Altitude illness

The three main types of altitude illness, characterised initially by nausea, headache, sleep disturbance and stomach upset, are acute mountain sickness (AMS) high altitude pulmonary oedema (HAPE) and high altitude cerebral oedema (HACK). They occur after rapid ascent to altitudes greater than 2,500 m (about 8,000 feet) in unacclimatised people. In unacclimatised mountaineers, the prevalence of AMS at 4,559 metres (15,000 feet) is approximately 50% and HAPE 4%. Risk depends on individual susceptibility, rate of ascent and pre-exposure to high altitude. AMS is not a pre-requisite for HAPE. 

Altitude illness is likely to be prevented by limiting rate of ascent above 2,500-3,000 m/day. Acetazo-lamide, dexamethasone, and nifedipine are all used for prophylaxis. 

Hackett PH, Roach RC High-altitude illness. N Engl 3 Med 2001 345 107. [PMID 11450659]... 

Gertsch JH, Basnyat B Johnson EW, Onopa J, Hoick PS, on behalf of the Prevention of High Altitude Illness Trial Research Group. Randomised, double blind, placebo controlled comparison of ginkgo biloba and acetazolamide for prevention of acute mountain sickness among Himalayan trekkers the prevention of high altitude illness trial (PHAIT). Br Med J 2004 328 797-801. 

Gyrometrin toxin is produced by the false morel (Gyromitra esculenta), a short-stalked mushroom with a brain-like cap of dark brown color. Fruiting bodies of this mushroom appear mostly in spring and are valued as edible, even as delicacies. While many people consume the mushroom without any troubles, others become ill, some of them severely. It has been shown that the toxin content may vary with growth conditions, such as altitude and temperature. More probably, however, the variation is caused by differences in handling or cooking as the toxic components are volatile. The toxin has been detected in cooked, frozen, and dried specimens. 

Figure 9. The predicted altitude for the plant collection sites vs. the true altitude of the sites. [Used by permission of Geological Society of America, from Forest et al. (1999), Geol. Soc. Am. Bull., Vol. Ill, Fig. 12, p. 509.]...

The medicinal and ceremonial uses of cocaine via coca leaves can be traced back over 4,000 years to pre-Columbian times. It continues to be used legally and is part of the daily culture of South American Indians. Coca leaves are chewed to combat fatigue and to ward off hunger. They are also used to alleviate problems of the larynx, digestive system, metabolism of carbohydrates, vertigo, altitude sickness, and for psychological ills. 

Thick Forest ecosystems are found only along the valley s of large rivers, occupying well-drained places of terraces, slopes and low hills, lying at an altitude of 700-750 m. White spruce (Picea canadensis), balsam poplar, aspen, and in some places white birch, are trees common to these Forest ecosystems black spruce, fir and larch are found more rarely. The latter is attracted to swampy areas. On flat, ill-drained surfaces, forest ecosystems are replaced by vast areas of bog mosses and, in relief depressions, sedge-cotton grass bog. 

Mountain climbers sometimes fall ill due to the lower oxygen content of air at high altitudes. Long-term exposure to an oxygen-poor environment causes the production of more hemoglobin. The additional hemoglobin facilitates the transport of oxygen to the body. 

Altitude-related illnesses and disorders are serious and should be considered hfe threatening. Acute cases can be rapidly reversed by descending or by administering oxygen, but the failure to diagnose a disorder early, with the inability to descend or relocate to sea level, or the lack of alternative treatments, can lead to death. Some altitude-related illnesses are listed below (Heath 1981 Berger and Rom 1998). 

Because of the risk of altitude-related illnesses and disorders for unacclimated individuals at high altitude, preventive risk management is critical. In Health Considerations for Managing Work at High Altitudes (1998), J.B. West recommends the following management concepts. 

Preventive Measures Because altitude-related illnesses and disorders are preventable in the majority of the population, efforts should be taken to prevent and reduce symptoms. The following highlights some of these recommendations (BHP 1997). 

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