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high-altitude pulmonary edema
Etiology:
1) rapid ascent to > 14,000 feet in elevation.
- may occur at altitudes > 8200 feet (2500 meters) [2]
1) hypoxic pulmonary vasoconstriction
2) cold weather & exertion contribute
Epidemiology:
1) incidence is 0.5-10% among mountaineers
2) incidence is 60% on re-exposure of susceptible individuals to high altitudes
Pathology:
- non-cardiogenic pulmonary edema
- leakage of fluid & hemorrhage into the alveolar spaces
Clinical manifestations:
1) symptoms appear 24-36 hours after ascent
- symptom onset generally insidious
2) dyspnea
- dyspnea on exertion
- dyspnea at rest is key feature [2]
3) cough
4) tachynea
5) tachycardia
6) crackles or wheezing
7) variable
- fatigue, nausea/vomiting, sleep disorder, frothy sputum, hemoptysis
5) altered mental status
6) somnolence
* left ventricular failure is NOT a manifestation.
Radiology:
- chest X-ray shows patchy infiltrates which resolve 6-48 hours after return to sea level or supplemental oxygen therapy
Management:
1) supplemental oxygen
2) furosemide
3) vasodilator:
- nifedipine (effective for prevention)
- phosphodiesterase-5 inhibitor
- sildenafil
- tadalafil
4) acetazolamide & dexamethasone are not useful
5) return to lower elevation
General
altitude sickness
pulmonary edema (pulmonary congestion, PE)
References
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed)
Lippincott-Raven, Philadelphia, 1998, pg 764
- Medical Knowledge Self Assessment Program (MKSAP) 14, 15, 16,
17, 18. American College of Physicians, Philadelphia 2006, 2009,
2012, 2015, 2018.