Evaluation of the policy of empiric treatment of suspected Toxoplasma encephalitis in patients with the acquired immunodeficiency syndrome.

This study was designed to measure response rates and survival in patients with acquired immunodeficiency syndrome (AIDS) and suspected Toxoplasma encephalitis treated empirically and in AIDS patients treated for biopsy-proven toxoplasmosis. AIDS patients identified at Bellevue Hospital between August 1985 and May 1986, who had abnormal computed tomographic scans of the brain and who received empiric treatment for toxoplasmosis, constitute the empirically treated cohort. A cohort with biopsy-proven toxoplasmosis was identified from Bellevue Hospital neuropathology records spanning 1981 through 1986. Patient records were reviewed with a standardized data form, and tomograms were evaluated by neuroradiologists unaware of the identity of the scans. Survival analysis was performed by the product limit method. Of 38 empirically treated patients, 26 responded clinically and radiographically within four weeks of initiation of therapy. Four of nine patients who underwent biopsy responded to treatment. There was no difference in these response rates (68% versus 44%, p = 0.24). The median survival of the empirically treated responders, from first diagnosis of AIDS to last follow-up, was 422 days. Among the 30 responders, five patients discontinued therapy and four of them had relapses. No relapses occurred in the 25 patients who continued full-dose therapy indefinitely (p = 0.0004). Sixteen of 30 patients (53%) receiving continuous therapy developed toxicity, which required a change in medication. There was no difference in the survival of patients who continued to receive sulfadiazine and pyrimethamine compared with those in whom clindamycin was substituted for sulfadiazine (median, 311 days versus 422 days, p = 0.25). A policy of empiric treatment of suspected Toxoplasma encephalitis is satisfactory, and patients who respond to such therapy and continue to take full therapeutic doses of anti-Toxoplasma drugs have relatively long survivals.