Thyroid Storm: A Diagnostic Conundrum

Abstract

Thyroid storm is a life threatening complication of hyperthyroidism which comes with multi-system involvement and is associated with a mortality of 8-25% despite modern advancements in treatment and supportive measures.A 47 year old woman with past medical history of hypertension and morbid obesity presented to the emergency room with 3 week history of shortness of breath and chest pain associated with productive cough, bilateral leg swelling, orthopnea and palpitations. Upon evaluation, she was in moderate respiratory distress, restless, tachypneic and tachycardic. She had bilateral proptosis and visible jugular venous pulsation along-with bibasilar crackles and pitting edema bilaterally. Lab tests revealed BNP 539 pg/ml and D-Dimer 6401 ng/ml. ECG showed atrial flutter, Chest X-Ray showed bilateral pleural effusions, and CT Chest was negative for pulmonary embolism but revealed anterior mediastinal mass, differential of which included thymoma or teratoma. She was admitted to CCU for aggressive diuresis, control of heart rate and was started on anticoagulation. A review of medical records from outside hospital revealed patient was hyperthyroid 8 months ago, however, was not on any medications. Given a Burch-Wartofsky score >70, she was started on IV hydrocortisone and cholestyramine for severe thyrotoxicosis. Endocrinology was consulted and added PTU to management. TFTs revealed a TSH 0.006 IU/ml, FT4 4 ng/dL and T3 2.5 ng/ml. Bedside ECHO showed LVEF of 14% with global hypokinesis and thyroid ultrasound revealed an enlarged, heterogenous thyroid with a solid, isoechoic, calcified left lobe nodule measuring 0.8 x 0.4 x 0.5 cm. Her serum TSI and thyrotropin receptor antibodies were elevated at 17.20 IU/L and 20.20 IU/L, respectively. She responded to treatment and was discharged on metoprolol, losartan, spironolactone, and furosemide for new-onset heart failure, apixaban for atrial flutter, and PTU and cholestyramine for hyperthyroidism, with Cardiology and Endocrinology follow-ups.Thyroid disease is a common illness affecting 9 to 15 percent of the adults. Thyrotoxicosis refers to the clinical syndrome of hyper-metabolism due to excessive amount of circulating thyroid hormones. The incidence of thyroid storm is 0.57 to 0.76 per 100,000 people per year in the US. It most commonly occurs in women and is more common in patients with underlying Grave’s Disease. The exact underlying mechanism that leads to thyroid storm is not well understood but adrenergic activation seems to have a major role. Our patient had long standing untreated hyperthyroidism with a solid nodule which led to the crisis. The most common cause of death is cardiopulmonary failure and hence treatment should be initiated as soon as diagnosis is suspected owing to high mortality.Awareness of thyroid pathology affecting the heart is important to remember in evaluating the etiology of heart failure in patients.