Acute Mountain Sickness

Approximately 200 million individuals travel to high-altitude destinations annually, a number that has increased with improved accessibility and infrastructure to remote regions. High-altitude destinations are defined as elevations above 1,500 m. However, altitude illness is uncommon below 2,500 m. Reduced partial pressure of oxygen at high altitude can produce several pathological conditions. The most common form of high-altitude illness is acute mountain sickness (AMS), which, if unrecognized or untreated, may progress to high-altitude cerebral edema (HACE). Cerebral manifestations differ from pulmonary presentations, such as high-altitude pulmonary edema (HAPE). Although AMS carries lower morbidity and mortality than HACE or HAPE, its high prevalence makes it a significant concern for individuals recreating at high altitude. Whereas HACE and HAPE are life-threatening emergencies requiring rapid descent, AMS symptoms are often prevented or managed with supportive measures and oral medications. Increasing numbers of travelers expose providers across all practice settings to the need for counseling and guidance on evidence-based strategies for prevention and management of high-altitude illness.