A Case of Amiodarone-Induced Thyrotoxicosis Successfully Treated With Prednisolone

We describe a patient who was treated with amiodarone for ventricular arrhythmia based on arrhythmogenic right ventricular dysplasia and who subsequently developed severe amiodarone-induced thyrotoxicosis. Discontinuation of amiodarone resulted in sustained ventricular tachycardia, which was successfully treated with a DC electrical shock, and subsequently atrial fibrillation, leading to brain embolism due to occlusion of the left middle cerebral artery. Combination treatment with amiodarone and prednisolone was effective both in reducing the serum concentration of thyroid hormones and in improving the patient's general condition. As the use of amiodarone becomes more widespread, treatment with prednisolone for this kind of thyrotoxicosis, which is resistant to conventional treatment, will be required increasingly frequently because iodine overload of the thyroid gland persists for some time after discontinuation of amiodarone treatment.