Ziauddin, Adnan Khan.
Amiodarone induced Thyrotoxicosis - A case you might encounter.
J Postgrad Med Inst Jan ;15(1):108-10.

A fifty-five years old woman was referred in September 2000 because of atrial fibrillation. She was being treated with digoxin 0.25mg daily and aspirin 75mg daily. Examination revealed no clinical abnormalities and was euthyroid. Routine blood tests were normal and her lipids were controlled (cholesterol 4.5mmol/L, HDL 1.0mmol/L, LDL 3.5mmol/L, Triglyceride 2.0mmol/L). Blood sugar was 6.5mmol/L. ECG showed atrial fibrillation and chest Xrays was normal. Echocardiography ruled out valvular heart disease, good left ventricular function and no clot in the left atrium or ventricle. She was commenced on amiodarone 200 mg eight hourly for one week (started concurrently with iv loading) followed by 200mg twelve hourly for one week. She was then maintained 200mg daily. Follow up was arranged for two months. Approximately six weeks later she was seen urgently because of development of goiter. Examination of thyroid status revealed all the features of thyrotoxicosis - anxious look, sweating, tremors, lid lag. Cardiovascular examination revealed sinus rhythm. Amiodarone was discontinued at once. Urgent thyroid function tests and thyroid scan were arranged. T3 was markedly elevated at 7.0 nmol/L with T4 elevated at 290nmol/L, TSH was less than detectable. Thyroid scan showed toxicnodular goiter. She was started on Carbimazole 30mg daily and Atenolol 50mg daily in order to maintain the sinus rhythm (as sotalol was not available in the market) and to control the adrenergic effects of thyrotoxicosis. She was then reviewed after six weeks in the medical out patients department. She was euthyroid clinically and in sinus rhythm. Repeat thyroid function tests showed T3 5.1 nmol/L, T4 190 nmol/L and TSH 2.5 u/L. She was then maintained on 15mg of Carbimazole daily.

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