2025-06-25 10:59am
Suggested Approach to the Diagnosis of HAPE
The diagnosis of HAPE requires a very specific clinical context–an unacclimatized lowlander ascending to elevations ≥2500 m–and relies on a characteristic set of symptoms, including dyspnea on exertion out of proportion to previous experiences at high altitude or that experienced by other individuals at the same elevation. Nonproductive cough, fatigue, weakness, and gurgling sensation in the chest may also be present. With progression, individuals become dyspneic with mild exertion or at rest and may develop cyanosis and cough productive of pink frothy sputum.
The setting in which the individual presents for evaluation influences the diagnostic approach. In the field environment, where diagnostic resources are limited, diagnosis may be made on the basis of history alone. If available, pulse oximetry can confirm the presence of hypoxemia out of proportion to that expected for a given elevation,123 a key feature for distinguishing HAPE from other sources of dyspnea, such as anxiety or poor physical conditioning, although care must be taken to avoid some of the pitfalls of such measurements at high altitude.124 Identification of B-lines on portable ultrasound is a sensitive but nonspecific diagnostic tool,125,126 but there is currently no accepted threshold for the number of B-lines necessary to confirm diagnosis. Individuals presenting to well-resourced health facilities should undergo pulse oximetry, plain chest radiography, and electrocardiography. The presence of hypoxemia and either unilateral or diffuse bilateral alveolar opacities on plain chest radiography is sufficient to confirm the diagnosis in the appropriate clinical context. Chest computed tomography scanning and echocardiography are generally only warranted when the initial evaluation is unrevealing or other problems remain high on the differential diagnosis.
Consideration should be given to other causes of respiratory symptoms at high altitude, such as asthma, bronchospasm, mucous plugging, pneumonia, pneumothorax, pulmonary embolism, viral upper respiratory tract infection, heart failure, or myocardial infarction.
