Medical consequences of acute exposure to high altitude

People who ascend rapidly to altitudes greater than 3,000 meters (10,000 ft) may become ill; rarely, some may die from an inability to adapt to hypoxia. Age, pre-existing cardiopulmonary or hematologic disease, and the rate and degree of ascent are known to limit man's adaptation to high altitudes. Other factors, such as blunted hypoxic respiratory drive and sublinical disease of the pulmonary vascular bed are probably also important. Pre-exposure with acetozolamide (Diamox) helps, but once symptoms of high altitude pulmonary edema (HAPE) occur, supplemental oxygen and rapid descent to lower altitudes are the only known remedies. In view of the steady increase in the number of people who work and play at high altitudes, physicians must understand the pathophysiologic mechanisms involved in order to treat properly and to counsel patients.