HAPE results from the accumulation of fluid on the lungs preventing the effective exchange of oxygen, leading to shortness of breath and a dry cough with a frothy, pink phlegm. This type of altitude illness occurs in 1-2% of people ascending to altitude and typically the symptoms being, to occur on the second night after arrival at altitude.
The initial symptoms do have a likeness to the natural increase in breathing rate when travelling to altitude, however, someone suffering from HAPE will be unable to catch their breath or to exert themselves.
Other symptoms include: headache, increased heart rate, low grade fever, severe fatigue and weakness, irrational behaviour and tightness of breath.
Furthermore, the sufferers will have a lower oxygen saturation level than non-sufferers at the same altitude.
There are a number of risk factors associated with HAPE these include; prior diagnosis of HAPE, obesity, the rare absence of a right pulmonary artery and those with an increased blood pressure in the arteries supplying the lungs.
If these symptoms occur the following treatments can be given:
Barry, P.W. and Pollard, A.J. (2003) “Altitude illness”, British Medical Journal, 326(7395), pp.915-919.
Bezruchka, S. (2005) Altitude illness: Prevention & Treatment, Seattle: Mountaineers Books.
Luks, A.M., Auerbach, P.S., Freer, L., Grissom, C.K., Keyes, L.E., McIntosh, S.E., Rodway, G.W., Schoene, R.B., Zafren, K. and Hackett, P.H. (2019) “Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update”, Wilderness & environmental medicine, 30(4), pp.3-18.