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Diseases » Mountain sickness » Wikipedia

Mountain sickness in Wikipedia


This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Altitude sickness". (Source - Retrieved 2006-09-07 14:17:53 from https://en.wikipedia.org/wiki/Altitude_sickness)


Altitude sickness, also known as acute mountain sickness (AMS) or altitude illness is a pathological condition that is caused by acute exposure to high altitudes. It commonly occurs above 2,500 metres (approximately 8,000 feet). Acute mountain sickness can progress to high altitude pulmonary oedema (HAPE) or high altitude cerebral oedema (HACE), ultimately resulting in death.

Another, rarer, type of altitude sickness caused by prolonged exposure to high altitude is chronic mountain sickness, also known as Monge's disease.


Different people have different susceptibilities to altitude sickness. For some otherwise healthy people symptoms can begin to appear at around 1,500 meters (5,000 feet) above sea level. This is the altitude of Mexico City (2,240m/7,349ft.) and Denver, Colorado (1,609m/5,280ft). Diets high in carbohydrates may make people suffering from AMS feel better. Carbohydrates require less oxygen to metabolise than fats, but the volumes involved are not large and the mechanism may not be so direct. High altitude pulmonary edema (HAPE) and cerebral edema HACE are the most ominous of these symptoms, while acute mountain sickness, retinal hemorrhages, and peripheral edema are the milder forms of the disease. The rate of ascent, the altitude attained, the amount of physical activity at high altitude, and individual susceptibility are contributing factors to the incidence and severity of high-altitude illness.

Altitude sickness usually occurs following a rapid ascent, and can usually be prevented by ascending slowly $[1]$. In most of these cases, the symptoms are only temporary and usually abate with time as altitude acclimatisation occurs.

Signs and symptoms

Headache is a primary symptom used to diagnose altitude sickness. A headache occurring at an altitude above 8000 feet (2,400 metres), combined with any one of the following symptoms, indicates probable altitude sickness.

The early symptoms of altitude sickness include drowsiness, general malaise, and weakness, especially during physical exertion. More severe symptoms are headache, insomnia, persistent rapid pulse, nausea and sometimes vomiting, especially in children. Extreme symptoms include confusion, psychosis, hallucination, symptoms resulting from pulmonary edema (fluid in the lungs) such as persistent coughing, and finally seizures, coma and death.

Severe cases

The most serious symptoms of altitude sickness are due to edema (fluid accumulation in the tissues of the body). At very high altitude, humans can get either high altitude pulmonary edema (HAPE), or high altitude cerebral edema (HACE). These syndromes are potentially fatal. The physiological cause of altitude-induced edema is not conclusively established. For those suffering HACE, dexamethasone may provide temporary relief from symptoms in order to keep descending under their own power.

HAPE occurs in ~2% of those who are adjusting to altitudes of ~3000 m (10,000 feet) or more. It can progress rapidly and is often fatal. Symptoms include fatigue, severe dyspnea at rest, and cough that is initially dry but may progress to produce pink, frothy sputum. Descent to lower altitudes alleviates the symptoms of HAPE.


Altitude acclimatisation


Acetazolamide may help some people in speeding up the acclimatisation process and can treat mild cases of altitude sickness. For centuries, indigenous cultures of the Altiplano, such as the Aymaras, have used coca leaves to treat mild altitude sickness. Drinking plenty of water will also help in acclimatisation to replace the fluids lost through heavier breathing in the thin, dry air found at altitude. Patients can sometimes control mild altitude sickness by consciously taking ten to twelve large, rapid breaths every five minutes. If overdone, this can blow off too much carbon dioxide and cause tingling in the extremities of the body. Other treatments include injectable steroids to reduce pulmonary edema, and inflatable pressure vessels to relieve and evacuate severe mountain-sick persons.

The only real cure once symptoms appear is for the sufferer to move to a lower altitude as quickly as possible. For serious cases of AMS, a Gamow bag can be used to reduce the effective altitude by as much at 1,500 meters (5,000 feet). A Gamow bag is a portable plastic pressure bag inflated with a foot pump.

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