Etiologies include thrombosis due to infection, DEHYDRATION, coagulation disorders (see THROMBOPHILIA), and CRANIOCEREBRAL TRAUMA.
  
• Sinusitis [M0019901]
  An inflammatory process of the mucous membranes of the paranasal sinuses that occurs in three stages: acute, subacute, and chronic. Sinusitis results from any condition causing ostial obstruction or from pathophysiologic changes in the mucociliary transport mechanism.
  
• Sjogren's Syndrome [M0019911]
  Chronic inflammatory and autoimmune disease in which the salivary and lacrimal glands undergo progressive destruction by lymphocytes and plasma cells resulting in decreased production of saliva and tears. The primary form, often called sicca syndrome, involves both KERATOCONJUNCTIVITIS SICCA and XEROSTOMIA. The secondary form includes, in addition, the presence of a connective tissue disease, usually rheumatoid arthritis.
  
• Sjogren-Larsson Syndrome [M0024610]
  An autosomal recessive neurocutaneous disorder characterized by severe ichthyosis MENTAL RETARDATION; SPASTIC PARAPLEGIA; and congenital ICHTHYOSIS. It is caused by mutation of gene encoding microsomal fatty ALDEHYDE DEHYDROGENASE leading to defect in fatty alcohol metabolism.
  
• Skin Abnormalities [M0019926]
  Congenital structural abnormalities of the skin.
  
• Skin and Connective Tissue Diseases [M0026454]
  A collective term for diseases of the skin and its appendages and of connective tissue.
  
• Skin Diseases [M0019929]
  
• Skin Diseases, Bacterial [M0026097]
  Skin diseases caused by bacteria.
  
• Skin Diseases, Bullous [M0019932]
  
• Skin Diseases, Eczematous [M0026466]
  Any of a variety of eruptive skin disorders characterized by erythema, oozing, vesiculation, and scaling. Etiology is varied.
  
• Skin Diseases, Genetic [M0019934]
  Diseases of the skin with a genetic component, usually the result of various inborn errors of metabolism.
  
• Skin Diseases, Infectious [M0019935]
  Skin diseases caused by bacteria, fungi, parasites, or viruses.
  
• Skin Diseases, Metabolic [M0019936]
  Diseases of the skin associated with underlying metabolic disorders.
  
• Skin Diseases, Papulosquamous [M0026467]
  A group of dermatoses with distinct morphologic features. The primary lesion is most commonly a papule, usually erythematous, with a variable degree of scaling on the surface. Plaques form through the coalescing of primary lesions.
  
• Skin Diseases, Parasitic [M0019937]
  Skin diseases caused by ARTHROPODS; HELMINTHS; or PROTOZOA.
  
• Skin Diseases, Vascular [M0026469]
  Skin diseases affecting or involving the cutaneous blood vessels and generally manifested as inflammation, swelling, erythema, or necrosis in the affected area.
  
• Skin Diseases, Vesiculobullous [M0019930]
  Skin diseases characterized by local or general distributions of blisters. They are classified according to the site and mode of blister formation. Lesions can appear spontaneously or be precipitated by infection, trauma, or sunlight. Etiologies include immunologic and genetic factors. (From Scientific American Medicine, 1990)
  
• Skin Diseases, Viral [M0026098]
  Skin diseases caused by viruses.
  
• Skin Ulcer [M0019944]
  
• Skull Fractures [M0019949]
  Fractures of the skull which may result from penetrating or nonpenetrating head injuries or rarely BONE DISEASES (see also FRACTURES, SPONTANEOUS). Skull fractures may be classified by location (e.g., SKULL FRACTURE, BASILAR), radiographic appearance (e.g., linear), or based upon cranial integrity (e.g., SKULL FRACTURE, DEPRESSED).
  
• Sleep Apnea Syndromes [M0019963]
  Disorders characterized by multiple cessations of respirations during sleep that induce partial arousals and interfere with the maintenance of sleep. Sleep apnea syndromes are divided into central (see SLEEP APNEA, CENTRAL), obstructive (see SLEEP APNEA, OBSTRUCTIVE), and mixed central-obstructive types.
  
• Sleep Apnea, Central [M0328294]
  A condition associated with multiple episodes of sleep apnea which are distinguished from obstructive sleep apnea (SLEEP APNEA, OBSTRUCTIVE) by the complete cessation of efforts to breathe. This disorder is associated with dysfunction of central nervous system centers that regulate respiration. This condition may be idiopathic (primary) or associated with lower brain stem lesions; chronic obstructive pulmonary disease (LUNG DISEASES, OBSTRUCTIVE); HEART FAILURE, CONGESTIVE; medication effect; and other conditions. Sleep maintenance is impaired, resulting in daytime hypersomnolence. Primary central sleep apnea is frequently associated with obstructive sleep apnea. When both forms are present the condition is referred to as mixed sleep apnea (see SLEEP APNEA SYNDROMES). (Adams et al., Principles of Neurology, 6th ed, p395; Neurol Clin 1996;14(3):611-28)
  
• Sleep Apnea, Mixed Central and Obstructive [M0334906]
  
• Sleep Apnea, Newborn, Primary [M0334907]
  
• Sleep Apnea, Obstructive [M0328295]
  A disorder characterized by recurrent apneas during sleep despite persistent respiratory efforts. It is due to upper airway obstruction. The respiratory pauses may induce HYPERCAPNIA or HYPOXIA. Cardiac ARRHYTHMIA and elevation of systemic and pulmonary arterial pressures may occur. Frequent partial arousals occur throughout sleep, resulting in relative SLEEP DEPRIVATION and daytime tiredness. Associated conditions include OBESITY; ACROMEGALY; MYXEDEMA; micrognathia; MYOTONIC DYSTROPHY; adenotonsilar dystrophy; and NEUROMUSCULAR DISEASES. (From Adams et al., Principles of Neurology, 6th ed, p395)
  
• Sleep Arousal Disorders [M0328298]
  Sleep disorders characterized by impaired arousal from the deeper stages of sleep (generally stage III or IV sleep).
  
• Sleep Bruxism [M0328299]
  A sleep disorder characterized by grinding and clenching of the teeth and forceful lateral or protrusive jaw movements. Sleep bruxism may be associated with TOOTH INJURIES; TEMPOROMANDIBULAR JOINT DISORDERS; sleep disturbances; and other conditions.
  
• Sleep Bruxism, Adult [M0335146]
  
• Sleep Bruxism, Childhood [M0335147]
  
• Sleep Disorders [M0019966]
  Conditions characterized by disturbances of usual sleep patterns or behaviors. Sleep disorders may be divided into three major categories: DYSSOMNIAS (i.e. disorders characterized by insomnia or hypersomnia), PARASOMNIAS (abnormal sleep behaviors), and sleep disorders secondary to medical or psychiatric disorders. (From Thorpy, Sleep Disorders Medicine, 1994, p187)
  
• Sleep Disorders, Extrinsic [M0334689]
  
• Sleep Disorders, Intrinsic [M0328301]
  Dyssomnias (i.e., insomnias or hypersomnias) associated with dysfunction of internal sleep mechanisms or secondary to a sleep-related medical disorder (e.g., sleep apnea, post-traumatic sleep disorders, etc.). (From Thorpy, Sleep Disorders Medicine, 1994, p187)
  
• Sleep Initiation and Maintenance Disorders [M0011403]
  Disorders characterized by impairment of the ability to initiate or maintain sleep. This may occur as a primary disorder or in association with another medical or psychiatric condition.
  
• Sleep Initiation Dysfunction [M0335063]
  
• Sleep Starts [M0335192]
  
• Sleep Talking [M0335193]
  
• Sleep-Related Abnormal Swallowing Syndrome [M0335109]
  
• Sleep-Related Bruxism [M0335148]
  
• Sleep-Related Neurogenic Tachypnea [M0334652]
  
• Sleep-Related Painful Erections [M0335128]
  
• Sliding Hiatal Hernia [M0010266]
  The most common kind of HIATAL HERNIA in which the ESOPHAGOGASTRIC JUNCTION slides above the DIAPHRAGM into the THORAX.
  
• Slow Virus Diseases [M0019974]
  Diseases of viral origin, characterized by incubation periods of months to years, insidious onset of clinical manifestations, and protracted clinical course. Though the disease process is protracted, viral multiplication may not be unusually slow. Conventional viruses produce slow virus diseases such as SUBACUTE SCLEROSING PANENCEPHALITIS, progressive multifocal leukoencephalopathy (LEUKOENCEPHALOPATHY, PROGRESSIVE MULTIFOCAL), and AIDS. Diseases produced by unconventional agents were originally considered part of this group. They are now called PRION DISEASES.
  
• Smallpox [M0019977]
  An acute, highly contagious, often fatal infectious disease caused by an orthopoxvirus characterized by a biphasic febrile course and distinctive progressive skin eruptions. Vaccination has succeeded in eradicating smallpox worldwide. (Dorland, 28th ed)
  
• Smith-Lemli-Opitz Syndrome [M0028480]
  An autosomal recessive disorder of CHOLESTEROL metabolism. It is caused by a deficiency of 7-dehydrocholesterol reductase (DHCR7), the enzyme that converts 7-dehydrocholesterol to cholesterol, leading to an abnormally low plasma cholesterol. This syndrome is characterized by multiple CONGENITAL ABNORMALITIES, growth deficiency, and MENTAL RETARDATION.
  
• Smith-Lemli-Opitz Syndrome, Type I [M0028481]
  
• Smith-Lemli-Opitz Syndrome, Type II [M0028482]
  
• Sneddon Syndrome [M0028214]
  A systemic non-inflammatory arteriopathy primarily of middle-aged females characterized by the association of livedo reticularis, multiple thrombotic CEREBRAL INFARCTION; CORONARY DISEASE, and HYPERTENSION. Elevation of antiphospholipid antibody titers (see also ANTIPHOSPHOLIPID SYNDROME), cardiac valvulopathy, ISCHEMIC ATTACK, TRANSIENT; SEIZURES; DEMENTIA; and chronic ischemia of the extremities may also occur. Pathologic examination of affected arteries reveals non-inflammatory adventitial fibrosis, thrombosis, and changes in the media. (From Jablonski, Dictionary of Syndromes & Eponymic Diseases, 2d ed; Adams et al., Principles of Neurology, 6th ed, p861; Arch Neurol 1997 Jan;54(1):53-60)
  
• Sodoku [M0018508]
  
• Soft Tissue Infections [M0027697]
  Infections of non-skeletal tissue, i.e., exclusive of bone, ligaments, cartilage, and fibrous tissue. The concept is usually referred to as skin and soft tissue infections and usually subcutaneous and muscle tissue are involved. The predisposing factors in anaerobic infections are trauma, ischemia, and surgery. The organisms often derive from the fecal or oral flora, particularly in wounds associated with intestinal surgery, decubitus ulcer, and human bites. (From Cecil Textbook of Medicine, 19th ed, p1688)
  
• Soft Tissue Injuries [M0026759]
  Injuries of tissue other than bone. The concept is usually general and does not customarily refer to internal organs or viscera. It is meaningful with reference to regions or organs where soft tissue (muscle, fat, skin) should be differentiated from bones or bone tissue, as "soft tissue injuries of the hand".
  
• Somatosensory Disorders [M0328308]
  Disorders of sensory information received from superficial and deep regions of the body. The somatosensory system conveys neural impulses which pertain to proprioception, tactile sensation, thermal sensation, pressure sensation, and pain. PERIPHERAL NERVOUS SYSTEM DISEASES; SPINAL CORD DISEASES; and BRAIN DISEASES may be associated with impaired or abnormal somatic sensation.
  
• Somnambulism [M0020164]
  A parasomnia characterized by a partial arousal that occurs during stage IV of non-REM sleep. Affected individuals exhibit semipurposeful behaviors such as ambulation and are difficult to fully awaken. Children are primarily affected, with a peak age range of 4-6 years.
  
• Somnolescent Starts [M0335194]
  
• Space Motion Sickness [M0027731]
  Disorder characterized by nausea, vomiting, and dizziness, possibly in response to vestibular disorientation or fluid shifts associated with space flight. (From Webster's New World Dictionary)
  
• Sparganosis [M0020195]
  Infection of animals, including fish and man, with a developmental stage of Diphyllobothrium. This stage has recently been referred to as a plerocercoid but the name sparganum has persisted. Therefore, infection of fish or other animals with the plerocercoid larvae is sparganosis. Fish-eating mammals, including man, are the final hosts.
  
• Spasmophilia [M0021206]
  
• Spasms, Infantile [M0020204]
  An epileptic syndrome characterized by the triad of infantile spasms, hypsarrhythmia, and arrest of psychomotor development at seizure onset. The majority present between 3-12 months of age, with spasms consisting of combinations of brief flexor or extensor movements of the head, trunk, and limbs. The condition is divided into two forms: cryptogenic (idiopathic) and symptomatic (secondary to a known disease process such as intrauterine infections; nervous system abnormalities; BRAIN DISEASES, METABOLIC, INBORN; prematurity; perinatal asphyxia; TUBEROUS SCLEROSIS; etc.). (From Menkes, Textbook of Child Neurology, 5th ed, pp744-8)
  
• Spasmus Nutans [M0020205]
  
• Spastic Paraplegia, Hereditary [M0023769]
  A group of inherited diseases that share similar phenotypes but are genetically diverse. Different genetic loci for autosomal recessive, autosomal dominant, and x-linked forms of hereditary spastic paraplegia have been identified. Clinically, patients present with slowly progressive distal limb weakness and lower extremity spasticity. Peripheral sensory neurons may be affected in the later stages of the disease. (J Neurol Neurosurg Psychiatry 1998 Jan;64(1):61-6; Curr Opin Neurol 1997 Aug;10(4):313-8)
  
• Spastic Quadriplegia [M0336498]
  
• Spastic Spinal Monoplegia Syndrome [M0336347]
  
• Special Senses Disorders [M0336525]
  
• Speech Disorders [M0020248]
  Acquired or developmental conditions marked by an impaired ability to comprehend or generate spoken forms of language.
  
• Spermatic Cord Torsion [M0020275]
  The twisting of the SPERMATIC CORD due to an anatomical abnormality that left the TESTIS mobile and dangling in the SCROTUM. The initial effect of testicular torsion is obstruction of venous return. Depending on the duration and degree of cord rotation, testicular symptoms range from EDEMA to interrupted arterial flow and testicular pain. If blood flow to testis is absent for 4 to 6 h, SPERMATOGENESIS may be permanently lost.
  
• Spermatocele [M0020277]
  A cystic dilation of the EPIDIDYMIS, usually in the head portion (caput epididymis). The cyst fluid contains dead SPERMATOZOA and can be easily differentiated from TESTICULAR HYDROCELE and other testicular lesions.
  
• Sphenoid Sinusitis [M0023884]
  Inflammation of the sphenoid sinus. This condition usually is accompanied by pansinusitis and may present itself in an acute or chronic form.
  
• Sphenopalatine Neuralgia [M0336099]
  
• Spherocytosis, Hereditary [M0020294]
  A familial congenital hemolytic anemia characterized by numerous abnormally shaped erythrocytes which are generally spheroidal. The erythrocytes have increased osmotic fragility and are abnormally permeable to sodium ions.
  
• Sphincter of Oddi Dysfunction [M0455022]
  Organic or functional motility disorder involving the SPHINCTER OF ODDI and associated with biliary COLIC. Pathological changes are most often seen in the COMMON BILE DUCT sphincter, and less commonly the PANCREATIC DUCT sphincter.
  
• Sphincter of Oddi Dyskinesia [M0455023]
  
• Sphincter of Oddi Stenosis [M0455024]
  
• Sphingolipidoses [M0020298]
  A group of inherited metabolic disorders characterized by the intralysosomal accumulation of SPHINGOLIPIDS primarily in the CENTRAL NERVOUS SYSTEM and to a variable degree in the visceral organs. They are classified by the enzyme defect in the degradation pathway and the substrate accumulation (or storage). Clinical features vary in subtypes but neurodegeneration is a common sign.
  
• Spider Veins [M0417864]
  
• Spinal Cord Compression [M0020310]
  Acute and chronic conditions characterized by external mechanical compression of the SPINAL CORD due to extramedullary neoplasm; EPIDURAL ABSCESS; SPINAL FRACTURES; bony deformities of the vertebral bodies; and other conditions. Clinical manifestations vary with the anatomic site of the lesion and may include localized pain, weakness, sensory loss, incontinence, and impotence.
  
• Spinal Cord Demyelinating Autoimmune Diseases [M0334184]
  
• Spinal Cord Diseases [M0020311]
  Pathologic conditions which feature SPINAL CORD damage or dysfunction, including disorders involving the meninges and perimeningeal spaces surrounding the spinal cord. Traumatic injuries, vascular diseases, infections, and inflammatory/autoimmune processes may affect the spinal cord.
  
• Spinal Cord Ischemia [M0328309]
  Reduced blood flow to the spinal cord which is supplied by the anterior spinal artery and the paired posterior spinal arteries. This condition may be associated with ARTERIOSCLEROSIS, trauma, emboli, diseases of the aorta, and other disorders. Prolonged ischemia may lead to INFARCTION of spinal cord tissue.
  
• Spinal Cord Vascular Diseases [M0328310]
  Hypoxic-ischemic and hemorrhagic disorders of the spinal cord. ARTERIOSCLEROSIS, emboli, and vascular malformations are potential causes of these conditions.
  
• Spinal Curvatures [M0020314]
  Deviations of the spine from its normal direction or position. (Dorland, 28th ed)
  
• Spinal Diseases [M0020315]
  
• Spinal Meningovascular Syphilis [M0336219]
  
• Spinal Muscular Atrophies of Childhood [M0022919]
  A group of recessively inherited diseases that feature progressive muscular atrophy and hypotonia. They are classified as type I (Werdnig-Hoffman disease), type II (intermediate form), and type III (Kugelberg-Welander disease). Type I is fatal in infancy, type II has a late infantile onset and is associated with survival into the second or third decade. Type III has its onset in childhood, and is slowly progressive. (J Med Genet 1996 Apr:33(4):281-3)
  
• Spinal Osteophytosis [M0020326]
  Outgrowth of immature bony processes from the vertebrae, reflecting the presence of degenerative disease and calcification. It includes cervical and lumbar spondylosis.
  
• Spinal Stenosis [M0020331]
  Narrowing of the spinal canal.
  
• Spinocerebellar Ataxia Type 1 [M0336155]
  
• Spinocerebellar Ataxia Type 2 [M0336156]
  
• Spinocerebellar Ataxia Type 4 [M0336157]
  
• Spinocerebellar Ataxia Type 5 [M0336158]
  
• Spinocerebellar Ataxia Type 6 [M0336159]
  
• Spinocerebellar Ataxia Type 7 [M0336160]
  A group of dominantly inherited, predominatly late-onset, cerebellar ataxias which have been divided into multiple subtypes based on clinical features and genetic mapping. Progressive ataxia is a central feature of these conditions, and in certain subtypes POLYNEUROPATHY; DYSARTHRIA; visual loss; and other disorders may develop. (From Joynt, Clinical Neurology, 1997, Ch65, pp 12-17; J Neuropathol Exp Neurol 1998 Jun;57(6):531-43)
  
• Spinocerebellar Ataxias [M0020337]
  A group of dominantly inherited, predominately late-onset, cerebellar ataxias which have been divided into multiple subtypes based on clinical features and genetic mapping. Progressive ataxia is a central feature of these conditions, and in certain subtypes POLYNEUROPATHY; DYSARTHRIA; visual loss; and other disorders may develop. (From Joynt, Clinical Neurology, 1997, Ch65, pp 12-17; J Neuropathol Exp Neurol 1998 Jun;57(6):531-43)
  
• Spinocerebellar Degenerations [M0020336]
  A heterogenous group of degenerative syndromes marked by progressive cerebellar dysfunction either in isolation or combined with other neurologic manifestations. Sporadic and inherited subtypes occur. Inheritance patterns include autosomal dominant, autosomal recessive, and X-linked.
  
• Spinopontine Atrophy [M0337350]
  
• Spirochaetales Infections [M0020349]
  Infections with bacteria of the order SPIROCHAETALES.
  
• Spirurida Infections [M0026109]
  Infections with nematodes of the order SPIRURIDA.
  
• Splenic Diseases [M0020368]
  
• Splenic Infarction [M0020369]
  Insufficiency of arterial or venous blood supply to the spleen due to emboli, thrombi, vascular torsion, or pressure that produces a macroscopic area of necrosis. (From Stedman, 25th ed)
  
• Splenosis [M0027033]
  The spontaneous transplantation of splenic tissue to unusual sites after open splenic trauma, e.g., after automobile accidents, gunshot or stab wounds. The splenic pulp implants appear as red-blue nodules on the peritoneum, omentum, and mesentery, morphologically similar to multifocal pelvic endometriosis. (Segen, Dictionary of Modern Medicine, 1992)
  
• Spondylarthritis [M0374010]
  Arthritis of the spine, specifically involving the intervertebral articulations.
  
• Spondylarthropathies [M0374011]
  Heterogeneous group of arthritic diseases sharing clinical and radiologic features and presence of the HLA-B27 ANTIGEN.
  
• Spondylitis [M0020376]
  Inflammation of the vertebrae. This includes both arthritic and non-arthritic conditions.
  
• Spondylitis, Ankylosing [M0020377]
  The form of rheumatoid arthritis affecting the spine. It occurs predominantly in young males and produces pain and stiffness as a result of inflammation of the sacroiliac, intervertebral, and costovertebral joints. Etiology is unknown.
  
• Spondyloepiphyseal Dysplasia [M0015527]
  
• Spondylolisthesis [M0020378]
  Forward displacement of one vertebra over another.
  
• Spondylolysis [M0020379]
  Dissolution of a vertebra, especially the pars interarticularis.
  
• Spondylosis [M0020327]
  
• Spondylosis Deformans [M0020328]
  
• Spontaneous Ocular Nystagmus [M0333596]
  
• Spontaneous Vertebral Artery Dissection [M0335605]
  
• Sporadic Cerebral Amyloid Angiopathy [M0334467]
  
• Sporotrichosis [M0020384]
  The commonest and least serious of the deep mycoses, characterized by nodular lesions of the cutaneous and subcutaneous tissues. It is caused by inhalation of contaminated dust or by infection of a wound.
  
• Sprue, Tropical [M0020397]
  A chronic malabsorption syndrome, occurring mainly in residents of or visitors to the tropics or subtropics. The failed INTESTINAL ABSORPTION of nutrients from the SMALL INTESTINE results in MALNUTRITION and ANEMIA that is due to FOLIC ACID deficiency.
  
• Stammering [M0020642]
  
• Staphylococcal Food Poisoning [M0020422]
  Poisoning by staphylococcal toxins present in contaminated food.
  
• Staphylococcal Infections [M0020423]
  Infections with bacteria of the genus STAPHYLOCOCCUS.
  
• Staphylococcal Scalded Skin Syndrome [M0020426]
  A disease of infants due to group 2 phage type 17 staphylococci that produce an epidermolytic exotoxin. Superficial fine vesicles and bullae form and rupture easily, resulting in loss of large sheets of epidermis.
  
• Staphylococcal Skin Infections [M0020427]
  Infections to the skin caused by bacteria of the genus STAPHYLOCOCCUS.
  
• Stasis Ulcer [M0022530]
  
• Status Asthmaticus [M0020462]
  A sudden intense and continuous aggravation of a state of asthma, marked by dyspnea to the point of exhaustion and collapse and not responding to the usual therapeutic efforts.
  
• Status Cataplexicus [M0334765]
  
• Status Epilepticus [M0020463]
  A prolonged seizure or seizures repeated frequently enough to prevent recovery between episodes occurring over a period of 20-30 minutes. The most common subtype is generalized tonic-clonic status epilepticus, a potentially fatal condition associated with neuronal injury and respiratory and metabolic dysfunction. Nonconvulsive forms include petit mal status and complex partial status, which may manifest as behavioral disturbances. Simple partial status epilepticus consists of persistent motor, sensory, or autonomic seizures that do not impair cognition (see also EPILEPSIA PARTIALIS CONTINUA). Subclinical status epilepticus generally refers to seizures occurring in an unresponsive or comatose individual in the absence of overt signs of seizure activity. (From N Engl J Med 1998 Apr 2;338(14):970-6; Neurologia 1997 Dec;12 Suppl 6:25-30)
  
• Status Epilepticus, Alcohol Withdrawal-Induced [M0335567]
  
• Status Epilepticus, Subclinical [M0336174]
  
• Status Lymphaticus [M0012794]
  
• Status Migrainosus [M0335688]
  
• Steatitis [M0020469]
  A disease of cats and mink characterized by a marked inflammation of adipose tissue and the deposition of "ceroid" pigment in the interstices of the adipose cells. It is believed to be caused by feeding diets containing too much unsaturated fatty acid and too little vitamin E. (Merck Veterinary Manual, 5th ed; Stedman, 25th ed)
  
• Steatorrhea [M0003737]
  A condition that is characterized by chronic fatty DIARRHEA, a result of abnormal DIGESTION and/or INTESTINAL ABSORPTION of FATS.
  
• Stephanurus dentatus Infections [M0026110]
  
• Steroid Metabolism, Inborn Errors [M0442596]
  Errors in metabolic processing of STEROIDS resulting from inborn genetic mutations that are inherited or acquired in utero.
  
• Stevens-Johnson Syndrome [M0020533]
  A variant of bullous erythema multiforme. It ranges from mild skin and mucous membrane lesions to a severe, sometimes fatal systemic disorder. Ocular symptoms include ulcerative conjunctivitis, keratitis, iritis, uveitis, and sometimes blindness. The cause of the disease is unknown.
  
• Stiff-Person Syndrome [M0025507]
  A condition characterized by persistent spasms (SPASM) involving multiple muscles, primarily in the lower limbs and trunk. The illness tends to occur in the fourth to sixth decade of life, presenting with intermittent spasms that become continuous. Minor sensory stimuli, such as noise and light touch, precipitate severe spasms. Spasms do not occur during sleep and only rarely involve cranial muscles. Respiration may become impaired in advanced cases. (Adams et al., Principles of Neurology, 6th ed, p1492; Neurology 1998 Jul;51(1):85-93)
  
• Still's Disease, Adult-Onset [M0025446]
  Systemic-onset rheumatoid arthritis in adults. It differs from classical rheumatoid arthritis in that it is more often marked by acute febrile onset, and generalized lymphadenopathy and hepatosplenomegaly are more prominent.
  
• Stomach Diseases [M0020542]
  Pathological processes involving the STOMACH.
  
• Stomach Rupture [M0020545]
  Bursting of the STOMACH.
  
• Stomach Ulcer [M0020546]
  Ulceration of the GASTRIC MUCOSA due to contact with GASTRIC JUICE. It is often associated with HELICOBACTER PYLORI infection or consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).
  
• Stomach Volvulus [M0020547]
  Twisting of the STOMACH that may result in gastric ISCHEMIA and GASTRIC OUTLET OBSTRUCTION. It is often associated with DIAPHRAGMATIC HERNIA.
  
• Stomatitis [M0020550]
  INFLAMMATION of the soft tissues of the MOUTH, such as MUCOSA; PALATE; GINGIVA; and LIP.
  
• Stomatitis, Aphthous [M0020551]
  A recurrent disease of the oral mucosa of unknown etiology. It is characterized by small white ulcerative lesions, single or multiple, round or oval. Two to eight crops of lesions occur per year, lasting for 7 to 14 days and then heal without scarring. (From Jablonski's Dictionary of Dentistry, 1992, p742)
  
• Stomatitis, Denture [M0020553]
  Inflammation of the mouth due to denture irritation.
  
• Stomatitis, Herpetic [M0020554]
  Stomatitis caused by Herpesvirus hominis. It usually occurs as acute herpetic stomatitis (or gingivostomatitis), an oral manifestation of primary herpes simplex seen primarily in children and adolescents.
  
• Stomatitis, Ulcerative [M0009247]
  
• Stomatognathic Diseases [M0014128]
  General or unspecified diseases of the stomatognathic system, comprising the mouth, teeth, jaws, and pharynx.
  
• Stomatognathic System Abnormalities [M0027934]
  Congenital structural abnormalities of the mouth and jaws, including the dentition.
  
• Strabismus [M0020559]
  Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)
  
• Strabismus, Comitant [M0336191]
  
• Strabismus, Noncomitant [M0336192]
  
• Streptococcal Infections [M0020568]
  Infections with bacteria of the genus STREPTOCOCCUS.
  
• Striatonigral Degeneration [M0029075]
  A sporadic neurodegenerative disease with onset in middle-age characterized clinically by Parkinsonian features (e.g., MUSCLE RIGIDITY; HYPOKINESIA; stooped posture) and HYPOTENSION. This condition is considered a clinical variant of MULTIPLE SYSTEM ATROPHY. Pathologic features include a prominent loss of neurons in the zona compacta of the SUBSTANTIA NIGRA and PUTAMEN. (From Adams et al., Principles of Neurology, 6th ed, p1075-6)
  
• Stroke, Acute [M0334621]
  
• Stromal Dystrophies, Corneal [M0005182]
  
• Strongyle Infections, Equine [M0020612]
  Infection of horses with parasitic nematodes of the superfamily STRONGYLOIDEA. Characteristics include the development of hemorrhagic nodules on the abdominal peritoneum.
  
• Strongylida Infections [M0026112]
  Infections with nematodes of the order STRONGYLIDA.
  
• Strongyloidiasis [M0020615]
  Infection with nematodes of the genus STRONGYLOIDES. The presence of larvae may produce pneumonitis and the presence of adult worms in the intestine could lead to moderate to severe diarrhea.
  
• Stunned Myocardium [M0026742]
  
• Stupor [M0337409]
  A state of reduced sensibility and response to stimuli which is distinguished from COMA in that the person can be aroused by vigorous and repeated stimulation. The person is still conscious and can make voluntary movements. It can be induced by CENTRAL NERVOUS SYSTEM AGENTS. The word derives from Latin stupere and is related to stunned, stupid, dazed or LETHARGY.
  
• Subacute Necrotising Myelitis [M0335750]
  
• Subacute Sclerosing Panencephalitis [M0020645]
  A rare, slowly progressive encephalitis caused by chronic infection with the MEASLES VIRUS. The condition occurs primarily in children and young adults, approximately 2-8 years after the initial infection. A gradual decline in intellectual abilities and behavioral alterations are followed by progressive MYOCLONUS; MUSCLE SPASTICITY; SEIZURES; DEMENTIA; autonomic dysfunction; and ATAXIA. DEATH usually occurs 1-3 years after disease onset. Pathologic features include perivascular cuffing, eosinophilic cytoplasmic inclusions, neurophagia, and fibrous gliosis. It is caused by the SSPE virus, which is a defective variant of MEASLES VIRUS. (From Adams et al., Principles of Neurology, 6th ed, pp767-8)
  
• Subacute Vestibular Neuritis [M0337544]
  
• Subarachnoid Hemorrhage [M0020646]
  Hemorrhage within the intracranial or spinal subarachnoid space, most often resulting from INTRACRANIAL ANEURYSM rupture or CRANIOCEREBRAL TRAUMA (see also SUBARACHNOID HEMORRHAGE, TRAUMATIC). Clinical features include HEADACHE; NAUSEA; VOMITING, nuchal rigidity, variable neurologic deficits, intraocular subhyaloid hemorrhages, and a reduced level of consciousness which may progress to coma or death. Spasm of intracranial arteries (see VASOSPASM, INTRACRANIAL) frequently accompanies this condition and may lead to BRAIN ISCHEMIA or CEREBRAL INFARCTION. (From N Engl J Med 1997 Jan 2;336(1):28-40)
  
• Subchondral Cysts [M0002774]
  
• Subclavian Steal [M0336210]
  
• Subclavian Steal Syndrome [M0020650]
  A clinically significant reduction in blood supply to the BRAIN STEM and CEREBELLUM (i.e., VERTEBROBASILAR INSUFFICIENCY) resulting from reversal of blood flow through the VERTEBRAL ARTERY from occlusion or stenosis of the proximal subclavian or brachiocephalic artery. Common symptoms include VERTIGO; SYNCOPE; and INTERMITTENT CLAUDICATION of the involved upper extremity. Subclavian steal may also occur in asymptomatic individuals. (From J Cardiovasc Surg 1994;35(1):11-4; Acta Neurol Scand 1994;90(3):174-8)
  
• Subclavian-Carotid Artery Steal Syndrome [M0336211]
  
• Subclinical Seizure [M0334955]
  
• Subcortical Infarction [M0334513]
  
• Subcortical Vascular Dementia [M0334731]
  
• Submandibular Gland Diseases [M0020667]
  
• Subphrenic Abscess [M0020672]
  Accumulation of purulent EXUDATES beneath the DIAPHRAGM, also known as upper abdominal abscess. It is usually associated with PERITONITIS or postoperative infections.
  
• Subwakefullness Syndrome [M0334653]
  
• Sulfatidosis [M0487455]
  A group of inherited metabolic disorders characterized by the intralysosomal accumulation of sulfur-containing lipids (SULFATIDES), including SULFOGLYCOSPHINGOLIPIDS normally found in the MYELIN SHEATH of the brain. These disorders are caused by defective degradative enzymes leading to substrate accumulation (or storage).
  
• Sulfatidosis, Juvenile, Austin Type [M0487462]
  
• Sulfhemoglobinemia [M0020766]
  A morbid condition due to the presence of sulfmethemoglobin in the blood. It is marked by persistent cyanosis, but the blood count does not reveal any special abnormality in the blood. It is thought to be caused by the action of hydrogen sulfide absorbed from the intestine. (Stedman, 25th ed)
  
• Sump Syndrome [M0026624]
  A complication after CHOLEDOCHODUODENOSTOMY when food, stones, or other debris accumulate in the common bile duct.
  
• Superinfection, Delta [M0005791]
  
• Superior Mesenteric Artery Syndrome [M0020821]
  DUODENAL OBSTRUCTION by the superior mesenteric artery (MESENTERIC ARTERY, SUPERIOR) which travels in the root of the MESENTERY and crosses over the DUODENUM. The syndrome is characterized by the dilated proximal duodenum and STOMACH, bloating, ABDOMINAL CRAMPS, and VOMITING. Often it is observed in patient with body casts after spinal surgery.
  
• Superior Oblique Myokymia [M0336340]
  
• Superior Oblique Palsy, Neurogenic [M0336341]
  
• Superior Vena Cava Syndrome [M0020822]
  Obstruction of the superior vena cava caused by neoplasm, thrombosis, aneurysm, or external compression and causing suffusion and/or cyanosis of the face, neck, and upper arms.
  
• Superior Vena Cava Thrombosis [M0020823]
  
• Supranuclear Palsy, Progressive [M0020849]
  A degenerative disease of the central nervous system characterized by balance difficulties; OCULAR MOTILITY DISORDERS (supranuclear ophthalmoplegia); DYSARTHRIA; swallowing difficulties; and axial DYSTONIA. Onset is usually in the fifth decade and disease progression occurs over several years. Pathologic findings include neurofibrillary degeneration and neuronal loss in the dorsal MESENCEPHALON; SUBTHALAMIC NUCLEUS; RED NUCLEUS; pallidum; dentate nucleus; and vestibular nuclei. (From Adams et al., Principles of Neurology, 6th ed, pp1076-7)
  
• Swayback [M0020917]
  Congenital locomotor ataxia of lambs, thought to be associated with copper deficiency. It is characterized clinically by progressive incoordination of the hind limbs and pathologically by disruption of neuron and myelin development in the central nervous system. It is caused by a deficiency of metabolizable copper in the ewe during the last half of her pregnancy. (Dorland, 28th ed; Stedman, 26th ed)
  
• Sweat Gland Diseases [M0020920]
  Diseases of the SWEAT GLANDS.
  
• Sweating, Gustatory [M0020924]
  An autonomic disorder characterized by excessive sweating of the forehead, upper lip, perioral region, or sternum subsequent to gustatory stimuli. The auriculotemporal syndrome features facial flushing or sweating limited to the distribution of the auriculotemporal nerve and may develop after trauma to the parotid gland, in association with PAROTID NEOPLASMS, or following their surgical removal. (From Ann Neurol 1997 Dec;42(6):973-5)
  
• Sweet's Syndrome [M0025149]
  Condition characterized by large, rapidly extending, erythematous, tender plaques on the upper body usually accompanied by fever and dermal infiltration of neutrophilic leukocytes. It occurs mostly in middle-aged women, is often preceded by an upper respiratory infection, and clinically resembles erythema multiforme. Sweet's syndrome may herald the appearance of leukemia.
  
• Swine Diseases [M0020933]
  Diseases of domestic swine and of the wild boar of the genus Sus.
  
• Swine Erysipelas [M0020934]
  An acute and chronic contagious disease of young pigs caused by Erysipelothrix insidiosa.
  
• Swine Vesicular Disease [M0020935]
  An enterovirus infection of swine clinically indistinguishable from FOOT-AND-MOUTH DISEASE, vesicular stomatitis, and VESICULAR EXANTHEMA OF SWINE. It is caused by a strain of HUMAN ENTEROVIRUS B.
  
• Swyer-James Syndrome [M0029057]
  
• Sycosis [M0008669]
  
• Symmetric Diabetic Proximal Motor Neuropathy [M0335864]
  
• Symptomatic Generalized Epilepsy [M0335040]
  
• Symptomatic Infantile Spasms [M0336066]
  
• Symptomatic Myoclonic Epilepsy [M0334940]
  
• Symptomatic Nystagmus [M0333597]
  
• Syncope, Cardiogenic [M0337333]
  
• Syncope, Carotid Sinus [M0337334]
  
• Syncope, Cerebral [M0337429]
  
• Syncope, Deglutitional [M0337336]
  
• Syncope, Hyperventilation [M0337338]
  
• Syncope, Malignant Neurocardiogenic [M0337431]
  
• Syncope, Micturition [M0337339]
  
• Syncope, Postural [M0337330]
  
• Syncope, Situational [M0337340]
  
• Syncope, Stokes-Adams [M0337341]
  
• Syncope, Supine [M0337430]
  
• Syncope, Tussive [M0337342]
  
• Syncope, Vasovagal [M0028953]
  Loss of consciousness due to a reduction in blood pressure that is associated with an increase in vagal tone and peripheral vasodilation.
  
• Syndrome [M0020957]
  A symptom complex of unknown etiology, that is characteristic of a particular abnormality.
  
• Syngamiasis [M0026111]
  
• Synovitis [M0020964]
  Inflammation of a synovial membrane. It is usually painful, particularly on motion, and is characterized by a fluctuating swelling due to effusion within a synovial sac. (Dorland, 27th ed)
  
• Synovitis, Pigmented Villonodular [M0020965]
  Outgrowths of synovial membrane composed of villi and fibrous nodules characterized histologically by hemosiderin- and lipid-containing macrophages and multinucleated giant cells. It usually occurs in the knee.
  
• Syphilis [M0020966]
  A contagious venereal disease caused by the spirochete TREPONEMA PALLIDUM.
  
• Syphilis, Cardiovascular [M0020971]
  Cardiovascular manifestations of SYPHILIS, an infection of TREPONEMA PALLIDUM. In the late stage of syphilis, sometimes 20-30 years after the initial infection, damages are often seen in the blood vessels including the AORTA and the AORTIC VALVE. Clinical signs include syphilitic aortitis, aortic insufficiency, or aortic ANEURYSM.
  
• Syphilis, Congenital [M0020973]
  Syphilis acquired in utero and manifested by any of several characteristic tooth (Hutchinson's teeth) or bone malformations and by active mucocutaneous syphilis at birth or shortly thereafter. Ocular and neurologic changes may also occur.
  
• Syphilis, Cutaneous [M0020975]
  Cutaneous lesions arising from infection with Treponema pallidum. In the primary stage, 18-21 days following infection, one or more chancres appear. If untreated, the subsequent stages of the disease appear as syphilids. These eruptions are superficial, nondestructive, exanthematic, transient, macular roseolas that may later be maculopapular or papular polymorphous or scaly, pustular, pigmented eruptions.(Arnold, Odom, and James, Andrew's Diseases of the Skin, 8th ed, p409)
  
• Syphilis, Latent [M0020976]
  
• Syringomyelia [M0020980]
  Longitudinal cavities in the spinal cord, most often in the cervical region, which may extend for multiple spinal levels. The cavities are lined by dense, gliogenous tissue and may be associated with SPINAL CORD NEOPLASMS; spinal cord traumatic injuries; and vascular malformations. Syringomyelia is marked clinically by pain and PARESTHESIA, muscular atrophy of the hands, and analgesia with thermoanesthesia of the hands and arms, but with the tactile sense preserved (sensory dissociation). Lower extremity spasticity and incontinence may also develop. (From Adams et al., Principles of Neurology, 6th ed, p1269)
  
• Systemic Inflammatory Response Syndrome [M0028081]
  A systemic inflammatory response to a variety of clinical insults, characterized by two or more of the following conditions: (1) fever >38 degrees C or HYPOTHERMIA <36 degrees C; (2) TACHYCARDIA >90 beat/minute; (3) tachypnea >24 breaths/minute; (4) LEUKOCYTOSIS >12,000 cells/cubic mm or 10% immature forms. While usually related to infection, SIRS can also be associated with noninfectious insults such as TRAUMA; BURNS; or PANCREATITIS. If infection is involved, a patient with SIRS is said to have SEPSIS.
  
• T-Lymphocytopenia, Idiopathic CD4-Positive [M0027578]
  Reproducible depletion of CD4+ lymphocytes below 300 per cubic millimeter in the absence of HIV infection or other known causes of immunodeficiency. This is a rare, heterogeneous syndrome and does not appear to be caused by a transmissible agent.
  
• Tabes Dorsalis [M0020992]
  Parenchymatous NEUROSYPHILIS marked by slowly progressive degeneration of the posterior columns, posterior roots, and ganglia of the spinal cord. The condition tends to present 15 to 20 years after the initial infection and is characterized by lightening-like pains in the lower extremities, URINARY INCONTINENCE; ATAXIA; severely impaired position and vibratory sense, abnormal gait (see GAIT DISORDERS, NEUROLOGIC), OPTIC ATROPHY; Argyll-Robertson pupils, hypotonia, hyperreflexia, and trophic joint degeneration (Charcot's Joint; see ARTHROPATHY, NEUROGENIC). (From Adams et al., Principles of Neurology, 6th ed, p726)
  
• Tachycardia, Atrioventricular Nodal Reentry [M0020998]
  A tachycardia characterized by rates between 150 and 250 beats per minute and a QRS complex of supraventricular origin.
  
• Tachycardia, Ectopic Atrial [M0020999]
  A tachycardia originating in the atrial myocardium and characterized by rates between 135 and 175 beats per minute.
  
• Tachycardia, Ectopic Junctional [M0021000]
  A tachycardia arising in the conduction tissues surrounding the atrioventricular node. It usually occurs during myocardial infarction, after heart surgery, or in digitalis intoxication. The rate may range from 140 to 250 beats per minute.
  
• Tachycardia, Paroxysmal [M0021001]
  Condition marked by attacks of rapid action of the heart having sudden onset and cessation.
  
• Tachycardia, Reciprocal [M0021003]
  
• Tachycardia, Sinoatrial Nodal Reentry [M0021004]
  A tachycardia arising from the sinus node region and characterized by rates between 115 and 140 beats per minute. It is paroxysmal rather than constant.
  
• Tachycardia, Sinus [M0021005]
  A simple tachycardia with origin in the sinus node with gradual onset and termination.
  
• Tachycardia, Supraventricular [M0021006]
  A generic expression for any tachycardia that originates above the BUNDLE OF HIS.
  
• Tachycardia, Ventricular [M0026083]
  An abnormally rapid ventricular rhythm with wide QRS complexes, usually in excess of 150 per minute. It is generated within the ventricle, below the BUNDLE OF HIS, and is most commonly associated with atrioventricular dissociation.
  
• Tactile Reflex Epilepsy [M0335123]
  
• Taeniasis [M0021014]
  Infection with tapeworms of the genus Taenia.
  
• Takayasu's Arteritis [M0021017]
  A thrombo-obliterative process of the great vessels stemming from the aortic arch, occurring generally in young women. Radial and carotid pulses are typically obliterated. Skin changes are due to the disturbed circulation. There may be loss of hair and atrophy of the skin and its appendages with underlying muscle atrophy. (Andrews' Diseases of the Skin, 8th ed)
  
• Talfan Disease [M0007372]
  
• Tangier Disease [M0021031]
  An autosomal recessively inherited disorder caused by mutation of ATP-BINDING CASSETTE TRANSPORTERS involved in cellular cholesterol removal (reverse-cholesterol transport). It is characterized by near absence of ALPHA-LIPOPROTEINS (high-density lipoproteins) in blood. The massive tissue deposition of cholesterol esters results in HEPATOMEGALY; SPLENOMEGALY; RETINITIS PIGMENTOSA; large orange tonsils; and often sensory POLYNEUROPATHY. The disorder was first found among inhabitants of Tangier Island in the Chesapeake Bay, MD.
  
• Tangier Disease Neuropathy [M0336851]
  
• Tarsal Tunnel Syndrome [M0021049]
  Entrapment of the distal branches of the posterior TIBIAL NERVE (which divides into the medial plantar, lateral plantar, and calcanial nerves) in the tarsal tunnel, which lies posterior to the internal malleolus and beneath the retinaculum of the flexor muscles of the foot. Symptoms include ankle pain radiating into the foot which tends to be aggravated by walking. Examination may reveal Tinel's sign (radiating pain following nerve percussion) over the tibial nerve at the ankle, weakness and atrophy of the small foot muscles, or loss of sensation in the foot. (From Foot Ankle 1990;11(1):47-52)
  
• Taste Disorder, Anterior Tongue [M0336672]
  
• Taste Disorder, Posterior Tongue [M0336673]
  
• Taste Disorder, Primary [M0336669]
  
• Taste Disorder, Primary, Bitter [M0336674]
  
• Taste Disorder, Primary, Salt [M0336675]
  
• Taste Disorder, Primary, Sweet [M0336676]
  
• Taste Disorder, Secondary [M0336670]
  
• Taste Disorder, Secondary, Bitter [M0336677]
  
• Taste Disorder, Secondary, Salt [M0336678]
  
• Taste Disorder, Secondary, Sweet [M0336679]
  
• Taste Disorders [M0021062]
  Conditions characterized by an alteration in gustatory function or perception. Taste disorders are frequently associated with OLFACTION DISORDERS. Additional potential etiologies include METABOLIC DISEASES; DRUG TOXICITY; and taste pathway disorders (e.g., TASTE BUD diseases; FACIAL NERVE DISEASES; GLOSSOPHARYNGEAL NERVE DISEASES; and BRAIN STEM diseases).
  
• Tauopathies [M0371891]
  Neurodegenerative disorders involving deposition of abnormal tau protein isoforms (TAU PROTEINS) in neurons and glial cells in the brain. Pathological aggregations of tau proteins are associated with mutation of the tau gene on chromosome 17 in patients with ALZHEIMER DISEASE; DEMENTIA; PARKINSONIAN DISORDERS; progressive supranuclear palsy (SUPRANUCLEAR PALSY, PROGRESSIVE); and corticobasal degeneration.
  
• Tay-Sachs Disease [M0021080]
  An autosomal recessive neurodegenerative disorder characterized by the onset in infancy of an exaggerated startle response, followed by paralysis, dementia, and blindness. It is caused by mutation in the alpha subunit of the HEXOSAMINIDASE A resulting in lipid-laden ganglion cells. It is also known as the B variant (with increased HEXOSAMINIDASE B but absence of hexosaminidase A) and is strongly associated with Ashkenazic Jewish ancestry.
  
• Tay-Sachs Disease, AB Variant [M0335225]
  A progressive neurodegenerative disorder that begins with muscle weakness, then progresses to startle reaction, retardation and seizures. It is characterized by the accumulation of G(M2) GANGLIOSIDE in neurons that is caused by a lack of G(M2) ACTIVATOR PROTEIN function. The AB variant designation refers to the increase of both HEXOSAMINIDASE A and HEXOSAMINIDASE B in tissues that lack of G(M2) activator protein.
  
• Teeth, Endodontically-Treated [M0029039]
  
• Telangiectasia, Hereditary Hemorrhagic [M0021123]
  An autosomal dominant vascular anomaly characterized by the presence of multiple small telangiectases of the skin, mucous membranes, gastrointestinal tract, and other organs, associated with recurrent episodes of bleeding from affected sites and gross or occult melena. (Dorland, 27th ed)
  
• Telangiectasis [M0021124]
  Permanent dilation of preexisting blood vessels (capillaries, arterioles, venules) creating small focal red lesions, most commonly in the skin or mucous membranes.
  
• Temporal Arteritis [M0021147]
  A systemic autoimmune vasculitis occurring primarily in people over the age of 50. Pathologic features include a necrotizing panarteritis including granulomas and giant cells. There is a predilection for involvement of central nervous system blood vessels and the most frequent neurologic complication is an OPTIC NEUROPATHY, ISCHEMIC. Large blood vessels may become involved, including the aorta. Clinical manifestations may include myalgias, weight loss, headache, visual loss, necrosis of the skin or tongue, and chest discomfort. Superficial scalp arteries may become tender and enlarged. A related condition, juvenile temporal arteritis, tends to occur in the first or second decade of life. (From Adams et al., Principles of Neurology, 6th ed, p856)
  
• Temporary Nystagmus [M0333598]
  
• Temporomandibular Joint Disorders [M0021153]
  A variety of conditions affecting the anatomic and functional characteristics of the temporomandibular joint. Factors contributing to the complexity of temporomandibular diseases are its relation to dentition and mastication and the symptomatic effects in other areas which account for referred pain to the joint and the difficulties in applying traditional diagnostic procedures to temporomandibular joint pathology where tissue is rarely obtained and x-rays are often inadequate or nonspecific. Common diseases are developmental abnormalities, trauma, subluxation, luxation, arthritis, and neoplasia. (From Thoma's Oral Pathology, 6th ed, pp577-600)
  
• Temporomandibular Joint Dysfunction Syndrome [M0021154]
  A symptom complex consisting of pain, muscle tenderness, clicking in the joint, and limitation or alteration of mandibular movement. The symptoms are subjective and manifested primarily in the masticatory muscles rather than the temporomandibular joint itself. Etiologic factors are uncertain but include occlusal dysharmony and psychophysiologic factors.
  
• Tendinitis [M0021155]
  Inflammation of TENDONS. It is characterized by the degeneration of tendons accompanied by an inflammatory repair response, fibroblastic proliferation, and formation of granulation tissue. Tendinitis is not a clinical diagnosis and can be confirmed only by histopathological findings.
  
• Tendinopathy [M0483885]
  Clinical syndrome describing overuse tendon injuries characterized by a combination of PAIN, diffuse or localized swelling, and impaired performance. Distinguishing tendinosis from tendinitis is clinically difficult and can be made only after histopathological examination.
  
• Tendinosis [M0483991]
  A disorder of TENDONS characterized by COLLAGEN degeneration, other changes to tenocytes and the EXTRACELLULAR MATRIX, and a lack of inflammatory cells. It is caused by aging, microtrauma, or vascular compromise. Tendinosis is not a clinical diagnosis and can be confirmed only by histopathological findings.
  
• Tendon Entrapment [M0495575]
  Narrowing or stenosis of a tendon's retinacular sheath. It occurs most often in the hand or wrist but can also be found in the foot or ankle. The most common types are DE QUERVAIN DISEASE and TRIGGER FINGER DISORDER.
  
• Tennis Elbow [M0021164]
  A condition characterized by pain in or near the lateral humeral epicondyle or in the forearm extensor muscle mass as a result of unusual strain. It occurs in tennis players as well as housewives, artisans, and violinists.
  
• Tenosynovitis [M0021165]
  Inflammation of the synovial lining of a tendon sheath. Causes include trauma, tendon stress, bacterial disease (gonorrhea, tuberculosis), rheumatic disease, and gout. Common sites are the hand, wrist, shoulder capsule, hip capsule, hamstring muscles, and Achilles tendon. The tendon sheaths become inflamed and painful, and accumulate fluid. Joint mobility is usually reduced.
  
• Tension-Type Headache [M0028116]
  A common primary headache disorder, characterized by a dull, non-pulsatile, diffuse, band-like (or vice-like) PAIN of mild to moderate intensity in the HEAD; SCALP; or NECK. The subtypes are classified by frequency and severity of symptoms. There is no clear cause even though it has been associated with MUSCLE CONTRACTION and STRESS. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)
  
• Tension-Vascular Headache [M0336226]
  
• Testicular Diseases [M0021188]
  Pathological processes of the TESTIS.
  
• Testicular Feminization [M0369550]
  A disorder also known as complete androgen insensitivity syndrome (CAIS). The 46,XY genetic male totally lacks androgen responsiveness in the target organs thus exhibits a female phenotype.
  
• Testicular Hydrocele [M0010698]
  Accumulation of serous fluid between the layers of membrane (tunica vaginalis) covering the TESTIS in the SCROTUM.
  
• Tetanilla [M0336514]
  
• Tetanus [M0021200]
  A disease caused by tetanospasmin, a powerful protein toxin produced by CLOSTRIDIUM TETANI. Tetanus usually occurs after an acute injury, such as a puncture wound or laceration. Generalized tetanus, the most common form, is characterized by tetanic muscular contractions and hyperreflexia. Localized tetanus presents itself as a mild condition with manifestations restricted to muscles near the wound. It may progress to the generalized form.
  
• Tetany [M0021207]
  A disorder characterized by muscle twitches, cramps, and carpopedal spasm, and when severe, laryngospasm and seizures. This condition is associated with unstable depolarization of axonal membranes, primarily in the peripheral nervous system. Tetany usually results from HYPOCALCEMIA or reduced serum levels of MAGNESIUM that may be associated with HYPERVENTILATION; HYPOPARATHYROIDISM; RICKETS; UREMIA; or other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1490)
  
• Tetany, Neonatal [M0336513]
  
• Thalamic Diseases [M0021262]
  Disorders of the centrally located thalamus, which integrates a wide range of cortical and subcortical information. Manifestations include sensory loss, MOVEMENT DISORDERS; ATAXIA, pain syndromes, visual disorders, a variety of neuropsychological conditions, and COMA. Relatively common etiologies include CEREBROVASCULAR DISORDERS; CRANIOCEREBRAL TRAUMA; BRAIN NEOPLASMS; BRAIN HYPOXIA; INTRACRANIAL HEMORRHAGES; and infectious processes.
  
• Thalassemia [M0021265]
  A group of hereditary hemolytic anemias in which there is decreased synthesis of one or more hemoglobin polypeptide chains. There are several genetic types with clinical pictures ranging from barely detectable hematologic abnormality to severe and fatal anemia.
  
• Thalassemia Major [M0025959]
  
• Thalassemia Minor [M0025962]
  
• Theileriasis [M0021278]
  Infection of cattle, sheep, or goats with protozoa of the genus THEILERIA. This infection results in an acute or chronic febrile condition.
  
• Thermal Sensation Disorders [M0336650]
  
• Thiamine Deficiency [M0021320]
  A nutritional condition produced by a deficiency of THIAMINE in the diet, characterized by anorexia, irritability, and weight loss. Later, patients experience weakness, peripheral neuropathy, headache, and tachycardia. In addition to being caused by a poor diet, thiamine deficiency in the United States most commonly occurs as a result of alcoholism, since ethanol interferes with thiamine absorption. In countries relying on polished rice as a dietary staple, BERIBERI prevalence is very high. (From Cecil Textbook of Medicine, 19th ed, p1171)
  
• Thoracic Cyst [M0013194]
  
• Thoracic Diseases [M0021393]
  Disorders affecting the organs of the thorax.
  
• Thoracic Outlet Nerve Compression Syndrome [M0336372]
  
• Thoracic Outlet Syndrome [M0021400]
  A neurovascular syndrome associated with compression of the BRACHIAL PLEXUS; SUBCLAVIAN ARTERY; and SUBCLAVIAN VEIN at the superior thoracic outlet. This may result from a variety of anomalies such as a cervical rib (CERVICAL RIB SYNDROME), anomalous fascial bands, and abnormalities of the origin or insertion of the anterior or medial scalene muscles. Clinical features may include pain in the shoulder and neck region which radiates into the arm, PARESIS or PARALYSIS of brachial plexus innervated muscles, PARESTHESIA, loss of sensation, reduction of arterial pulses in the affected extremity, ISCHEMIA, and EDEMA. (Adams et al., Principles of Neurology, 6th ed, pp214-5).
  
• Thrombasthenia [M0021418]
  A congenital bleeding disorder with prolonged bleeding time, absence of aggregation of platelets in response to most agents, especially ADP, and impaired or absent clot retraction. Platelet membranes are deficient in or have a defect in the glycoprotein IIb-IIIa complex (PLATELET GLYCOPROTEIN GPIIB-IIIA COMPLEX).
  
• Thromboangiitis Obliterans [M0021426]
  
• Thrombocythemia, Hemorrhagic [M0021427]
  A clinical syndrome characterized by repeated spontaneous hemorrhages and a remarkable increase in the number of circulating platelets.
  
• Thrombocytopenia [M0021428]
  A decrease in the number of blood platelets.
  
• Thrombocytosis [M0021429]
  Increased numbers of platelets in the peripheral blood. (Dorland, 27th ed)
  
• Thrombophilia [M0029461]
  A disorder of HEMOSTASIS in which there is a tendency for the occurrence of THROMBOSIS.
  
• Thrombophlebitis [M0021432]
  Inflammation of a vein associated with thrombus formation.
  
• Thrombotic Infarction, Middle Cerebral Artery [M0335397]
  
• Thrombotic Infarction, Posterior Cerebral Artery [M0335405]
  
• Thymic Cyst [M0013195]
  
• Thymus Hyperplasia [M0021470]
  Enlargement of the thymus. A condition described in the late 1940's and 1950's as pathological thymic hypertrophy was status thymolymphaticus and was treated with radiotherapy. Unnecessary removal of the thymus was also practiced. It later became apparent that the thymus undergoes normal physiological hypertrophy, reaching a maximum at puberty and involuting thereafter. The concept of status thymolymphaticus has been abandoned. Thymus hyperplasia is present in two thirds of all patients with myasthenia gravis. (From Segen, Dictionary of Modern Medicine, 1992; Cecil Textbook of Medicine, 19th ed, p1486)
  
• Thyroglossal Cyst [M0021473]
  A cyst in the neck caused by persistence of portions of, or by lack of closure of, the primitive thyroglossal duct. (Dorland, 27th ed)
  
• Thyroid Agenesis [M0472129]
  
• Thyroid Crisis [M0021477]
  A dangerous life-threatening hypermetabolic condition characterized by high FEVER and dysfunction of the cardiovascular, the nervous, and the gastrointestinal systems.
  
• Thyroid Diseases [M0021478]
  Pathological processes involving the THYROID GLAND.
  
• Thyroid Dysgenesis [M0472128]
  Defective development of the THYROID GLAND. This concept includes thyroid agenesis (aplasia), hypoplasia, or an ectopic gland (LINGUAL THYROID). Clinical signs usually are those of CONGENITAL HYPOTHYROIDISM.
  
• Thyroid Hormone Resistance Syndrome [M0027608]
  An inherited autosomal recessive trait, characterized by peripheral resistance to THYROID HORMONES and the resulting elevation in serum levels of THYROXINE and TRIIODOTHYRONINE. This syndrome is caused by mutations of gene THRB encoding the THYROID HORMONE RECEPTORS BETA in target cells. HYPOTHYROIDISM in these patients is partly overcome by the increased thyroid hormone levels.
  
• Thyroiditis [M0021487]
  Inflammatory diseases of the THYROID GLAND. Thyroiditis can be classified into acute (THYROIDITIS, SUPPURATIVE), subacute (granulomatous and lymphocytic), chronic fibrous (Riedel's), chronic lymphocytic (HASHIMOTO DISEASE), transient (POSTPARTUM THYROIDITIS), and other AUTOIMMUNE THYROIDITIS subtypes.
  
• Thyroiditis, Autoimmune [M0021488]
  Inflammatory disease of the THYROID GLAND due to autoimmune responses leading to lymphocytic infiltration of the gland. It is characterized by the presence of circulating thyroid antigen-specific T-CELLS and thyroid AUTOANTIBODIES. The clinical signs can range from HYPOTHYROIDISM to THYROTOXICOSIS depending on the type of autoimmune thyroiditis.
  
• Thyroiditis, Subacute [M0021490]
  Spontaneously remitting inflammatory condition of the THYROID GLAND, characterized by FEVER; MUSCLE WEAKNESS; SORE THROAT; severe thyroid PAIN; and an enlarged damaged gland containing GIANT CELLS. The disease frequently follows a viral infection.
  
• Thyroiditis, Suppurative [M0021492]
  Acute inflammatory disease of the THYROID GLAND due to infections by BACTERIA; FUNGI; PROTOZOA; or other microorganisms. Symptoms include tender swelling, FEVER, and often with LEUKOCYTOSIS.
  
• Thyrotoxicosis [M0021495]
  A hypermetabolic syndrome caused by excess THYROID HORMONES which may come from endogenous or exogenous sources. The endogenous source of hormone may be thyroid HYPERPLASIA; THYROID NEOPLASMS; or hormone-producing extrathyroidal tissue. Thyrotoxicosis is characterized by NERVOUSNESS; TACHYCARDIA; FATIGUE; WEIGHT LOSS; heat intolerance; and excessive SWEATING.
  
• Tibial Muscular Dystrophy [M0464105]
  
• Tibial Neuropathy [M0328647]
  Disease of the TIBIAL NERVE (also referred to as the posterior tibial nerve). The most commonly associated condition is the TARSAL TUNNEL SYNDROME. However, LEG INJURIES; ISCHEMIA; and inflammatory conditions (e.g., COLLAGEN DISEASES) may also affect the nerve. Clinical features include PARALYSIS of plantar flexion, ankle inversion and toe flexion as well as loss of sensation over the sole of the foot. (From Joynt, Clinical Neurology, 1995, Ch51, p32)
  
• Tibial Neuropathy, Post-Traumatic [M0336190]
  
• Tic Disorders [M0021514]
  Disorders characterized by recurrent TICS that may interfere with speech and other activities. Tics are sudden, rapid, nonrhythmic, stereotyped motor movements or vocalizations which may be exacerbated by stress and are generally attenuated during absorbing activities. Tic disorders are distinguished from conditions which feature other types of abnormal movements that may accompany general medical conditions. (From DSM-IV, 1994)
  
• Tic Disorders, Vocal [M0336231]
  
• Tick Infestations [M0021521]
  Infestations with soft-bodied (Argasidae) or hard-bodied (Ixodidae) ticks.
  
• Tick Paralysis [M0021522]
  Paralysis caused by a neurotropic toxin secreted by the salivary glands of ticks.
  
• Tick Toxicoses [M0021523]
  Toxicoses caused by toxic substances secreted by the salivary glands of ticks; include tick paralysis (neurotropic toxin), sweating sickness (dermotropic toxin), and Rhipicephalus appendiculatus toxicosis (leukotropic toxin).
  
• Tick-Borne Diseases [M0026236]
  Bacterial, viral, or parasitic diseases transmitted to humans and animals by the bite of infected ticks. The families Ixodidae and Argasidae contain many bloodsucking species that are important pests of man and domestic birds and mammals and probably exceed all other arthropods in the number and variety of disease agents they transmit. Many of the tick-borne diseases are zoonotic.
  
• Tick-Borne Infections [M0026235]
  
• Tietze's Syndrome [M0021529]
  Idiopathic painful nonsuppurative swellings of one or more costal cartilages, especially of the second rib. The anterior chest pain may mimic that of coronary artery disease. (Dorland, 27th ed.)
  
• Tinea [M0021562]
  A general term describing various dermatophytoses. Specific types include TINEA CAPITIS (ringworm of the scalp), TINEA FAVOSA (of scalp and skin), TINEA PEDIS (athlete's foot), and tinea unguium (see ONYCHOMYCOSIS, ringworm of the nails). (Dorland, 27th ed)
  
• Tinea Capitis [M0021564]
  Ringworm of the scalp caused by species of Microsporum and Trichophyton, which may occasionally involve the eyebrows and eyelashes. (Dorland, 27th ed)
  
• Tinea Favosa [M0021565]
  A disease of the scalp that may affect the glabrous skin and the nails and is recognized by the concave sulfur-yellow crusts that form around loose, wiry hairs. Atrophy ensues, leaving a smooth, glossy, thin, paper-white patch. This type of disease is rare in the United States and more frequently seen in the Middle East, Africa, Southeastern Europe, and other countries bordering the Mediterranean Sea. (Arnold, Odom, and James, Andrew's Diseases of the Skin, 8th ed, p319)
  
• Tinea Pedis [M0021566]
  Dermatological pruritic lesion in the feet, caused by Trichophyton rubrum, T. mentagrophytes, or Epidermophyton floccosum.
  
• Tinea Versicolor [M0021568]
  A common chronic, noninflammatory and usually symptomless disorder, characterized by the occurrence of multiple macular patches of all sizes and shapes, and varying in pigmentation from fawn-colored to brown. It is seen most frequently in hot, humid, tropical regions, and is caused by Pityrosporon orbiculare. (Dorland, 27th ed)
  
• Togaviridae Infections [M0021618]
  Virus diseases caused by the TOGAVIRIDAE.
  
• Tolosa-Hunt Syndrome [M0015333]
  An idiopathic syndrome characterized by the formation of granulation tissue in the anterior cavernous sinus or superior orbital fissure, producing a painful ophthalmoplegia. (Adams et al., Principles of Neurology, 6th ed, p271)
  
• Tongue Diseases [M0021657]
  
• Tongue, Fissured [M0021660]
  
• Tongue, Hairy [M0021661]
  A benign condition of the tongue characterized by hypertrophy of the filiform papillae that give the dorsum of the tongue a furry appearance. The color of the elongated papillae varies from yellowish white to brown or black, depending upon staining by substances such as tobacco, food, or drugs. (Dorland, 27th ed)
  
• Tonsillitis [M0021666]
  Inflammation of the tonsils, especially the palatine tonsils. It is often caused by a bacterium. Tonsillitis may be acute, chronic, or recurrent.
  
• Tooth Ankylosis [M0029918]
  Solid fixation of a tooth resulting from fusion of the cementum and alveolar bone, with obliteration of the periodontal ligament. It is uncommon in the deciduous dentition and very rare in permanent teeth. (Jablonski's Dictionary of Dentistry, 1992)
  
• Tooth Attrition [M0028623]
  The wearing away of a tooth as a result of tooth-to-tooth contact, as in mastication, occurring only on the occlusal, incisal, and proximal surfaces. It is chiefly associated with aging. It is differentiated from TOOTH ABRASION (the pathologic wearing away of the tooth substance by friction, as brushing, bruxism, clenching, and other mechanical causes) and from TOOTH EROSION (the loss of substance caused by chemical action without bacterial action). (Jablonski, Dictionary of Dentistry, 1992, p86)
  
• Tooth Crowding [M0012941]
  
• Tooth Demineralization [M0025834]
  A tooth's loss of minerals, such as calcium in hydroxyapatite from the tooth matrix, caused by acidic exposure. An example of the occurrence of demineralization is in the formation of dental caries.
  
• Tooth Diseases [M0021674]
  
• Tooth Erosion [M0021675]
  Progressive loss of the hard substance of a tooth by chemical processes that do not involve bacterial action. (Jablonski, Dictionary of Dentistry, 1992, p296)
  
• Tooth Eruption, Ectopic [M0021678]
  
• Tooth Loss [M0025066]
  The failure to retain teeth as a result of disease or injury.
  
• Tooth Resorption [M0021696]
  Resorption of calcified dental tissue, involving demineralization due to reversal of the cation exchange and lacunar resorption by osteoclasts. There are two types: external (as a result of tooth pathology) and internal (apparently initiated by a peculiar inflammatory hyperplasia of the pulp). (From Jablonski, Dictionary of Dentistry, 1992, p676)
  
• Tooth, Nonvital [M0029038]
  A tooth from which the dental pulp has been removed or is necrotic. (Boucher, Clinical Dental Terminology, 4th ed)
  
• Top of the Basilar Syndrome [M0334265]
  
• Torovirus Infections [M0027403]
  Infections with viruses of the genus TOROVIRUS, family CORONAVIRIDAE.
  
• Torsades de Pointes [M0024685]
  A ventricular tachycardia characterized by periodic twisting of the points of the QRS complexes and rates between 200 and 250 beats per minute. It may be self-limited or may progress to ventricular fibrillation.
  
• Total Third-Nerve Palsy [M0333510]
  
• Toxascariasis [M0026140]
  Infections with nematodes of the genus TOXASCARIS.
  
• Toxemia [M0021721]
  A condition produced by the presence of toxins or other harmful substances in the BLOOD.
  
• Toxocariasis [M0021726]
  Infection by round worms of the genus TOXOCARA, usually found in wild and domesticated cats and dogs and foxes, except for the larvae, which may produce visceral and ocular larva migrans in man.
  
• Toxoplasmosis [M0021732]
  The acquired form of infection by Toxoplasma gondii in animals and man.
  
• Toxoplasmosis, Animal [M0021733]
  Acquired infection of non-human animals by organisms of the genus TOXOPLASMA.
  
• Toxoplasmosis, Central Nervous System [M0336247]
  
• Toxoplasmosis, Cerebral [M0025573]
  Infections of the BRAIN caused by the protozoan TOXOPLASMA gondii that primarily arise in individuals with IMMUNOLOGIC DEFICIENCY SYNDROMES (see also AIDS-RELATED OPPORTUNISTIC INFECTIONS). The infection may involve the brain diffusely or form discrete abscesses. Clinical manifestations include SEIZURES, altered mentation, headache, focal neurologic deficits, and INTRACRANIAL HYPERTENSION. (From Joynt, Clinical Neurology, 1998, Ch27, pp41-3)
  
• Toxoplasmosis, Congenital [M0021734]
  Prenatal protozoal infection with TOXOPLASMA gondii which is associated with injury to the developing fetal nervous system. The severity of this condition is related to the stage of pregnancy during which the infection occurs; first trimester infections are associated with a greater degree of neurologic dysfunction. Clinical features include HYDROCEPHALUS; MICROCEPHALY; deafness; cerebral calcifications; SEIZURES; and psychomotor retardation. Signs of a systemic infection may also be present at birth, including fever, rash, and hepatosplenomegaly. (From Adams et al., Principles of Neurology, 6th ed, p735)
  
• Toxoplasmosis, Fetal [M0336256]
  
• Toxoplasmosis, Ocular [M0021735]
  Infection caused by the protozoan parasite TOXOPLASMA in which there is extensive connective tissue proliferation, the retina surrounding the lesions remains normal, and the ocular media remain clear. Chorioretinitis may be associated with all forms of toxoplasmosis, but is usually a late sequel of congenital toxoplasmosis. The severe ocular lesions in infants may lead to blindness.
  
• Tracheal Cyst [M0013196]
  
• Tracheal Diseases [M0021744]
  
• Tracheal Stenosis [M0021746]
  
• Tracheitis [M0021747]
  
• Trachoma [M0021752]
  A chronic infection of the conjunctiva and cornea caused by CHLAMYDIA TRACHOMATIS.
  
• Transient Hypertension, Pregnancy [M0452742]
  HYPERTENSION that develops as a result of PREGNANCY and regresses post partum. It is hypertension without PROTEINURIA or pathological EDEMA.
  
• Transient Ischemic Attack, Anterior Circulation [M0335467]
  
• Transient Ischemic Attack, Vertebrobasilar Circulation [M0335468]
  
• Transient Vegetative State [M0335851]
  
• Trematode Infections [M0021868]
  Infections caused by infestation with worms of the class Trematoda.
  
• Trench Fever [M0021872]
  An intermittent fever characterized by intervals of chills, fever, and splenomegaly each of which may last as long as 40 hours. It is caused by BARTONELLA QUINTANA and transmitted by the human louse.
  
• Treponemal Infections [M0021878]
  Infections with bacteria of the genus TREPONEMA.
  
• Trichinosis [M0021915]
  A disease due to infection with TRICHINELLA SPIRALIS. It is caused by eating undercooked meat, usually pork.
  
• Trichomonas Infections [M0021928]
  Infections in birds and mammals produced by various species of Trichomonas.
  
• Trichomonas Vaginitis [M0021930]
  Inflammation of the vagina, marked by a purulent discharge. This disease is caused by the protozoan TRICHOMONAS VAGINALIS.
  
• Trichophytosis [M0021563]
  
• Trichostrongyloidiasis [M0021935]
  Infection by roundworms of the superfamily TRICHOSTRONGYLOIDEA, including the genera TRICHOSTRONGYLUS; OSTERTAGIA; Cooperia, HAEMONCHUS; Nematodirus, Hyostrongylus, and DICTYOCAULUS.
  
• Trichostrongylosis [M0021936]
  Infestation with nematode worms of the genus TRICHOSTRONGYLUS. Man and animals become infected by swallowing larvae, usually with contaminated food or drink, although the larvae may penetrate human skin.
  
• Trichuriasis [M0021941]
  Infection with nematodes of the genus TRICHURIS, formerly called Trichocephalus.
  
• Tricuspid Valve Insufficiency [M0021948]
  Backflow of blood from the right ventricle into the right atrium, owing to imperfect functioning of the tricuspid valve.
  
• Tricuspid Valve Prolapse [M0021949]
  Abnormal protrusion of one or more of the leaflets of the tricuspid valve into the right atrium during systole.
  
• Tricuspid Valve Stenosis [M0021950]
  The pathologic narrowing of the orifice of the tricuspid valve. (Stedman, 25th ed)
  
• Trigeminal Autonomic Cephalalgias [M0480084]
  Primary headache disorders that show symptoms caused by the activation of the AUTONOMIC NERVOUS SYSTEM of the TRIGEMINAL NERVE. These autonomic features include redness and tearing of the EYE, nasal congestion or discharge, facial SWEATING and other symptoms. Most subgroups show unilateral cranial PAIN.
  
• Trigeminal Nerve Diseases [M0328651]
  Diseases of the trigeminal nerve or its nuclei, which are located in the pons and medulla. The nerve is composed of three divisions: ophthalmic, maxillary, and mandibular, which provide sensory innervation to structures of the face, sinuses, and portions of the cranial vault. The mandibular nerve also innervates muscles of mastication. Clinical features include loss of facial and intra-oral sensation and weakness of jaw closure. Common conditions affecting the nerve include brain stem ischemia, INFRATENTORIAL NEOPLASMS, and TRIGEMINAL NEURALGIA.
  
• Trigeminal Neuralgia [M0021966]
  A syndrome characterized by recurrent episodes of excruciating pain lasting several seconds or longer in the sensory distribution of the trigeminal nerve. Pain may be initiated by stimulation of trigger points on the face, lips, or gums or by movement of facial muscles or chewing. Associated conditions include MULTIPLE SCLEROSIS, vascular anomalies, ANEURYSMS, and neoplasms. (Adams et al., Principles of Neurology, 6th ed, p187)
  
• Trigeminal Neuralgia, Idiopathic [M0336285]
  
• Trigeminal Neuropathy, Idiopathic [M0336271]
  
• Trigger Finger Disorder [M0487904]
  A painful disability in the hand affecting the finger or thumb. It is caused by mechanical impingement of the digital flexor tendons as they pass through a narrowed retinacular pulley at the level of the metacarpal head. Thickening of the sheath and fibrocartilaginous metaplasia can occur, and nodules can form. (From Green's Operative Hand Surgery, 5th ed, p2137-58).
  
• Trigger Thumb [M0495684]
  
• Triple Nuchal Cord [M0494862]
  
• Trismus [M0022018]
  Spasmodic contraction of the masseter muscle resulting in forceful jaw closure. This may be seen with a variety of diseases, including TETANUS, as a complication of radiation therapy, trauma, or in association with neoplastic conditions.
  
• Trochlear Nerve Diseases [M0328652]
  Diseases of the fourth cranial (trochlear) nerve or its nucleus in the midbrain. The nerve crosses as it exits the midbrain dorsally and may be injured along its course through the intracranial space, cavernous sinus, superior orbital fissure, or orbit. Clinical manifestations include weakness of the superior oblique muscle which causes vertical DIPLOPIA that is maximal when the affected eye is adducted and directed inferiorly. Head tilt may be seen as a compensatory mechanism for diplopia and rotation of the visual axis. Common etiologies include CRANIOCEREBRAL TRAUMA and INFRATENTORIAL NEOPLASMS.
  
• Trombiculiasis [M0022028]
  Infestation with mites of the genus Trombicula, whose larvae carry the rickettsial agent of scrub typhus.
  
• Trypanosomiasis [M0022072]
  Infection with protozoa of the genus TRYPANOSOMA.
  
• Trypanosomiasis, African [M0022074]
  A disease endemic among people and animals in Central Africa. It is caused by various species of trypanosomes, particularly T. gambiense and T. rhodesiense. Its second host is the tsetse fly. Involvement of the central nervous system produces "African sleeping sickness." Nagana is a rapidly fatal trypanosomiasis of horses and other animals.
  
• Trypanosomiasis, Bovine [M0022075]
  Infection in cattle caused by various species of trypanosomes.
  
• Tubal Obstruction [M0008172]
  
• Tuberculid [M0022113]
  
• Tuberculoma [M0022105]
  A tumor-like mass resulting from the enlargement of a tuberculous lesion.
  
• Tuberculoma, Intracranial [M0025665]
  A well-circumscribed mass composed of tuberculous granulation tissue that may occur in the cerebral hemispheres, cerebellum, brain stem, or perimeningeal spaces. Multiple lesions are quite common. Management of intracranial manifestations vary with lesion site. Intracranial tuberculomas may be associated with SEIZURES, focal neurologic deficits, and INTRACRANIAL HYPERTENSION. Spinal cord tuberculomas may be associated with localized or radicular pain, weakness, sensory loss, and incontinence. Tuberculomas may arise as OPPORTUNISTIC INFECTIONS, but also occur in immunocompetent individuals.
  
• Tuberculosis [M0022106]
  Any of the infectious diseases of man and other animals caused by species of MYCOBACTERIUM.
  
• Tuberculosis, Avian [M0022108]
  A variety of TUBERCULOSIS affecting various birds, including chickens and ducks. It is caused by MYCOBACTERIUM AVIUM and characterized by tubercles consisting principally of epithelioid cells.
  
• Tuberculosis, Bovine [M0022109]
  An infection of cattle caused by MYCOBACTERIUM BOVIS. It is transmissible to man and other animals.
  
• Tuberculosis, Cardiovascular [M0022110]
  Pathological conditions of the CARDIOVASCULAR SYSTEM caused by infection of MYCOBACTERIUM TUBERCULOSIS. Tuberculosis involvement may include the HEART; the BLOOD VESSELS; or the PERICARDIUM.
  
• Tuberculosis, Central Nervous System [M0328653]
  Tuberculosis of the brain, spinal cord, or meninges (TUBERCULOSIS, MENINGEAL), most often caused by MYCOBACTERIUM TUBERCULOSIS and rarely by MYCOBACTERIUM BOVIS. The infection may be limited to the nervous system or coexist in other organs (e.g., TUBERCULOSIS, PULMONARY). The organism tends to seed the meninges causing a diffuse meningitis and leads to the formation of TUBERCULOMA, which may occur within the brain, spinal cord, or perimeningeal spaces. Tuberculous involvement of the vertebral column (TUBERCULOSIS, SPINAL) may result in nerve root or spinal cord compression. (From Adams et al., Principles of Neurology, 6th ed, pp717-20)
  
• Tuberculosis, Cutaneous [M0022111]
  Tuberculosis of the skin. It includes scrofuloderma and tuberculid, but not lupus vulgaris, which is LUPUS.
  
• Tuberculosis, Drug-Resistant [M0027283]
  
• Tuberculosis, Endocrine [M0022114]
  Infection of the ENDOCRINE GLANDS with species of MYCOBACTERIUM, most often MYCOBACTERIUM TUBERCULOSIS.
  
• Tuberculosis, Female Genital [M0022115]
  MYCOBACTERIUM infections of the female reproductive tract (GENITALIA, FEMALE).
  
• Tuberculosis, Gastrointestinal [M0022116]
  TUBERCULOSIS that involves any region of the GASTROINTESTINAL TRACT, mostly in the distal ILEUM and the CECUM. In most cases, MYCOBACTERIUM TUBERCULOSIS is the pathogen. Clinical features include ABDOMINAL PAIN; FEVER; and palpable mass in the ileocecal area.
  
• Tuberculosis, Hepatic [M0022117]
  Infection of the LIVER with species of MYCOBACTERIUM, most often MYCOBACTERIUM TUBERCULOSIS. It is characterized by localized small tuberculous miliary lesions or tumor-like mass (TUBERCULOMA), and abnormalities in liver function tests.
  
• Tuberculosis, Laryngeal [M0022118]
  Tuberculosis involving the larynx, producing ulceration of the vocal cords and laryngeal mucosa. It is commonly attended by hoarseness, cough, pain on swallowing, and hemoptysis.
  
• Tuberculosis, Lymph Node [M0022120]
  Infection of the lymph nodes by tuberculosis. Tuberculous infection of the cervical lymph nodes is scrofula.
  
• Tuberculosis, Male Genital [M0022121]
  MYCOBACTERIUM infections of the male reproductive tract (GENITALIA, MALE).
  
• Tuberculosis, Meningeal [M0022122]
  A form of bacterial meningitis caused by MYCOBACTERIUM TUBERCULOSIS or rarely MYCOBACTERIUM BOVIS. The organism seeds the meninges and forms microtuberculomas which subsequently rupture. The clinical course tends to be subacute, with progressions occurring over a period of several days or longer. Headache and meningeal irritation may be followed by SEIZURES, cranial neuropathies, focal neurologic deficits, somnolence, and eventually COMA. The illness may occur in immunocompetent individuals or as an OPPORTUNISTIC INFECTION in the ACQUIRED IMMUNODEFICIENCY SYNDROME and other immunodeficiency syndromes. (From Adams et al., Principles of Neurology, 6th ed, pp717-9)
  
• Tuberculosis, Miliary [M0022123]
  An acute form of TUBERCULOSIS in which minute tubercles are formed in a number of organs of the body due to dissemination of the bacilli through the blood stream.
  
• Tuberculosis, Multidrug-Resistant [M0027284]
  Tuberculosis resistant to chemotherapy with two or more ANTITUBERCULAR AGENTS. The problem of resistance is particularly troublesome in tuberculous OPPORTUNISTIC INFECTIONS associated with HIV INFECTIONS.
  
• Tuberculosis, Ocular [M0022124]
  Tuberculous infection of the eye, primarily the iris, ciliary body, and choroid.
  
• Tuberculosis, Oral [M0022125]
  Tuberculosis of the mouth, tongue, and salivary glands.
  
• Tuberculosis, Osteoarticular [M0022128]
  Tuberculosis of the bones or joints.
  
• Tuberculosis, Pleural [M0022130]
  Tuberculosis of the serous membrane lining the thoracic cavity and surrounding the lungs.
  
• Tuberculosis, Pulmonary [M0022131]
  Tuberculosis of the lungs.
  
• Tuberculosis, Renal [M0022132]
  Infection of the KIDNEY with species of MYCOBACTERIUM.
  
• Tuberculosis, Spinal [M0022133]
  Osteitis or caries of the vertebrae, usually occurring as a complication of tuberculosis of the lungs.
  
• Tuberculosis, Splenic [M0022134]
  Infection of the spleen with species of MYCOBACTERIUM.
  
• Tuberculosis, Urogenital [M0022135]
  A general term for MYCOBACTERIUM infections of any part of the UROGENITAL SYSTEM in either the male or the female.
  
• Tuberculous Hypertrophic Pachymeningitis [M0336259]
  
• Tubular Aggregate Myopathy [M0335643]
  
• Tularemia [M0022145]
  A plague-like disease of rodents, transmissible to man. It is caused by FRANCISELLA TULARENSIS and is characterized by fever, chills, headache, backache, and weakness.
  
• Tumor Lysis Syndrome [M0023515]
  A syndrome resulting from cytotoxic therapy, occurring generally in aggressive, rapidly proliferating lymphoproliferative disorders. It is characterized by combinations of hyperuricemia, lactic acidosis, hyperkalemia, hyperphosphatemia and hypocalcemia.
  
• Turner Syndrome [M0022170]
  A syndrome of defective gonadal development in phenotypic women with a karyotype of sex chromosome monosomy (45,X or 45,XO), associated with the loss of a sex chromosome X or Y. Patients generally are of short stature with undifferentiated (streak) gonads, sexual infantilism (HYPOGONADISM), webbing of the neck, cubitus valgus, elevated GONADOTROPINS and decreased ESTRADIOL level in blood. Studies of Turner Syndrome and its variants have contributed significantly to the understanding of SEX DIFFERENTIATION. NOONAN SYNDROME bears similarity to this disorder; however, it also occurs in males, has normal karyotype, and is inherited as an autosomal dominant.
  
• Turner Syndrome, Male [M0014958]
  
• Tympanic Membrane Perforation [M0027248]
  An opening in the tympanic membrane usually caused by trauma. There are four general categories: compression injuries (the most common and usually the result of a blow to the ear); instrumentation injuries (the second most common, usually inadvertent, caused often by cotton swabs or bobby-pins); burn-slag injuries (frequently seen in industry, from hot metal from machines or welding); and blast injuries (usually seen during war or as a result of terrorist bombing). In the absence of infection, most traumatic tympanic membrane perforations heal spontaneously. Persistent perforation is usually a manifestation of tubotympanitis, an inflammation of the eustachian tube and tympanic cavity (middle ear). (From Paparella, Shumrick, Gluckman, and Meyerhoff: Otolaryngology, vol. II, 3d ed, pp1363-65)
  
• Type I Mucolipidosis [M0335702]
  
• Type II Mucolipidosis [M0014163]
  
• Type III Mucolipidosis [M0335704]
  
• Type IV Mucolipidosis [M0335703]
  
• Typhlitis [M0445579]
  Necrotizing inflammation of the CECUM ("typhlon" in Greek), sometimes spreading to the APPENDIX and/or the ILEUM. Symptoms include ABDOMINAL PAIN and DIARRHEA. Its pathogenesis is multifactorial. Typhlitis is often associated with NEUTROPENIA and chemotherapy in immunocompromised individuals (IMMUNOCOMPROMISED HOST).
  
• Typhoid Fever [M0022185]
  An acute systemic febrile infection caused by SALMONELLA TYPHI, a serotype of SALMONELLA ENTERICA.
  
• Typhus [M0022192]
  
• Typhus, Endemic Flea-Borne [M0022190]
  An infectious disease clinically similar to epidemic louse-borne typhus (TYPHUS, EPIDEMIC LOUSE-BORNE), but caused by RICKETTSIA TYPHI, which is transmitted from rat to man by the rat flea, Xenopsylla cheopis.
  
• Typhus, Epidemic Louse-Borne [M0022193]
  The classic form of typhus, caused by RICKETTSIA PROWAZEKII, which is transmitted from man to man by the louse Pediculus humanus corporis. This disease is characterized by the sudden onset of intense headache, malaise, and generalized myalgia followed by the formation of a macular skin eruption and vascular and neurologic disturbances.
  
• Tyrosinemia, Type I [M0336266]
  
• Tyrosinemia, Type II [M0336267]
  
• Tyrosinemia, Type III [M0336268]
  A group of disorders which have in common elevations of tyrosine in the blood and urine secondary to an enzyme deficiency. Type I tyrosinemia features episodic weakness, self-mutilation, hepatic necrosis, renal tubular injury, and seizures and is caused by a deficiency of the enzyme fumarylacetoacetase. Type II tyrosinemia features mental retardation, painful corneal ulcers, and keratoses of the palms and plantar surfaces and is caused by a deficiency of the enzyme TYROSINE TRANSAMINASE. Type III tyrosinemia features mental retardation and is caused by a deficiency of the enzyme 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE. (Menkes, Textbook of Child Neurology, 5th ed, pp42-3)
  
• Tyrosinemias [M0328654]
  A group of disorders which have in common elevations of tyrosine in the blood and urine secondary to an enzyme deficiency. Type I tyrosinemia features episodic weakness, self-mutilation, hepatic necrosis, renal tubular injury, and seizures and is caused by a deficiency of the enzyme fumarylacetoacetase. Type II tyrosinemia features mental retardation, painful corneal ulcers, and keratoses of the palms and plantar surfaces and is caused by a deficiency of the enzyme TYROSINE TRANSAMINASE. Type III tyrosinemia features mental retardation and is caused by a deficiency of the enzyme 4-HYDROXYPHENYLPYRUVATE DIOXYGENASE. (Menkes, Textbook of Child Neurology, 5th ed, pp42-3)
  
• UDPglucose 4-Epimerase Deficiency Disease [M0335206]
  
• Ulnar Nerve Compression Syndromes [M0026858]
  Ulnar neuropathies caused by mechanical compression of the nerve at any location from its origin at the BRACHIAL PLEXUS to its terminations in the hand. Common sites of compression include the retroepicondylar groove, cubital tunnel at the elbow (CUBITAL TUNNEL SYNDROME), and Guyon's canal at the wrist. Clinical features depend on the site of injury, but may include weakness or paralysis of wrist flexion, finger flexion, and ulnar innervated intrinsic hand muscles, and impaired sensation over the ulnar aspect of the hand, fifth finger, and ulnar half of the ring finger. (Joynt, Clinical Neurology, 1995, Ch51, p43)
  
• Ulnar Nerve Entrapment Syndrome [M0026857]
  
• Ulnar Nerve External Compression Syndrome [M0336236]
  
• Ulnar Nerve Palsy [M0336228]
  
• Ulnar Neuritis [M0336229]
  
• Ulnar Neuropathies [M0328655]
  Disease involving the ULNAR NERVE from its origin in the BRACHIAL PLEXUS to its termination in the hand. Clinical manifestations may include PARESIS or PARALYSIS of wrist flexion, finger flexion, thumb adduction, finger abduction, and finger adduction. Sensation over the medial palm, fifth finger, and ulnar aspect of the ring finger may also be impaired. Common sites of injury include the AXILLA, cubital tunnel at the ELBOW, and Guyon's canal at the wrist. (From Joynt, Clinical Neurology, 1995, Ch51 pp43-5)
  
• Umbilical Cyst [M0022299]
  
• Uncinate Seizures [M0334956]
  
• Unidirectional Nystagmus [M0333599]
  
• Unilateral Multicystic Dysplastic Kidney [M0482862]
  
• Unilateral Vocal Cord Paresis [M0336424]
  
• Unverricht-Lundborg Syndrome [M0328656]
  An autosomal recessive condition characterized by recurrent myoclonic and generalized seizures, ATAXIA, slowly progressive intellectual deterioration, dysarthria, and intention tremor. Myoclonic seizures are severe and continuous, and tend to be triggered by movement, stress, and sensory stimuli. The age of onset is between 8 and 13 years, and the condition is relatively frequent in the Baltic region, especially Finland. (From Menkes, Textbook of Child Neurology, 5th ed, pp109-110)
  
• Upper Airway Resistance Sleep Apnea Syndrome [M0335104]
  
• Upper Brachial Plexus Neuropathy [M0335825]
  
• Urachal Cyst [M0022300]
  Cyst occurring in a persistent portion of the urachus, presenting as an extraperitoneal mass in the umbilical region. It is characterized by abdominal pain, and fever if infected. It may rupture, leading to peritonitis, or it may drain through the umbilicus.
  
• Ureaplasma Infections [M0025672]
  Infections with bacteria of the genus UREAPLASMA.
  
• Uremia [M0022319]
  A clinical syndrome associated with the retention of renal waste products or uremic toxins in the blood. It is usually the result of RENAL INSUFFICIENCY. Most uremic toxins are end products of protein or nitrogen CATABOLISM, such as UREA or CREATININE. Severe uremia can lead to multiple organ dysfunctions with a constellation of symptoms.
  
• Ureteral Diseases [M0022325]
  Pathological processes involving the URETERS.
  
• Ureteral Obstruction [M0022327]
  Blockage in any part of the URETER causing obstruction of urine flow from the kidney to the URINARY BLADDER. The obstruction may be congenital, acquired, unilateral, bilateral, complete, partial, acute, or chronic. Depending on the degree and duration of the obstruction, clinical features vary greatly such as HYDRONEPHROSIS and obstructive nephropathy.
  
• Ureterocele [M0022328]
  A cystic dilatation of the end of a URETER as it enters into the URINARY BLADDER. It is characterized by the ballooning of the ureteral orifice into the lumen of the bladder and may obstruct urine flow.
  
• Ureterolithiasis [M0490215]
  Formation of stones in the URETER.
  
• Urethral Diseases [M0022332]
  Pathological processes involving the URETHRA.
  
• Urethral Obstruction [M0022334]
  Partial or complete blockage in any part of the URETHRA that can lead to difficulty or inability to empty the URINARY BLADDER. It is characterized by an enlarged, often damaged, bladder with frequent urges to void.
  
• Urethral Stricture [M0022335]
  Narrowing of any part of the URETHRA. It is characterized by decreased urinary stream and often other obstructive voiding symptoms.
  
• Urethritis [M0022336]
  Inflammation involving the URETHRA. Similar to CYSTITIS, clinical symptoms range from vague discomfort to painful urination (DYSURIA), urethral discharge, or both.
  
• Urinary Bladder Diseases [M0002630]
  Pathological processes of the URINARY BLADDER.
  
• Urinary Bladder Neck Obstruction [M0002634]
  Blocked urine flow through the bladder neck, the narrow internal urethral opening at the base of the URINARY BLADDER. Narrowing or strictures of the URETHRA can be congenital or acquired. It is often observed in males with enlarged PROSTATE GLAND.
  
• Urinary Bladder Neurogenesis [M0337437]
  
• Urinary Bladder, Neurogenic [M0002636]
  Dysfunction of the URINARY BLADDER due to disease of the central or peripheral nervous system pathways involved in the control of URINATION. This is often associated with SPINAL CORD DISEASES, but may also be caused by BRAIN DISEASES or PERIPHERAL NERVE DISEASES.
  
• Urinary Incontinence [M0022370]
  Involuntary loss of URINE, such as leaking of urine. It is a symptom of various underlying pathological processes. Major types of incontinence include URINARY URGE INCONTINENCE and URINARY STRESS INCONTINENCE.
  
• Urinary Incontinence, Stress [M0022371]
  Involuntary discharge of URINE as a result of physical activities that increase abdominal pressure on the URINARY BLADDER without detrusor contraction or overdistended bladder. The subtypes are classified by the degree of leakage, descent and opening of the bladder neck and URETHRA without bladder contraction, and sphincter deficiency.
  
• Urinary Incontinence, Urge [M0461242]
  Involuntary discharge of URINE that is associated with an abrupt and strong desire to void. It is usually related to the involuntary contractions of the detrusor muscle of the bladder (detrusor hyperreflexia or detrusor instability).
  
• Urinary Tract Infections [M0022373]
  Inflammatory responses of the epithelium of the URINARY TRACT to microbial invasions. They are often bacterial infections with associated BACTERIURIA and PYURIA.
  
• Urination Disorders [M0022377]
  Abnormalities in the process of URINE voiding, including bladder control, frequency of URINATION, as well as the volume and composition of URINE.
  
• Urogenital Abnormalities [M0022390]
  Congenital structural abnormalities of the UROGENITAL SYSTEM in either the male or the female.
  
• Urolithiasis [M0022363]
  Formation of stones in any part of the URINARY TRACT, usually in the KIDNEY; URINARY BLADDER; or the URETER.
  
• Urologic Diseases [M0022400]
  Pathological processes of the URINARY TRACT in both males and females.
  
• Urticaria [M0022414]
  A vascular reaction of the skin characterized by erythema and wheal formation due to localized increase of vascular permeability. The causative mechanism may be allergy, infection, or stress.
  
• Urticaria Pigmentosa [M0022417]
  The most common form of cutaneous mastocytosis (MASTOCYTOSIS, CUTANEOUS) that occurs primarily in children. It is characterized by the multiple small reddish-brown pigmented pruritic macules and papules.
  
• Usher Syndrome, Type I [M0483845]
  
• Usher Syndrome, Type II [M0483847]
  
• Usher Syndrome, Type III [M0483846]
  
• Usher Syndromes [M0483844]
  Autosomal recessive hereditary disorders characterized by congenital SENSORINEURAL HEARING LOSS and RETINITIS PIGMENTOSA. Genetically and symptomatically heterogeneous, clinical classes include type I, type II, and type III. Their severity, age of onset of retinitis pigmentosa and the degree of vestibular dysfunction are variable.
  
• Uterine Cervical Diseases [M0003936]
  Pathological processes of the UTERINE CERVIX.
  
• Uterine Cervical Erosion [M0003938]
  Loss or destruction of the epithelial lining of the UTERINE CERVIX.
  
• Uterine Cervical Incompetence [M0003939]
  Incompetent UTERINE CERVIX is usually diagnosed in the second trimester of PREGNANCY. It is characterized by passive painless cervical dilation in the absence of UTERINE CONTRACTION; BLEEDING; INFECTION; and sometimes with the amniotic sac (AMNIOTIC MEMBRANE) bulging through the partially dilated cervix. Left untreated, this condition may lead to premature pregnancy loss, such as HABITUAL ABORTION.
  
• Uterine Cervicitis [M0003932]
  Inflammation of the UTERINE CERVIX.
  
• Uterine Diseases [M0022426]
  Pathological processes involving any part of the UTERUS.
  
• Uterine Inversion [M0029237]
  A complication of OBSTETRIC LABOR in which the corpus of the UTERUS is forced completely or partially through the UTERINE CERVIX. This can occur during the late stages of labor and is associated with IMMEDIATE POSTPARTUM HEMORRHAGE.
  
• Uterine Perforation [M0022432]
  A hole or break through the wall of the UTERUS, usually made by the placement of an instrument or INTRAUTERINE DEVICES.
  
• Uterine Prolapse [M0022433]
  Downward displacement of the UTERUS. It is classified in various degrees: in the first degree the UTERINE CERVIX is within the vaginal orifice; in the second degree the cervix is outside the orifice; in the third degree the entire uterus is outside the orifice.
  
• Uterine Rupture [M0022435]
  A complete separation or tear in the wall of the UTERUS with or without expulsion of the FETUS. It may be due to injuries, multiple pregnancies, large fetus, previous scarring, or obstruction.
  
• Uveal Diseases [M0022443]
  Diseases of the uvea.
  
• Uveitis [M0022445]
  Inflammation of part or all of the uvea, the middle (vascular) tunic of the eye, and commonly involving the other tunics (sclera and cornea, and the retina). (Dorland, 27th ed)
  
• Uveitis, Anterior [M0022446]
  Inflammation of the anterior uvea comprising the iris, angle structures, and the ciliary body. Manifestations of this disorder include ciliary injection, exudation into the anterior chamber, iris changes, and adhesions between the iris and lens (posterior synechiae). Intraocular pressure may be increased or reduced.
  
• Uveitis, Intermediate [M0024295]
  Inflammation of the pars plana, ciliary body, and adjacent structures.
  
• Uveitis, Posterior [M0024294]
  Inflammation of the choroid as well as the retina and vitreous body. Some form of visual disturbance is usually present. The most important characteristics of posterior uveitis are vitreous opacities, choroiditis, and chorioretinitis.
  
• Uveitis, Suppurative [M0024247]
  Intraocular infection caused mainly by pus-producing bacteria and rarely by fungi. The infection may be caused by an injury or surgical wound (exogenous) or by endogenous septic emboli in such diseases as bacterial endocarditis or meningococcemia.
  
• Uveomeningoencephalitic Syndrome [M0022447]
  A syndrome characterized by bilateral granulomatous UVEITIS with IRITIS and secondary GLAUCOMA, premature ALOPECIA, symmetrical VITILIGO, poliosis circumscripta (a strand of depigmented hair), HEARING DISORDERS, and meningeal signs (neck stiffness and headache). Examination of the cerebrospinal fluid reveals a pattern consistent with MENINGITIS, ASEPTIC. (Adams et al., Principles of Neurology, 6th ed, p748; Surv Ophthalmol 1995 Jan;39(4):265-292)
  
• Uveoparotid Fever [M0022448]
  A manifestation of sarcoidosis marked by chronic inflammation of the parotid gland and the uvea.
  
• Vaccinia [M0022460]
  The cutaneous and occasional systemic reactions associated with vaccination using smallpox (variola) vaccine.
  
• Vaginal Discharge [M0029010]
  A common gynecologic disorder characterized by an abnormal, nonbloody discharge from the genital tract.
  
• Vaginal Diseases [M0022482]
  Pathological processes of the VAGINA.
  
• Vaginal Prolapse [M0022434]
  
• Vaginismus [M0029730]
  Recurrent or persistent involuntary SPASM of the outer muscles of the VAGINA, occurring during vaginal penetration.
  
• Vaginitis [M0022488]
  Inflammation of the vagina characterized by pain and a purulent discharge.
  
• Vaginitis, Monilial [M0393246]
  
• Vaginosis, Bacterial [M0025299]
  Polymicrobial, nonspecific vaginitis associated with positive cultures of Gardnerella vaginalis and other anaerobic organisms and a decrease in lactobacilli. It remains unclear whether the initial pathogenic event is caused by the growth of anaerobes or a primary decrease in lactobacilli.
  
• Vagus Nerve Diseases [M0328657]
  Diseases of the tenth cranial nerve, including brain stem lesions involving its nuclei (solitary, ambiguus, and dorsal motor), nerve fascicles, and intracranial and extracranial course. Clinical manifestations may include dysphagia, vocal cord weakness, and alterations of parasympathetic tone in the thorax and abdomen.
  
• Varicocele [M0022528]
  A condition characterized by the dilated tortuous veins of the SPERMATIC CORD with a marked left-sided predominance. Adverse effect on male fertility occurs when varicocele leads to an increased scrotal (and testicular) temperature and reduced testicular volume.
  
• Varicose Ulcer [M0022529]
  Ulcer due to varicose veins. Chronic venous insufficiency in the deep veins of the legs leads to shunting the venous return into the superficial veins, in which pressure and flow rate, as well as oxygen content, are increased.
  
• Variola Minor [M0019976]
  
• Vascular Dementia, Acute Onset [M0334732]
  
• Vascular Diseases [M0022535]
  
• Vascular Headaches [M0022536]
  Secondary headache disorders attributed to a variety of cranial or cervical vascular disorders, such as BRAIN ISCHEMIA; INTRACRANIAL HEMORRHAGES; and CENTRAL NERVOUS SYSTEM VASCULAR MALFORMATIONS.
  
• Vascular Hemostatic Disorders [M0029879]
  Alterations in the mechanical integrity or structure of the blood vessels leading to bleeding disorders.
  
• Vasculitis [M0022540]
  Inflammation of a blood vessel.
  
• Vasculitis, Allergic Cutaneous [M0022541]
  Vasculitis due to allergic reaction, marked by such cutaneous lesions as papules, macules, vesicles, urticarial wheals, purpura, and small ulcers, and accompanied by itching and usually a slight fever and malaise.
  
• Vasculitis, Central Nervous System [M0328658]
  Inflammation of blood vessels within the central nervous system. Etiologies include autoimmune disorders (see also LUPUS ERYTHEMATOSUS, SYSTEMIC; POLYARTERITIS NODOSA; WEGENER'S GRANULOMATOSIS), infections, exposure to radiation or toxins, and other conditions. Autoimmune or idiopathic vasculitides limited to the central nervous system are referred to as primary CNS vasculitides. CNS vasculitides associated with a systemic process or known pathogens are referred to as secondary CNS vasculitides. Clinical manifestations are highly variable but include headaches; SEIZURES; behavioral alterations; INTRACRANIAL HEMORRHAGES; transient ischemic attacks (ISCHEMIC ATTACK, TRANSIENT); and BRAIN INFARCTION. (From Adams et al., Principles of Neurology, 6th ed, pp856-61)
  
• Vasculitis, Hemorrhagic [M0018181]
  
• Vasculitis, Hypersensitivity [M0027595]
  Heterogeneous group of disorders characterized by a vasculitic syndrome presumed to be associated with a hypersensitivity reaction following exposure to an antigen such as an infectious agent, a drug, or other foreign or endogenous substance (Wilson et al, Harrison's Principles of Internal Medicine, 12th ed, p1459).
  
• Vasospasm, Intracranial [M0328659]
  Narrowing of the lumen of one or more intracranial arteries due to contraction of arterial smooth muscle or to morphologic changes of the blood vessel wall. Large blood vessels near the base of the brain are primarily affected and reduced blood flow may result in hypoxic-ischemic brain injury (HYPOXIA-ISCHEMIA, BRAIN). Vasospasm may be associated with SUBARACHNOID HEMORRHAGE; CRANIOCEREBRAL TRAUMA; and other disorders. (From Neurosurg Clin N Am, 1998 Jul;9(3):615-27)
  
• Vegetative State [M0335845]
  
• Velocardiofacial Syndrome [M0474269]
  
• Venous Infarction, Brain [M0334192]
  
• Venous Insufficiency [M0022591]
  Inadequacy of the venous valves and impairment of venous return (venous stasis) usually from the legs, often with edema and sometimes with stasis ulcers at the ankle.
  
• Ventricular Fibrillation [M0022595]
  
• Ventricular Outflow Obstruction [M0022598]
  Occlusion of the ventricular outflow or inflow tract on either side of the heart. It may result from a congenital defect or predisposing heart disease, or as a complication of surgery or tumors of the heart or its vessels.
  
• Ventricular Outflow Obstruction, Left [M0022596]
  
• Ventricular Outflow Obstruction, Right [M0022597]
  
• Ventricular Septal Rupture [M0027957]
  Rupture of the intraventricular septum of the heart, usually secondary to myocardial infarction.
  
• Verbal Fluency Disorders [M0337317]
  
• Verruga Peruana [M0002191]
  
• Versive Seizures [M0335067]
  
• Vertebral Artery Dissection [M0328660]
  Dissection of the wall of the vertebral artery, leading to the formation of an aneurysm that may occlude the vessel. Thrombus formation may occur and give rise to emboli. Cervical fractures or related NECK INJURIES and CRANIOCEREBRAL TRAUMA are commonly associated conditions, although this process may occur spontaneously. Ischemia, infarction, and hemorrhage in the vascular distribution of the affected vertebral artery may complicate this condition.
  
• Vertebral Artery Insufficiency [M0022626]
  
• Vertebral Artery Stenosis [M0336310]
  
• Vertebrobasilar Dolichoectasia [M0336311]
  
• Vertebrobasilar Insufficiency [M0022627]
  Localized or diffuse reduction in blood flow through the vertebrobasilar arterial system, which supplies the BRAIN STEM; CEREBELLUM; OCCIPITAL LOBE; medial TEMPORAL LOBE; and THALAMUS. Characteristic clinical features include SYNCOPE; lightheadedness; visual disturbances; and VERTIGO. BRAIN STEM INFARCTIONS or other BRAIN INFARCTION may be associated.
  
• Vertebrogenic Pain Syndrome [M0336344]
  
• Vertical Nystagmus [M0333562]
  
• Vertiginous Partial Seizure [M0335092]
  
• Vertigo, Aural [M0013358]
  
• Vertigo, Paroxysmal [M0337363]
  
• Vesico-Ureteral Reflux [M0022634]
  Retrograde flow of urine from the URINARY BLADDER into the URETER. This is often due to incompetence of the vesicoureteral valve leading to ascending bacterial infection into the KIDNEY.
  
• Vesicular Exanthema of Swine [M0022636]
  A calicivirus infection of swine characterized by hydropic degeneration of the oral and cutaneous epithelia.
  
• Vesicular Skin Diseases [M0019931]
  
• Vestibular Diseases [M0024253]
  Diseases of the vestibule, the part of the inner ear that contains organs involved with balance.
  
• Vestibular Nerve Diseases [M0333670]
  
• Vestibular Neuronitis [M0328661]
  Idiopathic inflammation of the vestibular nerve, characterized clinically by the acute or subacute onset of vertigo, nausea, and imbalance. The cochlear nerve is typically spared and hearing loss and tinnitus do not usually occur. Symptoms usually resolve over a period of days to weeks. (Adams et al., Principles of Neurology, 6th ed, p304)
  
• Vestibular Neuropathy [M0337541]
  
• Vestibulocochlear Nerve Diseases [M0000242]
  Diseases of the vestibular and/or cochlear (acoustic) nerves, which join to form the vestibulocochlear nerve. VESTIBULAR NEURITIS, cochlear neuritis, and acoustic neuromas (NEUROMA, ACOUSTIC) are relatively common conditions that affect these nerves. Clinical manifestations vary with which nerve is primarily affected, and include hearing loss, vertigo, and tinnitus.
  
• Vibrio Infections [M0022654]
  Infections with bacteria of the genus VIBRIO.
  
• Vincent Angina [M0447115]
  VINCENT INFECTION where the lesions spread to the SOFT PALATE and OROPHARYNX.
  
• Viremia [M0022739]
  The presence of viruses in the blood.
  
• Virus Diseases [M0022758]
  A general term for diseases produced by viruses.
  
• Visceral Myopathy [M0011582]
  
• Visceral Prolapse [M0022766]
  The prolapse or downward displacement of the VISCERA.
  
• Vision Disorders [M0022771]
  Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions. Visual disability refers to inability of the individual to perform specific visual tasks, such as reading, writing, orientation, or traveling unaided. (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132)
  
• Vision, Low [M0023639]
  Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. Low vision generally refers to visual disorders that are caused by diseases that cannot be corrected by refraction (e.g., MACULAR DEGENERATION; RETINITIS PIGMENTOSA; DIABETIC RETINOPATHY, etc.).
  
• Visna [M0024699]
  Demyelinating leukoencephalomyelitis of sheep caused by the VISNA-MAEDI VIRUS. It is similar to but not the same as SCRAPIE.
  
• Visual Partial Seizure [M0335093]
  
• Vitamin A Deficiency [M0022791]
  A nutritional condition produced by a deficiency of VITAMIN A in the diet, characterized by NIGHT BLINDNESS and other ocular manifestations such as dryness of the conjunctiva and later of the cornea (XEROPHTHALMIA). Vitamin A deficiency is a very common problem worldwide, particularly in developing countries as a consequence of famine or shortages of vitamin A-rich foods. In the United States it is found among the urban poor, the elderly, alcoholics, and patients with malabsorption. (From Cecil Textbook of Medicine, 19th ed, p1179)
  
• Vitamin B 12 Deficiency [M0022796]
  A nutritional condition produced by a deficiency of VITAMIN B 12 in the diet, characterized by megaloblastic anemia. Since vitamin B 12 is not present in plants, humans have obtained their supply from animal products, from multivitamin supplements in the form of pills, and as additives to food preparations. A wide variety of neuropsychiatric abnormalities is also seen in vitamin B 12 deficiency and appears to be due to an undefined defect involving myelin synthesis. (From Cecil Textbook of Medicine, 19th ed, p848)
  
• Vitamin B 6 Deficiency [M0378655]
  A nutritional condition produced by a deficiency of VITAMIN B 6 in the diet, characterized by dermatitis, glossitis, cheilosis, and stomatitis. Marked deficiency causes irritability, weakness, depression, dizziness, peripheral neuropathy, and seizures. In infants and children typical manifestations are diarrhea, anemia, and seizures. Deficiency can be caused by certain medications, such as isoniazid.
  
• Vitamin B Deficiency [M0022793]
  A condition due to deficiency in any member of the VITAMIN B COMPLEX. These B vitamins are water-soluble and must be obtained from the diet because they are easily lost in the urine. Unlike the lipid-soluble vitamins, they cannot be stored in the body fat.
  
• Vitamin D Deficiency [M0022798]
  A nutritional condition produced by a deficiency of VITAMIN D in the diet, insufficient production of vitamin D in the skin, inadequate absorption of vitamin D from the diet, or abnormal conversion of vitamin D to its bioactive metabolites. It is manifested clinically as RICKETS in children and OSTEOMALACIA in adults. (From Cecil Textbook of Medicine, 19th ed, p1406)
  
• Vitamin E Deficiency [M0022804]
  A nutritional condition produced by a deficiency of VITAMIN E in the diet, characterized by posterior column and spinocerebellar tract abnormalities, areflexia, ophthalmoplegia, and disturbances of gait, proprioception, and vibration. In premature infants vitamin E deficiency is associated with hemolytic anemia, thrombocytosis, edema, intraventricular hemorrhage, and increasing risk of retrolental fibroplasia and bronchopulmonary dysplasia. An apparent inborn error of vitamin E metabolism, named familial isolated vitamin E deficiency, has recently been identified. (Cecil Textbook of Medicine, 19th ed, p1181)
  
• Vitamin K Deficiency [M0022808]
  A nutritional condition produced by a deficiency of VITAMIN K in the diet, characterized by an increased tendency to hemorrhage (HEMORRHAGIC DISORDERS). Such bleeding episodes may be particularly severe in newborn infants. (From Cecil Textbook of Medicine, 19th ed, p1182)
  
• Vitiligo [M0022818]
  A disorder consisting of areas of macular depigmentation, commonly on extensor aspects of extremities, on the face or neck, and in skin folds. Age of onset is often in young adulthood and the condition tends to progress gradually with lesions enlarging and extending until a quiescent state is reached.
  
• Vitreoretinopathy, Proliferative [M0027923]
  Vitreoretinal membrane shrinkage or contraction secondary to the proliferation of primarily retinal pigment epithelial cells and glial cells, particularly fibrous astrocytes, followed by membrane formation. The formation of fibrillar collagen and cellular proliferation appear to be the basis for the contractile properties of the epiretinal and vitreous membranes.
  
• Vitreous Detachment [M0029919]
  Detachment of the corpus vitreum (VITREOUS BODY) from its normal attachments, especially the retina, due to shrinkage from degenerative or inflammatory conditions, trauma, myopia, or senility.
  
• Vocal Cord Palsy, Congenital [M0336425]
  
• Vocal Cord Paralysis [M0022824]
  Paralysis of one or both vocal cords, which produces hoarseness or aphonia. This condition may be caused by diseases of the medulla (e.g., LATERAL MEDULLARY SYNDROME;), VAGUS NERVE; or recurrent laryngeal nerve. Neuromuscular junction diseases and local myopathic processes may also affect vocal cord function. (Adams et al., Principles of Neurology, 6th ed, p1380)
  
• Voice Disorder, Neurologic [M0337378]
  
• Voice Disorders [M0022831]
  Disorders of voice pitch, loudness, or quality. Dysphonia refers to impaired utterance of sounds by the vocal folds.
  
• Volkmann Contracture [M0004910]
  
• von Willebrand Disease [M0022853]
  Group of hemorrhagic disorders in which the von Willebrand factor (Factor VIII-related antigen) is either quantitatively or qualitatively abnormal. They are usually inherited as an autosomal dominant trait though rare kindreds are autosomal recessive. Symptoms vary depending on severity and disease type but may include prolonged bleeding time, deficiency of factor VIII, and impaired platelet adhesion.
  
• Vulvar Diseases [M0022856]
  Pathological processes of the VULVA.
  
• Vulvar Lichen Sclerosus [M0012079]
  Atrophy and shriveling of the SKIN of the VULVA that is characterized by the whitish LICHEN SCLEROSUS appearance, inflammation, and PRURITUS.
  
• Vulvitis [M0022858]
  Inflammation of the VULVA. It is characterized by PRURITUS and painful urination.
  
• Vulvovaginitis [M0022859]
  Inflammation of the VULVA and the VAGINA, characterized by discharge, burning, and PRURITUS.
  
• Waardenburg's Syndrome [M0022860]
  Rare, autosomal dominant disease with variable penetrance and several known clinical types. Characteristics may include depigmentation of the hair and skin, congenital deafness, heterochromia iridis, medial eyebrow hyperplasia, hypertrophy of the nasal root, and especially dystopia canthorum. The underlying cause may be defective development of the neural crest (neurocristopathy). Waardenburg's syndrome may be closely related to piebaldism. Klein-Waardenburg Syndrome refers to a disorder that also includes upper limb abnormalities.
  
• Wandering Spleen [M0477931]
  A congenital or acquired condition in which the SPLEEN is not in its normal anatomical position but moves about in the ABDOMEN. This is due to laxity or absence of suspensory ligaments which normally provide peritoneal attachments to keep the SPLEEN in a fixed position. Clinical symptoms include ABDOMINAL PAIN, splenic TORSION and ISCHEMIA.
  
• Warm Ischemia [M0483148]
  A tissue or organ remaining at physiological temperature during decreased BLOOD perfusion or in the absence of blood supply. During ORGAN TRANSPLANTATION it begins when the organ reaches physiological temperature before the completion of SURGICAL ANASTOMOSIS and ends with reestablishment of the BLOOD CIRCULATION through the tissue.
  
• Warts [M0022875]
  Benign epidermal proliferations or tumors; some are viral in origin.
  
• Wasting Disease, Chronic [M0404623]
  A transmissible spongiform encephalopathy (prion disease) of DEER and elk characterized by chronic weight loss leading to death. It is thought to spread by direct contact between animals or through environmental contamination with the prion protein (PRIONS).
  
• Wasting Syndrome [M0028712]
  A condition of involuntary weight loss of greater then 10% of baseline body weight. It is characterized by atrophy of muscles and depletion of lean body mass. Wasting is a sign of MALNUTRITION as a result of inadequate dietary intake, malabsorption, or hypermetabolism.
  
• Water Intoxication [M0022885]
  A condition resulting from the excessive retention of water with sodium depletion.
  
• Water Stress [M0410970]
  
• Waterhouse-Friderichsen Syndrome [M0022902]
  A condition caused by overwhelming BACTERIAL INFECTIONS or SEPTICEMIA, leading to HEMORRHAGE and NECROSIS of the ADRENAL GLAND. It is characterized by rapidly developing ADRENAL INSUFFICIENCY; HYPOTENSION; and widespread cutaneous PURPURA. This syndrome may occur at any age but is more common in children.
  
• Watson Syndrome [M0374985]
  A syndrome characterized by the presence of PULMONARY STENOSIS; CAFE-AU-LAIT SPOTS; MENTAL RETARDATION; and short stature caused by mutations in the NF1 gene (GENES, NEUROFIBROMATOSIS 1).
  
• Weber Syndrome [M0334266]
  
• Weber-Cockayne Syndrome [M0024609]
  
• Wegener Granulomatosis [M0022908]
  A multisystemic disease of a complex genetic background. It is characterized by inflammation of the blood vessels (VASCULITIS) leading to damages in any number of organs. The common features include granulomatous inflammation of the RESPIRATORY TRACT and kidneys (GLOMERULONEPHRITIS). Most patients have measurable autoantibodies (ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES) against neutrophil proteinase-3 (WEGENER AUTOANTIGEN).
  
• Weil Disease [M0022917]
  A severe form of LEPTOSPIROSIS, usually caused by LEPTOSPIRA INTERROGANS SEROVAR ICTEROHAEMORRHAGIAE and occasionally other serovars. It is transmitted to humans by the rat and is characterized by hemorrhagic and renal symptoms with accompanying JAUNDICE.
  
• Welander Distal Myopathy [M0464101]
  
• Werner Syndrome [M0022920]
  An autosomal recessive disorder that causes premature aging in adults, characterized by sclerodermal skin changes, cataracts, subcutaneous calcification, muscular atrophy, a tendency to diabetes mellitus, aged appearance of the face, baldness, and a high incidence of neoplastic disease.
  
• Wernicke Encephalopathy [M0022921]
  An acute neurological disorder characterized by the triad of ophthalmoplegia, ataxia, and disturbances of mental activity or consciousness. Eye movement abnormalities include nystagmus, external rectus palsies, and reduced conjugate gaze. THIAMINE DEFICIENCY and chronic ALCOHOLISM are associated conditions. Pathologic features include periventricular petechial hemorrhages and neuropil breakdown in the diencephalon and brainstem. Chronic thiamine deficiency may lead to KORSAKOFF SYNDROME. (Adams et al., Principles of Neurology, 6th ed, pp1139-42; Davis & Robertson, Textbook of Neuropathology, 2nd ed, pp452-3)
  
• West Nile Fever [M0022928]
  A mosquito-borne viral illness caused by the WEST NILE VIRUS, a FLAVIVIRUS and endemic to regions of Africa, Asia, and Europe. Common clinical features include HEADACHE; FEVER; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. MENINGITIS; ENCEPHALITIS; and MYELITIS may also occur. The disease may occasionally be fatal or leave survivors with residual neurologic deficits. (From Joynt, Clinical Neurology, 1996, Ch26, p13; Lancet 1998 Sep 5;352(9130):767-71)
  
• West Nile Fever Meningitis [M0336329]
  
• West Nile Fever Meningoencephalitis [M0336332]
  
• West Nile Fever Myelitis [M0336333]
  
• Wheat Hypersensitivity [M0351833]
  Allergic reaction to wheat that is triggered by the immune system.
  
• Whipple Disease [M0012563]
  A chronic systemic infection by a gram-positive bacterium, Tropheryma whippelii, mainly affecting the SMALL INTESTINE but also the JOINTS; CARDIOVASCULAR SYSTEM; and the CENTRAL NERVOUS SYSTEM. The disease is characterized by fat deposits in the INTESTINAL MUCOSA and LYMPH NODES, malabsorption, DIARRHEA with fatty stools, MALNUTRITION, and ARTHRITIS.
  
• White Heifer Disease [M0008833]
  A congenital reproductive abnormality in white female offspring (heifers) in certain breeds of CATTLE, such as Belgian Blue and Shorthorn. The white color is inherited as a recessive trait which is associated with defects in the female reproductive tract (Muellerian system). These heifers are usually sterile.
  
• White Muscle Disease [M0022971]
  A myodegeneration most frequent in calves and lambs whose dams have been fed during gestation or longer on feeds, especially legumes (FABACEAE), grown in certain areas where selenium is either deficient or unavailable in the soil. It has been recorded in many countries. It has been produced experimentally in several species of animals on low-selenium intake. A similar myopathy occurs naturally in goats, deer, foals, and dogs but proof of the etiology is lacking. (Merck Veterinary Manual, 5th ed)
  
• Whooping Cough [M0022977]
  A respiratory infection caused by BORDETELLA PERTUSSIS and characterized by paroxysmal coughing ending in a prolonged crowing intake of breath.
  
• Williams Syndrome [M0028351]
  A contiguous gene syndrome associated with a heterozygous microdeletion in the chromosomal region 7q11.23, encompassing the ELASTIN gene. Clinical manifestations include supravalvular aortic stenosis (AORTIC STENOSIS, SUPRAVALVULAR), MENTAL RETARDATION, elfin facies, impaired visuospatial constructive abilities, and transient hypercalcemia in infancy. The condition affects both sexes, with onset at birth or in early infancy.
  
• Wiskott-Aldrich Syndrome [M0022985]
  A rare, X-linked immunodeficiency syndrome characterized by eczema, thrombocytopenic purpura, and recurrent pyogenic infection. It is seen exclusively in young boys. Typically, IMMUNOGLOBULIN M levels are low and IMMUNOGLOBULIN A and IMMUNOGLOBULIN E levels are elevated. Lymphoreticular malignancies are common.
  
• Wissler's Syndrome [M0022986]
  A rheumatic syndrome of possibly allergic origin, usually affecting children and adolescents, and characterized by high fever, exanthema, arthralgia, leukocytosis, and increased sedimentation rate.
  
• Wolff-Parkinson-White Syndrome [M0022990]
  A form of pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave.
  
• Wolfram Syndrome [M0022993]
  A hereditary condition characterized by multiple symptoms including those of DIABETES INSIPIDUS; DIABETES MELLITUS; OPTIC ATROPHY; and DEAFNESS. This syndrome is also known as DIDMOAD (first letter of each word) and is usually associated with VASOPRESSIN deficiency. It is caused by mutations in gene WFS1 encoding wolframin, a 100-kDa transmembrane protein.
  
• Wolman Disease [M0023386]
  The severe infantile form of inherited lysosomal lipid storage diseases due to deficiency of acid lipase (CHOLESTEROL ESTERASE). It is characterized by the accumulation of neutral lipids, particularly CHOLESTEROL ESTERS in leukocytes, fibroblasts, and hepatocytes. It is also known as Wolman's xanthomatosis and is an allelic variant of CHOLESTEROL ESTER STORAGE DISEASE.
  
• Writer's Cramp [M0334823]
  
• Writing-Induced Reflex Epilepsy [M0335124]
  
• X-Linked Combined Immunodeficiency [M0495085]
  A form of combined immunodificiency caused by mutations in the gene for INTERLEUKIN RECEPTOR COMMON GAMMA-CHAIN.
  
• X-Linked Combined Immunodeficiency Diseases [M0495084]
  Forms of combined immunodeficiency caused by mutations in the gene for INTERLEUKIN RECEPTOR COMMON GAMMA SUBUNIT. Both severe and non-severe subtypes of the disease have been identified.
  
• X-Linked Emery-Dreifuss Muscular Dystrophy [M0335586]
  
• X-Linked Lymphoproliferative Disorder [M0012827]
  
• X-Linked, Spastic Paraplegia, Hereditary [M0336727]
  
• Xanthogranuloma, Juvenile [M0023048]
  Benign disorder of infants and children caused by proliferation of HISTIOCYTES, macrophages found in tissues. These histiocytes, usually lipid-laden non-Langerhans cells, form multiple yellow-red nodules most often in the skin, the eye, and sometimes in the viscera. Patients appear to have normal lipid metabolism and are classified as a normolipemic non-Langerhans cell histiocytosis.
  
• Xanthoma [M0023051]
  
• Xanthoma Disseminatum [M0023962]
  
• Xanthomatosis [M0023050]
  A condition marked by the development of widespread xanthomas, yellow tumor-like structures filled with lipid deposits. Xanthomas can be found in a variety of tissues including the SKIN; TENDONS; joints of KNEES and ELBOWS. Xanthomatosis is associated with disturbance of LIPID METABOLISM and formation of FOAM CELLS.
  
• Xanthomatosis, Cerebrotendinous [M0028726]
  An autosomal recessive lipid storage disorder due to mutation of the gene CYP27A1 encoding sterol 27-hydroxylase. It is characterized by large deposits of CHOLESTEROL and CHOLESTANOL in various tissues resulting in xanthomatous swelling of tendons, early CATARACT, and progressive neurological symptoms.
  
• Xeroderma [M0010979]
  
• Xerophthalmia [M0023065]
  Dryness of the eye surfaces caused by deficiency of tears or conjunctival secretions. It may be associated with vitamin A deficiency, trauma, or any condition in which the eyelids do not close completely.
  
• Xerostomia [M0023067]
  Decreased salivary flow.
  
• XYY Karyotype [M0023079]
  Abnormal genetic constitution in males characterized by an extra Y chromosome.
  
• Yaws [M0023084]
  A systemic non-venereal infection of the tropics caused by Treponema pallidum subspecies pertenue.
  
• Yellow Fever [M0023087]
  An acute infectious disease primarily of the tropics, caused by a virus and transmitted to man by mosquitoes of the genera Aedes and Haemagogus.
  
• Yersinia Infections [M0023096]
  Infections with bacteria of the genus YERSINIA.
  
• Yersinia pseudotuberculosis Infections [M0023099]
  Infections with bacteria of the species YERSINIA PSEUDOTUBERCULOSIS.
  
• Zellweger Syndrome [M0023373]
  An autosomal recessive disorder due to defects in PEROXISOME biogenesis which involves more than 13 genes encoding peroxin proteins of the peroxisomal membrane and matrix. Zellweger syndrome is typically seen in the neonatal period with features such as dysmorphic skull; MUSCLE HYPOTONIA; SENSORINEURAL HEARING LOSS; visual compromise; SEIZURES; progressive degeneration of the KIDNEYS and the LIVER. Zellweger-like syndrome refers to phenotypes resembling the neonatal Zellweger syndrome but seen in children or adults with apparently intact peroxisome biogenesis.
  
• Zellweger-Like Syndrome [M0336337]
  
• Zenker Diverticulum [M0025405]
  A DIVERTICULUM at the upper end of the ESOPHAGUS through the cricopharyngeal muscle at the junction of the PHARYNX and the esophagus.
  
• Zinsser-Cole-Engman Syndrome [M0385213]
  
• Zollinger-Ellison Syndrome [M0023152]
  A syndrome that is characterized by the triad of severe PEPTIC ULCER, hypersecretion of GASTRIC ACID, and GASTRIN-producing tumors of the PANCREAS or other tissue (GASTRINOMA). This syndrome may be sporadic or be associated with MULTIPLE ENDOCRINE NEOPLASIA TYPE 1.
  
• Zoonoses [M0023156]
  Diseases of non-human animals that may be transmitted to HUMANS or may be transmitted from humans to non-human animals.
  
• Zoster Sine Herpete [M0397313]
  HERPES ZOSTER but without eruption of vesicles. Patients exhibit the characteristic pain minus the skin rash, sometimes making diagnosis difficult.
  
• Zygomycosis [M0029826]
  Infection in humans and animals caused by fungi in the class Zygomycetes. It includes MUCORMYCOSIS and entomophthoramycosis. The latter is a tropical infection of subcutaneous tissue or paranasal sinuses caused by fungi in the order Entomophthorales. Phycomycosis, closely related to zygomycosis, describes infection with members of Phycomycetes, an obsolete classification.