Successful treatment of severe thyrotoxicosis with radioiodine therapy in a patient with thyrotoxic cardiomyopathy

Thyrotoxic cardiomyopathy (TCM) is a potential life threatening complication of thyrotoxicosis which is potentially reversible with early achievement of euthyroid state. Management of severe thyrotoxicosis in the presence of TCM is a challenging task, especially when thioamides are contraindicated. A 58 yr old male with poorly controlled Grave’s disease of 10 years presented with worsening symptoms of thyrotoxicosis and leg swelling. On examination he was thyrotoxic with a smooth diffuse goiter and also had inactive Grave’s orbitopathy. He had irregularly irregular pulse rate, grossly elevated jugular venous pulses, enlarged heart with tricuspid regurgitation and pulmonary hypertension. FT4 was >8.34 ng/dl (0.8-1.6 ng/dl), free T3 was 20.39 pg/ml (2.3-4.3 pg/ml) and TSH was 0.01 mU (0.5-5.0 mU/L). Serial ECGs showed slow atrial fibrillation with transient complete hear block and echocardiogram showed dilated TCM. He had pancytopenia, most likely resulting from concurrent carbimazole therapy. Medical management of cardiomyopathy was initiated along with lithium, prednisolone and judicious use of beta blockers to control his thyroid status. Within one week he was subjected to radioactive iodine (RAI) therapy following which he was rendered euthyroid . RAI is a safe mode of definitive therapy in patients with TCM provided carful stabilization of underlying cardiac status. Early definitive therapy is required to achieve euthyroid status to minimize irreversible TCM.