Which signs warrant immediate consideration of altitude-related emergency (HACE) in a patient?

• A. Severe chest pain and leg swelling.
• B. Mild dizziness with no neurologic signs.
• C. Severe headache with no neuro signs.
• D. Altered mental status, ataxia, confusion, and severe neurologic signs.

Answer: (D)

A sudden combination of mental status changes with neurological impairment at altitude signals a life-threatening form of altitude illness that needs immediate action. Altered mental status plus ataxia and other severe neurologic signs are the hallmark of high-altitude cerebral edema (HACE). HACE occurs when hypoxia at high elevation leads to brain swelling, and it can deteriorate quickly. Because the brain is involved, these signs demand rapid descent, supplemental oxygen, and urgent medical care—time matters.

The other options don’t point to HACE. Severe chest pain with leg swelling suggests a cardiac or vascular problem, such as a heart issue or a thromboembolism, not the neurologic profile of HACE. Mild dizziness without neurologic signs is nonspecific and can be due to mild altitude illness or other benign factors; it doesn’t indicate the brain edema seen in HACE. Severe headache without neurologic signs could be a high-altitude headache or mild altitude illness, but without neuro involvement, it isn’t HACE.