SUN-310 - Myxedema without Coma Presenting with Bradycardic Hypotension 59-Year-Old Man: Case Report

Background: Myxedema coma is a rare, life-threatening manifestation of severe hypothyroidism, usually presenting with impaired mental status, hypothermia, hypoventilation, hypotension, and bradycardia. We present a case of severe myxedema without coma manifesting as bradycardic hypotension and acute kidney injury.

Case: A 59-year-old man presented with upper arm tightness and pressure. He was alert and oriented but provided a limited historyHe reported only a recent hospitalization for a fall. He lives alone. Vital signs were significant for bradycardia and hypotension: T 99.1°F, HR 47 bpm, BP 76/47 mmHg, and SpO₂ 96% on 6L NC. Admission labs revealed Potassium 7.1 mmol/L, Bicarbonate 15 mmol/L, BUN 70 mg/dL, Creatinine 4.96 mg/dL, Troponin 1.11 ng/mL, and WBC 14.3 K/µL.
The patient’s hemodynamic instability was initially thought to be secondary to hyperkalemia and acute kidney injury (AKI). He was started on atropine, vasopressors, and emergent CRRT. However, thyroid function tests available on day 2 revealed a TSH of 246 mIU/L and Free T4 < 0.5 ng/dL. Collateral history confirmed recent nonadherence to a high-dose levothyroxine regimen (225 µg Mon–Sat/425 µg Sun). Treatment was adjusted to include IV Levothyroxine (150 µg bolus) and empiric hydrocortisone, followed by daily oral levothyroxine. Echocardiography showed preserved LVEF with grade-I diastolic dysfunction. Following hormone replacement, his creatinine was stabilized at 3.6 mg/dL and the patient was weaned off vasopressors and CRRT.

Discussion: While our patient showed the severe cardiovascular and renal collapse typical of myxedema, he retained his mental clarity. His Popoveniuc score (Myxedema Coma Diagnostic Score) reached 70, which established the diagnosis of myxedema coma even without coma. This high score was driven by hypotension, bradycardia, and decreased GFR, in the setting of medication nonadherence. This emphasizes a critical point that myxedema coma can occur even in the absence of coma or neurological decline

Conclusion: Severe hypothyroidism without coma can drive bradycardia, hypotension, and AKI. Early thyroid hormone plus empiric steroids until adrenal insufficiency is excluded, and definitive potassium correction and renal support are pivotal. Popoveniuc’s scoring can help frame “coma” versus“at-risk” presentations.

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