Prevention and Treatment of Iodine-Induced Thyrotoxicosis

*Melinda Kolcsár and Zsolt Gáll*

## **Abstract**

Etiologies of thyrotoxicosis are diverse, one of them being caused by iodineinduced hyperthyroidism. The clinical signs of the disease are the classical signs of any form of hyperthyroidism, but the treatment of the different forms presents particular aspects. This chapter reviews the risk factors for thyrotoxicosis following an excess iodine load, pointing out the major sources of iodine: supplementation programs, dietary intake, nutritional supplements, iodine-containing contrast medium, and amiodarone. Prevention of iodine-induced thyrotoxicosis is critical in geriatric patients who often have thyroid nodular disease, underlying heart conditions, and therefore, hyperthyroidism may be more difficult to detect clinically. Treatment of iodine-induced thyrotoxicosis could be performed with thioamides or perchlorate prior to the administration of an iodine containing product (e.g., food, dietary supplements, and contrast media). On the other hand, amiodarone-induced thyrotoxicosis needs further attention and a close collaboration between cardiology and endocrinology to overcome complications, but individualization of the therapy should be undertaken. Based on the specific features of amiodarone-induced thyrotoxicosis thioamides, perchlorate, high-dose glucocorticoids, or radioiodine therapy may be considered for an optimal therapeutic intervention.

**Keywords:** iodine deficiency, iodine supplementation, dietary iodine, iodine containing contrast media, amiodarone, thyrotoxicosis, thioamides, perchlorate, glucocorticoids
