Chronic lymphocytic (autoimmune) thyroiditis in children.

Chronic lymphocytic (autoimmune) thyroiditis is one of the most common causes of non-toxic goiter in children and accounts for most of the acquired juvenile hypothyroidism. Asymptomatic goiter is the most common presentation though subclinical hypothyroidism and growth failure are frequently seen. Thyroid function is variable depending on the degree of thyroid destruction. Thyroiditis is the prototype of autoimmune diseases. Thyroglobulin or microsomal antibodies are present in serum of virtually all individuals. Cellular destruction is currently thought to be related to a dysfunction of suppressor T-lymphocytes, allowing appearance of "forbidden clones" of helper T-lymphocytes which stimulate production of cytotoxic auto-antibodies against thyroid tissue. The resultant lymphocytic infiltration, disruption of thyroid follicles and fibrosis produce the typical pathologic and clinical picture of an enlarged, firm thyroid with gradual loss of thyroid function. In children, the process may arrest before complete loss of thyroid function and spontaneous recovery occurs. Those who become hypothyroid must take thyroxine supplement.