In iodine-induced thyrotoxicosis, steroid therapy today could keep the surgical knife at bay

Amiodarone-induced thyrotoxicosis (AIT) type 2, characterized as a destructive thyroiditis, is well described in the medical literature; however, iodine-induced thyrotoxicosis (IIT) is not, though the latter has similar features and can be managed similarly.

We present a 17-year-old female who presented with a history of an intermittent goiter with thyroid function tests (TFTs): thyroid-stimulating hormone (TSH)<0.015 (0.4-4 μU/mL), free thyroxine (T4)≥6 (0.7-2.1 ng/dL) and total triiodothyronine (T3) 651 (50-200 mg/dL). Thyroid antibodies were all negative. Despite methimazole therapy for 6 weeks, hyperthyroidism proved refractory to medical management. 123I scan uptake was suppressed. With hyperthyroidism being recalcitrant to therapy, a nutritional history revealed consumption of an iodine supplement containing at least 7 times the recommended daily allowance (RDA) for 5 years, contributing to the Jod-Basedow phenomenon. Urinary spot and 24-hour urinary iodine were both elevated. Though a surgical consult was obtained, surgery was cancelled once TFTs improved and then normalized with steroid therapy. The TFTs and urinary iodine levels remained normal post steroid therapy.

We suggest that in addition to the need for a thorough nutritional history, a trial of corticosteroids should be utilized in the management of IIT which can present with findings similar to AIT type 2 which is recalcitrant to thionamide therapy. If successful, corticosteroids may delay or prevent surgical management thus avoiding possible complications with the latter approach.