High-altitude pulmonary edema

High-altitude pulmonary edema
Other names	High-altitude pulmonary oedema (HAPO)[1]
Chest x-ray of HAPE showing characteristic patchy alveolar infiltrates with right middle lobe predominance.
Specialty	Emergency medicine, wilderness medicine

High-altitude pulmonary edema (HAPE) is a life-threatening form of non-cardiogenic pulmonary edema that occurs in otherwise healthy people at altitudes typically above 2,500 meters (8,200 ft).^[2] However, cases have also been reported between 1,500–2,500 metres or 4,900–8,200 feet in more vulnerable subjects.

Classically, HAPE occurs in persons normally living at low altitude who travel to an altitude above 2,500 meters (8,200 feet).^[3] Re-entry HAPE is also an entity that has been described in persons who normally live at high altitude but who develop pulmonary edema after returning from a stay at low altitude.^[3] It is severe presentation of altitude sickness.

There are many factors that can make a person more susceptible to developing HAPE, including genetic factors, but detailed understanding is lacking and currently under investigation. HAPE remains the major cause of death related to high-altitude exposure, with a high mortality rate in the absence of adequate emergency treatment.^[3]