Refractory amiodarone-associated thyrotoxicosis: An indication for thyroidectomy

Background: Tasmania is an area of endemic iodine deficiency. Amiodarone is a class III anti-arrhythmic drug that is widely used for the management of ventricular and supraventricular tachydysrhythmias. Individuals from areas of endemic iodine deficiency appear more likely to manifest hyperthyroidis m following amiodarone therapy, whereas hypothyroidism is a more frequent c omplication in iodine-replete communities. Methods: Cases series. The clinical and biochemical response to medical and surgical management of five consecutive Tasmanian patients presenting with severe type-II amiodarone-associated thyrotoxicosis was reviewed. Results: Five patients were identified. Combinations of antithyroid therapy including propylthiouracil, lithium carbonate, dexamethasone and cholestyr amine were used. Thyroidectomy was required in two cases (40%) due to sever e unremitting thyrotoxicosis despite combined drug regimens. Anaesthesia an d total thyroidectomy were undertaken without complication despite the pres ence of severe hyperthyroidism at the time of surgery. In both cases thyroi d histopathology demonstrated degenerative and destructive follicular lesio ns with multinuclear cell infiltrate and focal fibrosis. Conclusion: Amiodarone-associated thyrotoxicosis may be severe and refracto ry to medical therapy. Despite the potential risks of anaesthesia associate d with uncontrolled thyrotoxicosis, thyroidectomy should be considered in t he setting of life-threatening thyrotoxicosis.