Altitude sickness, also known as acute mountain sickness, is a medical condition that most commonly occurs above 2,400 m (8,000 ft). Most people are not affected by this condition and it is not understood why certain people are susceptible. Most cases of altitude sickness occur in mountain climbers and cause minor symptoms, which disappear when the person descends to a lower altitude. However, serious cases can cause high altitude pulmonary edema (fluid in the lungs) and high altitude cerebral edema (brain swelling) and these are often life threatening. Let’s find out what causes this potential fatal condition.
What causes altitude sickness?
Altitude sickness occurs when the body cannot take enough oxygen from the air at higher altitudes. Although the percentage of oxygen in the air remains constant until 21,000 m (70,000 feet) the air density changes with altitude and this means that less oxygen molecules are available in each breath. Contributing factors include dehydration, rate of ascent and physical exertion.
Early signs of altitude sickness include; headaches, nausea, vomiting, fatigue/weakness, drowsiness, insomnia, dizziness/lightheadedness, nosebleed, shortness of breath, pins and needles, rapid heartbeat, and/or swelling of the hands, feet or face. The symptoms of pulmonary edema include; dry cough, fever and/or shortness of breath. The symptoms of cerebral edema include; headache that doesn’t respond to medication, fatigue, bladder and/or bowel dysfunction, paralysis, confusion, unsteadiness, loss of consciousness, severe nausea and/or retinal bleeding. These symptoms can develop very quickly and you should seek treatment immediately.
The most common treatment for non life threatening altitude sickness is to slowly descend to a lower altitude. In more serious cases additional oxygen and a Gamow bag may be used to treat the victim while they are transported to a lower altitude. There are some medicines that help with the symptoms of altitude sickness, but they are not effective treatments.