Jod-Basedow phenomenon: Reactivation of thyroid eye disease after contrast computed tomography

To report a case of Jod-Basedow phenomenon, where a patient with quiescent thyroid eye disease became active after a contrast computed tomography (CT). A patient with clinically inactive thyroid eye disease underwent a contrast CT, after which her clinical activity score increased for 1 to 6/10 with optic nerve dysfunction. She was managed medically with intravenous steroids, neomercazole and propranolol. Jod-Basedow phenomenon is a rare condition where thyroid eye disease reactivates after a large iodine bolus. It is important for clinicians to be aware of this when considering special investigations, such as contrast scans, where iodine is given in large doses.