What is a high altitude illness?
A person with high altitude illness has symptoms that occur after a rapidly ascending to an altitude over 7,500 feet. Worsening high altitude illness can lead to high altitude pulmonary edema or high altitude cerebral edema. About 12% of people develop symptoms of high altitude illness at an altitude of 9,000 feet.

What are the symptoms of a high altitude illness?
Symptoms depend on whether the brain or lungs are affected. Initial symptoms of high altitude illness include weakness, fatigue, headache, and nausea. Symptoms of worsening high altitude illness include vomiting, difficulty with balance, lethargy, confusion, and seizures. Initial symptoms of high altitude illness may include dry cough, nausea, headache, fever, weakness, fatigue, and mild difficulty breathing that worsens at night and with exertion. Symptoms of severe high altitude illness include a bloody cough, severe difficulty breathing, confusion, cyanosis, and coma.

How does the doctor treat a high altitude illness?
Treatment depends on how much the brain or the lungs are affected. High altitude cerebral edema and pulmonary edema are medical emergencies. Treatment for both requires immediate descent to a lower altitude. Additional measures include oxygen therapy and hyperbaric therapy.