Diffuse "encephalitic" cerebral toxoplasmosis in AIDS. Report of four cases.

Four patients with AIDS presented with a rapidly fatal global neurological illness. CT did not show any focal lesion and gross post mortem examination of the brain was normal in three of the four cases. Microscopic examination revealed numerous widespread microglial nodules in the brain parenchyma, most containing central toxoplama cysts or free tachyzoites. Such diffuse, non-necrotic, "encephalitic" forms of cerebral toxoplasmosis appear unique to AIDS and, to our knowledge, have not been documented previously. They represent a treatable, often misdiagnosed cause of diffuse neurological involvement in AIDS patients.