Ocular toxoplasmosis in AIDS patients

Abstract

We describe 16 cases of ocular and, in some patients, associated CNS toxoplasmosis in AIDS patients. T gondii is commonly associated with infection in the immunocompromised host. The lesions are most often seen in the CNS and eyes; involvement in the brain, heart, lung, liver, spleen, and lymph nodes may be observed. CNS involvement by toxoplasmosis may be an initial manifestation of AIDS and may be associated with discrete or diffuse lesions. CT scan and MR imaging may demonstrate a multitude of lesions often displaying the characteristic ring-shaped enhancement after contrast injection. Ocular involvement by toxoplasmosis, though less common than CNS involvement, is characterized by several features. These may be manifested as single or multifocal retinal lesions in one or both eyes or massive areas of retinal necrosis. Invariably these lesions are unassociated with a pre-existing retinochoroidal scar suggesting that the lesions are a manifestation of acquired rather than congenital disease. Presence of IgM antibodies may support this observation although antibody levels in AIDS patients may not reflect the magnitude of disease. Vitreous reaction is often minimal. Anterior uveitis has been reported in one case. Treatment of the ocular infection with pyrimethamine, clindamycin and sulfadiazine is effective in over 75% of patients. Once resolution of the ocular infection is observed, maintenance therapy is continued as relapses occur in the absence of treatment. Corticosteroid treatment is unnecessary and its use has been associated with the development of CMV retinitis. Other retinal infections in AIDS patients which should be considered in the differential diagnosis include CMV, herpetic-associated ARN and syphilis. Concomitant CMV and toxoplasmosis in the same eye have been seen.