Myxedema Coma Leading to Acute Coronary Syndrome: A Case Report

Myxedema coma is a rare and life-threatening medical condition. We present a case of poorly controlled hypothyroidism that initially caused myxedema coma and then led to acute coronary syndrome (ACS). A 57-year-old woman with a history of Hashimoto's thyroiditis and coronary artery bypass grafting (CABG) came in with fatigue and worsening left-sided chest pain that occurred even at rest for the past 12 hours. She has not been taking her levothyroxine as prescribed and has not been seeing her endocrinologist for follow-up. When she arrived, her vitals showed that she had a heart rate of 53 beats per minute (sinus bradycardia), but otherwise, she was stable. The laboratory tests showed elevated levels of high sensitivity troponin T at 42 ng/L (normal value: <14 ng/L), a thyroid stimulating hormone level of 408 mIU/L (normal value: 0.5-2.5 mIU/L), a free thyroxine level of 0.4 (normal range: 0.8-1.8 ng/mL), and a decreased glomerular filtration rate of 71 mL/min/1.73 m² (normal range: 90-120 mL/min/1.73 m²). Although the electrocardiogram did not show ST-T wave changes, the thrombolysis in myocardial infarction (TIMI) risk score was five. Additionally, there was a new onset decrease in ejection fraction to 40% and mild hypokinesia of the left ventricle on the echocardiogram. She was started on a heparin drip in the emergency department and subsequently underwent cardiac catheterization with drug-eluting stent (DES) placement. Myxedema coma score was 40 suggestive of coma risk myxedema and eventually, she was admitted to the intensive care unit. Her condition was managed using intravenous levothyroxine, liothyronine, and hydrocortisone. After her symptoms subsided, she was discharged with a prescription for dual antiplatelet agents and levothyroxine. Due to its rarity and high mortality rate, it is crucial for physicians to maintain a high level of suspicion for myxedema coma and promptly initiate treatment. This is especially important when a patient with a history of hypothyroidism presents with cardiac issues such as ACS or bradycardia that do not entirely align with the clinical picture.