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ABSTRACT A large world population resides at moderate altitudes. In the Valley of Mexico (2240 m above sea level) and for patients with respiratory diseases implies more hypoxemia and clinical deterioration, unless supplementary oxygen is prescribed or patients move to sea level. A group of individuals residing at 2500 or more meters above sea level may develop acute or chronic mountain disease but those conditions may develop at moderate altitudes although less frequently and in predisposed individuals. In the valley of México, at 2200 m above sea level, re-entry pulmonary edema has been reported. The frequency of other altitude-related diseases at moderate altitude, described in skiing resorts, remains to be known in visitors to Mexico City and other cities at similar or higher altitudes. Residents of moderate altitudes inhale deeply the city's air with all pollutants and require more often supplementary oxygen.
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Se describen las respuestas fisiológicas que el ser humano desarrolla en respuesta a la exposición a la altitud geográfica. Se describen no sólo las alteraciones debidas a una mala coordinación de los ajustes fisiológicos desencadenados durante la aclimatación a la altura sino también sus manifestaciones clínicas más relevantes. Se detallan los mecanismos moleculares subyacentes a tales respuestas y cómo su mejor conocimiento puede permitir aplicar la exposición intermitente a hipoxia como una herramienta útil para la resolución o alivio de determinadas alteraciones y patologías.
We depict the physiological responses developed by the human body in response to the exposure to geographic altitude. The main alterations due to a noncoordinated setup of the physiological adjustments triggered during the acclimatization at altitude are also described, as its most relevant clinical manifestations. The molecular mechanisms underlying such responses are detailed, and how a better knowledge of these processes can allow us to apply intermittent exposure to hypoxia programs as a useful tool for the resolution or relief of certain disorders and pathologies.
Subject(s)
Humans , Adaptation, Physiological , Altitude , Altitude Sickness , Brain Edema , Acclimatization , HypoxiaABSTRACT
Objective: To test the anti-plateau hypoxia effect of Potentilla anserina polysaccharide(PAP), Cynomorium songarieum Rupr. polysaccharide(SCRP), Sphallerocarpus gracilis polysaccharide(SGP)and Lilium brownii polysaccharide(LP), and then investigate the protective effect of most effective polysaccharide on the high altitude cerebral edema(HACE)and high altitude pulmonary edema(HAPE)in rats. Methods: PAP, CSRP, SGP and LP were prepared by the water extraction-alcohol precipitation method. The normobaric hypoxia test and acute hypoxia test were performed to find out the polysaccharide with the best anti-hypoxia effect and the related dose-dependent effect in mice. A large hypobaric hypoxia chamber stimulating 8000 m altitude was used to investigate pathological changes and water contents in rat brain and lung tissue before and after hypoxia, and the concerned oxidative stress and inflammation related parameters were also measured. The protective effect of PAP on the high altitude cerebral and pulmonary edema was evaluated by the rat model experiments. Results: PAP showed the best and dose-dependent anti-hypoxia effect among the four polysaccharides. The water content in brain and lung tissues of rats increased obviously in the hypoxia model(HM)group, and the brain tissue cell hierarchical fuzzy, lung tissue congestion and edema as well as the heavy inflammatory cell infiltration, widening of alveolar interval and thickening of alveolar wall were also found in the HM group. The enzymatic activity of SOD was notablely depressed, while both the MDA and IL-1β contents in brain and lung tissues remarkably increased(P<0.01)in the HM group. Com- pared with the HM group, the water content in the rat brain and lung tissues significantly decreased in each of the different dose PAP groups(P<0.05 or P<0.01), and the inflammatory cell infiltration, alveolar interval, and thickness of alveolar wall all notabely decreased in the HM group. Furthermore, the enzymatic activity of SOD increased, while both the MDA and IL-1β contents decreased, all significantly in the PAP groups than in the HM group(P<0.05 or P<0.01). Conclusion: PAP showed a good anti-hypoxia effect and effectively inhibited HACE and HAPE to exert a certain protective effect in a rat model.
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High altitude cerebral edema (HACE) and High altitude pulmonary edema (HAPO) are the most dreaded complications related to high altitude. Authors managed a case of HACE and HAPO simultaneously set at unusually low height (1200 ft) in a patient. The altitude was not too much to develop these comorbidities as studied earlier. Relationship with altitude was immaterial in our case. However, rapid ascent without proper acclimatisation, young and tender age, male sex and smoking were associated contributing factors. He was managed with standard protocol and descent to lower altitude.
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High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE) are two dreaded altitude emergencies which can independently lead to complications. Two cases of suspected comorbid HACE and HAPE were managed at 5800 m/19000 ft in Karakoram Himalayas. Altitude acclimatization, purported to prevent high altitude illness, may not be protective. Comorbid HACE and HAPE at extreme altitude may present atypically necessitating high index of suspicion and prompt clinical decision making in challenging situations. One man HAPE bag/PHC is an excellent temporary measure in cases of delayed descent/evacuation. Due attention to extreme altitude emergencies is required in view of increased recreational, scientific and military activities at extreme altitude.
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OBJECTIVE:To investigate the improving effect of phenylethanoid glycosides (PhGCs) from Tibetan medicine Phlomis younghusbandii on rats with acute high-altitude cerebral edema. METHODS:60 Wistar rats were randomly divided into a normoxia control group (isometric sterile water for injection),a hypoxia model group (isometric sterile water for injection),a dexamethasone group(4 mg/kg),and three groups of PhGCs at high(400 mg/kg),middle(200 mg/kg)and low(50 mg/kg)dos-es,with 10 rats in each group. The rats were given drugs,ig,6 d before the establishment of models. On the 4th day of administra-tion,ig,the rats in all groups except the normoxia blank group were placed in a simulated 8 000 m altitude plateau environment for 72 h hypoxic exposure to establish the rat models of high-altitude cerebral edema. Following HE stain,the pathological changes in rats’brain tissues were observed under the light microscope. Dry-wet proportion method was used to determine the water con-tents in rats’brain. The content of MDA and the activities of SOD and GSH in rats’brain tissues were detected. Enzyme-linked im-munosorbent assay was adopted to determine the contents of IL-1β and TNF-α in rats’serum and brain tissues. RESULTS:Com-pared to the rats in the normoxia control group,those in the hypoxia model group showed obvious brain edema,and thickened lacu-nas around cells and vessels and inflammatory cell infiltration, higher water contents and MDA and weaker activities of SOD and GSH in brain,and higher contents of IL-1β and TNF-α in serum and brain tissues. There were statistically significances (P<0.01 or P<0.05). Compared to the rats in the hypoxia model group,those in the groups of PhGCs at high,middleand low dosages demonstrated less inflammatory cell infiltration and lower water contents in brain tissues,in which the groups of PhGCs at high and middle dosages demonstrated lower content of MDA and stronger activities of SOD and GSH in brain tissues, and lower contents of IL-1β and TNF-α in serum and brain tissues. There were statistically significances (P<0.01 or P<0.05). CONCLUSIONS:PhGCs can obviously alleviate the acute cerebral injury in rats which is caused by acute hypoxia and has im-provement effect to some degree on the rats with acute high-altitude cerebral edema.
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High-altitude illness is used to describe various symptoms that can develop in unacclimatized persons on ascent to high altitude. Symptoms usually include headache, anorexia, nausea, vomiting, fatigue, dizziness, and sleep disturbance. In fact, high-altitude illness comprises of acute mountain sickness (AMS) and its life-threatening complications, high-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE). Since there are many travelers who visit high-altitude locations these days, high-altitude illness has become a public health problem. Therefore, physicians need to be familiar with the condition and be able to advise those who are going to reach high altitude how to prevent or minimize the illness and treat patients who suffer from it.
Subject(s)
Humans , Altitude Sickness , Altitude , Anorexia , Brain Edema , Dizziness , Fatigue , Headache , Nausea , Public Health , Pulmonary Edema , VomitingABSTRACT
Acute mountain sickness, HAPE (high altitude pulmonary edema) and HACE (high altitude cerebral edema) are associated with acute exposure to altitudes greater than 8000 ft. Although usually self limiting, they can be life threatening. We are not yet clear abour the pathophysiological processes in acute mountain sickness. Descent to lower elevation is the definitive treatment for altitude illness. There is no unanimity of opinion regarding other modes of therapy. Treatment consists of bed rest, orygen inhalation and judicious use of morphine, diuretics, steroids and niftdipine as vasodilator therapy.
Subject(s)
Altitude Sickness , HypoxiaABSTRACT
When rats in different hydration states (normal control,furosemide treated,and water loaded) were exposed to hypoxia due to simulated altitudes from 5 000 to 8 000 meters,the water content of the lungs and brain was measured.It was found that the water loaded animals had an increase of the water content of the lungs and cerebral cortex under simulated high altitudes.The pulmonary extravascular water content was higher at an altitude of 5 000 meters than at an altitude of 8 000 meters.The increase of water content in the brain mainly happened to the cerebral cortex.The diuresis after the administration of furosemide could lower the water content of the lungs and brain in rats at high altitudes.The results listed above support the hypothesis that pulmonary edema may occur simultaneously with brain edema at high altitude,both of which are two important constituents of acute mountain sickness.