---
title: "HACE on the Annapurna Base Camp Trek: Confusion,…"
description: "High-altitude cerebral edema is a severe neurological emergency. Confusion, unusual behavior, extreme drowsiness, poor coordination or inability to walk…"
canonical: "https://www.nepaltibetbhutan.com/annapurna-base-camp/annapurna-base-camp-hace"
last-updated: "2026-08-21T00:00:00+05:45"
image: "https://www.nepaltibetbhutan.com/_next/static/images/annapurna-base-camp-hero-1280.webp"
---

Safety hub

# HACE on the Annapurna Base Camp Trek: Confusion, Coordination and Emergency Response

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.

**High altitude**Context

**Act early**Priority

**Local help**Coordinate

**Medical**Professional advice

DB
**By [Dinesh Bhusal](/author-dinesh-bhusal)**7 min read

**✓ Reviewed 21 Aug 2026**

Information checked against current official and local sources. Fees, access, permits and transport can change.
[Sources & methodology →](/data-methodology)

Current information
✓ Last checked: 21 Aug 2026

Permits, fees, flights, border rules and operating conditions can change. We use official and current sources whenever possible and recommend reconfirming time-sensitive details before travel.

[Official sources ↗](https://ntb.gov.np/en/plan-your-trip/before-you-come/tims-card)[What to recheck →](/data-methodology)
Details and source context

Status

Planning guidance reviewed

Applies to

Annapurna Base Camp Trek

Last checked

21 Aug 2026

On this page

## 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

Local Planning Note · Amigo Treks Team
**Field advice**

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. In the HACE guide, 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.

## Neurological red flags and urgent evacuation at ABC

High Altitude Cerebral Edema (HACE) occurs when brain swelling results from severe oxygen starvation. In the Annapurna Sanctuary, HACE can strike trekkers who sleep at Machhapuchhre Base Camp (3,700m) or Annapurna Base Camp (4,130m) after pushing through early headache, dizziness, or nausea without resting.

The primary neurological indicator is ataxia—impaired coordination and balance. Perform the heel-to-toe tandem walk test: if the trekker cannot walk ten steps in a straight line without swaying or falling, HACE is present. Accompanying symptoms include confusion, irrational statements, extreme lethargy (difficulty waking from sleep), and slurred speech.

- Test coordination with the heel-to-toe tandem walk test at MBC and ABC.

- Treat confusion, persistent vomiting, or unsteadiness as a medical emergency.

- Administer Dexamethasone (8mg initial dose, then 4mg every 6 hours) under medical guidance.

- Administer high-flow supplemental oxygen if emergency cylinders are available at the lodge.

## Acclimatization buffers between Deurali and Base Camp

Preventing cerebral edema requires smart itinerary design. Rather than rushing from Bamboo (2,310m) to ABC in two days, break the ascent by sleeping at Deurali (3,200m) and then Machhapuchhre Base Camp (3,700m) before pushing to ABC. This limits the daily sleeping altitude gain to 500 meters or less, staying within safe wilderness medicine parameters.

If HACE symptoms appear, descent must begin immediately with total assistance. The patient must be guided or carried down toward Dovan and Bamboo. Never leave the person unattended in a cold lodge room to sleep it off, as cerebral edema can progress to coma during sleep.

- Break the upper trek into manageable stages: sleep at Deurali (3,200m) and MBC (3,700m).

- Never ascend to ABC if you experience headache or nausea at MBC.

- Begin continuous assisted descent immediately down the valley at the first sign of ataxia.

- Coordinate with Pokhara emergency medical teams for transfer upon reaching the roadhead.

Continue planning

## Related planning guides

[Related guide
### Compare the full itinerary

Continue with the related planning details.](/annapurna-base-camp/annapurna-base-camp-trek-itinerary)[Related guide
### Read altitude guidance

Continue with the related planning details.](/annapurna-base-camp/annapurna-base-camp-altitude-sickness)[Related guide
### Check the packing list

Continue with the related planning details.](/annapurna-base-camp/annapurna-base-camp-trek-packing-list)[Related guide
### Check high-altitude insurance

Continue with the related planning details.](/annapurna-base-camp/annapurna-base-camp-trek-insurance)

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.
What simple field test detects ataxia and early HACE?+
The tandem gait test (walking heel-to-toe in a straight line); inability to balance or walking like an intoxicated person strongly indicates HACE.
What immediate medical intervention is used for HACE before descent?+
Administration of high-flow oxygen, oral Dexamethasone if prescribed/available, and immediate assisted descent to lower altitude.
What is the recommended sleeping altitude pacing for the upper Annapurna trek?+
Sleep at Deurali (3,200m) on night 1, then MBC (3,700m) on night 2, before reaching ABC (4,130m). This keeps net sleeping gains near the 500m recommended safety ceiling.
How does HACE present in teahouses at Machhapuchhre Base Camp?+
Trekkers may become unusually clumsy, drop items, display irrational mood swings, or struggle to walk straight to the dining hall. These neurological signs require immediate descent.

## Sources & methodology

Use the dated sources below for the claims they support. Recheck time-sensitive permits, fees, transport and border procedures before booking.

[**National Trust for Nature Conservation — ACAP** ↗](https://www.ntnc.org.np/project/annapurna-conservation-area-project-acap)National Trust for Nature ConservationSupports: Annapurna Conservation Area management and conservation context

[**Nepal Tourism Board — TIMS and trekking information** ↗](https://ntb.gov.np/en/plan-your-trip/before-you-come/tims-card)Nepal Tourism BoardSupports: Official Nepal trekking-document and visitor-planning context

[**CDC Yellow Book — high-altitude travel** ↗](https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html)Centers for Disease Control and PreventionSupports: Altitude-illness prevention, symptoms and descent-oriented medical guidance

Continue planning

## Related Annapurna Base Camp guides

[Safety hub
### HAPE guide

Read the HAPE guide guide →](/annapurna-base-camp/annapurna-base-camp-hape)[Health and safety
### Altitude safety

Read the Altitude safety guide →](/annapurna-base-camp/annapurna-base-camp-altitude-sickness)[Safety hub
### AMS symptoms

Read the AMS symptoms guide →](/annapurna-base-camp/annapurna-base-camp-ams-symptoms)[Safety hub
### Diamox guide

Read the Diamox guide guide →](/annapurna-base-camp/annapurna-base-camp-diamox-guide)

Personalised planning

## Plan Your Annapurna Base Camp Journey

Tell our Kathmandu-based planning team your travel dates, group size and preferred pace. We will help you shape a realistic Annapurna Base Camp itinerary with clear inclusions and proper acclimatization buffers.

[Plan with Amigo Treks →](/contact#planning-enquiry)[Ask on WhatsApp ↗](https://wa.me/9779851136878?text=Hello%20Amigo%20Treks%2C%20I%20need%20help%20planning%20a%20Annapurna%20Base%20Camp%20journey.)[Back to Annapurna Base Camp](/annapurna-base-camp)

Plan with context

## Custom Himalayan Route Planning

Our Kathmandu operations team arranges itemised itineraries, verified permits, and private transport matched to your travel dates and pacing.
[Request custom itinerary →](/contact#planning-enquiry)[WhatsApp a trip planner ↗](https://wa.me/9779851136878?text=Hello%20Amigo%20Treks%2C%20I%20need%20help%20planning%20HACE%20guide.)[← All Annapurna Base Camp guides](/annapurna-base-camp)

Talk through the next decision

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Community Insights

## Route Experiences & Field Updates

Recent field reports, route conditions, and practical observations shared by travellers and local leaders.

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