Toxoplasmic encephalitis (TC) is the most common opportunistic infection of the Central Nervous System (CNS) in patients with the acquired immunodeficiency syndrome (AIDS). In order to investigate its clinical course, we reviewed the records of 133 patients with AIDS and central nervous system (CNS) toxoplasmosis treated at the Clinic of Infectious Diseases, University of Milan, between 1987 and 1992. The most common presenting symptoms were headache, confusion, disorientation and fever. Focal neurologic deficits were present in more than half of cases. Median CD4+ cell count at presentation was 65 per cubic millimeter. 25 (19%) out of 133 patients diagnosed with TC had undetectable anti-T. gondii IgG antibodies using an Elisa technique. Enhancing lesions on Computered Tomography (CT) were demonstrated in 119 (90%) patients. Solitary lesions were present in 26 cases; edema was evident in 19 patients. A complete clinica! and neuroradiological improvement after the acute episode was obtained in 126 (95%) of the cases. Adverse drug reactions occurred in 40 (30%) cases. Relapses occurred in 18/92 patients after a median time of 6 months.
In conclusion: TC occurs in advanced stages of human immunodeficiency syndrome, and the absence of anti-T.gondii antibodies does not exclude the diagnosis. The clinical and radiographic response to therapy is usually rapid, but long-term treatment is frequently limited by adverse drug effects.