Study of Nepalese pilgrims challenges diagnosis of acute mountain sickness

The Lake Louise Score Questionnaire has been used for more than two decades to determine if someone was suffering from acute mountain sickness (AMS), which strikes people at elevations above 2,500 metres. The lack of oxygen causes a spectrum of ailments, from headaches to vomiting to potentially fatal swelling of the brain or lungs.

The questionnaire, valued for its simplicity under austere conditions, asks people who are feeling ill at altitude to rate themselves in five areas -- headache, nausea, weakness, dizziness and sleep quality.

A team co-directed by Dr. Michael Koehle, an associate professor in UBC's Faculty of Medicine and the School of Kinesiology, used the questionnaire on nearly 500 Nepalis who hiked to a 4,380-metre-high lake for a religious festival. Nearly a third of them were diagnosed with AMS.

A statistical analysis of the results, published recently in the journal High Altitude Medicine & Biology, found that the sleep score did not coincide with the answers on the other four parts of the questionnaire. If sleep quality was removed from the questionnaire, the reliability of the overall score increased.

Including the sleep score in the questionnaire, Koehle says, could lead to some people being treated unnecessarily, and others not getting treatment they need -- which usually consists of going down to lower elevations.

"Although people with AMS frequently do have trouble sleeping, that symptom can be affected by many other factors, including noise, comfort and the mild dehydration that often occurs at high altitude," Koehle says. "And while the entire questionnaire is based on a self-assessment, rating the quality of your own sleep is particularly subjective. So I would recommend removing that from the questionnaire."