Editing Altitude sickness (section)

{{Short description|Medical condition due to rapid exposure to low oxygen at high altitude}}
{{Use British English|date=April 2012}}
{{Use dmy dates|date=February 2023}}
{{Infobox medical condition (new)
| name            = Altitude sickness
| image           = Altitude Sickness Warning.jpg
| caption         = Altitude sickness warning – [[Indian Army]]
| pronounce       =
| field           = [[Emergency medicine]]
| alt             = Sign displays "Caution! You are at 17586&nbsp;ft (5360&nbsp;m)"
| synonyms        = High-altitude sickness,<ref name=Fer2016/> altitude illness,<ref name=Fer2016/> hypobaropathy, altitude bends, soroche
| symptoms        = [[Headache]], [[vomiting]], [[Fatigue|feeling tired]], [[Insomnia|trouble sleeping]], [[dizziness]]<ref name=Fer2016/>
| complications   = [[High-altitude pulmonary edema]] (HAPE),<br>[[high-altitude cerebral edema]] (HACE)<ref name=Fer2016/>
| onset           = Within 24 hours<ref name=Fer2016/>
| duration        =
| types           = Acute mountain sickness, [[high-altitude pulmonary edema]], [[high-altitude cerebral edema]], [[chronic mountain sickness]]<ref name=Mer2018Pro/>
| causes          = Low [[Breathing gas#Partial pressure of oxygen|amounts of oxygen]] at [[high altitude|high elevation]]<ref name=Fer2016/><ref name=Mer2018Pro/>
| risks           = Prior episode, high degree of activity, rapid increase in elevation<ref name=Mer2018Pro/>
| diagnosis       = Based on symptoms<ref name=Mer2018Pro/>
| differential    = [[Fatigue|Exhaustion]], viral infection, [[hangover]], [[dehydration]], [[carbon monoxide poisoning]]<ref name=Fer2016/>
| prevention      = Gradual ascent<ref name=Fer2016/>
| treatment       = Descent to lower altitude, sufficient fluids<ref name=Fer2016/><ref name=Mer2018Pro/>
| medication      = [[Ibuprofen]], [[acetazolamide]], [[dexamethasone]], [[oxygen therapy]]<ref name=Mer2018Pro/>
| prognosis       =
| frequency       = 20% at {{convert|2500|m|ft|sigfig=1}}<br>40% at {{convert|3000|m|ft|sigfig=1}}<ref name=Fer2016/><ref name=Mer2018Pro/>
| deaths          =
}}
<!-- Definition and symptoms -->

'''Altitude sickness''', the mildest form being '''acute mountain sickness''' ('''AMS'''), is a harmful [[effects of high altitude on humans|effect of high altitude]], caused by rapid exposure to low [[Breathing gas#Partial pressure of oxygen|amounts of oxygen]] at [[high altitude|high elevation]].<ref name=Fer2016/><ref name=Mer2018Pro>{{cite web |title=Altitude Diseases – Injuries; Poisoning |url=https://www.merckmanuals.com/professional/injuries-poisoning/altitude-diseases/altitude-diseases |website=Merck Manuals Professional Edition |access-date=3 August 2018 |date=May 2018}}</ref><ref>{{cite book |last1=Rose |first1=Stuart R. |chapter=CHAPTER 15 – Altitude Illness |date=1 January 2006 |chapter-url=https://www.sciencedirect.com/science/article/pii/B9780323040501500201 |title=International Travel Health Guide 2006-2007 |pages=216–229 |editor-last=Rose |editor-first=Stuart R. |place=Philadelphia |publisher=Mosby |language=en |isbn=978-0-323-04050-1|last2=Keystone |first2=Jay S. |last3=Connor |first3=Bradley A. |last4=Hackett |first4=Peter |last5=Kozarsky |first5=Phyllis E. |last6=Quarry |first6=Doug |editor2-last=Keystone |editor2-first=Jay S. |editor3-last=Connor |editor3-first=Bradley A. |editor4-last=Hackett |editor4-first=Peter |edition=Thirteenth |archive-date=11 October 2022 |archive-url=https://web.archive.org/web/20221011143411/https://www.sciencedirect.com/science/article/pii/B9780323040501500201 |url-status=live}}</ref> People's bodies can respond to high altitude in different ways. Symptoms of altitude sickness may include [[headache]]s, vomiting, tiredness, confusion, trouble sleeping, and [[dizziness]].<ref name=Fer2016/> Acute mountain sickness can progress to [[high-altitude pulmonary edema]] (HAPE) with associated [[shortness of breath]] or [[high-altitude cerebral edema]] (HACE) with associated confusion.<ref name=Fer2016/><ref name=Mer2018Pro/> [[Chronic mountain sickness]] may occur after long-term exposure to high altitude.<ref name=Mer2018Pro/>

<!-- Cause and diagnosis -->
Altitude sickness typically occurs only above {{convert|2500|m|ft|sigfig=1}}, though some people are affected at lower altitudes.<ref name=Mer2018Pro/><ref name=Sim2018/> Risk factors include a prior episode of altitude sickness, a high degree of activity, and a rapid increase in elevation.<ref name=Mer2018Pro/> Being physically fit does not decrease the risk.<ref name=Mer2018Pro/> Diagnosis is based on symptoms and is supported for those who have more than a minor reduction in activities.<ref name=Mer2018Pro/><ref name="Clinical Examination Systematic Review 2017">{{cite journal |vauthors=Meier D, Collet TH, Locatelli I, Cornuz J, Kayser B, Simel DL, Sartori C |title=Does This Patient Have Acute Mountain Sickness?: The Rational Clinical Examination Systematic Review |journal=[[JAMA]] |volume=318 |issue=18 |pages=1810–1819 |date=November 2017 |pmid=29136449 |doi=10.1001/jama.2017.16192 |url=https://serval.unil.ch/notice/serval:BIB_78F586DBF354 |s2cid=205087288}}</ref> It is recommended that at high altitude any symptoms of headache, nausea, shortness of breath, or vomiting be assumed to be altitude sickness.<ref>{{cite book |title=A Comprehensive Guide to Wilderness & Travel Medicine |edition=3rd |vauthors=Weiss E |date=2005 |isbn=978-0-9659768-1-7 |chapter=Altitude Illness |pages=137–141 |publisher=Adventure Medical Kits |quote=The Golden Rules of Altitude Illness 1) Above 8,000 feet, headache, nausea, shortness of breath, and vomiting should be considered to be altitude illness until proven otherwise. 2) No one with mild symptoms of altitude illness should ascend any higher until symptoms have resolved. 3) Anyone with worsening symptoms or severe symptoms of altitude illness should descend immediately to a lower altitude.}}</ref>

<!-- Prevention and treatment -->
Sickness is prevented by gradually increasing elevation by no more than {{convert|300|m|ft|sigfig=1}} per day.<ref name=Fer2016/>  Generally, descent and sufficient fluid intake can treat symptoms.<ref name=Fer2016/><ref name=Mer2018Pro/> Mild cases may be helped by [[ibuprofen]], [[acetazolamide]], or [[dexamethasone]].<ref name=Mer2018Pro/> Severe cases may benefit from [[oxygen therapy]] and a [[portable hyperbaric bag]] may be used if descent is not possible.<ref name=Fer2016>{{cite book |vauthors=Ferri FF |title=Ferri's Clinical Advisor 2017 E-Book: 5 Books in 1 |date=2016 |publisher=Elsevier Health Sciences |isbn=9780323448383 |page=590 |url=https://books.google.com/books?id=rRhCDAAAQBAJ&pg=PA590 |language=en}}</ref> The only definite and reliable treatment for severe AMS, HACE, and HAPE is to descend immediately until symptoms resolve. Other treatment efforts have not been well studied.<ref name=Sim2018>{{cite journal |vauthors=Simancas-Racines D, Arevalo-Rodriguez I, Osorio D, Franco JV, Xu Y, Hidalgo R |title=Interventions for treating acute high altitude illness |journal=The Cochrane Database of Systematic Reviews |volume=6 |pages=CD009567 |date=June 2018 |issue=12 |pmid=29959871 |pmc=6513207 |doi=10.1002/14651858.CD009567.pub2}}</ref>

<!-- Epidemiology and history -->
AMS occurs in about 20% of people after rapidly going to {{convert|2500|m|ft|sigfig=1}} and in 40% of people after going to {{convert|3000|m|ft|sigfig=1}}.<ref name=Fer2016/><ref name=Mer2018Pro/> While AMdS and HACE occurs equally frequently in males and females, HAPE occurs more often in males.<ref name=Fer2016/> The earliest description of altitude sickness is attributed to a Chinese text from around 30 BCE that describes "Big Headache Mountains", possibly referring to the [[Karakoram Mountains]] around [[Kilik Pass]].<ref>{{cite book |vauthors=West JB |title=High Life: A History of High-Altitude Physiology and Medicine |date=2013 |publisher=Springer |isbn=9781461475736 |pages=2–7 |url=https://books.google.com/books?id=o0rhBwAAQBAJ&pg=PA2 |language=en}}</ref>