Materiały źródłowe

• #1 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9325098/

  High altitude can be a hostile environment and a paradigm of how environmental factors can determine illness when human biological adaptability is exceeded. […] The first section of our work defines high altitude and considers the mechanisms of adaptation to it and the associated risk factors for low adaptability. […] With a deeper understanding of the pathogenesis of high-altitude diseases, as well as a reasoned approach to environmental or physical factors, we examine the main high-altitude diseases. Such an approach is critical for the effective treatment of patients in a hostile environment, or treatment in the emergency room after exposure to extreme physical or environmental factors. […] The symptoms of acute mountain sickness (AMS) occur when people move to high altitudes from sea level, due to an inadequate acclimatization process.

• #2 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://www.mdpi.com/2077-0383/11/14/3937

  Physiological adaptation to decreasing oxygen pressure in the high-altitude environment is known as acclimatization. […] Acclimatization is a complex and not yet fully understood mechanism to minimize hypoxemia and preserve cell function, despite reduced PO2. […] The symptoms of acute mountain sickness (AMS) occur when people move to high altitudes from sea level, due to an inadequate acclimatization process. […] It appears necessary to underline and add that, in some specific subpopulations, following the previous stay at sea level, HAPE re-entry pulmonary edema (HAPE) can occur. […] The evolutionary pathway traveled by the Andeans increased their hemoglobin levels and selected a series of mutations in genes linked to the morphology of the cardiovascular system to make it more efficient in these subjects, resulting in very viscous blood.

• #3 Acute Mountain Sickness – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK430716/

  At higher altitudes, the decreased partial pressure of oxygen can cause several pathological presentations, including high altitude pulmonary edema, high altitude cerebral edema, and the more mild, but much more common acute mountain sickness (also referred to as altitude illness or altitude sickness). […] Acute Mountain Sickness is caused by the bodys reaction to the reduced oxygen level in respired air and resultant tissue hypoxia. […] As the brain has the highest baseline need for oxygen supply, the symptoms of Acute Mountain Sickness are neurologic (central nervous system CNS). […] Lower respiratory rate, typical during sleep, increases the risk for Acute Mountain Sickness, and symptoms are often first noticed upon awakening. […] The hallmark of Acute Mountain Sickness is a headache, with other symptoms including nausea, vomiting, loss of appetite, fatigue/malaise (particularly at rest), sleep disturbance, and dizziness/lightheadedness.

• #4 Altitude Illness – Cerebral Syndromes: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/768478-overview

  Altitude illness refers to a group of syndromes that result from hypoxia. Acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) are manifestations of the brain pathophysiology, while high-altitude pulmonary edema (HAPE) is that of the lung. […] The exact pathophysiology of AMS/HACE is unknown. The current hypothesis is that hypoxia elicits neurohumoral and hemodynamic responses in the brain that ultimately result in capillary leakage from microvascular beds and edema. […] Factors that might contribute to a hydrostatic brain edema are multiple and include cerebral vasodilation, elevated cerebral capillary pressure, impaired cerebral autoregulation, as well as alterations in the permeability of the blood-brain barrier through cytokine activation.

• #5 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The acute phase is associated with a steady increase in ventilation, improved oxygenation, and changes in cerebral blood flow. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #6 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The human body can adjust to moderate hypoxia at altitudes up to approximately 5,200 m (17,000 ft) but requires time to do so. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #7 Acute mountain sickness: MedlinePlus Medical EncyclopediaLock

  https://medlineplus.gov/ency/article/000133.htm

  Acute mountain sickness is caused by reduced air pressure and lower oxygen levels at high altitudes. […] The faster you climb to a high altitude, the more likely you will get acute mountain sickness. […] The main treatment for all forms of mountain sickness is to climb down (descend) to a lower altitude as rapidly and safely as possible. […] Dexamethasone (Decadron) may help reduce acute mountain sickness symptoms and swelling in the brain (cerebral edema). […] Severe cases may result in death due to lung problems (pulmonary edema) or brain swelling (cerebral edema). […] Anemia lowers the amount of oxygen in your blood. This makes you more likely to have mountain sickness.

• #8 How Diamox Deals With Acute Mountain Sickness (AMS)

  https://indiahikes.com/blog/benefits-of-using-diamox-to-deal-with-ams

  Anyone can get AMS. There is no significant effect of age, gender, physical fitness, or previous altitude experience on AMS. […] 90% of the blood’s carbon dioxide exists in a chemical called bicarbonate. This carbon dioxide after travelling through your blood is exhaled by your lungs. Diamox forces the kidneys to excrete bicarbonate from your body (when you urinate). […] When Diamox forces you to excrete biocarbonates, your blood, which is used to a certain level of acidity, becomes more acidic. When the blood gets acidic it believes that it has more carbon dioxide in it. So the body gets rid of this excess carbon dioxide in a simple way. It starts to breathe deeper and faster, getting rid of the carbon dioxide, and also taking in more oxygen. […] In effect, the increased oxygen speeds up the acclimatisation process. It also greatly reduces you of any symptoms of altitude sickness. […] Remember, Diamox accelerates acclimatization. It does not cure anything. If you have headache with any of the above symptoms, even after taking Diamox, it means your acclimatization is not complete and you must descend. Under no circumstances should you climb higher if your symptoms still persists.

• #9 When to Take Diamox for Altitude Sickness? (7 Scenarios) – Travel Medicine – Consultation & Medications | Runway Health

  https://runwayhealth.com/when-to-take-diamox/

  Altitude sickness, or acute mountain sickness, occurs when you ascend to elevations typically above 8,000 feet faster than your body can acclimatize to the decreased oxygen levels. […] Diamox works by altering the blood’s pH level to increase respiratory rate, which helps your body take in more oxygen. It’s one of the most effective medications for high altitude symptoms (if not the most effective). […] Rapid ascents increase the risk of altitude sickness due to insufficient acclimatization time. Diamox can help compensate for this by accelerating your respiratory rate and aiding in faster acclimatization. […] Individuals who have had altitude sickness once are more likely to face it again under similar conditions. By starting Diamox prior to ascent, you can significantly reduce the likelihood of recurrence.

• #10 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://www.mdpi.com/2077-0383/11/14/3937

  Physiological adaptation to decreasing oxygen pressure in the high-altitude environment is known as acclimatization. […] Acclimatization is a complex and not yet fully understood mechanism to minimize hypoxemia and preserve cell function, despite reduced PO2. […] The symptoms of acute mountain sickness (AMS) occur when people move to high altitudes from sea level, due to an inadequate acclimatization process. […] It appears necessary to underline and add that, in some specific subpopulations, following the previous stay at sea level, HAPE re-entry pulmonary edema (HAPE) can occur. […] The evolutionary pathway traveled by the Andeans increased their hemoglobin levels and selected a series of mutations in genes linked to the morphology of the cardiovascular system to make it more efficient in these subjects, resulting in very viscous blood.

• #11 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The acute phase is associated with a steady increase in ventilation, improved oxygenation, and changes in cerebral blood flow. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #12 Altitude sickness – Wikipedia

  https://en.wikipedia.org/wiki/Altitude_sickness

  Altitude sickness, the mildest form being acute mountain sickness (AMS), is a harmful effect of high altitude, caused by rapid exposure to low amounts of oxygen at high elevation. […] The physiological cause of altitude-induced edema is not conclusively established. It is currently believed, however, that HACE is caused by local vasodilation of cerebral blood vessels in response to hypoxia, resulting in greater blood flow and, consequently, greater capillary pressures. On the other hand, HAPE may be due to general vasoconstriction in the pulmonary circulation which, with constant or increased cardiac output, also leads to increases in capillary pressures. […] The hypoxia leads to an increase in minute ventilation (hence both low CO2, and subsequently bicarbonate), Hb increases through haemoconcentration and erythrogenesis. Alkalosis shifts the haemoglobin dissociation constant to the left, 2,3-BPG increases to counter this. Cardiac output increases through an increase in heart rate.

• #13 Altitude sickness pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Altitude_sickness_pathophysiology

  Altitude sickness caused by an increase in pulmonary artery pressure due to the normal pulmonary vasoconstriction induced by hypoxia. Hypoxia leads to increase oxygen delivery to the tissues and increases ventilation, cardiac output and haemoglobin concentrations. These changes improve ventilation-perfusion matching and gas exchange and lead to high altitude pulmonary hypertension. […] It is believed that altitude sickness is secondary to body’s response to hypoxia due to low pressure at high altitude; not just normobaric hypoxia. […] Physiological responses in mild to moderate altitude sickness includes: Relative hypoventilation, Impaired gas exchange, Fluid retention and redistribution, Increased sympathetic drive. […] Physiological responses in moderate to severe altitude sickness includes: Raised intracranial pressure, Cerebral edema.

• #14 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The acute phase is associated with a steady increase in ventilation, improved oxygenation, and changes in cerebral blood flow. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #15 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The human body can adjust to moderate hypoxia at altitudes up to approximately 5,200 m (17,000 ft) but requires time to do so. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #16 Altitude Illness – Injuries; Poisoning – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/injuries-poisoning/altitude-illness/altitude-illness

  Severe acute hypoxemia can cause altered central nervous system function within a matter of minutes, but acute altitude illness develops more slowly, from 1 to 5 days after ascent to a given elevation. […] The pathogenesis of acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) remain unclear despite considerable research in this area. The diseases likely have the same pathophysiology and fall on a continuum of severity, with HACE representing the extreme of the spectrum. […] Some features differ between these disorders. AMS may involve activation of the trigeminovascular system due to a variety of stimuli, while HACE involves blood-brain barrier leakage and increased intracranial pressure. […] High-altitude pulmonary edema (HAPE) is caused by hypoxia-induced elevation of pulmonary artery pressure, which causes interstitial and alveolar pulmonary edema, resulting in impaired oxygenation. Small-vessel hypoxic vasoconstriction is patchy, causing elevated pressure, capillary wall damage, and capillary leakage in less constricted areas. Other factors, such as sympathetic overactivity, may also be involved.

• #17 Acute High-Altitude Illness: Updated Principles of Pathophysiology, Prevention, and Treatment

  https://www.germanjournalsportsmedicine.com/archive/archive-2020/issue-11-12/acute-high-altitude-illness-updated-principles-of-pathophysiology-prevention-and-treatment/

  The pathophysiology of AMS is still incompletely understood, and no consistent or strong correlations between an overall assessment of AMS and single pathophysiologic factors have been found in a large number of studies over the last 50 years. […] Hypoxemia is an indispensable requirement for the development of AMS and HACE. […] The increase in CBF may lead to an increase in hydrostatic vascular pressure, particularly if a limitation in venous outflow exists as it may be the case in supine position. An increased hydrostatic vascular pressure favours the development of HACE, especially if vascular permeability is also increased. […] A further consequence of hypoxemia may be an increase in vascular permeability through higher levels of oxidative stress, inflammation or upregulation of vascular endothelial growth factor (VEGF), which might be involved in the pathophysiology of HACE.

• #18 Altitude Illness – Injuries; Poisoning – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/injuries-poisoning/altitude-illness/altitude-illness

  Severe acute hypoxemia can cause altered central nervous system function within a matter of minutes, but acute altitude illness develops more slowly, from 1 to 5 days after ascent to a given elevation. […] The pathogenesis of acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) remain unclear despite considerable research in this area. The diseases likely have the same pathophysiology and fall on a continuum of severity, with HACE representing the extreme of the spectrum. […] Some features differ between these disorders. AMS may involve activation of the trigeminovascular system due to a variety of stimuli, while HACE involves blood-brain barrier leakage and increased intracranial pressure. […] High-altitude pulmonary edema (HAPE) is caused by hypoxia-induced elevation of pulmonary artery pressure, which causes interstitial and alveolar pulmonary edema, resulting in impaired oxygenation. Small-vessel hypoxic vasoconstriction is patchy, causing elevated pressure, capillary wall damage, and capillary leakage in less constricted areas. Other factors, such as sympathetic overactivity, may also be involved.

• #19 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9325098/

  It appears necessary to underline and add that, in some specific subpopulations, following the previous stay at sea level, HAPE re-entry pulmonary edema (HAPE) can occur. […] The pathophysiological mechanism of AMS/HACE is proven to be the basis of vasogenic edema by the following evidence: disease course (from the symptoms at onset to resolution), several experiments on animals, clinical responses to corticosteroids, the absence of neurological sequelae, and hypoxia-induced increase in endothelial permeability in vitro. […] The exact cause of HAPE remains unknown. […] However, bronchoalveolar lavage fluid has been shown to be rich in high molecular weight proteins, cells, and inflammatory markers in HAPE patients, suggesting increased capillary permeability as a major event. […] The manifestations of HACE may be considered as a clinical evolution of AMS; both involve neurological dysfunction.

• #20 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://www.mdpi.com/2077-0383/11/14/3937

  The pathophysiological mechanism of AMS/HACE is proven to be the basis of vasogenic edema by the following evidence: disease course (from the symptoms at onset to resolution), several experiments on animals, clinical responses to corticosteroids, the absence of neurological sequelae, and hypoxia-induced increase in endothelial permeability in vitro. […] The exact cause of HAPE remains unknown. […] However, bronchoalveolar lavage fluid has been shown to be rich in high molecular weight proteins, cells, and inflammatory markers in HAPE patients, suggesting increased capillary permeability as a major event.

• #21 High Altitude Cerebral Edema and Acute Mountain Sickness | SpringerLink

  https://link.springer.com/chapter/10.1007/978-1-4615-4711-2_2

  The diagnosis, treatment and prevention of high altitude cerebral edema (HACE) are fairly well established. […] The blood-brain barrier and intracranial hemodynamics are the two key elements in the pathophysiology of HACE and AMS. […] In the context of the two types of cerebral edema, cytotoxic (intracellular) and vasogenic, a leaking of proteins and water through the blood-brain barrier (BBB), a recent MRI study in persons ill with HACE (16) suggested a predominantly vasogenic mechanism. […] Causes of increased BBB permeability might include mechanical factors (loss of autoregulation and increased capillary pressure), ischemia, neurogenic influences (adrenergic and cholinergic activation), and a host of permeability mediators. […] Once vasogenic edema develops, cytotoxic edema generally follows, and although likely in HACE, this is still unproven.

• #22 High-altitude cerebral edema – Wikipedia

  https://en.wikipedia.org/wiki/High-altitude_cerebral_edema

  High-altitude cerebral edema (HACE) is a medical condition in which the brain swells with fluid because of the physiological effects of traveling to a high altitude. […] It appears to be a vasogenic edema (fluid penetration of the bloodbrain barrier), although cytotoxic edema (cellular retention of fluids) may play a role as well. […] The primary cause of HACE is hypoxia (oxygen deprivation). […] The brain swelling is likely a result of vasogenic edema, the penetration of the bloodbrain barrier by fluids. […] Hypoxia increases extracellular fluid, which passes through the vasogenic endothelium in the brain. […] It has been hypothesized that vascular endothelial growth factor may cause the vascular permeability at the root of HACE. […] While there is strong evidence that vasogenic edema plays a major role in HACE, cytotoxic edema, cellular retention of fluids, may contribute as well.

• #23 Altitude Illness – Cerebral Syndromes: Background, Pathophysiology, Etiology

  https://emedicine.medscape.com/article/768478-overview

  Altitude illness refers to a group of syndromes that result from hypoxia. Acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) are manifestations of the brain pathophysiology, while high-altitude pulmonary edema (HAPE) is that of the lung. […] The exact pathophysiology of AMS/HACE is unknown. The current hypothesis is that hypoxia elicits neurohumoral and hemodynamic responses in the brain that ultimately result in capillary leakage from microvascular beds and edema. […] Factors that might contribute to a hydrostatic brain edema are multiple and include cerebral vasodilation, elevated cerebral capillary pressure, impaired cerebral autoregulation, as well as alterations in the permeability of the blood-brain barrier through cytokine activation.

• #24 High Altitude Cerebral Edema and Acute Mountain Sickness | SpringerLink

  https://link.springer.com/chapter/10.1007/978-1-4615-4711-2_2

  The diagnosis, treatment and prevention of high altitude cerebral edema (HACE) are fairly well established. […] The blood-brain barrier and intracranial hemodynamics are the two key elements in the pathophysiology of HACE and AMS. […] In the context of the two types of cerebral edema, cytotoxic (intracellular) and vasogenic, a leaking of proteins and water through the blood-brain barrier (BBB), a recent MRI study in persons ill with HACE (16) suggested a predominantly vasogenic mechanism. […] Causes of increased BBB permeability might include mechanical factors (loss of autoregulation and increased capillary pressure), ischemia, neurogenic influences (adrenergic and cholinergic activation), and a host of permeability mediators. […] Once vasogenic edema develops, cytotoxic edema generally follows, and although likely in HACE, this is still unproven.

• #25 Acute High-Altitude Illness: Updated Principles of Pathophysiology, Prevention, and Treatment

  https://www.germanjournalsportsmedicine.com/archive/archive-2020/issue-11-12/acute-high-altitude-illness-updated-principles-of-pathophysiology-prevention-and-treatment/

  The pathophysiology of AMS is still incompletely understood, and no consistent or strong correlations between an overall assessment of AMS and single pathophysiologic factors have been found in a large number of studies over the last 50 years. […] Hypoxemia is an indispensable requirement for the development of AMS and HACE. […] The increase in CBF may lead to an increase in hydrostatic vascular pressure, particularly if a limitation in venous outflow exists as it may be the case in supine position. An increased hydrostatic vascular pressure favours the development of HACE, especially if vascular permeability is also increased. […] A further consequence of hypoxemia may be an increase in vascular permeability through higher levels of oxidative stress, inflammation or upregulation of vascular endothelial growth factor (VEGF), which might be involved in the pathophysiology of HACE.

• #26 Altitude Illness: Risk Factors, Prevention, Presentation, and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2010/1101/p1103.html

  Altitude illness affects 25 to 85 percent of travelers to high altitudes, depending on their rate of ascent, home altitude, individual susceptibility, and other risk factors. […] Acute mountain sickness and high-altitude cerebral edema is not completely understood, but current evidence suggests that hypobaric hypoxemia leads to relative fluid retention, in contrast with the usual response of marked diuresis in nonaffected climbers. This may lead to the mild cerebral edema that occurs in persons with moderate to severe acute mountain sickness and high-altitude cerebral edema. Proposed mediators of this response include vascular endothelial growth factor, nitric oxide synthase, and bradykinin. […] The pathophysiology of high-altitude pulmonary edema is not completely understood, but the primary mechanism is thought to be exaggerated hypoxic pulmonary vasoconstriction that causes increased pulmonary capillary pressure. Elevated pulmonary capillary pressure leads to mechanical disruption of the pulmonary capillaries and subsequent extravasation of fluid into the interstitial and alveolar spaces without inflammation. Limited availability of nitric oxide may increase pulmonary arterial pressure, and impaired sodium and water transportation within the lung may also contribute to the pathophysiology.

• #27 Altitude Illness: Risk Factors, Prevention, Presentation, and Treatment | AAFP

  https://www.aafp.org/pubs/afp/issues/2010/1101/p1103.html

  Altitude illness affects 25 to 85 percent of travelers to high altitudes, depending on their rate of ascent, home altitude, individual susceptibility, and other risk factors. […] Acute mountain sickness and high-altitude cerebral edema is not completely understood, but current evidence suggests that hypobaric hypoxemia leads to relative fluid retention, in contrast with the usual response of marked diuresis in nonaffected climbers. This may lead to the mild cerebral edema that occurs in persons with moderate to severe acute mountain sickness and high-altitude cerebral edema. Proposed mediators of this response include vascular endothelial growth factor, nitric oxide synthase, and bradykinin. […] The pathophysiology of high-altitude pulmonary edema is not completely understood, but the primary mechanism is thought to be exaggerated hypoxic pulmonary vasoconstriction that causes increased pulmonary capillary pressure. Elevated pulmonary capillary pressure leads to mechanical disruption of the pulmonary capillaries and subsequent extravasation of fluid into the interstitial and alveolar spaces without inflammation. Limited availability of nitric oxide may increase pulmonary arterial pressure, and impaired sodium and water transportation within the lung may also contribute to the pathophysiology.

• #28 Travelling safely to places at high altitude – Understanding and preventing altitude illness

  https://www.racgp.org.au/afp/2017/june/travelling-safely-to-places-at-high-altitude-under

  Acclimatisation to high altitude is a complex process and when inadequate leads to the pathological changes of altitude illness, including high-altitude headache, cerebral oedema, pulmonary oedema and acute mountain sickness. […] The decreased oxygen in inspired air in places at high altitude, hypobaric hypoxia, is the central causative factor for the development of altitude illness. […] Although the exact pathogenesis remains unclear, increased capillary leakage causing cerebral oedema in acute mountain sickness (AMS) and high-altitude cerebral oedema (HACE), and similar pulmonary changes in HAPE, have been consistently described. […] The likely causes for this are hypoxia-induced blood flow and pressure increases, and capillary leakage mediated by chemicals such as bradykinin, nitric oxide, arachidonic acid and vascular endothelial growth factor.

• #29 High Altitude Cerebral Edema and Acute Mountain Sickness | SpringerLink

  https://link.springer.com/chapter/10.1007/978-1-4615-4711-2_2

  The diagnosis, treatment and prevention of high altitude cerebral edema (HACE) are fairly well established. […] The blood-brain barrier and intracranial hemodynamics are the two key elements in the pathophysiology of HACE and AMS. […] In the context of the two types of cerebral edema, cytotoxic (intracellular) and vasogenic, a leaking of proteins and water through the blood-brain barrier (BBB), a recent MRI study in persons ill with HACE (16) suggested a predominantly vasogenic mechanism. […] Causes of increased BBB permeability might include mechanical factors (loss of autoregulation and increased capillary pressure), ischemia, neurogenic influences (adrenergic and cholinergic activation), and a host of permeability mediators. […] Once vasogenic edema develops, cytotoxic edema generally follows, and although likely in HACE, this is still unproven.

• #30 High-altitude cerebral edema – Wikipedia

  https://en.wikipedia.org/wiki/High-altitude_cerebral_edema

  Cytotoxic edema may be caused by the failure of cellular ion pumps, which results from hypoxia. […] Elevated intracranial pressure is generally accepted to be a late effect of HACE. […] What role the sympathetic nervous system plays in determining who gets HACE is unclear, but it may have an effect. […] Another theory about the cause of HACE is that hypoxia may induce nitrous oxide synthase.

• #31 Progress in the treatment of high altitude cerebral edema | JIR

  https://www.dovepress.com/progress-in-the-treatment-of-high-altitude-cerebral-edema-targeting-re-peer-reviewed-fulltext-article-JIR

  With the increasing of altitude activities from low-altitude people, the study of high altitude cerebral edema (HACE) has been revived. […] As for the pathogenesis of HACE, previous studies suggested that it might be related to the disorder of cerebral blood flow, the destruction of blood-brain barrier and the injury of brain parenchyma cells caused by inflammatory factors. […] In recent years, studies have confirmed that the imbalance of REDOX homeostasis is also involved in the pathogenesis of HACE, which mainly leads to abnormal activation of microglia and destruction of tight junction of vascular endothelial cells through the excessive production of mitochondrial-related reactive oxygen species. […] Previous studies have suggested that the main causes of HACE are cerebral hemodynamic disorders (increased cerebral blood flow and velocity) caused by hypobaric hypoxia, destruction of blood-brain barrier and abnormal inflammatory factors.

• #32 Progress in the treatment of high altitude cerebral edema | JIR

  https://www.dovepress.com/progress-in-the-treatment-of-high-altitude-cerebral-edema-targeting-re-peer-reviewed-fulltext-article-JIR

  Oxidative stress injury has been proven to be ubiquitous in the pathogenesis of HACE and HAPE and has become a new research hotspot in recent years. […] In the high altitude hypoxia environment, the body produces a large number of free radicals and oxidants, while hypoxia and ischemia lead to the lack of intracellular reductants, resulting in the imbalance of REDOX homeostasis in the body. […] This REDOX homeostasis imbalance can cause a variety of pathophysiological reactions, including abnormal intracellular metabolism, inflammation, cell apoptosis and so on, resulting in the occurrence of HACE. […] REDOX homeostasis in vivo is a critical condition for maintaining the integrity of BBB. However, high altitude hypoxia environment can lead to REDOX imbalance, BBB damage, and induces HACE.

• #33 Progress in the treatment of high altitude cerebral edema | JIR

  https://www.dovepress.com/progress-in-the-treatment-of-high-altitude-cerebral-edema-targeting-re-peer-reviewed-fulltext-article-JIR

  Oxidative stress injury has been proven to be ubiquitous in the pathogenesis of HACE and HAPE and has become a new research hotspot in recent years. […] In the high altitude hypoxia environment, the body produces a large number of free radicals and oxidants, while hypoxia and ischemia lead to the lack of intracellular reductants, resulting in the imbalance of REDOX homeostasis in the body. […] This REDOX homeostasis imbalance can cause a variety of pathophysiological reactions, including abnormal intracellular metabolism, inflammation, cell apoptosis and so on, resulting in the occurrence of HACE. […] REDOX homeostasis in vivo is a critical condition for maintaining the integrity of BBB. However, high altitude hypoxia environment can lead to REDOX imbalance, BBB damage, and induces HACE.

• #34 Progress in the treatment of high altitude cerebral edema | JIR

  https://www.dovepress.com/progress-in-the-treatment-of-high-altitude-cerebral-edema-targeting-re-peer-reviewed-fulltext-article-JIR

  Under the condition of hypoxia at high altitude, mitochondrial function is inhibited, resulting in abnormal mitochondrial energy metabolism and excessive production of ROS, leading to brain oxidative stress damage and inducing the occurrence of HACE. […] Therefore, the role of mitochondrial dysfunction in HACE is essential, and the study of the improvement and protection of mitochondrial function is of great significance for the prevention and treatment of HACE. […] These pathological changes lead to a breakdown of the blood-brain barrier, swelling of brain tissue, and eventually HACE disease. […] Therefore, maintaining REDOX homeostasis of brain cells is an important method to prevent and treat HACE.

• #35 Altitude Illness – Injuries; Poisoning – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/injuries-poisoning/altitude-illness/altitude-illness

  Severe acute hypoxemia can cause altered central nervous system function within a matter of minutes, but acute altitude illness develops more slowly, from 1 to 5 days after ascent to a given elevation. […] The pathogenesis of acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) remain unclear despite considerable research in this area. The diseases likely have the same pathophysiology and fall on a continuum of severity, with HACE representing the extreme of the spectrum. […] Some features differ between these disorders. AMS may involve activation of the trigeminovascular system due to a variety of stimuli, while HACE involves blood-brain barrier leakage and increased intracranial pressure. […] High-altitude pulmonary edema (HAPE) is caused by hypoxia-induced elevation of pulmonary artery pressure, which causes interstitial and alveolar pulmonary edema, resulting in impaired oxygenation. Small-vessel hypoxic vasoconstriction is patchy, causing elevated pressure, capillary wall damage, and capillary leakage in less constricted areas. Other factors, such as sympathetic overactivity, may also be involved.

• #36 Acute High-Altitude Illness: Updated Principles of Pathophysiology, Prevention, and Treatment

  https://www.germanjournalsportsmedicine.com/archive/archive-2020/issue-11-12/acute-high-altitude-illness-updated-principles-of-pathophysiology-prevention-and-treatment/

  An important factor in the pathophysiology of HAPE is an excessive hypoxic pulmonary vasoconstriction causing fluid leakage into the lung. […] Several mechanisms have been suggested to explain how an exaggerated hypoxic pulmonary vasoconstriction induces pulmonary edema formation. […] As described above, a rapid increase in hydrostatic pressure in the pulmonary vasculature leading to increased transvascular fluid filtration is the hallmark of the pathophysiology of HAPE.

• #37 Altitude Illness – Injuries; Poisoning – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/injuries-poisoning/altitude-illness/altitude-illness

  Severe acute hypoxemia can cause altered central nervous system function within a matter of minutes, but acute altitude illness develops more slowly, from 1 to 5 days after ascent to a given elevation. […] The pathogenesis of acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) remain unclear despite considerable research in this area. The diseases likely have the same pathophysiology and fall on a continuum of severity, with HACE representing the extreme of the spectrum. […] Some features differ between these disorders. AMS may involve activation of the trigeminovascular system due to a variety of stimuli, while HACE involves blood-brain barrier leakage and increased intracranial pressure. […] High-altitude pulmonary edema (HAPE) is caused by hypoxia-induced elevation of pulmonary artery pressure, which causes interstitial and alveolar pulmonary edema, resulting in impaired oxygenation. Small-vessel hypoxic vasoconstriction is patchy, causing elevated pressure, capillary wall damage, and capillary leakage in less constricted areas. Other factors, such as sympathetic overactivity, may also be involved.

• #38 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9325098/

  It appears necessary to underline and add that, in some specific subpopulations, following the previous stay at sea level, HAPE re-entry pulmonary edema (HAPE) can occur. […] The pathophysiological mechanism of AMS/HACE is proven to be the basis of vasogenic edema by the following evidence: disease course (from the symptoms at onset to resolution), several experiments on animals, clinical responses to corticosteroids, the absence of neurological sequelae, and hypoxia-induced increase in endothelial permeability in vitro. […] The exact cause of HAPE remains unknown. […] However, bronchoalveolar lavage fluid has been shown to be rich in high molecular weight proteins, cells, and inflammatory markers in HAPE patients, suggesting increased capillary permeability as a major event. […] The manifestations of HACE may be considered as a clinical evolution of AMS; both involve neurological dysfunction.

• #39 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://www.mdpi.com/2077-0383/11/14/3937

  The pathophysiological mechanism of AMS/HACE is proven to be the basis of vasogenic edema by the following evidence: disease course (from the symptoms at onset to resolution), several experiments on animals, clinical responses to corticosteroids, the absence of neurological sequelae, and hypoxia-induced increase in endothelial permeability in vitro. […] The exact cause of HAPE remains unknown. […] However, bronchoalveolar lavage fluid has been shown to be rich in high molecular weight proteins, cells, and inflammatory markers in HAPE patients, suggesting increased capillary permeability as a major event.

• #40 High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

  https://opencardiovascularmedicinejournal.com/VOLUME/10/PAGE/19/

  On a molecular level, hypoxia alters the activity of ion channels. More specifically, hypoxia downregulates the activity of potassium channels and modulates the activity of calcium channels, leading to an increase in intracellular calcium. These changes in turn augment smooth muscle cell proliferation, reduce the apoptosis of smooth muscle cells and alter the activity of pulmonary endothelial cells, favoring the production of vasoconstrictive substances such as endothelin, thromboxane A2 and others. […] Nitric oxide (NO) is a key vasodilator of the pulmonary circulation and its decreased availability is believed to play a major role in the development of PH. It has been shown by Anand that inhaled NO can mitigate pulmonary vascular resistance in patients with acute mountain sickness in the form of high-altitude pulmonary edema. Furthermore, certain medications used in the management of PH target the bioavailability of NO as will be discussed in the treatment section.

• #41 High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

  https://opencardiovascularmedicinejournal.com/VOLUME/10/PAGE/19/

  On a molecular level, hypoxia alters the activity of ion channels. More specifically, hypoxia downregulates the activity of potassium channels and modulates the activity of calcium channels, leading to an increase in intracellular calcium. These changes in turn augment smooth muscle cell proliferation, reduce the apoptosis of smooth muscle cells and alter the activity of pulmonary endothelial cells, favoring the production of vasoconstrictive substances such as endothelin, thromboxane A2 and others. […] Nitric oxide (NO) is a key vasodilator of the pulmonary circulation and its decreased availability is believed to play a major role in the development of PH. It has been shown by Anand that inhaled NO can mitigate pulmonary vascular resistance in patients with acute mountain sickness in the form of high-altitude pulmonary edema. Furthermore, certain medications used in the management of PH target the bioavailability of NO as will be discussed in the treatment section.

• #42 High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

  https://opencardiovascularmedicinejournal.com/VOLUME/10/PAGE/19/

  On a molecular level, hypoxia alters the activity of ion channels. More specifically, hypoxia downregulates the activity of potassium channels and modulates the activity of calcium channels, leading to an increase in intracellular calcium. These changes in turn augment smooth muscle cell proliferation, reduce the apoptosis of smooth muscle cells and alter the activity of pulmonary endothelial cells, favoring the production of vasoconstrictive substances such as endothelin, thromboxane A2 and others. […] Nitric oxide (NO) is a key vasodilator of the pulmonary circulation and its decreased availability is believed to play a major role in the development of PH. It has been shown by Anand that inhaled NO can mitigate pulmonary vascular resistance in patients with acute mountain sickness in the form of high-altitude pulmonary edema. Furthermore, certain medications used in the management of PH target the bioavailability of NO as will be discussed in the treatment section.

• #43 High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

  https://opencardiovascularmedicinejournal.com/VOLUME/10/PAGE/19/

  Scientific data suggest that genetics plays a role in the susceptibility to HAPH. For example, the Sherpa ethnic group living in Nepal has a Glu 298Asp polymorphism of the G allele of the NO synthase gene. The role of angiotensin converting enzyme (ACE) polymorphisms has also been studied. […] In summary, hypoxic stimuli lead to an increase in pulmonary arterial vasoconstriction and vascular remodeling through the alteration of ion channel activity. Vascular remodeling includes the proliferation of smooth muscle cells in pulmonary vessels that are normally devoid of them and decreased apoptosis of these cells. Moreover, it also modulates the biochemical activity of pulmonary endothelium with a shift towards the production of substances such as endothelin-1. The role of genetic predisposition seems to be essential for the development of disease, but is not entirely understood at this time. Other factors and comorbidities may also play some role in selected circumstances.

• #44 High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management

  https://opencardiovascularmedicinejournal.com/VOLUME/10/PAGE/19/

  Scientific data suggest that genetics plays a role in the susceptibility to HAPH. For example, the Sherpa ethnic group living in Nepal has a Glu 298Asp polymorphism of the G allele of the NO synthase gene. The role of angiotensin converting enzyme (ACE) polymorphisms has also been studied. […] In summary, hypoxic stimuli lead to an increase in pulmonary arterial vasoconstriction and vascular remodeling through the alteration of ion channel activity. Vascular remodeling includes the proliferation of smooth muscle cells in pulmonary vessels that are normally devoid of them and decreased apoptosis of these cells. Moreover, it also modulates the biochemical activity of pulmonary endothelium with a shift towards the production of substances such as endothelin-1. The role of genetic predisposition seems to be essential for the development of disease, but is not entirely understood at this time. Other factors and comorbidities may also play some role in selected circumstances.

• #45 Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care

  https://pmc.ncbi.nlm.nih.gov/articles/PMC9325098/

  It appears necessary to underline and add that, in some specific subpopulations, following the previous stay at sea level, HAPE re-entry pulmonary edema (HAPE) can occur. […] The pathophysiological mechanism of AMS/HACE is proven to be the basis of vasogenic edema by the following evidence: disease course (from the symptoms at onset to resolution), several experiments on animals, clinical responses to corticosteroids, the absence of neurological sequelae, and hypoxia-induced increase in endothelial permeability in vitro. […] The exact cause of HAPE remains unknown. […] However, bronchoalveolar lavage fluid has been shown to be rich in high molecular weight proteins, cells, and inflammatory markers in HAPE patients, suggesting increased capillary permeability as a major event. […] The manifestations of HACE may be considered as a clinical evolution of AMS; both involve neurological dysfunction.

• #46 Altitude Illness – Injuries; Poisoning – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/injuries-poisoning/altitude-illness/altitude-illness

  Long-time high-altitude residents can develop HAPE when they return after a brief stay at low altitude, a phenomenon referred to as reentry pulmonary edema. Reports suggest that long-term high-altitude residents can also develop noncardiogenic pulmonary edema referred to as high-altitude resident HAPE even if they do not descend to and then return from a lower elevation.

• #47 Altitude Illness | 5-Minute Pediatric Consult

  https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/617259/all/Altitude_Illness

  High-altitude illness represents a spectrum of clinical entities with neurologic and pulmonary manifestations that overlap presentations and share elements of pathophysiology. […] Severe AMS/HACE: rising intracranial volume and pressure from vasogenic edema (HACE). Mechanism for mild AMS remains unclear. A tight-fitting CNS within the skull and spine has less ability to buffer early edema. Activation of the trigeminovascular system may play a role. […] HAPE: elevated pulmonary artery pressure, uneven vasoconstriction, pulmonary overperfusion injury and leakage, inflammation, and impaired alveolar fluid clearance. […] Among children who reside at high altitude, reentry HAPE decreases with increasing age suggesting a role in pulmonary vasculature remodeling.

• #48 Acute Mountain Sickness – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK430716/

  Acute mountains sickness is a clinical diagnosis based on the presence of a headache, with or without the other typical symptoms, in the appropriate setting. […] For a traveler going to an at-risk altitude, the most significant modifiable risk factor is the rate of ascent. […] Acetazolamide is currently used most commonly for both prophylaxis and treatment of Acute Mountain Sickness. […] Dexamethasone use is less frequent for Acute Mountain Sickness, and it is used primarily as a treatment, though occasionally may be considered for prophylaxis in certain settings. […] The management of acute mountain sickness is an interprofessional. […] For most patients the outcome after suffering from acute mountain sickness is good; however, complete recovery may take time.

• #49 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The acute phase is associated with a steady increase in ventilation, improved oxygenation, and changes in cerebral blood flow. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #50 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The human body can adjust to moderate hypoxia at altitudes up to approximately 5,200 m (17,000 ft) but requires time to do so. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #51 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://wwwnc.cdc.gov/travel/yellowbook/2024/environmental-hazards-risks/high-elevation-travel-and-altitude-illness

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The acute phase is associated with a steady increase in ventilation, improved oxygenation, and changes in cerebral blood flow. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #52 High-Altitude Travel and Altitude Illness | Yellow Book | CDC

  https://www.cdc.gov/yellow-book/hcp/environmental-hazards-risks/high-altitude-travel-and-altitude-illness.html

  The magnitude and consequences of hypoxic stress depend on the altitude, rate of ascent, and duration of exposure; host genetic factors may also contribute. […] Altitude illness can develop before the acute acclimatization process is complete, but not afterward. […] The human body can adjust to moderate hypoxia at altitudes up to approximately 5,200 m (17,000 ft) but requires time to do so. […] Acetazolamide hastens acclimatization to high-altitude hypoxia, thereby reducing the occurrence and severity of AMS. […] The drug works primarily by inducing bicarbonate diuresis and metabolic acidosis, which counteracts the respiratory alkalosis, thereby stimulating ventilation and increasing alveolar and arterial oxygenation, especially during sleep.

• #53 Acetazolamide for Prevention of Acute Mountain Sickness (AMS) – TheNNT

  https://thennt.com/nnt/acetazolamide-prevention-acute-mountain-sickness-ams/

  Above 2,500 meters, the partial pressure of oxygen in the atmosphere drops, requiring the human body to adapt. […] If ascent occurs rapidly, and physiologic adaptation is insufficient, Acute Mountain Sickness (AMS) can result. The symptoms AMS include headache, nausea, anorexia, vomiting, lightheadedness, insomnia and fatigue. […] Although the exact mechanism of action is unclear, one theory is that acetazolamide inhibits carbonic anhydrase in the kidneys, increasing bicarbonate excretion, resulting in a metabolic acidosis that offsets the hyperventilation-induced alkalosis experienced at altitude. […] However, acetazolamide likely has multiple effects throughout the body that help to prevent AMS.

• #54 How Diamox Deals With Acute Mountain Sickness (AMS)

  https://indiahikes.com/blog/benefits-of-using-diamox-to-deal-with-ams

  Anyone can get AMS. There is no significant effect of age, gender, physical fitness, or previous altitude experience on AMS. […] 90% of the blood’s carbon dioxide exists in a chemical called bicarbonate. This carbon dioxide after travelling through your blood is exhaled by your lungs. Diamox forces the kidneys to excrete bicarbonate from your body (when you urinate). […] When Diamox forces you to excrete biocarbonates, your blood, which is used to a certain level of acidity, becomes more acidic. When the blood gets acidic it believes that it has more carbon dioxide in it. So the body gets rid of this excess carbon dioxide in a simple way. It starts to breathe deeper and faster, getting rid of the carbon dioxide, and also taking in more oxygen. […] In effect, the increased oxygen speeds up the acclimatisation process. It also greatly reduces you of any symptoms of altitude sickness. […] Remember, Diamox accelerates acclimatization. It does not cure anything. If you have headache with any of the above symptoms, even after taking Diamox, it means your acclimatization is not complete and you must descend. Under no circumstances should you climb higher if your symptoms still persists.

• #55 How Diamox Deals With Acute Mountain Sickness (AMS)

  https://indiahikes.com/blog/benefits-of-using-diamox-to-deal-with-ams

  Anyone can get AMS. There is no significant effect of age, gender, physical fitness, or previous altitude experience on AMS. […] 90% of the blood’s carbon dioxide exists in a chemical called bicarbonate. This carbon dioxide after travelling through your blood is exhaled by your lungs. Diamox forces the kidneys to excrete bicarbonate from your body (when you urinate). […] When Diamox forces you to excrete biocarbonates, your blood, which is used to a certain level of acidity, becomes more acidic. When the blood gets acidic it believes that it has more carbon dioxide in it. So the body gets rid of this excess carbon dioxide in a simple way. It starts to breathe deeper and faster, getting rid of the carbon dioxide, and also taking in more oxygen. […] In effect, the increased oxygen speeds up the acclimatisation process. It also greatly reduces you of any symptoms of altitude sickness. […] Remember, Diamox accelerates acclimatization. It does not cure anything. If you have headache with any of the above symptoms, even after taking Diamox, it means your acclimatization is not complete and you must descend. Under no circumstances should you climb higher if your symptoms still persists.

• #56 How Diamox Deals With Acute Mountain Sickness (AMS)

  https://indiahikes.com/blog/benefits-of-using-diamox-to-deal-with-ams

  Anyone can get AMS. There is no significant effect of age, gender, physical fitness, or previous altitude experience on AMS. […] 90% of the blood’s carbon dioxide exists in a chemical called bicarbonate. This carbon dioxide after travelling through your blood is exhaled by your lungs. Diamox forces the kidneys to excrete bicarbonate from your body (when you urinate). […] When Diamox forces you to excrete biocarbonates, your blood, which is used to a certain level of acidity, becomes more acidic. When the blood gets acidic it believes that it has more carbon dioxide in it. So the body gets rid of this excess carbon dioxide in a simple way. It starts to breathe deeper and faster, getting rid of the carbon dioxide, and also taking in more oxygen. […] In effect, the increased oxygen speeds up the acclimatisation process. It also greatly reduces you of any symptoms of altitude sickness. […] Remember, Diamox accelerates acclimatization. It does not cure anything. If you have headache with any of the above symptoms, even after taking Diamox, it means your acclimatization is not complete and you must descend. Under no circumstances should you climb higher if your symptoms still persists.

• #57 Acute Mountain Sickness – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK430716/

  Acute mountains sickness is a clinical diagnosis based on the presence of a headache, with or without the other typical symptoms, in the appropriate setting. […] For a traveler going to an at-risk altitude, the most significant modifiable risk factor is the rate of ascent. […] Acetazolamide is currently used most commonly for both prophylaxis and treatment of Acute Mountain Sickness. […] Dexamethasone use is less frequent for Acute Mountain Sickness, and it is used primarily as a treatment, though occasionally may be considered for prophylaxis in certain settings. […] The management of acute mountain sickness is an interprofessional. […] For most patients the outcome after suffering from acute mountain sickness is good; however, complete recovery may take time.

• #58 Acute mountain sickness: MedlinePlus Medical EncyclopediaLock

  https://medlineplus.gov/ency/article/000133.htm

  Acute mountain sickness is caused by reduced air pressure and lower oxygen levels at high altitudes. […] The faster you climb to a high altitude, the more likely you will get acute mountain sickness. […] The main treatment for all forms of mountain sickness is to climb down (descend) to a lower altitude as rapidly and safely as possible. […] Dexamethasone (Decadron) may help reduce acute mountain sickness symptoms and swelling in the brain (cerebral edema). […] Severe cases may result in death due to lung problems (pulmonary edema) or brain swelling (cerebral edema). […] Anemia lowers the amount of oxygen in your blood. This makes you more likely to have mountain sickness.

• #59 Multimodal analysis of the effects of dexamethasone on high-altitude cerebral oedema: protocol for a pilot study | Trials | Full Text

  https://trialsjournal.biomedcentral.com/articles/10.1186/s13063-019-3681-0

  Since dexamethasone is therapeutic in this setting, the next stage of research is to demonstrate that dexamethasone administration has a direct effect on cerebral vasculature during a prolonged period of normobaric hypoxia to provide evidence of the mechanisms behind the development of AMS. […] Ultimately, we would like to discover whether dexamethasone is an effective therapy for oedema associated with brain and spinal cord ischaemia.

• #60 Ibuprofen versus acetazolamide for prevention of acute mountain sickness – Medwave

  http://viejo.medwave.cl/link.cgi/English/Updates/Epistemonikos/7732.act?ver=sindiseno

  Acute mountain sickness or high altitude illness is a condition that can arise when a subject ascents to more than 2500 meters above sea level without prior acclimatization. […] Acetazolamide has been the most used pharmacological prevention. It inhibits carbonic anhydrase at renal level, causing bicarbonate excretion through urine and metabolic acidosis. Its effect would offset hyperventilation and respiratory alkalosis, thus favoring the physiological response to hypoxic stimuli. […] An alternative treatment that has gained support during the last years has been ibuprofen, due to its availability and easy access. This drug inhibits the synthesis of prostaglandin, which increases microvascular permeability at the brain as a physiopathological mechanism of acute mountain sickness. […] We are uncertain whether ibuprofen is better or worse than acetazolamide for prevention of acute mountain sickness because the certainty of the evidence has been assessed as very low. […] Considering the uncertainty of ibuprofen being better or worse than acetazolamide for prevention of acute mountain sickness, the authors of this review concluded that the use of acetazolamide is preferable since it is the standard pharmacological preventive measure.

• #61 Ibuprofen decreases likelihood of altitude sickness, researchers find | News Center

  https://med.stanford.edu/news/all-news/2012/03/ibuprofen-decreases-likelihood-of-altitude-sickness-researchers-find.html

  Ibuprofen, an anti-inflammatory medication often used as a painkiller, was found to significantly reduce the incidence of altitude sickness in a new study. […] The exact physiological mechanisms that lead to acute mountain sickness are not clearly understood. Some researchers think the condition occurs because a lack of oxygen to the brain causes it to swell with fluids. Ibuprofen may help to reduce that swelling.

• #62 Molecular Mechanisms of High-Altitude Acclimatization

  https://www.mdpi.com/1422-0067/24/2/1698

  A comprehensive understanding of the pathophysiology of HAI is essential for the development of new treatment options, for example, to facilitate successful acclimatization by targeting adaptive or maladaptive signaling pathways and molecular processes. […] Increased intracranial pressure, brain swelling and edema formation may constitute AMS pathophysiology and explain the symptoms. […] The occurrence of white matter edema in HACE indicates dysfunction or disruption of the blood-brain barrier (BBB), which may be caused by ROS-related membrane destabilization and inflammation and/or local HIF and VEGF activation. […] The activation of gene programs driven by HIF-1, Nrf2 and other regulators of transcription affects a powerful, comprehensive response to the bioenergetic and oxidative challenges imposed by hypoxia. […] The modifying changes in the proteomic makeup of cells, tissues or circulating media may represent powerful biomarkers for the acclimatization status and diagnosis or prediction of HAIs.

• #63 High-altitude physiology and pathophysiology: implications and relevance for intensive care medicine | Critical Care | Full Text

  https://ccforum.biomedcentral.com/articles/10.1186/cc5142

  Cellular hypoxia is a fundamental mechanism of injury in the critically ill. […] The present review explores the idea that human responses to the hypoxia of high altitude may be used as a means of exploring elements of the pathophysiology of critical illness. […] Hypoxia fulfils criteria as a causative agent for the acute high-altitude illnesses. […] A number of studies also suggest, however, that inflammation may be contributory in the pathogenesis of altitude illness. […] The initial pathogenesis in HAPE is thought to be nonuniform hypoxic pulmonary vasoconstriction leading to pulmonary capillary stress failure and a high-permeability type of oedema in the face of a normal left atrial pressure. […] The development of an inflammatory component may modify the natural history of HAPE; anecdotally, the recovery time for HAPE (and high-altitude cerebral oedema) seems to be related to the duration of illness.

• #64 High-altitude physiology and pathophysiology: implications and relevance for intensive care medicine | Critical Care | Full Text

  https://ccforum.biomedcentral.com/articles/10.1186/cc5142

  Exploring these differences by studying humans exposed to the hypoxia of high altitude has the potential to identify mechanisms important in established critical illness and perhaps to alter our therapeutic focus towards increasing the efficiency of oxygen utilisation rather than improving delivery. […] Studying human responses to hypobaric hypoxia may offer important insights into the pathophysiology of critical illness.

• #65 High altitude illness and related diseases – a review | 11. tbl. 105. árg. 2019 | Læknablaðið

  https://www.laeknabladid.is/tolublod/2019/11/high-altitude-illness-and-related-diseases-a-review

  Upon reaching a height over 2500 m above sea level symptoms of altitude illness can develop over 1 5 days. […] The causes of AMS, HACE and HAPE are lack of oxygen and insufficient acclimatization, but the presenting form is determined by the responses of the body to the lack of oxygen. […] The symptoms of high altitude illness overlap considerably as their pathophysiology except that the pathophysiology of high altitude pulmonary edema is a bit different from high altitude illness and high altitude cerebral edema. […] The emphasis is on preventive measures and treatment but new knowledge on pathogenesis is also addressed.

• #66 Travelling safely to places at high altitude – Understanding and preventing altitude illness

  https://www.racgp.org.au/afp/2017/june/travelling-safely-to-places-at-high-altitude-under

  Acclimatisation to high altitude is a complex process and when inadequate leads to the pathological changes of altitude illness, including high-altitude headache, cerebral oedema, pulmonary oedema and acute mountain sickness. […] The decreased oxygen in inspired air in places at high altitude, hypobaric hypoxia, is the central causative factor for the development of altitude illness. […] Although the exact pathogenesis remains unclear, increased capillary leakage causing cerebral oedema in acute mountain sickness (AMS) and high-altitude cerebral oedema (HACE), and similar pulmonary changes in HAPE, have been consistently described. […] The likely causes for this are hypoxia-induced blood flow and pressure increases, and capillary leakage mediated by chemicals such as bradykinin, nitric oxide, arachidonic acid and vascular endothelial growth factor.

• #67 High Altitude illness • LITFL • CCC Respiratory

  https://litfl.com/high-altitude-illness/

  The cause of AMS and HACE is not entirely understood […] A vasogenic mechanism is thought to be responsible for the cerebral oedema. Hypoxia-induced cerebral vasodilation and alteration of the permeability of cerebral capillaries are likely causes. […] Cytotoxic oedema may also play a role, with failure of the Na+-K+ ATPase due to oxygen radicals. […] HAPE is caused by heterogenous hypoxia-induced pulmonary vasoconstriction. […] HAPE prone individuals exhibit greater rises in their pulmonary artery pressure at altitude. […] The heterogeneity of the response causes diversion of flow to the less constricted areas with subsequent capillary leakage. […] Diminished reabsorption of alveolar fluid is also likely to be important, with hypoxia inhibiting Na+ transport across the alveolar membrane.

• #68 High-altitude physiology and pathophysiology: implications and relevance for intensive care medicine | Critical Care | Full Text

  https://ccforum.biomedcentral.com/articles/10.1186/cc5142

  Cellular hypoxia is a fundamental mechanism of injury in the critically ill. […] The present review explores the idea that human responses to the hypoxia of high altitude may be used as a means of exploring elements of the pathophysiology of critical illness. […] Hypoxia fulfils criteria as a causative agent for the acute high-altitude illnesses. […] A number of studies also suggest, however, that inflammation may be contributory in the pathogenesis of altitude illness. […] The initial pathogenesis in HAPE is thought to be nonuniform hypoxic pulmonary vasoconstriction leading to pulmonary capillary stress failure and a high-permeability type of oedema in the face of a normal left atrial pressure. […] The development of an inflammatory component may modify the natural history of HAPE; anecdotally, the recovery time for HAPE (and high-altitude cerebral oedema) seems to be related to the duration of illness.

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