Pulmonary oedema high altitude

The three main types of altitude illness, characterised initially by nausea, headache, sleep disturbance and stomach upset, are acute mountain sickness (AMS) high altitude pulmonary oedema (HAPE) and high altitude cerebral oedema (HACK). They occur after rapid ascent to altitudes greater than 2,500 m (about 8,000 feet) in unacclimatised people. In unacclimatised mountaineers, the prevalence of AMS at 4,559 metres (15,000 feet) is approximately 50% and HAPE 4%. Risk depends on individual susceptibility, rate of ascent and pre-exposure to high altitude. AMS is not a pre-requisite for HAPE. 

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