CNS toxoplasmosis in acquired immunodeficiency syndrome

Several distinct patterns of neurological involvement occur in epidemic acquired immune deficiency syndrome (AIDS). Two patients with this disorder had Toxoplasma gondii encephalitis, one suspected and one proved. Computed tomographic (CT) scanning showed focal lesions in both patients. Spinal fluids were remarkable for elevated protein, hypoglycorrhachia, and absence of pleocytosis. In patients with AIDS, focal CT scan findings and serum indication of past T gondii infection should prompt strong consideration of the diagnosis of CNS toxoplasmosis. The absence of specific IgM antibody or rise in IgG antibody titer to T gondii does not exclude this condition in the immune compromised host. In the patient with AIDS, CNS lesions mimicking brain abscess warrant biopsy or empiric therapy for T gondii. Early recognition and initiation of a prolonged or indefinite course of pyrimethamine plus sulfonamide therapy could reduce the mortality associated with this infection in AIDS. Computed tomographic scans, repeated frequently, appear, at present, to be the best guide to monitor the status of CNS involvement.