Causes and Symptoms (Magill’s Medical Guide, Sixth Edition)
There are four types of altitude sickness: acute mountain sickness, high-altitude pulmonary edema (HAPE), high-altitude cerebral edema (HACE), and high-altitude retinopathy (HAR). Though most patients have mild symptoms, death is not uncommon in severe cases. Illness is associated with rapid ascent to mountain areas by tourists, skiers, and mountaineers. Residents of mountainous regions are less susceptible because their bodies have adapted to lower oxygen levels. It is estimated that up to one-quarter of tourists skiing in the mountains of the western United States have experienced some manifestations, although mild ones, of altitude sickness.
Acute mountain sickness is characterized by headache, decreased appetite, insomnia, fatigue, nausea, and onset at altitudes above 1,980 meters (6,500 feet). The risk of becoming affected increases with young age, quick ascent, and a past history of acute mountain sickness. Symptoms usually last for a few days. Between 5 and 10 percent of patients with acute mountain sickness progress to HAPE, which occurs when the small pulmonary blood vessels leak, allowing fluid accumulation in the lungs. Mortality from HAPE ranges from 11 to 44 percent. The related condition HACE occurs when fluid accumulation in the brain causes increased pressure within the skull. Neurologic signs such as confusion and coma may be noted.
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Treatment and Therapy (Magill’s Medical Guide, Sixth Edition)
Prevention is crucial to the reduction of morbidity and mortality from altitude sickness. Ascents should be slow, especially those involving physical exertion. Sedatives and salt should be avoided. Most people adapt to altitude changes within three days. Returning to lower altitudes at night is advised. Premedication with acetazolamide, a prescription drug, will hasten adaptation and reduce symptoms. In serious cases, descent to lower altitudes is vital. Corticosteroids, oxygen, and hyperbaric treatments may be used. Chronically ill persons should check with their doctors before attempting strenuous activity at high altitudes.
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For Further Information: (Magill’s Medical Guide, Sixth Edition)
Auerbach, Paul S. Medicine for the Outdoors. Rev. ed. Boston: Little, Brown, 1999. This is a revised and updated edition of Auerbach’s first-rate guide, providing brief explanations of a wide variety of vacation/exploration medical problems (from diarrhea to Gila monster bites).
Reeves, John T., and Robert F. Grover. Attitudes on Altitude: Pioneers of Medical Research in Colorado’s High Mountains. Boulder: University of Colorado Press, 2001. Brings together the personal stories and findings of the innovative researchers who examined altitude sickness in the Rocky Mountains.
Rennie, D. “The Great Breathlessness Mountains.” Journal of the American Medical Association 256 (July 4, 1986): 81-82. Findings on high-altitude cerebral and pulmonary edema (HACE and HAPE) are discussed in an editorial. The history of acute mountain sickness (AMS) is outlined.
Ward, Michael P., John B. West, and James S. Milledge. High Altitude Medicine and Physiology. 4th ed. New York: Oxford University Press, 2007. Examines the practice and management of common medical and surgical conditions in the mountains.
Wilkerson, James A., ed. Medicine for Mountaineering and Other Wilderness Activities. 6th ed. Seattle: The Mountaineers Books, 2010. This book is a first-aid guide that goes beyond traditional treatment protocols. It was written for those who need to care for...
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Altitude Sickness (Encyclopedia of Medicine)
Altitude sickness is a general term encompassing a spectrum of disorders that occur at higher altitudes. Since the severity of symptoms varies with altitude, it is important to understand the range of the different altitudes that may be involved. High altitude is defined as height greater than 8, 000 feet (2, 438 m); medium altitude is defined as height between 5, 000 and 8, 000 feet (1, 524, 438 m); and extreme altitude is defined as height greater than 19, 000 feet (5, 791 m). The majority of healthy individuals suffer from altitude sickness when they reach very high altitudes. In addition, about 20% of people ascending above 9, 000 (2, 743 m) feet in one day will develop altitude sickness. Children under six years and women in the premenstrual part of their cycles may be more vulnerable. Individuals with preexisting medical conditionsven a minor respiratory infectionay become sick at more moderate altitudes.
There are three major clinical syndromes that fall under the heading of altitude sickness: acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE). These syndromes are not separate, individual syndromes as much as they are a continuum of severity, all resulting from a decrease in oxygen in the air. AMS is the mildest, and the other two...
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