Clinical features of patients with severe altitude illness in Nepal

Trekking in Nepal is a popular adventure travel activity involving more than 80,000 people of all ages annually. This study focuses on the demographic characteristics and clinical course of altitude illness patients evacuated to Kathmandu and estimates the rates of evacuation in different regions of Nepal.

During the years 1999 to 2006, all patients who presented with altitude illness to the CIWEC clinic in Kathmandu were evaluated and included in the study if the final diagnosis was compatible with high-altitude cerebral edema (HACE), high-altitude pulmonary edema (HAPE), or acute mountain sickness (AMS). Altitude illness-related deaths were reported according to death certificates issued by selected embassies in Kathmandu.

A total of 406 patients were evaluated, among them 327 retrospectively and 79 prospectively. HACE was diagnosed in 21%, HAPE in 34%, combined HAPE and HACE in 27%, and AMS in 18%. Mean patient age was older than trekker controls (44 +/- 13.5 vs 38.6 +/- 13.9 y, p < 0.0001). Everest region trekkers were more likely to be evacuated for altitude illness than trekkers in other regions. The estimated incidence of altitude illness-related death was 7.7/100,000 trekkers. Most altitude illness symptoms resolved completely within 2 days of evacuation.

Altitude illness that results in evacuation occurs more commonly among trekkers in the Everest region and among older trekkers. The outcome of all persons evacuated for altitude illness was uniformly good, and the rate of recovery was rapid. However, the incidence of altitude illness-related death continued to rise over past decade.