Treatment with Thyroxine Reduces Thyroid Volume in Euthyroid Children and Adolescents with Chronic Autoimmune Thyroiditis

BACKGROUND/AIMS: Treatment with thyroxine in children with chronic autoimmune thyroiditis (AT) is controversial. The aim of this study is to investigate, by using thyroid ultrasonography, whether thyroxine influences thyroid volume in non-goitrous euthyroid children with AT. METHODS: We studied 50 euthyroid non-goitrous children and adolescents with AT for 2 years by thyroid function tests and ultrasonography; 25 were randomized to receive thyroxine and 25 did not receive treatment. Median (IQR) age was 12.1 (11.1-13.2) years. RESULTS: At baseline there was no difference in thyroid volume SDS between the two groups (treatment group 1.1 (0.7-1.5) and controls 0.9 (0.4-1.4), respectively). After 2 years the treatment group had lower thyroid volume SDS compared to the controls (0.6 (0.3-1.0) vs. 2.0 (1.1-2.3), p = 0.001). One child of the treatment group and 12 of the control group developed goiter. Two control children developed subclinical hypothyroidism. Within the treatment group, thyroid volume SDS was lower after 2 years of treatment (p = 0.002). Within the control group, thyroid volume SDS and TSH levels increased after 2 years of follow-up (p = 0.016, 1.9 (1.5-2.8) vs. 3.2 (2.4-4.4) mIU/ml, p = 0.006, respectively). CONCLUSIONS: Treatment with thyroxine reduces thyroid volume in non-goitrous euthyroid children with AT and may prevent goiter development.