| malignant hyperpyrexia | A severe and often fatal illness produced by exposure to excessively high temperatures, especially when accompanied by marked exertion. It can manifest by elevated body temperature, lack of sweating, hot dry skin, and neurologic symptoms; unconsciousness, paralysis, headache, vertigo, confusion. In severe cases very high fever, vascular collapse, and coma develop. Synonym: heat apoplexy, heat hyperpyrexia, malignant hyperpyrexia, thermic fever. (05 Mar 2000) |
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| malignant hypertension | A severe form of acute hypertension that results in the abrupt rise in the blood pressure (diastolic pressure often over 120 mmHg). If left untreated, malignant hypertension can cause damage to the blood vessels in the eye, kidneys, brain and heart. Complications include stroke, heart attack, blindness and renal failure. Symptoms include headache, blurred vision, nausea, vomiting and lethargy. Neurologic symptoms are also a common finding. Malignant hypertension occurs more commonly in males, African Americans and those with a history for hypertension. (27 Sep 1997) |
| malignant hyperthermia | A severe form of fever that occurs as a reaction to certain anaesthetic agents and muscle relaxants. Malignant hyperthermia is an inherited autosomal dominant condition. Inheritance: autosomal dominant. (27 Sep 1997) |
| malignant jaundice | Jaundice associated with high fever and delirium; seen in severe hepatitis and other diseases of the liver with severe functional failure. Synonym: malignant jaundice. (05 Mar 2000) |
| malignant lentigo melanoma | <tumour> A melanoma arising from a malignant lentigo. (05 Mar 2000) |
| malignant liver tumours | <radiology> EPITHELIAL TUMORS, hepatocellular, hepatoblastoma (7%), hepatocellular carcinoma (HCC) (75%), cholangiocellular (6%), cholangiocarcinomarcinoma, cystadenocarcinoma, MESENCHYMAL TUMORS, tumours of blood vessels, angiosarcoma, haemangioendothelioma, other tumours, embryonal sarcoma, fibrosarcoma, TUMORS OF MUSCLE TISSUE, leiomyosarcoma, rhabdomyosarcoma, MISCELLANEOUS, carcinosarcoma, teratoma, yolk sac tumour, carcinoid, squamous carcinoma, primary lymphoma see: benign liver tumours (12 Dec 1998) |
| malignant lymphadenosis | An obsolete term for malignant lymphoma. (05 Mar 2000) |
| malignant lymphoma | <tumour> A general term for ordinarily malignant neoplasms of lymphoid and reticuloendothelial tissues which present as apparently circumscribed solid tumours composed of cells that appear primitive or resemble lymphocytes, plasma cells, or histiocytes. Lymphomas appear most frequently in lymph nodes, spleen, or other normal sites of lymphoreticular cells; when disseminated, Lymphoma's, especially of the lymphocytic type, may invade the peripheral blood and manifest as leukaemia. Lymphomas are classified by cell type, degrees of differentiation, and nodular or diffuse pattern; Hodgkin's disease and Burkitt's lymphoma are special forms. (05 Mar 2000) |
| malignant malnutrition | A nutritional deficiency illness in children who are not getting enough protein, this results in anaemia, poor growth, weakness, and oedema (which isparticularly characterised by a pronounced pot belly). Infamine-stricken regions, children typically develop kwashiorkor rightafter they are weaned. (09 Oct 1997) |
| malignant melanoma | <oncology, tumour> A malignant tumour which arises from the pigment producing cells (melanosomes) of the deeper layers of the skin (or the eye). Melanoma is the leading cause of death attributable to skin lesions. Described as an irregular dark skin lesion that may have areas of varying colour. Often greater than 6 mm in diameter. (27 Sep 1997) |
| malignant melanoma: gallium imaging | <radiology> Greater than50% sensitivity for primary and metastatic sites: 73% sensitivity if lesion is greater than 2 cm, 17% sensitivity if less than 2 cm, see: gallium: indications malignant melanoma (12 Dec 1998) |
| malignant melanoma in situ | A melanoma limited to the epidermis and composed of nests of atypical melanocytes and scattered single cells extending into the upper epidermis; local excision is curative although the lesion, if untreated, may soon invade the dermis. Malignant lentigo may be considered a slowly progressive type of malignant melanoma in situ. (05 Mar 2000) |
| malignant melanoma: staging | <radiology> Clark staging: level I: all tumour cells above basement membrane (in situ), level II: tumour extends to papillary dermis, level III: tumour extends to interface between papillary and reticular dermis, level IV: tumour extends between bundles of collagen of reticular dermis, level V: tumour invasion of sucutaneous tissue (87% metastases) Breslow staging: thin: less than 0.75 mm depth of invasion, intermediate: 0.76 - 3.99 mm depth of invasion, thick: greater than 4 mm depth of invasion see: malignant melanoma (12 Dec 1998) |
| malignant meningioma | <tumour> Meningioma that either invades brain parenchyma or metastasizes. (05 Mar 2000) |
| malignant mesothelioma | <oncology, tumour> A mesothelioma is a tumour of the lining of the lung and chest cavity, known as the pleura. Benign mesotheliomas do occur but are much more rare than the malignant type. Malignant mesothelioma affects men more commonly and about 80% of cases have a history for prior exposure to asbestos. Symptoms include chest pain, shortness of breath, cough and weight loss. (27 Sep 1997) |