Emergency Medical Minute

Contributor: Jorge Chalit-Hernandez, OMS3 Educational Pearls: Acute mountain sickness (AMS) is the term given to what is otherwise colloquially known as altitude sickness High altitude cerebral edema (HACE) is a severe form of AMS marked by encephalopathic changes Symptoms begin at elevations as low as 6500 feet above sea level for people who ascend rapidly May develop more severe symptoms at higher altitudes The pathophysiology involves cerebral vasodilation Occurs in everyone ascending to high altitudes but is more pronounces in those that develop symptoms The reduced partial pressure of oxygen induces hypoxic vasodilation in the brain, which results in edema and, ultimately, HACE in some patients Symptomatic presentation Headache, nausea, and sleeping difficulties occur within 2-24 hours of arrival at altitude HACE may occur between 12-72 hours after AMS and presents with ataxia, confusion, irritability, and ultimately results in coma if left untreated Clinical presentation may