Evaluation of thyroid functions with respect to iodine status and TRH test in chronic autoimmune thyroiditis

Objective: chronic autoimmune thyroiditis (cat) is the most common form of thyroiditis in childhood and a frequent cause of acquired hypothyroidism. the objective of this study was to evaluate the thyroid status of children and adolescents with cat with respect to iodine status and diagnostic values of thyrotropin-releasing hormone (trh) test. methods: seventy-one children (mean age: 11.6 years) were studied in a retrospective analysis. free thyroxine (t4),thyrotropin (tsh),tsh response to trh test,thyroid autoantibodies,thyroid sonography,and urinary iodine excretion (uie) were evaluated. results: at diagnosis,8.5% of patients had overt hypothyroidisim and 36.6% subclinical hypothyroidism; 5.6% had overt hyperthyroidisim and 8.5% had subclinical hyperthyroidism. of them,40.8% were euthyroid. median uie was 51 μg/l in overt hypothyroidism and 84 μg/l in subclinical hypothyroidism. the values were 316 μg/l and 221 μg/l in overt and subclinical hyperthyroidism,respectively. basal tsh showed a strong correlation with peak tsh level on trh test. thirtyfour percent of patients with normal basal tsh level showed an exaggerated tsh response. conclusion: iodine deficiency was seen more in cases with hypothyroidism,while excess of iodine was observed to be more frequent in hyperthyroid patients. iodine status was a strong predictor of the thyroid status in cat. trh test may be helpful in further delineating patients with subclinical hypothyroidism. © journal of clinical research in pediatric endocrinology,published by galenos publishing.