History

HAPE generally occurs 2-4 days after ascent to high altitude, often worsening at night. Decreased exercise performance is the earliest symptom, usually associated with a dry cough. The early course is subtle; as the illness progresses, the cough worsens and becomes productive; dyspnea can be severe, tachypnea and tachycardia develop, and drowsiness or other CNS symptoms may develop. Chest radiographs characteristically show patchy unilateral or bilateral fluffy infiltrates and a normal cardiac silhouette. The presence of a low-grade fever has led to misdiagnosis as pneumonia and to subsequent deaths.

HAPE varies in severity from mild to immediately life-threatening. It can be fatal within a few hours, and it is the most common cause of death related to high altitude. Left untreated, HAPE has a mortality rate near 50%.^[20]Differential diagnosis is sometimes problematic, but HAPE improves dramatically with descent or oxygen, whereas other diagnoses do not; these should be pursued in patients who do not fit this pattern.

Differential Diagnoses

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Media Gallery

High-altitude pulmonary edema (HAPE). Image courtesy Dr Matthew Cushing.
Hyperbaric treatment at 4250 m in a Gamow bag.
Thoracic ultrasonography: comet tail sign. Patient with acute high-altitude pulmonary edema (HAPE). Note wedge-shaped forms extending from pleural lining. In contrast, normal thoracic sonogram (below) reveals only diffuse, "snow storm" appearance. Courtesy of Dr Peter Fagenholz, et al.
Thoracic ultrasonography. Normal thoracic sonogram reveals only diffuse, "snow storm" appearance without comet tail sign. Courtesy of Dr Peter Fagenholz, et al.

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Author

N Stuart Harris, MD, MFA, FACEP Chief, Division of Wilderness Medicine, Fellowship Director, MGH Wilderness Medicine Fellowship, Attending Physician, Massachusetts General Hospital; Assistant Professor, Department of Surgery, Harvard Medical School

N Stuart Harris, MD, MFA, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Massachusetts Medical Society, International Society for Mountain Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Eddy S Lang, MDCM, CCFP(EM), CSPQ Associate Professor, Senior Researcher, Division of Emergency Medicine, Department of Family Medicine, University of Calgary Faculty of Medicine; Assistant Professor, Department of Family Medicine, McGill University Faculty of Medicine, Canada

Eddy S Lang, MDCM, CCFP(EM), CSPQ is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, Canadian Association of Emergency Physicians

Disclosure: Nothing to disclose.

Chief Editor

Joe Alcock, MD, MS Associate Professor, Department of Emergency Medicine, University of New Mexico Health Sciences Center

Joe Alcock, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Samuel M Keim, MD, MS Professor and Chair, Department of Emergency Medicine, University of Arizona College of Medicine

Samuel M Keim, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Public Health Association, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Acknowledgements

Thomas E Dietz, MD Consulting Staff, Department of Emergency Medicine, Providence Hood River Memorial Hospital

Disclosure: Nothing to disclose.

Sara W Nelson, MD Resident Physician, Harvard Affiliated Emergency Medicine Residency, Brigham and Women's Hospital and Massachusetts General Hospital

Sara W Nelson, MD is a member of the following medical societies: American College of Emergency Physicians, Emergency Medicine Residents Association, and Phi Beta Kappa

Disclosure: Nothing to disclose.