Altitude sickness

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
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W8MD medical weight loss NYC and sleep center NYC

Altitude sickness
Synonyms	Acute mountain sickness (AMS), altitude illness
Pronounce	N/A
Specialty	N/A
Symptoms	Headache, nausea, dizziness, fatigue, insomnia
Complications	High-altitude cerebral edema (HACE), high-altitude pulmonary edema (HAPE)
Onset	6 to 12 hours after ascent
Duration	Usually resolves in 1 to 3 days
Types	N/A
Causes	Rapid ascent to high altitudes
Risks	High altitude, rapid ascent, lack of acclimatization
Diagnosis	Based on symptoms and history of recent ascent
Differential diagnosis	Dehydration, hangover, migraine, viral infection
Prevention	Gradual ascent, acclimatization, medications such as acetazolamide
Treatment	Descent, oxygen therapy, medications
Medication	N/A
Prognosis	N/A
Frequency	Common in people who ascend rapidly to altitudes above 2,500 meters (8,200 feet)
Deaths	N/A

Altitude sickness, also known as acute mountain sickness (AMS), is a pathological effect of high altitude on humans, caused by acute exposure to low partial pressure of oxygen at high altitude. It commonly occurs above 2,400 meters (approximately 8,000 feet). Early symptoms are headache, fatigue, shortness of breath, nausea, and sleep disturbances. Severe symptoms include pulmonary edema (fluid in the lungs) and cerebral edema (swelling of the brain).

Causes

Altitude sickness is caused by reduced air pressure and lower oxygen levels at high altitudes. The faster you climb to a high altitude, the more likely you will get acute mountain sickness. You can also get it if you go to a high altitude and exercise (like skiing, hiking, or biking) before your body has adjusted to the altitude.

Symptoms

Symptoms of altitude sickness usually appear within hours of moving to higher altitudes. They vary depending on the speed of your climb and how hard you push (exert) yourself. Symptoms usually come on within 12 to 24 hours of reaching a higher elevation and then get better within a day or two as your body adjusts to the change in altitude.

Prevention

Prevention of altitude sickness includes acclimatization, the process of gradually adjusting to changes in environment, such as altitude. It is recommended to ascend no more than 1,000 feet per day to sleep, as the body makes adjustments during sleep to the higher altitude.

Treatment

Treatment of altitude sickness includes rest, hydration, and descending to a lower altitude as quickly and safely as possible. Medications such as acetazolamide and dexamethasone can also be used to help prevent and treat high altitude sickness.

Gallery

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  Peripheral edema of a woman's face, before and after; Annapurna Base Camp, 2015

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  Mount Everest as seen from Drukair

See also

• High altitude pulmonary edema
• High altitude cerebral edema
• Acclimatization
• Hypoxia (medical)

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