| acute myeloid leukaemia | <haematology> A rapidly progressing cancer of the blood affecting immature cells of the bone marrow, usually of the white cell population. It is much more common in adults than in children. Symptoms include fatigue, weight loss, fevers, weakness, pallor, bone pains, bleeding gums, nosebleeds, easy bruising, enlarged lymph nodes and joint pains. Treatment includes chemotherapy and/or bone marrow transplant. This leukaemia demonstrates granulocyte differentiation, eosinophilia and Auer rods and is associated with a reciprocal translocation between 8 and 21 (q22;q22), which is the most common translocation in acute myeloid leukaemia and is found more often in younger patients than in older patients. The oncogene involved in this translocation is AML1, which can be detected by Southern blot. Numerical abnormalities, particularly monosomy-7, trisomy-4, trisomy-8, trisomy-21, -Y, monosomy-7 and deletions of the long arms of chromosomes 5 and 7 are quite common in all acute myeloid leukaemia and not restricted to any one FAB classification. Many of these abnormalities are observed at diagnosis and at later stage disease, particularly after chemotherapy. Prognosis is generally more favorable than in FAB-M2 patients showing no translocation, because the latter patients show better remission rates for longer periods of time. Immunophenotyping is useful in diagnosis and expression of one or more of the myeloid antigens CD13, CD14 or CD33 must be detected to make a diagnosis of acute myeloid leukaemia. Acronym: AML Incidence: 2,000 new cases per year in the UK. Origin: Gr. Haima = blood (07 Apr 1998) |
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| acute necrotizing encephalitis | An acute form of encephalitis, characterised by destruction of brain parenchyme. (05 Mar 2000) |
| acute necrotizing haemorrhagic encephalomyelitis | A fulminating demyelinating disorder of the central nervous system that affects mainly children and young adults. Almost always preceded by a respiratory infection, characterised by the abrupt onset of fever, headache, confusion, and nuchal rigidity, soon followed by focal seizures, hemiplegia, or quadriplegia, brainstem findings, and coma; the CSF shows evidence of an inflammatory process; due to the massive destruction of the white matter of one or both hemispheres, often accompanied by similar destruction of the white matter of the brainstem and cerebellar peduncles; of unknown aetiology. Synonym: acute haemorrhagic leukoencephalitis, acute necrotizing haemorrhagic leukoencephalitis. (05 Mar 2000) |
| acute necrotizing haemorrhagic leukoencephalitis | A fulminating demyelinating disorder of the central nervous system that affects mainly children and young adults. Almost always preceded by a respiratory infection, characterised by the abrupt onset of fever, headache, confusion, and nuchal rigidity, soon followed by focal seizures, hemiplegia, or quadriplegia, brainstem findings, and coma; the CSF shows evidence of an inflammatory process; due to the massive destruction of the white matter of one or both hemispheres, often accompanied by similar destruction of the white matter of the brainstem and cerebellar peduncles; of unknown aetiology. Synonym: acute haemorrhagic leukoencephalitis, acute necrotizing haemorrhagic leukoencephalitis. (05 Mar 2000) |
| acute necrotizing myelitis | A spinal cord disorder, probably a demyelinating disease, which affects persons of all ages and either sex. Presents with abrupt or more gradual onset with sensory abnormalities and upper motor neuron weakness; soon a reflexic flaccid motor paralysis and sphincter paralysis supervenes, which is permanent. In some, but not all cases, bilateral or unilateral optic neuritis is associated. In the cerebrospinal fluid, the protein is increased, and mononuclear cells are present. After autopsy, the lesion has been identified as a necrotizing haemorrhagic leukomyelitis. (05 Mar 2000) |
| acute necrotizing ulcerative gingivitis | An acute or recurrent gingivitis of young and middle-aged adults characterised clinically by gingival erythema and pain, fetid odour, and necrosis and sloughing of interdental papillae and marginal gingiva which gives rise to a gray pseudomembrane; fever, regional lymphadenopathy, and other systemic manifestations also may be present. A fusiform bacillus and Treponema vincentii can be isolated from the gingival tissues in large numbers and are felt to play a significant but poorly defined role in the pathogenesis. Synonym: fusospirochetal gingivitis, trench mouth, ulceromembranous gingivitis, Vincent's disease, Vincent's infection. (05 Mar 2000) |
| acute nephritic syndrome | <nephrology, syndrome> A disease of the kidneys that results in inflammation of the glomerulus (the portion of the kidney that filters the blood). Conditions which may cause glomerulonephritis include post-streptococcal disease (strep throat), lupus, syphilis, bacterial endocarditis, membranoproliferative glomerulonephritis, sepsis, vasculitis, Goodpasture's syndrome, typhoid fever, Henoch-Schonlein purpura, hepatitis or a viral infection (for example mumps, measles, mononucleosis). (15 Jan 1998) |
| acute nephritis | <nephrology> A disease of the kidneys that results in inflammation of the glomerulus (the portion of the kidney that filters the blood). Conditions which may cause glomerulonephritis include post-streptococcal disease (strep throat), lupus, syphilis, bacterial endocarditis, membranoproliferative glomerulonephritis, sepsis, vasculitis, Goodpasture's syndrome, typhoid fever, Henoch-Schonlein purpura, hepatitis or a viral infection (for example mumps, measles, mononucleosis). (27 Sep 1997) |
| acute nephrosis | Acute oliguric renal failure, especially that caused by certain poisons. (05 Mar 2000) |
| acute non-lymphocytic leukaemia | <haematology> A form of leukaemia which is characterised by the proliferation of immature bone marrow precursor cells in the marrow and immature white blood cells (granulocytes) in the bloodstream. Occurs primarily in adults and in infants under 1 year of age. Complications include abnormal bleeding and susceptibility to infections. Symptoms include fatigue, weight loss, fevers, weakness, pallor, bone pains, bleeding gums, nosebleeds, easy bruising, enlarged lymph nodes and joint pains. Trisomy-8 is the most common cytogenetic abnormality observed, followed by monosomy-7 and monosomy-5. Approximately 8% of cases show trisomy-8, mostly in AML (M1), AM (M4) and acute monocytic leukaemia (M5). Many pre-leukaemic conditions, acute non-lymphocytic leukaemia and secondary leukemia show monosomy-7 or deletion of the long arm of chromosome 7. Treatment includes chemotherapy and/or bone marrow transplant. Acronym: ANLL Incidence: 2.5 cases per 100,000 (all ages). Origin: Gr. Haima = blood (07 Apr 1998) |
| acute organic brain syndrome | <syndrome> A constellation of behavioural or psychological signs and symptoms including problems with attention, concentration, memory, confusion, anxiety, and depression caused by transient or permanent dysfunction of the brain. Synonym: acute organic brain syndrome, OBS, organic mental syndrome. (05 Mar 2000) |
| acute pancreatitis | <radiology> Findings: elevated hemidiaphragm, atelectasis / consolidation, pulmonary oedema (direct toxic effect? cardiosuppression?), pleural effusion (more common on left), sentinel loops, colon cut-off sign, antral pad, duodenum: widened loop, thickened folds, inverted 3 (Frostberg sign) (12 Dec 1998) |
| acute parenchymatous hepatitis | A lesion in which there is extensive and rapid death of parenchymal cells of the liver, sometimes with fatty degeneration of the size of the organ; the necrosis may result from fulminant viral infection or chemical poisoning; associated with jaundice. Synonym: acute parenchymatous hepatitis, Rokitansky's disease. (05 Mar 2000) |
| acute-phase protein | <haematology> These plasma proteins (in addition to fibrinogen) increase 25% or more in response to inflammation and injury are under direct control of interleukin-6 (IL-6) (hepatocyte-stimulating factor). Other proteins which increase are ceruloplasmin, C3 and C4 which increase 50% or more; alpha-1 acid glycoprotein, alpha-1 antitrypsin, haptoglobin and fibrinogen (the major determinant of viscosity 1 ) which increase two- to fourfold; C-reactive protein (CRP) and serum amyloid A which increase several hundred-fold. Despite long-held clinical opinion to the contrary, available data indicate that neither ESR nor measurement of specific acute-phase reactants are useful in excluding underlying infection or inflammation regardless of the pretest probability. These proteins are secreted into the blood in increased or decreased quantities by hepatocytes in response to trauma, inflammation, or disease. They can serve as inhibitors or mediators of the inflammatory processes. Certain acute-phase proteins have been used to diagnose and follow the course of diseases or as tumour markers. See also: amyloid, c-reactive protein, erythrocyte sedimentation rate, viscosity. (25 Jun 1999) |
| acute-phase reaction | <immunology, rheumatology> Refers to the changes in synthesis of certain proteins within the serum during an inflammatory response, which provides rapid protection for the host against microorganisms via non-specific defense mechanisms. It consists of fever, an increase in inflammatory humoral factors, and an increased synthesis by hepatocytes of a number of proteins or glycoproteins usually found in the plasma; the reaction is mediated by endogenous pyrogens, the hypothalamus, adrenal hormones, and other factors. (12 Jul 2000) |