MON-386 - When Dementia Masks an Endocrine Emergency: Sepsis-Induced Myxedema Coma in an Elderly Patient

Title: When Dementia Masks an Endocrine Emergency: Sepsis-Induced Myxedema Coma

Background:
Myxedema coma is a rare, life-threatening manifestation of severe hypothyroidism, most commonly precipitated by infection in elderly patients, with reported mortality rates of 30–60%.¹ Diagnosis is frequently delayed due to nonspecific symptoms, and the term is misleading, as most patients present with progressive lethargy and altered mental status rather than coma.¹ In patients with advanced dementia, acute cognitive decline may be misattributed to disease progression, obscuring recognition of reversible endocrine emergencies and delaying life-saving therapy.

Case Presentation:
A 78-year-old woman with hypothyroidism, advanced dementia, chronic obstructive pulmonary disease, atrial fibrillation, and chronic hepatitis C presented with one week of worsening lethargy and confusion. Symptoms were initially attributed to dementia progression. On arrival, she was febrile (102.8°F) and obtunded, with dry skin, hoarse voice, generalized nonpitting edema, and periorbital swelling. Laboratory evaluation revealed leukocytosis (15.1 ×10⁹/L), hyponatremia (129 mmol/L), severe microcytic anemia (hemoglobin 6.6 g/dL), acute kidney injury, markedly elevated thyroid-stimulating hormone, and profoundly decreased free thyroxine. Blood and urine cultures grew Escherichia coli, confirming urosepsis. Imaging demonstrated a moderate pericardial effusion, a recognized manifestation of severe hypothyroidism.² Hemodynamic instability and metabolic derangements supported the diagnosis of myxedema coma precipitated by sepsis.

Management and Outcome:
The patient was treated with intravenous levothyroxine, empiric corticosteroids, and broad-spectrum antibiotics per guideline-based recommendations.² Corticosteroids were discontinued after cortisol levels were confirmed to be appropriate. Over several days, mental status, renal function, and electrolyte abnormalities improved. She was transitioned to oral levothyroxine and discharged in stable condition at her cognitive baseline.

Conclusion:
Advanced dementia can conceal life-threatening endocrine emergencies. Acute cognitive decline in elderly patients should prompt evaluation for reversible causes, including myxedema coma. Early recognition and prompt initiation of thyroid hormone replacement, empiric corticosteroid coverage, and treatment of precipitating infections are critical for improving survival and preventing unnecessary morbidity.¹²

References:

Wall CR. Myxedema coma: diagnosis and treatment. Am Fam Physician. 2000;62:2485–2490.

Rizzo LFL, Mana DL, Bruno OD, Wartofsky L. Myxedema coma. Medicina (B Aires). 2017;77:321–328.

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