To Örebro University

Aim: To study the incidence of childhood thyrotoxicosis in five counties in central Sweden during 1990–2009 and to study the treatment outcome.

Methods: Children below the age of 16 years diagnosed with thyrotoxicosis during the 20-years period and living in the study area were identified retrospectively. Data on the total number of children below 16 years of age living in the area during the study period was collected from the National Board of Statistics, Sweden. Data regarding clinical and biochemical characteristics and the outcome of the treatment were collected from medical records.

Results: 113 patients were identified. The annual incidence was 2.2/100,000 children during the whole study period. The incidence was higher during the last ten studied years as compared to the first ten studied years (2.8 vs. 1.6/100,000, p = 0.006). The increase in incidence was seen in both girls and boys (p = 0.041 and p = 0.038, respectively). Treatment with antithyroid drugs (ATD) was the first hand choice, but 69% of the patients relapsed within three years after the planned discontinuation of the ATD treatment. Boys relapsed more often than girls (p = 0.013), but we could not identify any other significant predictor for relapse.

Conclusion: Thyrotoxicosis is uncommon in pediatric patients but the incidence seems to be increasing. The outcome of the initial treatment with ATD is poor with high relapse rates. Boys seems to have an increased risk for relapse compared to girls. More studies are needed to identify an optimal treatment protocol for each individual.