(267) Hashimoto Thyrotoxicosis With Rare Complication of Cardiomyopathy

Introduction: Thyroid storm is a rare form of thyrotoxicosis, found in less than 10% of cases, however, it has a mortality at 20-30%. A majority of such cases of thyrotoxicosis leading to thyroid storm are due to Graves’ disease, and less likely due to solitary toxic adenomas, toxic multinodular goiter, and thyrotropin-producing pituitary adenomas. It is, however, well researched that patients with Hashimoto’s thyroiditis do present with short periods of mild thyrotoxicosis that cease spontaneously, leading to a euthyroid and eventual hypothyroidism state slowly over time. The disease, characterized by the presence of thyroid autoantibodies (TAbs) against thyroid peroxidase (TPO) and thyroglobulin (Tg), is found in 18% of the population without previously known thyroid disease, regardless of age or gender. In addition, thyroid storm causing sustained tachycardia, has a rare documented incidence of cardiomyopathy. We present a case in which a young male with no known thyroid disease possessed TPO antibodies and was found in thyroid storm.

Description: A 19 year old male with no previous medical history presents with several days of generalized weakness, sweating, and palpitations, thought to be caused by ingestion of multiple energy drinks. On assessment, the patient was found in supraventricular tachycardia with heart rate of 170s, and was given adenosine, procainamide, and diltiazem. Exophthalmos and myxedema were not present on the exam. TSH was noted to be undetectable and T3 level was 286, and T4 found to be greater than 8. He was placed on hydrocortisone, propylthiouracil, and propranolol. Thyrotropin receptor antibodies were found elevated at 3.11, and thyroid peroxidase antibodies were found elevated at 256. Echocardiogram revealed borderline global hypokinesis of the left ventricle and an ejection fraction of 50%. He was later discharged with methimazole and metoprolol.

Discussion: We encourage providers to keep thyroid storm secondary to Hashimoto's in their differential, when dealing with sustained tachycardia in the setting of hyperthyroidism. In addition, a screening echocardiogram is recommended to check for cardiomyopathy induced by tachycardia. Incidentally, treatment remains the same, despite the etiology, which consists of PTU/methimazole, beta-blockers, and steroids.