(272) Apathetic Thyroid Storm With Thyrotoxicosis-Induced Cardiomyopathy

Introduction: Thyroid storm is a rare endocrine emergency, with an incidence of 0.57-0.76/100,000 people in the US per year, with a high mortality rate of nearly 7.4%.1,2 The diagnosis of thyroid storm mainly relies on clinical suspicion, as there is no widely accepted diagnostic criteria or thyroid function tests cutoff.3 Patients exhibit a wide variety of symptoms, including CNS manifestations, thermoregulatory dysfunction and multi-organ affection. However, some patients with thyroid storm can have an atypical presentation without hyperactive symptoms.

Description: A 49-year-old patient with no significant medical history presented with progressive generalized anasarca over the two weeks prior to admission, along with palpitations and nonspecific gastrointestinal symptoms. On evaluation, he was found to have uncontrolled atrial fibrillation with rapid ventricular response and manifestations of congestive heart failure, including venous congestion, pulmonary edema and peripheral edema. His workup revealed undetectable TSH and significantly elevated free T3 (7.77) and T4 (4.23). An echocardiogram showed depressed systolic function with EF of 20% and global hypokinesia. The Burch–Wartofsky point scale (BWPS) score was 60, strongly indicating thyroid storm. He developed cardiogenic shock but did not require inotropic support and improved with rate control and vigilant diuresis. He was treated with esmolol, methimazole and glucocorticoids, leading to improvement. Outpatient workup revealed Grave's disease. At his one-year follow-up, the patient remains euthyroid and his LVEF is improving.

Discussion: Thyroid storm is a rare and potentially fatal condition that remains a clinical diagnosis due to the lack of standard diagnostic criteria. While various criteria have been developed to aid in diagnosis, including the BWPS and those outlined by Akamizu et al, the diagnosis ultimately relies on clinician assessment.4 Our case highlights an unusual presentation of apathetic thyroid storm, observed in < 1% of cases, without the typical symptoms associated with thyroid Storm.3 More research is needed to establish definitive diagnosis and treatment guidelines. Until then, thyroid storm should be considered in the differential diagnosis of dilated cardiomyopathy, even in absence of typical signs or presentations.