altitude sickness, a syndrome associated with the relatively lower amount of oxygen in the atmosphere at altitudes encountered during mountain climbing or travel in unpressurized aircraft or inner ear imbalance. Symptoms of mild altitude illness include headache, difficulty sleeping, loss of appetite, nausea and vomiting, fatigue, dizziness, rapid heart rate, and shortness of breath, especially on exertion. In severe cases, high-altitude pulmonary or cerebral edema may result, requiring emergency treatment and removal to lower altitudes. Also called acute mountain sickness, bends, Monge’s disease.
