Endocrine Abstracts

Amiodarone is commonly prescribed anti-arrhythmic drug which can lead to thyroid dysfunction manifesting as either hypothyroidism or hyperthyroidism. This clinical case of amiodarone induced thyrotoxicosis is being reported to highlight the challenges faced during its management. A 72-year-old gentleman was admitted with history of recurrent falls. He had past medical history of non-ischemic cardiomyopathy, CRT, atrial fibrillation, vascular dementia, osteoporosis, primary hyperparathyroidism, type 2 Diabetes mellitus, severe frailty. He was on amiodarone for last 3 years for atrial fibrillation. Other than confusion and mild tremors, his systemic and thyroid examination was unremarkable. As a part of his confusion screen thyroid functions were tested which showed thyrotoxicosis with suppressed TSH (<0.01) and high T4 (59.9 pmol/l) and FT3 (12.2 pmol/l). These tests were confirmed by repeating them. His thyroid antibodies were negative. Vascular ultrasound of thyroid did not show increased vascularity. Likewise, technetium uptake scan of thyroid revealed absent uptake on the expected location of thyroid. As likely diagnosis in this case was amiodarone induced thyrotoxicosis type 2, prednisolone was started at 30 mg daily for 2 weeks with aim of gradual tapering in 2 to 3 months. Cardiologist consultation was taken and amiodarone was stopped. After 2 weeks there was no improvement in thyroid functions and with suspicion of mixed Type I and Type II AIT, carbimazole was added on to the treatment regimen. The dose of Prednisolone and carbimazole was gradually increased to 40 mg and 60 mg respectively. Even after 4 months of the above treatment thyrotoxicosis persisted (Table 1). Due to other medical conditions and family’s unwillingness surgical management was not an option in this case. Afterwards, Cholestyramine was added to treatment regimen and in next 2 months, patient’s confusion state and TFTs started improving and became euthyroid (Table 2). Further plan of management is made to gradually taper off steroids and carbimazole with frequent monitoring of TFTs. This case highlights the challenges in the management of Amiodarone induced thyrotoxicosis. It was unusual that despite on high dose of steroids and carbimazole patient responded slowly. It should also be noted that other than steroids and carbimazole, cholestyramine is also an adjunctive to treat this condition.