EXTRACEREBRAL TOXOPLASMOSIS IN THE ACQUIRED-IMMUNODEFICIENCY-SYNDROME (AIDS)

Although Toxoplasma gondii frequently causes lesions of the central nervous system in AIDS, the exact incidence of extracerebral toxoplasmosis in these immunodepressed patients remains difficult to determine. Isolation of the parasite outside the central nervous system is rarely performed ante mortem, and most diagnoses of extracerebral toxoplasmosis are made post mortem. This article describes 23 cases of extracerebral toxoplasmosis diagnosed between 1987 and 1991 in an autopsy series of 170 patients infected with the human immunodeficiency virus (HIV). Ante mortem diagnosis of extracerebral involvement was affirmed in 4 of these 23 patients by identification of trophozoites in bronchoalveolar lavage fluid (2 cases), a surgical pulmonary biopsy specimen, and a bladder biopsy. Clinical and paraclinical findings suggested cardiac involvement in 4 other patients. Post mortem examination demonstrated disseminated toxoplasmosis in 18 cases and extracerebral monovisceral involvement in S cases. Extracerebral toxoplasmosis was directly responsible for the death of 6 patients. The most frequent extracerebral sites of Toxoplasma gondii involvement were the heart (21/23 cases; 91 %), the lungs (14/23 cases; 61 %) and the pancreas (6/23 cases; 26 %). The tissular consequences of toxoplasmic involvement varied considerably, from formation of pseudocysts or cysts without any surrounding inflammatory reaction to necrotic lesions rich in neutrophilic polynuclear cells containing numerous free parasites. Immunoperoxidase study using antitoxoplasmic antibodies contributed to the diagnosis of 8 extracerebral localizations. Electron microscopy examination of a surgical lung biopsy and myocardial specimens (2 cases) demonstrated the ultrastructural characteristics of Toxoplasma gondii trophozoites. The particularly elevated incidence of extracerebral toxoplasmosis in this autopsy series (14 %) can be explained by the high prevalence of toxoplasmosis in France, the prolonged survival of HIV-infected patients and the high number of post mortem samples examined.