Two cases of cerebral toxoplasmosis in AIDS patients mimicking HIV-related dementia.

Two unusual cases of cerebral toxoplasmosis in AIDS patients are presented. Two homosexual males aged 33 and 52 years in CDC stage IV C1 complained of memory loss during the past 6 months, as well as weight loss and mild fever. They showed severe intellectual deterioration and discrete basal ganglia dysfunction. Motor performance and cognitive function as well as the conventional EEG findings were grossly abnormal. MRI was normal in the younger patient but showed signal-intensive zones in the basal ganglia and cortical atrophy in the older one. CSF and serological antibody tests were normal; immunological function was severely impaired. The patients were diagnosed as late "HIV-related dementia". Both deteriorated rapidly and died within a few weeks. Neuropathological examination revealed histologically severe Toxoplasma gondii encephalitis, involving the basal ganglia in particular. It is concluded that in AIDS patients with a severely impaired immune status cerebral opportunistic infection may present as dementia with mild basal ganglia impairment in the absence of other focal neurological signs or the characteristic radiological findings.