This occurs when one ascends to high altitudes especially if the ascent occurs over a short period of time. Commonly affects the younger, male, those with past history of altitude sickness and those who ascend quickly.
Symptoms can start within hours to days after exposure to high altitudes.
Altitude sickness accompanies mountaineers. If mild symptoms occur, stop ascent and stay at the same altitude for a day or two, then ascend cautiously. Severe symptoms require immediate descent to a lower altitude and drug treatment. Consult a doctor in the area. Normally, both descent and drug treatment are required for severe symptoms.