The natural history of euthyroid Hashimoto's thyroiditis in children

Objective: To study the natural history of Hashimoto's thyroiditis (HT) in children and identify factors predictive of thyroid dysfunction. Study design: We evaluated 160 children (43 males and 117 females, mean age 9.10 ± 3.6 years, with HT and normal (group 0; 105 patients) or slightly elevated (group 1; 55 patients) serum thyroid-stimulating hormone (TSH) concentrations. The patients were assessed at presentation and then followed for at least 5 years if they remained euthyroid or if their TSH did not rise twofold over the upper normal limit. Results: At baseline, age, sex, thyroid volume, free thyroxine, free triiodothyronine, thyroid peroxidase antibody (TPOab), and thyroglobulin antibody (TGab) serum concentrations were similar in the 2 groups. During follow-up, 68 patients of group 0 remained euthyroid, and 10 patients moved from group 0 to group 1. In 27 patients, TSH rose twofold above the upper normal limit (group 2), and 9 of these patients developed overt hypothyroidism. Sixteen patients of group 1 ended up in group 0, 16 remained in group 1, and 23 moved to group 2. A comparison of the data of the patients who maintained or improved their thyroid status with those of the patients whose thyroid function deteriorated revealed significantly increased TGab levels and thyroid volume at presentation in the latter group. However, none of these parameters alone or in combination were of any help in predicting the course of the disease in a single patient. Conclusions: The presence of goiter and elevated TGab at presentation, together with progressive increase in both TPOab and TSH, may be predictive factors for the future development of hypothyroidism. At 5 years of follow-up, more than 50% of the patients remained or became euthyroid.