High altitude pulmonary edema (HAPE) is a medical condition characterized by the accumulation of fluid in the lungs, commonly occurring in individuals who ascend to high altitudes rapidly. It is a type of non-cardiogenic pulmonary edema, meaning that it is not caused by heart dysfunction but rather by the increased pressures in the pulmonary blood vessels at high altitudes.
At high altitudes, where the oxygen levels are lower and air pressure is reduced, the body may struggle to maintain adequate oxygenation. This can cause constriction of the pulmonary blood vessels, resulting in increased pressure within them. As a consequence, fluid leaks out of the vessels and accumulates in the air sacs of the lungs, impairing oxygen exchange and causing breathlessness, cough, chest tightness, and fatigue.
HAPE is most commonly seen in individuals who ascend rapidly to altitudes above 2,500 meters (8,000 feet) without sufficient acclimatization. Those who are inexperienced in high-altitude activities, have a genetic predisposition, or have pre-existing lung conditions are at higher risk of developing HAPE.
Immediate descent to lower altitudes is the primary treatment for HAPE, which helps to relieve symptoms and reduce the risk of further complications. Supplemental oxygen, rest, and medications such as nifedipine and sildenafil may also be used to manage the condition.
Preventive measures for HAPE include gradual ascent to higher altitudes, allowing the body to acclimatize, and maintaining proper hydration. Further prevention factors involve adequate physical fitness, avoiding strenuous activities at high altitudes, and the use of medications like acetazolamide.
