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This article keeps the decision near the top, separates planning guidance from changing conditions and points you back to the complete internal library.
Browse the full Annapurna Base Camp library →High-altitude cerebral edema is a severe neurological emergency. Confusion, unusual behavior, extreme drowsiness, poor coordination or inability to walk normally should be treated as an emergency.
What this means
HACE may develop from severe altitude illness and can progress rapidly. A person who appears intoxicated, cannot walk a straight line or becomes difficult to wake needs immediate help.
What to do on the trail
- Confusion, disorientation or unusual behavior
- Ataxia: stumbling or inability to walk heel-to-toe
- Severe drowsiness, reduced responsiveness or seizure
- A rapid change in mental state at altitude
Do not leave the person alone or send them ahead. Stop ascent, arrange urgent descent and professional care, and use oxygen or prescribed emergency treatment only under an appropriate plan.
Build it into the itinerary
Share the plan with every trek member before departure. Agree who makes the decision to stop or descend, where the nearest help is expected and how the operator and insurer will be contacted.
Current weather, transport, local medical access and trail conditions can change. Reconfirm the operational plan in Kathmandu and again with the guide before the high stages.
Useful answers
Frequently asked questions
Is a severe headache required for HACE?
No. Neurological change and poor coordination are more important warning signs. Do not wait for every symptom to appear.
Can a person with HACE sleep it off?
No. Reduced responsiveness can be a sign of deterioration. Treat suspected HACE as an emergency requiring urgent descent and medical care.
Sources and fact-checking
Rules, prices, access, weather and local procedures can change. Reconfirm current conditions before travel.
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