acute mountain sickness
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Etiology
acute ascent of lowlanders to > 7000 feet
Physiology
- PiO2 decreased by 4-5 mm Hg for every 1000 feet in elevation
- high-altitude induced hypoxia increases minute ventilation & decreased pCO2
- hemoglobin concentration increases secondary to diuresis
- transient increase in erythropoietin levels
History
- travel to above 1900 meters, 6300 feet
- history of previous acute mountain sickness
Clinical manifestations
- symptoms occur 6-90 hours after ascent
- fatigue, lethargy
- insomnia or other sleep disorder
- high-altitude periodic breathing is common[2]
- headache
- ataxia
- nausea/vomiting
- anorexia
- dyspnea
- high-altitude pulmonary edema
- cerebral edema in severe cases
- high-altitude retinopathy
Management
- return to lower elevation
- prophylaxis
- acetazolamide 125 to 250 mg BID-TID prophylactically
- start 1 day before ascent
- continue for 2 days after reaching destination[3]
- higher dose more effective, but with more risk of adverse effect[5]
- ibuprofen as effective as acetazolamide[4]
- 600 mg every 6 hours beginning 6 hours before ascent
- number needed to treat = 4
- acetazolamide 125 to 250 mg BID-TID prophylactically
- rest, hydration, oxygen
- urgent descent to lower elevation, supplemental oxygen &
- dexamethasone for cerebral edema (also descent to lower elevation)[2]
- nifedipine, sildenafil or tadalafil for pulmonary edema
- patient education:
- advise cardiac & elderly patients to take extra precautions; patients who are stable at sea level maynot be at high altitudes
- advise against exercise above 5000 feet until acclimation for patients with:
- unstable angina
- uncontrolled arrhythmias
- poorly controlled heart failure
- advise staying < 8000 feet for patients with
- atrial fibrillation can be exacerbated at high altitudes due to hypoxia & tachycardia
- consider increasing rate-control med if patients are rapidly ascending over 5000 feet[3]
More general terms
References
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 764
- ↑ 2.0 2.1 2.2 Medical Knowledge Self Assessment Program (MKSAP) 14, 16, 17, 18, 19. American College of Physicians, Philadelphia 2006, 2012, 2015, 2018, 2022.
- ↑ 3.0 3.1 3.2 3.3 Prescriber's Letter 17(2): 2010 Moving On Up: Altitude and Your Cardiac Patients Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=260204&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 4.0 4.1 Lipman GS et al. Ibuprofen prevents altitude illness: A randomized controlled trial for prevention of altitude illness with nonsteroidal anti-inflammatories. Ann Emerg Med 2012 Jun; 59:484. PMID: https://www.ncbi.nlm.nih.gov/pubmed/22440488
- ↑ 5.0 5.1 Low EV et al. Identifying the lowest effective dose of acetazolamide for the prophylaxis of acute mountain sickness: Systematic review and meta-analysis. BMJ 2012 Oct 18; 345:e6779 PMID: https://www.ncbi.nlm.nih.gov/pubmed/23081689
- ↑ 6.0 6.1 Willmann G et al Retinal Vessel Leakage at High Altitude. JAMA. 2013;309(21):2210-2212 <PubMed> PMID: https://www.ncbi.nlm.nih.gov/pubmed/23736726 <Internet> http://jama.jamanetwork.com/article.aspx?articleid=1693883
- ↑ Bartsch P, Swenson ER Clinical practice: Acute high-altitude illnesses. N Engl J Med. 2013 Jun 13;368(24):2294-302. PMID: https://www.ncbi.nlm.nih.gov/pubmed/23758234
- ↑ Meier D, Collet TH, Locatelli I et al Does This Patient Have Acute Mountain Sickness? The Rational Clinical Examination Systematic Review. JAMA. 2017; 318(18):1810-1819 PMID: https://www.ncbi.nlm.nih.gov/pubmed/29136449 https://jamanetwork.com/journals/jama/article-abstract/2662895