Testing for thyroid function recovery in children and adolescents with Hashimoto thyroiditis.

Thyroid function in children and adolescents with primary hypothyroidism owing to Hashimoto thyroiditis was studied to evaluate criteria for the discontinuation of thyroxine therapy. A cohort of 29 children and adolescents was prospectively studied for one year. A thyrotropin-releasing hormone stimulation test with measurements of basal and stimulated thyrotropin and thyroxine was performed at the beginning of the study and 6 and 12 months later. In 59 percent of patients, persistent biochemical evidence of hypothyroidism was observed. Interindividual variations and variations among measurements in individual patients were much greater than those reported for healthy individuals. In one patient, all measured values were consistently normal, and the therapy was successfully discontinued. No single measurement or test could predict the natural course of disease. In summary, children and adolescents with hypothyroidism owing to Hashimoto thyroiditis can not have discontinued replacement thyroxine therapy on the basis of any single evaluation of thyroid function, as proposed for adults. If the decision to discontinue the therapy in this age group is made on the basis of previous follow-up, a substantial possibility of relapse remains and continuous follow up is necessary.