Intended for healthcare professionals

Clinical Review

Acute altitude illnesses

BMJ 2011; 343 doi: (Published 15 August 2011) Cite this as: BMJ 2011;343:d4943

This article has a correction. Please see:

  1. Chris Imray, professor of vascular and endovascular surgery1,
  2. Adam Booth, general practioner2,
  3. Alex Wright, consultant physician3,
  4. Arthur Bradwell, professor of immunology4
  1. 1Warwick Medical School, University Hospitals Coventry and Warwickshire NHS Trust, Coventry CV2 2DX, UK
  2. 2Jiggins Lane Medical Centre, Birmingham, UK
  3. 3Medical School, University of Birmingham, Birmingham
  4. 4Immunodiagostic Research Laboratory, Medical School, University of Birmingham
  1. Correspondence to: C Imray Christopher.imray{at}
  • Accepted 27 July 2011

Summary points

  • High altitude headache and acute mountain sickness often occur a few hours after arrival at altitudes over 3000 m

  • Occurrence of acute mountain sickness is reduced by slow ascent, and severity can be modified by prophylactic acetazolamide

  • Mild to moderate acute mountain sickness usually resolves with rest, hydration, halting ascent, and analgesics

  • Occasionally people with acute mountain sickness develop high altitude cerebral oedema with confusion, ataxia, persistent headache, and vomiting

  • Severe acute mountain sickness and high altitude cerebral oedema require urgent treatment with oxygen if available, dexamethasone, possibly acetazolamide, and rapid descent

  • High altitude pulmonary oedema is a rare but potentially life threatening condition that occurs 1-4 days after arrival at altitudes above 2500 m; treatment should include oxygen if available, nifedipine, and rapid descent to lower altitude

  • Treat for both high altitude pulmonary and cerebral oedema if in doubt

Acute altitude illnesses are potentially serious conditions that can affect otherwise fit individuals who ascend too rapidly to altitude. They include high altitude headache, acute mountain sickness, high altitude cerebral oedema, and high altitude pulmonary oedema. The number of people travelling to altitude for work (soldiers, miners, construction workers, and astronomers) or for recreation (skiing, trekking, mountain biking, and climbing) is rising, and increased media attention towards these activities has also raised the profile of altitude related illness. Typical scenarios in which such illness might occur are a family trek to Everest base camp in Nepal (5360 m), a fund raising climb of Mount Kilimanjaro (5895 m), or a tourist visit to Machu Picchu (2430 m). Awareness of potential altitude related problems is important even for healthcare practitioners working at lower altitude, because patients may ask for advice about the safety of a proposed journey and how to prevent illness at altitude.

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