Thyrotoxicosis Associated with Autoimmune Thyroiditis in Children and Adolescents

ABSTRACT

PURPOSE: The aims of this study are to estimate the frequency of thyrotoxicosis associated with autoimmune thyroiditis (TAIT) and to investigate the characteristics of TAIT in children and adolescents. METHODS: 220 subjects who had shown thyroid autoimmunity before the age of 18 were included. All the subjects were divided as autoimmune thyroiditis (AIT), Graves' disease and unspecified group. In addition, AIT was subdivided as TAIT and euthyroid or hypothyroid AIT. Clinical data were review and the variation of thyroid hormone status was investigated among the subjects with TAIT. RESULTS: Of 220 subjects who showed thyroid autoimmunity, 147 subjects were diagnosed as AIT and 47 were as Graves' disease. Among 147 subjects with AIT, 14 subjects (9.5%) had presented TAIT. Among 65 subjects who had initially presented with thyrotoxicosis, 8 subjects (12.3%) were compatible with TAIT. Whereas presenting symptoms of TAIT were similar to those of Graves' disease, Technetium-99m scan had showed thyroid with decreased uptake. The durations of thyrotoxicosis were several weeks. 6 of 14 TAIT subjects showed recurrent thyrotoxicosis, and 4 of 8 patients who had initially presented with thyrotoxicosis showed subclinical or overt hypothyroidism during follow-up. CONCLUSIONS: Possibility of TAIT should not be overlooked when a patient presents thyrotoxicosis, because this condition is not so rare in children and adolescents. Long term follow-up after resolution of thyrotoxicosis is necessary because of a diverse clinical course.