Altitude Illness - Pulmonary Syndromes Clinical Presentation

Updated: Jun 22, 2022
  • Author: N Stuart Harris, MD, MFA, FACEP; Chief Editor: Joe Alcock, MD, MS  more...
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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.