Terminology and classification of acute mountain sickness

Abstract

There are several unsolved questions about acute mountain sickness. Climbers and trekkers want to know how to recognise cases, how to assess their severity, and how to act to avoid deaths. They also need clear guidance about prevention. Some of the terms currently used are briefly discussed. The relationship between the common, milder forms of acute mountain sickness and the rarer, more severe forms is still uncertain. Some patients certainly seem to progress from mild to severe states, so that the former may well be a useful warning of the risk of the latter. On the other hand, some patients seem to develop life-threatening disease with little or no useful warning. Perhaps most important of all, the agreed terminology and disease descriptions should guide non-qualified personnel in their management of companions ascending to high altitude. They need to know who must be sent down urgently, who should remain at their current altitude, and who may be allowed to continue ascent. The author believes the most appropriate classification and terminology to be as follows: acute mountain sickness, benign acute mountain sickness, and malignant acute mountain sickness, including cerebral acute mountain sickness, pulmonary acute mountain sickness, and mixed forms (cerebral + pulmonary). These terms are discussed. This article asks the question whether it is possible to agree on a terminology that is accurate up to the point of our present knowledge but not beyond, which forms a useful basis for communication and further study, and which allows helpful instruction for those who go to high altitude. The author believes the proposed terminology meets these criteria.