E03.5

HCC Category Mapping

What This Code Means

A life-threatening emergency condition where severe hypothyroidism causes a coma-like state with dangerously low body temperature, heart rate, and blood pressure.

Coding Tips

• •This is a medical emergency requiring ICU-level care; always code with appropriate severity indicators and comorbidities
• •Document precipitating factors (infection, medication non-compliance, cold exposure) as these are critical for treatment decisions

Clinical Significance

Myxedema coma is a life-threatening endocrine emergency representing the most severe form of hypothyroidism, characterized by profound hypothermia, altered mental status progressing to coma, cardiovascular collapse, hypoventilation, and multiorgan dysfunction. Despite the name, true coma may not be present; severe obtundation or lethargy qualifies. Mortality rates range from 20-60% even with aggressive treatment, making rapid recognition and intravenous thyroid hormone replacement critical.

Documentation Requirements

• ✓Documentation must clearly establish myxedema coma or crisis with clinical findings including altered mental status, hypothermia, bradycardia, hypotension, and hypoventilation.
• ✓Severely deranged thyroid function tests (profoundly elevated thyroid-stimulating hormone, very low or undetectable free thyroxine) must be documented.
• ✓The precipitating factor (infection, medication non-adherence, cold exposure, surgery) should be identified.
• ✓Treatment with intravenous levothyroxine and/or liothyronine, stress-dose hydrocortisone, and intensive care management should be recorded.

Commonly Confused Codes