Acute Coronary Syndrome with Non-ST-Elevation Myocardial Infarction and Refractory Unstable Ventricular Tachycardia Complicated by Severe Acute Kidney and Liver Injury in Myxedema Crisis: A Case Report

Abstract

Background: Myxedema crisis, which occurs due to hypothyroidism, is a rare and life-threatening condition that can lead to severe myocardial infarction and lethal arrhythmia, as presented in this case.
Case Presentation: A 63-year-old man presented with typical prolonged chest pain, palpitations leading to near syncope, severe fatigue, loss of appetite, dizziness, and somnolence 2 days before admission. The patient exhibited somnolence, hypotension, thin eyebrows, and pretibial pitting edema. Electrocardiography revealed sinus rhythm with a prolonged QT interval, inferolateral-anterior ischemia, and a troponin-T value five times above the upper limit of normal. Therefore, the working diagnosis included non–ST-elevation myocardial infarction Killip IV, severe biventricular heart failure, severe acute kidney injury, and severe acute liver injury. On the third day of treatment, the patient experienced two consecutive episodes of unstable ventricular tachycardia and one episode of return of spontaneous circulation cardiac arrest. Thyroid examination incidentally revealed severe hypothyroidism with severe hyperkalemia. After other causes were excluded, the diagnosis of myxedema crisis was assumed. Oral thyroid therapy, levothyroxine (100 µg once daily), was administered. Within 3 days of initiating all treatments, the patient experienced significant hemodynamic improvement, improved kidney function, and normalization of liver function, accompanied by the disappearance of dyspnea, chest pain, and edema, with a compos mentis status. The patient was discharged with stable hemodynamics without support on the tenth day of treatment and underwent a coronary computed tomography angiography at an outpatient facility, which showed near-normal coronary results. The patient has been on routine follow-up for almost 1 year with levothyroxine (50 µg once daily) and has recently demonstrated good left ventricular function (ejection fraction=50%) and good functional capacity on an exercise test.
Conclusion: Clinicians should consider hypothyroidism crisis in the differential diagnosis for myocardial infarction, heart failure, and lethal arrhythmia, and treatment should be initiated immediately.