BACKGROUND. Patients with autoimmune thyroiditis can present with thyroid function that varies from euthyroidism to frank hypothyroidism or occasionally hyperthyroidism. Although there is a risk of progression from the euthyroid or subclinical hypothyroid state to frank hypothyroidism, the rate of progression is not known.
OBJECTIVES. Subjects with diffuse goiter and autoimmune thyroiditis were followed up to observe the rate of deterioration in thyroid function from euthyroid and subclinical hypothyroid states to hypothyroidism.
METHODS. Patients who presented with goiter and autoimmune thyroiditis were grouped as those with euthyroidism, subclinical hypothyroidism, and overt hypothyroidism on the basis of levels of thyroxine and thyrotropin at presentation. Patients were followed up for a minimum duration of 24 months with periodic monitoring of thyroid function.
RESULTS. Ninety-eight consecutive subjects (aged of 8–18 years) with a diagnosis of autoimmune thyroiditis and diffuse goiter were studied. At presentation, in 24 subjects (24.5%) thyroid function was normal (euthyroidism), 32 (32.6%) had subclinical hypothyroidism, and the remaining 42 subjects (42.9%) had hypothyroidism. All of the subjects with hypothyroid were maintained euthyroid on thyroxine during follow-up. Hypothyroidism developed in 3 of 24 patients with euthyroidism and in 4 of 32 patients with subclinical hypothyroidism.
CONCLUSIONS. Subjects with goitrous autoimmune thyroiditis need periodic monitoring of thyroid function. Development of thyroid dysfunction is insidious and may not be accompanied by symptoms and clinical signs. In pediatric and adolescent age groups it is imperative to correct thyroid dysfunction to achieve optimal growth and development.