Abstract 17455: Heart in Crisis: Graves’ Thyrotoxicosis-Induced Cardiomyopathy

Abstract

Background: We present a case of a young healthy male who presented with signs and symptoms of congestive heart failure and was subsequently diagnosed with dilated cardiomyopathy secondary to an unknown history of Graves’ disease. Case Presentation: A 40-year-old male with no medical history presented to the hospital with scrotal and bilateral lower leg edema for 4 days with associated shortness of breath. Physical examination was significant for an irregularly irregular heart rhythm. Electrocardiogram showed atrial fibrillation with a rapid ventricular response (Image B). Initial laboratory findings were elevated NT-proBNP of 1,240 pg/mL (<125 pg/mL). Chest x-ray revealed significant cardiomegaly (Image A). Echocardiogram demonstrated an ejection fraction of 20% with a severely dilated bilateral atrium, left ventricle with severe diffuse hypokinesis of the left ventricle, and severe mitral regurgitation (Images C and D). Endocrine was consulted for abnormal thyroid function tests with TSH of <0.010 mU/L (0.27-4.2 mU/L), free T4 of 6.06 ng/dL (.93-1.70 ng/dL), T3 of 258 ng/dL (80-200 ng/dL), thyroid-stimulating immunoglobulin of 9.51 IU/L (0.00-.55 IU/L) and TSH receptor antibody 14.00 IU/L (0.00-1.75 IU/L). The patient was started on methimazole and metoprolol with close follow-up with cardiology and endocrinology. Discussion: Severe Cardiomyopathy in adult patients with hyperthyroidism is rare occurring in approximately 6% of patients with less than 1% developing dilated cardiomyopathy with impaired left ventricular systolic function. Although the mechanism of dilated cardiomyopathy is still being researched it has been suggested that prolonged uncontrolled hyperthyroidism and autoimmunity as the potential causes. Further studies are needed to develop optimal management studies as it has been shown that the management of thyrotoxicosis can reverse cardiovascular manifestations and prevent irreversible cardiomyopathy.