Steroid-responsive encephalopathy and autoimmune thyroiditis in a young boy.

Steroid-responsive encephalopathy with autoimmune thyroiditis is a relatively uncommon entity in the pediatric population. Although the pathogenesis of steroid-responsive encephalopathy with autoimmune thyroiditis is uncertain, an autoimmune mechanism is suspected to be the most likely cause. Seizures of unknown etiology are a common presenting sign in the pediatric intensive care unit, and steroid-responsive encephalopathy with autoimmune thyroiditis should be considered as a possible cause of recurrent seizures. The outcome of steroid-responsive encephalopathy with autoimmune thyroiditis is variable in children, and is partly dependent on early diagnosis and the administration of intravenous steroids. Only 31 pediatric cases of steroid-responsive encephalopathy with autoimmune thyroiditis were described in the English-language literature since 1966. Very few were reported in the United States or among males. We describe a 13-year-old boy presenting with a new onset of seizures as a manifestation of steroid-responsive encephalopathy with autoimmune thyroiditis. This report presents, to the best of our knowledge, the youngest male with steroid-responsive encephalopathy with autoimmune thyroiditis, and the only reported child with other autoimmune manifestations in addition to encephalopathy.