High-Altitude Pulmonary Edema (HAPE) Workup

Updated: Apr 07, 2020
  • Author: Rohit Goyal, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
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Approach Considerations

The clinical diagnosis of high-altitude pulmonary edema (HAPE) generally includes at least two of the following signs/symptoms [1, 18] :

  • Dyspnea at rest
  • Cough
  • Weakness or reduced exercise performance
  • Chest tightness or congestion
  • Tachycardia
  • Tachypnea
  • Rales/wheezes in at least one lung field
  • Central cyanosis 

In patients with chest radiographic evidence of infiltrates, rapid clinical and oxygen saturation improvement with administration of supplemental oxygen is pathognomonic for high-altitude pulmonary edema. [1]  

Laboratory studies are general of limited use. [1]

Always consider the possibility of concomitant acute mountain sickness and/or high-altitude cerebral edema. [1, 2, 3, 4]

Note that the coronavirus disease 2019 (COVID-19) pandemic has raised concerns over whether affected patients with respiratory distress have presentations more like high-altitude pulmonary edema (HAPE) than that of acute respiratory distress syndrome (ARDS). [20, 21] Therefore, the Guidelines section also contains the following COVID-19-related guidance:

For more COVID-19 information, please go to Medscape's Novel Coronavirus Resource CenterCOVID-19 Clinical Guidelines, and Coronavirus Disease 2019 (COVID-19).


Laboratory Studies

Findings on laboratory studies from high-altitude pulmonary edema (HAPE) patients are nonspecific.

Arterial blood gas (ABG) measurement typically shows severe hypoxemia and respiratory alkalosis. The partial pressure of oxygen is usually between 30 and 40 mm Hg. [7] A mild leukocytosis also may be present.

Some studies have demonstrated increase in interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra), and cross-reacting protein (CRP) in response to high altitude. The systemic increase of these inflammatory markers may reflect considerable local inflammation. [22]


Imaging Studies


Chest radiography in high-altitude pulmonary edema (HAPE) patients reveals bilateral patchy infiltrates, with a normal heart size/mediastinum.{ref29) [7] If infiltrates are absent, consider an alternative diagnosis.

High-altitude pulmonary edema (HAPE). Plain chest High-altitude pulmonary edema (HAPE). Plain chest x-ray (radiograph) of a patient diagnosed with HAPE. There are patchy infiltrates throughout the lung tissue, with predominant changes in the right middle lobe/right central hemithorax. Courtesy of Wikipedia (https://en.wikipedia.org/wiki/File:Chest_XR_of_HAPE.png).
High-altitude pulmonary edema (HAPE). Initial ches High-altitude pulmonary edema (HAPE). Initial chest x-ray showing pulmonary infiltrates in the right lung especially in the right mid and lower lung zones indicative of pulmonary edema. The patient was a middle-aged woman trekker who was emergency air-lifted from an altitude of 4410 m in the Nepal Himalayas to 1300 m in Kathamandu. She had continued ascending despite experiencing mild altitude symptoms at Namche (3440 m), with considerably worsened symptoms at Tengboche (3860 m). Courtesy of Extreme Physiology & Medicine (PMID: 24636661, online at https://extremephysiolmed.biomedcentral.com/track/pdf/10.1186/2046-7648-3-6).
High-altitude pulmonary edema (HAPE). Repeat chest High-altitude pulmonary edema (HAPE). Repeat chest x-ray after 2 days showing rapid resolution of the pulmonary edema in the same Himalayan trekker discussed in the previous image. The patient received bed rest, supplemental oxygen, and oral sustained-release nifedipine 20 mg twice daily. Courtesy of Extreme Physiology & Medicine (PMID: 24636661, online at https://extremephysiolmed.biomedcentral.com/track/pdf/10.1186/2046-7648-3-6).


B-lines consistent with pulmonary edema may be seen on sonograms [1]

In one study, stress echocardiography was used to quantitate pulmonary artery systolic pressure responses to prolonged hypoxia and normoxic exercise. [23] The data from the study indicate that individuals who are susceptible to HAPE have abnormal vascular responses not only to hypoxia but also to supine bicycle exercise under normoxic conditions. Thus, this modality may be a useful noninvasive screening method to identify subjects susceptible to HAPE.

Chest ultrasonography was evaluated in one study and showed that the comet-tail technique, which has been shown in cardiogenic pulmonary edema, effectively recognizes and evaluates the degree of pulmonary edema in HAPE patients. [24]


Electrocardiography (ECG) in high-altitude pulmonary edema (HAPE) patients may reveal a right-sided heart strain pattern suggestive of pulmonary hypertension [7]  and/or ischemia. [1]