Altitude sickness history and symptoms

Overview
Generally, different people have different susceptibilities to altitude sickness. For some otherwise healthy people Acute mountain sickness (AMS) can begin to appear at around 2000 meters (6,500 feet) above sea level such as at many mountain ski resorts. AMS is the most frequent type of altitude sickness encountered. Symptoms often manifest themselves 6 to 10 hours after ascent and generally subside in 1 to 2 days, but they occasionally develop into the more serious conditions. Symptoms are described as headache with fatigue, stomach sickness, dizziness, and sleep disturbance as additional possible symptoms. Exertion aggravates the symptoms.

History
Altitude sickness usually occurs following a rapid ascent and can usually be prevented by ascending slowly. In most of these cases, the symptoms are only temporary and usually abate with time as altitude acclimatisation occurs. However, in more extreme cases symptoms can be fatal.

High altitude pulmonary edema (HAPE) and cerebral edema (HACE) are the most ominous of these symptoms, while acute mountain sickness, retinal haemorrhages, and peripheral edema are the less severe forms of the disease. The rate of ascent, the altitude attained, the amount of physical activity at high altitude, as well as individual susceptibility, are contributing factors to the incidence and severity of high-altitude illness.

Symptoms
Symptoms that may indicate life-threatening altitude sickness include:
 * Persistent dry cough
 * Fever
 * Shortness of breath even when resting
 * headache that does not respond to analgesics
 * Unsteady gait
 * Increased vomiting
 * Gradual loss of consciousness.

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). DIARYfatal. The physiological cause of altitude-induced edema is not conclusively established. It is currently believed, however, that HACE is caused by local vasodilation of cerebral blood vessels in response to hypoxia, resulting in greater blood flow and, consequently, greater capillary pressures. On the other hand, HAPE may be due to general vasoconstriction in the pulmonary circulation (normally a response to regional ventilation-perfusion mismatches) which, with constant or increased cardiac output, also leads to increases in capillary pressures. 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: Descent to lower altitudes alleviates the symptoms of HAPE.
 * Fatigue
 * Severe dyspnea at rest
 * Cough that is initially dry but may progress to produce pink, frothy sputum.

HACE is a life threatening condition that can lead to coma or death. It occurs in about 1% of people adjusting to altitudes above ~2700 m (9,000 feet). Symptoms include: Descent to lower altitudes may save those afflicted with HACE.
 * Headache
 * Fatigue
 * Visual impairment
 * Bladder dysfunction
 * Bowel dysfunction
 * Loss of coordination
 * paralysis on one side of the body
 * Confusion