ATYPICAL, SEVERE TOXOPLASMIC RETINOCHOROIDITIS IN ELDERLY PATIENTS

Background: The diagnosis of toxoplasmic retinochoroiditis is based pr imarily on characteristic ocular findings, with supportive serologic e vidence. Clinical recognition of atypical presentations is critical fo r timely antiparasitic drug therapy. Methods: Case histories were revi ewed for seven presumed immunocompetent elderly patients with atypical ly severe (multifocal or diffuse or both) toxoplasmic retinochoroiditi s. Three cases initially were misdiagnosed as acute retinal necrosis s yndrome. The correct diagnosis was confirmed in each case by response to antiparasitic drug therapy, polymerase chain reaction studies of in traocular specimens, or histopathologic analysis. Results: The patient s ranged in age from 69 to 82 years (median, 74 years). Only three pat ients had intercurrent medical conditions that may be associated with subtle immune dysfunction (diabetes mellitus and hepatitis C). The ext ensive necrotizing retinochoroiditis in each patient was nonhemorrhagi c and not associated with occlusive retinal arteritis. Despite prompt response to antiparasitic drug therapy, prolonged treatment usually wa s required, and four patients had retinitis reactivation after discont inuing treatment. Significant visual loss accompanied the infection in most eyes. Conclusion: Toxoplasmosis should be considered as a cause of multifocal or diffuse necrotizing retinitis or both in elderly pati ents. Older patients may be more susceptible to severe ocular Toxoplas ma infections because of age-related decline in cell-mediated immunity and chronic underlying diseases.