Acute altitude illnesses

Imray, Chris; Booth, Adam S.; Wright, Alex; Bradwell, Arthur R.

doi:10.1136/bmj.d4943

Cited by 121 publications

(107 citation statements)

References 34 publications

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“…Characterization of the influence of O 2 availability on the brain is therefore an essential step toward a better understanding of brain energy homeostasis and also has important clinical implications. For example, acclimatization to high altitudes is triggered by hypoxia and > 80% of people experience a certain degree of discomfort, including headache and shortness of breath, with a fraction of them developing acute mountain sickness that includes nausea, vomiting, fatigue, dizziness, and difficulty sleeping (Imray et al, 2011). However, hyperoxia has been used as a therapeutic intervention in patients with traumatic brain injury and focal ischemia (Thom, 2009).…”

Section: Introductionmentioning

confidence: 99%

Effect of Hypoxia and Hyperoxia on Cerebral Blood Flow, Blood Oxygenation, and Oxidative Metabolism

Liu

Pascual

et al. 2012

J Cereb Blood Flow Metab

152

182

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Characterizing the effect of oxygen (O 2 ) modulation on the brain may provide a better understanding of several clinically relevant problems, including acute mountain sickness and hyperoxic therapy in patients with traumatic brain injury or ischemia. Quantifying the O 2 effects on brain metabolism is also critical when using this physiologic maneuver to calibrate functional magnetic resonance imaging (fMRI) signals. Although intuitively crucial, the question of whether the brain's metabolic rate depends on the amount of O 2 available has not been addressed in detail previously. This can be largely attributed to the scarcity and complexity of measurement techniques. Recently, we have developed an MR method that provides a noninvasive (devoid of exogenous agents), rapid ( < 5 minutes), and reliable (coefficient of variant, CoV < 3%) measurement of the global cerebral metabolic rate of O 2 (CMRO 2 ). In the present study, we evaluated metabolic and vascular responses to manipulation of the fraction of inspired O 2 (FiO 2 ). Hypoxia with 14% FiO 2 was found to increase both CMRO 2 (5.0±2.0%, N = 16, P = 0.02) and cerebral blood flow (CBF) (9.8±2.3%, P < 0.001). However, hyperoxia decreased CMRO 2 by 10.3 ± 1.5% (P < 0.001) and 16.9 ± 2.7% (P < 0.001) for FiO 2 of 50% and 98%, respectively. The CBF showed minimal changes with hyperoxia. Our results suggest that modulation of inspired O 2 alters brain metabolism in a dose-dependent manner.

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Section: Introductionmentioning

confidence: 99%

Effect of Hypoxia and Hyperoxia on Cerebral Blood Flow, Blood Oxygenation, and Oxidative Metabolism

Liu

Pascual

et al. 2012

J Cereb Blood Flow Metab

152

182

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“…Using the LLss, which included measurements of headache, dizziness, gastrointestinal symptoms, difficulty sleeping and fatigue (23), it was found that the incidence of these five symptoms was significantly different between the two groups, with the AMS group exhibiting significantly higher incidences than the controls (all P<0.001), particularly with regard to the incidence of headache. The total LLss score of the AMS group was 5.05±1.89, which was significantly (P<0.001) higher than that of the non-AMS group (1.56±1.17).…”

Section: Resultsmentioning

confidence: 99%

Genetic variants of endothelial PAS domain protein 1 are associated with susceptibility to acute mountain sickness in individuals unaccustomed to high altitude: A nested case-control study

Guo

Zhang

Jin

et al. 2015

Experimental and Therapeutic Medicine

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Abstract. The endothelial PAS domain protein 1 (EPAS1) gene functions to sense the blood oxygen level by regulating the hypoxia-inducible transcription factor pathway, and single nucleotide polymorphisms (SNPs) of EPAS1 have been found to have a strong and positive selection in the adaptation of the native Tibetan highland population to high-altitude hypoxia. The aim of the present study was to investigate the effect of EPAS1 SNPs on the risk of acute mountain sickness (AMS) and the physiological responses to acute high-altitude hypoxia in lowland humans. Three tag SNPs (rs6756667, rs13419896 and rs4953354; minor allele frequency, ≥5%) were selected and genotyped in 603 unrelated Han Chinese men, who had traveled to Lhasa (a high-altitude hypoxia environment) by plane, using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry method. The data showed that the EPAS1 rs6756667 wild-type GG homozygous genotype was associated with elevated AMS risk compared with the AA and AG genotypes (odds ratio, 1.815; 95% confidence interval, 1.233-2.666; P=0.0023) using the dominant-model analysis. EPAS1 rs6756667 GG genotypes were also associated with higher levels of hemoglobin, red blood cells and hematocrit than those carrying the AG heterozygote during AMS development. These findings indicate that EPAS1 SNPs play a role in the physiological effects of AMS, and these effects could be further evaluated as a therapeutic strategy to control acute hypoxia-related human diseases.

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“…Further, no clinical feature or test has been shown to predict an individual's susceptibility to developing AMS at HA with any reliability [3]. Based on previous studies [2][3] and our experience with studying AMS in the past, we conducted an analysis to evaluate the factors that could have a clinically significant predictive capacity for high Lake Louise Score (LLS).…”

Section: Introductionmentioning

confidence: 99%

“…The occurrence of AMS or HA illness (HAI) depends on multiple factors like study population [1][2][3], geographic region [4][5][6], individual susceptibility [1,[6][7], rate of ascent to altitude [1,3], absolute height achieved [1,4], and height at which the individual resides/lives before beginning the climb [1,[8][9].…”

Section: Introductionmentioning

confidence: 99%

Acute mountain sickness in athletes with neurological impairments

Kamaraj

Dicianno²,

Cooper³

et al. 2013

JRRD

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Abstract-Acute mountain sickness (AMS) is a symptom complex noticed commonly among high altitude travelers. The occurrence of AMS depends on multiple factors that have been studied extensively. However, AMS in individuals with neurological impairments has not been considered in detail. A total of 168 subjects, including active controls, inactive controls, and those with spinal cord injury (SCI), multiple sclerosis, and traumatic brain injury (TBI), were studied at the National Veterans Winter Sports Clinic in Snowmass, Colorado, from 2007 to 2009 for the occurrence of AMS. Lake Louise Score was used to quantify symptoms. A higher than anticipated occurrence of AMS (42.85%) among the study population was noted, with significantly higher Lake Louis Scores among athletes with neurological impairments. Disability group, prior history of AMS, and prior occurrence of headache at high altitude could be used as predictors for the development of AMS symptoms. More research is warranted specifically targeting the interaction between factors affecting AMS and the pathophysiology of neurological impairments like SCI and TBI to further our understanding about prophylactic medications and treatments for AMS, especially because many military personnel with neurological impairments continue on Active Duty.

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Acute altitude illnesses

Cited by 121 publications

References 34 publications

Effect of Hypoxia and Hyperoxia on Cerebral Blood Flow, Blood Oxygenation, and Oxidative Metabolism

Effect of Hypoxia and Hyperoxia on Cerebral Blood Flow, Blood Oxygenation, and Oxidative Metabolism

Genetic variants of endothelial PAS domain protein 1 are associated with susceptibility to acute mountain sickness in individuals unaccustomed to high altitude: A nested case-control study

Acute mountain sickness in athletes with neurological impairments

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