Toxoplasmosis and the acquired immune deficiency syndrome

Abstract

The literature on toxoplasmosis in the acquired immune deficiency syndrome is reviewed with reference to more than 140 cases from various centres. The incidence, pathogenesis, clinical features, diagnosis, treatment and prognosis are considered.

PIP: Toxoplasmosis as an opportunistic infection in patients with acquired immunodeficiency syndrome (AIDS) is a life-threatening condition. A review of the literature reveals over 140 cases of toxoplasmosis in AIDS victims, and there is sufficient clinical detail on 81 of these cases for in-depth evaluation. Toxoplasma infection in immunocompromised individuals generally affects the central nervous system and is the most common cause of focal brain lesions. Toxoplasmosis seems to be more frequent in AIDS patients in Africa than those from Europe or America. A clinical review of the 81 cases culled from the literature revealed deterioration in mental status in 42, neurological signs in 39, fever in 36, and persistent headache in 31. When human immunodeficiency virus (HIV) infection is associated with slowly evolving dementia and the preservation of consciousness, toxoplasmosis typically results in an acute deterioration in mental state. In AIDS, most cases of clinical toxoplasmosis result from an exacerbation of a chronic infection. Among the techniques that have been used to diagnose toxoplasmosis in AIDS patients are serology, cerebrospinal fluid samples, isolation of the parasite, radiology, and histology. Pyrimethamine plus a sulphonamide has been the traditional treatment for toxoplasma infection in AIDS patients and is associated with a greatly improved clinical state. Regardless of the drug therapy used, complete elimination of toxoplasma from viable cysts is unlikely and the subsequent emergence of trophozoites should be expected. A poor response to toxoplasmosis treatment is associated with failure to reach an early diagnosis, late initiation of drug therapy, and the lack of contrast enhancement of lesions detectable by computerized tomography.