Differential diagnosis and clinical course of amiodarone-induced thyroid dysfunction.

BACKGROUND

Amiodarone is an iodine-rich drug widely used for the management of various arrhythmias, but its clinical utility is usually limited by the high frequency of numerous side effects, most frequently disturbance of thyroid function.

MATERIAL/METHODS: The present study presents the laboratory tests, color flow Doppler sonography (CFDS) findings, treatment and prognosis of 22 patients with amiodarone-induced thyroid dysfunction.

RESULTS

Eleven patients developed amiodarone- induced thyrotoxicosis (AIT), ten developed amiodarone-induced hypothyroidism (AIH) and one patient first developed AIT, followed by AIH. Age, amiodarone doses, duration of amiodarone treatment and discontinuation of amiodarone were similar in the patients with AIT and AIH. AIT was found more commonly in male patients, AIH in female patients. Color flow Doppler sonographic examination was performed in all patients with AIT to differentiate type 1 and 2 AIT. In ten patients, CFDS demonstrated increased glandular vascularity, diagnostic for type 1 AIT.

CONCLUSIONS

This paper presents patients with AIT treated successfully with propylthiouracil or prednisolone after developing thyroid dysfunction as a consequence of amiodarone use. The role of thyroid Doppler in managing these patients is emphasized.