Which statement most accurately reflects signs that suggest HACE requiring immediate action?

• A. Altered mental status with mild dizziness.
• B. Severe headache with nausea but normal mental status.
• C. Altered mental status, ataxia, confusion, and severe neurologic signs.
• D. Normal mental status with no symptoms.

Answer: (C)

High-altitude cerebral edema (HACE) is a dangerous progression of altitude illness that affects the brain. When HACE is present, you’ll see clear central nervous system involvement, especially changes in mental status along with noticeable neurological deficits. The combination of altered mental status with ataxia and confusion indicates cerebral edema is underway and requires immediate action, usually rapid descent to a lower altitude with supplemental oxygen and urgent treatment. The other scenarios describe symptoms that are milder or non-neurological (or no symptoms at all) and do not reflect the brain involvement seen in HACE.