AMIODARONE-INDUCED THYROTOXICOSIS - CLINICAL PRESENTATION AND EXPANDED INDICATIONS FOR THYROIDECTOMY

Background. Amiodarone-induced thyrotoxicosis (AIT) is a rare disorder that is frequently refractory to conventional pharmacologic therapy. Methods. An analysis of seven patients who underwent thyroidectomy for control of AIT between 1987 and 1993 was completed to examine the cli nical manifestations and the indications for surgical therapy. Results . Five men and two women, 53 to 72 years of age, had AIT after 3 to 55 months of amiodarone treatment (mean, 21 months). The primary manifes tations of AIT were ventricular tachycardia (five), exacerbation of ch ronic pulmonary disease (one), and occult hyperthyroidism (one). Medic al therapy included propylthiouracil in doses up to 1200 mg/day in fiv e patients, a beta-receptor antagonist in three, and withdrawal of ami odarone in five. Near-total or total thyroidectomy resulted in resolut ion of thyrotoxicosis in all patients. Morbidity included pneumonia (o ne) and cardiac dysrhythmias (two). One patient died of ventricular dy srhythmias 4 months after thyroidectomy. The mean thyroid weight was 5 0 gm (range, 17 to 216 gm). Microscopic examination showed destructive follicular lesions with fibrosis in all patients. Associated thyroid pathologic condition included multinodular goiter in four patients and a follicular adenoma in one. Conclusions. AIT may be clinically occul t or manifested by unusual symptoms requiring a high index of suspicio n for diagnosis. Near-total thyroidectomy is safe and effective in pro ducing rapid resolution of AIT and is indicated for the initial treatm ent of patients who present with a resurgence of life-threatening card iac arrhythmias and for all patients with AIT refractory to medical th erapy.