Recurrence of 131I-induced thyroid storm after discontinuing glucocorticoid therapy.

A 19-year-old woman with Graves' disease developed thyroid storm 8 days after radioactive iodine therapy. The clinical manifestations of thyroid storm promptly improved after treatment with large doses of propylthiouracil, potassium iodide, propranolol hydrochloride, and dexamethasone. Four days after discontinuing dexamethasone, the syndrome recurred and was corrected by reinstitution of the glucocorticoid. We conclude that dexamethasone was an important adjunct for treating thyroid storm and was effective mainly by reducing peripheral triiodothyronine production.