SAT-341 - Impending Myxedema Coma Presenting with Chest Pain and Unmasking Severe Coronary Artery Disease: A Management Dilemma

Abstract
Background

Myxedema coma represents a life-threatening manifestation of severe hypothyroidism and is often precipitated by systemic stressors such as infection, trauma, or myocardial infarction. Management typically includes prompt thyroid hormone replacement; however, aggressive therapy may precipitate ischemia in patients with underlying coronary artery disease (CAD), posing a therapeutic challenge.

Clinical Case

A 70-year-old woman with hypothyroidism on chronic levothyroxine therapy and type 2 diabetes mellitus presented with diffuse chest pain, dizziness, and an unwitnessed fall. She was a poor historian, with family reporting recent recurrent falls. Examination revealed bradyphrenia, flat affect, puffy facies, periorbital edema, macroglossia, and mild bradycardia with severe hypertension. Laboratory evaluation showed markedly elevated TSH (>100 μIU/mL) and undetectable free T4 ( < 0.1 ng/dL), consistent with severe hypothyroidism and impending myxedema coma. Cardiac biomarkers were stable, and echocardiography demonstrated preserved systolic function with a small pericardial effusion.

Given concern for occult CAD, intravenous levothyroxine was deferred, and her home oral levothyroxine dose (200 μg daily) was continued cautiously. Morning cortisol was obtained prior to steroid administration. Further cardiac evaluation revealed a coronary calcium score of 264 and severe (80%) mid-LAD stenosis on CT coronary angiography, confirmed on left heart catheterization. The patient underwent successful IVUS-guided percutaneous coronary intervention with drug-eluting stent placement. Her mental status, energy, and chest discomfort improved during hospitalization, and she was discharged in stable condition.

Conclusion

This case highlights the importance of individualized thyroid hormone replacement in severe hypothyroidism, particularly in elderly patients with suspected or unrecognized CAD. Cautious oral levothyroxine therapy, alongside thorough cardiac evaluation, may be appropriate in select cases of impending myxedema coma to avoid precipitating myocardial ischemia.

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