Two cases of pilots with amiodarone-induced thyroid dysfunction and literature review

Abstract

Objective To summarize the clinic feature, diagnosis, treatment, and prognosis of amiodarone-induced thyroid dysfunction in the pilots with arrhythmia and gather the experiences on treatment and aviation medical assessment. Methods Retrospective analysis was done on the process of 2 cases with amiodarone induced abnormal thyroid function in pilots with atrial fibrillation and on the literatures to summary the clinic feature, diagnosis, treatment, and prognosis were reviewed. Results Case 1 had taken amiodarone for 7 months and low T3 syndrome was diagnosed 1 month later. Two years later, he took amiodarone again for 1 month and was induced type 2 thyrotoxicosis iodine. After he stopped taking amiodarone for 3 months his thyroid function returned to normal. Case 2 was diagnosed iodine induced hypothyroidism after intermittent taking amiodarone for 9 years. The patient changed to the treatment with 75 μg levothyroxine daily for 5 months and his thyroid function was in normal. By 2-year levothyroxine treatment his thyroid function completely recovered. Aviation medical assessment of two pilots is temporary dlisqualified as arrhythmias. Conclusions The thyroid related examination is necessary before taking amiodarone. In the treatment of amiodarone, or after withdrawal for 6-9 months or even longer, the regular follow-up is suggested, especially for the patients with thyroid diseases history and with risk factors. Amiodarone-induced abnormal thyroid function could be treated. The aviation medical assessment should be concerned arrhythmias and thyroid function. Key words: Amiodarone; Thyrotoxicosis; Hypothyroidism; Diagnosis; Treatment outcome; Pilots