Acute mountain sickness

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Respiratory system

Acute mountain sickness

Definition:

Acute mountain sickness is an illness that can affect mountain climbers, hikers, skiers, or travelers who ascend too rapidly to high altitude (typically above 8,000 feet or 2,400 meters). This is especially for persons who normally reside at or near sea level.

Alternative Names:
High altitude cerebral edema; Altitude anoxia; Altitude sickness; Mountain sickness; High altitude pulmonary edema
Causes, incidence, and risk factors:

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Reduced atmospheric pressure and a lower concentration of oxygen at high altitude are the causes of this illness. It affects the nervous system, lungs, muscles, and heart. Symptoms can range from mild to life-threatening.

In most cases the symptoms are mild, but in severe cases fluid collects in the lungs (pulmonary edema) causing extreme shortness of breath and further decreasing oxygenation. Swelling may also occur in the brain (cerebral edema), causing confusion, coma, and, if untreated, death.

The likelihood and severity of altitude illness is greater with increasing rate of ascent, higher altitude attained, and higher levels of exertion.

Approximately 20% of people will develop mild symptoms at altitudes between 6,300 to 9,700 feet, but pulmonary and cerebral edema are extremely rare at these heights. However, above 14,000 feet, a majority of people will experience at least mild symptoms, while approximately 10% and 1.5%, respectively, of un-acclimatized people staying at this altitude will develop pulmonary or cerebral edema.