High Frequency of Bone Marrow Depression During Congenital Toxoplasmosis Therapy in a Cohort of Children Identified by Neonatal Screening in Minas Gerais, Brazil.

Background: There are few studies reporting frequency and control of adverse events associated with congenital toxoplasmosis treatment. The objective of this study is to describe treatment adherence and adverse hematologic events in a cohort of children identified with congenital toxoplasmosis in Minas Gerais, Brazil.
Methods: Children were treated with sulfadiazine, pyrimethamine and folinic acid and were evaluated clinically and by laboratory tests at regular intervals.
Results: Of 146,307 live newborns who participated in the Neonatal Screening Program in Minas Gerais in 2006-2007, 190 had congenital toxoplasmosis. Among the 171 children whose treatment data were available, 73.1% completely adhered to antiparasitic therapy. Hematologic adverse events (macrocytic anemia and/or neutropenia and/or thrombocytopenia) were diagnosed in 44% of them. The most common adverse event was neutropenia (31%). In most cases, it was not severe and reversed after increase in folinic acid dosage (25.7%) or temporary treatment suspension (1.8%). No infections were observed in association with neutropenic events. Significant associations were detected between macrocytic anemia and lower weight Z score at first medical appointment (P = 0.03), and between severe neutropenia (<500/mm) and lower weight Z score toward the end of treatment (P = 0.04).
Conclusions: The high frequency of hematologic adverse events found, especially in malnourished children, highlight the importance of careful monitoring of these children throughout treatment, as well as considering nutritional aspects and the need for higher doses of folinic acid. With adequate monitoring, antiparasitic treatment was feasible and relatively safe in the setting of this large screening program for congenital toxoplasmosis.