Acute mountain sickness: influence of susceptibility, preexposure, and ascent rate

Schneider, Michael; Bernasch, Dirke; Weymann, Jörn; Holle, Rolf; Bärtsch, Peter

doi:10.1097/00005768-200212000-00005

Cited by 276 publications

(275 citation statements)

References 14 publications

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“…The major determinants of AMS are the altitude attained [22], individual susceptibility, rate of ascent and degree of preacclimatisation [13,23,24]. Therefore, prevalence of AMS depends very much on the study setting.…”

Section: Epidemiologymentioning

confidence: 99%

“…Therefore, prevalence of AMS depends very much on the study setting. Prevalence of AMS varies between 40% and 90%, depending on altitude and individual susceptibility in unacclimatised individuals ascending considerably more than 500 m·day −1 to altitudes of 4500-6000 m [23,25], whereas prevalence with passive ascent to 3000-3500 m is ∼25-40% [26,27]. HACE occurs rarely at altitudes <4000 m, and its prevalence between 4200 m and 5500 m is estimated to be 0.5-1% [17].…”

Section: Epidemiologymentioning

confidence: 99%

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Acute high-altitude sickness

2017

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At any point 1-5 days following ascent to altitudes ⩾2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases.

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Section: Epidemiologymentioning

confidence: 99%

Section: Epidemiologymentioning

confidence: 99%

Acute high-altitude sickness

2017

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“…AMS is promoted by a rapid ascent rate, depends on the altitude reached, and on acclimatisation [3]. It occurs in both sexes, at all ages, and athletic fitness does not protect against it [1,4,5].Despite its high prevalence, the pathophysiology of AMS is incompletely understood. Hypoxia seems to play an important role [3,6,7].…”

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confidence: 99%

mentioning

confidence: 99%

Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation

Pa¹,

Anastasi²,

Senn³

et al. 2004

Eur Respir J

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Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation. P. Erba, S. Anastasi, O. Senn, M. Maggiorini, K.E. Bloch. #ERS Journals Ltd 2004. ABSTRACT: The purpose of the study was to investigate determinants of acute mountain sickness after rapid ascent to high altitude.A total of 21 climbers were studied ascending from v1,200 m to Capanna Regina Margherita, a hut in the Alps at 4,559 m, within v24 h. During their overnight stay at 4,559 m, breathing patterns and ventilation were recorded by calibrated respiratory inductive plethysmography along with pulse oximetry. In the following morning, acute mountain sickness was assessed.Altogether, 11 mountaineers developed pronounced symptoms of acute mountain sickness (Lake Louise score o5) and 10 did not (controls). Compared to controls, subjects with acute mountain sickness had lower nocturnal oxygen saturation (mean¡SD 59¡13% versus 73¡6%), higher minute ventilation (7.94¡2.35 versus 6.06¡ 1.34 L?min -1 ), and greater mean inspiratory flow, a measure of respiratory centre drive (0.29¡0.09 versus 0.22¡0.05 L?s -1 ). Periodic respiration was prevalent but not significantly different among the two groups (apnoea/hypopnea index 60.1¡34.6 versus 47.1¡42.6 events per h).The data suggest that pronounced nocturnal hypoxemia, which was not related to hypoventilation, may have promoted acute mountain sickness. Periodic breathing seems not to play a predominant role in the pathogenesis of acute mountain sickness. Otherwise healthy subjects ascending rapidly to altitudes w2,500 m often develop acute mountain sickness (AMS), a condition characterised by insomnia, headache, dizziness, loss of appetite, nausea and vomiting [1]. In the Alps, symptoms and signs of AMS sufficiently severe to force a reduction in activity were found in 6-8% of climbers examined at altitudes between 2,850 and 3,650 m, and in 30% of climbers at 4,559 m [2]. AMS is promoted by a rapid ascent rate, depends on the altitude reached, and on acclimatisation [3]. It occurs in both sexes, at all ages, and athletic fitness does not protect against it [1,4,5].Despite its high prevalence, the pathophysiology of AMS is incompletely understood. Hypoxia seems to play an important role [3,6,7]. A reduced ventilatory response to hypoxia, and impaired pulmonary gas exchange related to pulmonary fluid accumulation, and water and salt retention have been implicated in development of exaggerated hypoxemia in subjects with AMS [8][9][10]. As AMS often develops or worsens over the night, when periodic breathing and repetitive oxygen desaturation are also prevalent, a causal relationship or a common pathophysiological pathway have been evaluated [11,12]. However, the results of these earlier studies were inconclusive due to the small number of subjects with AMS enrolled, and the lack of quantitative estimation of ventilation during sleep.Therefore, the purpose of the current study was to further explore the potential role of periodic respiration, and other characteristics of breathing patterns, in p...

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“…Known risk factors for HAI in individuals without disabilities include no exposure to HA in the preceding 2 months and ascent in ≤3 days [5,[7][8] as well as the altitude reached, the altitude at which the individual generally sleeps, and physical exertion at altitude [1]. However, independent risk factors for those with disabilities are still unknown.…”

Section: Introductionmentioning

confidence: 99%

Acute mountain sickness in disability and adaptive sports: Preliminary data

Dicianno

Aguila

Cooper

et al. 2008

JRRD

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Abstract-Acute mountain sickness (AMS) is a frequent complication for military personnel, veterans, athletes, and travelers at high altitudes. Symptoms may occur in individuals with less cerebrospinal fluid volume and less ability to accommodate increased brain volume. No studies on AMS exist in individuals with neurological impairments. We studied 64 subjects, including active and sedentary controls and those with tetraplegia, paraplegia, multiple sclerosis, and traumatic brain injury at the 2007 National Veterans Winter Sports Clinic in Snowmass, Colorado. Subjects completed three Lake Louise Score surveys to quantify symptoms. We found a higher than expected occurrence of AMS overall (51.6%) but no differences among groups, and few participants sought treatment. Fatigue and weakness were common symptoms. High subject activity levels may explain these findings. More research is warranted on larger sample sizes and on preventative medications and treatments for AMS, especially since many military personnel with neurological impairments are returning to full active service.

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Acute mountain sickness: influence of susceptibility, preexposure, and ascent rate

Abstract: Individual susceptibility, rate of ascent, and preexposure are the major, independent determinants for prevalence of AMS.

Cited by 276 publications

References 14 publications

Acute high-altitude sickness

Acute high-altitude sickness

Acute mountain sickness is related to nocturnal hypoxemia but not to hypoventilation

Acute mountain sickness in disability and adaptive sports: Preliminary data

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