Longitudinal study of new eye lesions in treated congenital toxoplasmosis.

Objective: To determine the incidence of new chorioretinal lesions in patients with congenital toxoplasmosis who were treated throughout their first year of life.

Design: Prospective longitudinal observation of a cohort.

Participants: One hundred thirty-two children were studied as part of the longitudinal observation.

Methods: One hundred thirty-two children were treated during their first year of life with pyrimethamine, sulfadiazine, and leucovorin. They had eye examinations at prespecified intervals.

Main Outcome Measures: New chorioretinal lesions on fundus examination and fundus photographs.

Results: The mean age (+/- standard deviation) is 10.8+/-5.1 years (range, 0.2-23). One hundred eight children have been evaluated for new chorioretinal lesions. Thirty-four (31%; 95% confidence interval, 23%-41%) of 108 children developed at least one chorioretinal lesion that was previously undetected. These occurred at varying times during their follow-up course. Fifteen children (14%) developed new central lesions, and 27 (25%) had newly detected lesions peripherally. Ten (9%) had more than one occurrence of new lesions developing, and 13 (12%) had new lesions in both eyes. Of those who developed new lesions, 14 children (41%) did so at age 10 or later.

Conclusion: New central chorioretinal lesions are uncommon in children with congenital toxoplasmosis who are treated during their first year of life. This finding contrasts markedly with earlier reports in the literature for untreated children or those treated for only 1 month near birth, in whom new lesions were much more prevalent (>/=82%). Our observation that 14 (41%) of the 34 children with new chorioretinal lesions had occurrences when they were 10 years or older indicates that long-term follow-up into the second decade of life is important in assessing the efficacy of treating toxoplasmosis during infancy.