Endocrine Abstracts

Background: Amiodarone induced thyrotoxicosis (AIT) is one of the most important and severe complications caused by amiodarone therapy. The multidisciplinary medical cooperation and combined therapeutic strategies are necessary in some cases.

Aim: Analysis of patients suffered from AIT with focus on clinical picture, laboratory findings and possible therapeutic options.

Methods and results: We performed retrospective analysis of 35 consecutive patients with AIT, (27 men and 8 female, mean age 61.91 ± 9.5 years) who were examined and long-term monitored on Department of Internal Medicine University Hospital Banska Bystrica (Endocrinology section) during the period 2005–2018. All of analysed patients (n = 35) have been treated for arterial hypertension, 49% (n = 17) ischaemic heart disease, 63% (n = 22) had heart failure and 23% (n = 8) had implantable cardioverter defibrillator. The atrial fibrillation was the most frequent indication for amiodarone therapy (in 71%) and in 29% of patients it was ventricular tachyarrhythmias. The mean time of amiodarone administration was 980 ± 566 days, median 866 days. Mean TSH in the time of diagnosis was 0.024 ± 0.06 mIU/l and mean free T4 was 46.2 ± 16.71 pmol/l. The prevalence of different types of AIT was: AIT type 1 (34%, n = 12), AIT type 2 (49%, n = 17) and mixed type AIT (17%, n = 6). Twenty four patients (69%) had been hospitalized and four patients (11%) developed thyrotoxic crisis. All of patients (n = 35) have been treated with antithyroid drugs and 13 of them (37%) with corticoids co-administration. The mean time to achieve AIT remission (defined as free T4 decrease to physiological ranges) was 112 ± 52 days, median 99.5 days. In 12 patients (32%) thyroidectomy was performed, in five patients urgently and seven electivly. The thyroid papillary microadenocarcinoma was histologically confirmed in two of observed patients.

Conclusion: Amiodarone induced thyrotoxicosis is one of the most severe complications caused by amiodarone therapy. Thorough knowledge of its adverse effects allow us to perform appropriate therapeutic mesures in care of patients