High Altitude Medicine Guide logo

The Lake Louise Consensus on
the Definition of Altitude Illness

The following definitions on the diagnosis of altitude illness were adopted at the 1991 International Hypoxia Symposium, held at Lake Louise in Alberta, Canada.


In the setting of a recent gain in altitude, the presence of headache and at least one of the following symptoms:

  - gastrointestinal (anorexia, nausea or vomiting)
- fatigue or weakness
- dizziness or lightheadedness
- difficulty sleeping


Can be considered "end stage" or severe AMS. In the setting of a recent gain in altitude, either:

  - the presence of a change in mental status and/or ataxia in a person with AMS
- or, the presence of both mental status changes and ataxia in a person without AMS


In the setting of a recent gain in altitude, the presence of the following:

  Symptoms: at least two of:
    - dyspnea at rest
- cough
- weakness or decreased exercise performance
- chest tightness or congestion
  Signs: at least two of:
    - crackles or wheezing in at least one lung field
- central cyanosis
- tachypnea
- tachycardia

The symposium consensus committee also developed an AMS scoring system (the "Lake Louise score") which is widely used today to assess the severity of illness. We have developed a clinical worksheet, which uses the Lake Louise scoring system, and another which has phonetic translations in Nepali.

Reference: "The Lake Louise Consensus on the Definition and Quantification of Altitude Illness" in Sutton JR, Coates G, Houston CS (Eds), Hypoxia and Mountain Medicine. Queen City Printers, Burlington, Vermont, 1992.

Home - Search - Links - About this website - About the Webmaster - Feedback - Bookstore

Copyright© Thomas E. Dietz, MD
Emergency & Wilderness Medicine

This Page URL: http://www.high-altitude-medicine.com/AMS-LakeLouise.html
Last modified 8-May-2000