High-altitude pulmonary edema (HAPE) is a rare cause of pulmonary edema that presents with dyspnea on exertion, dry cough, tachypnea, and sometimes blood-tinged or pink frothy sputum. It is the most common fatal manifestation of altitude illness.

HAPE develops after rapid ascent to high altitudes, typically those above 2500 meters (about 8000 feet). Onset is usually within 2-4 days. Altitude-induced changes in pulmonary vasculature (increased sympathetic tone, vasoconstriction) along with uneven perfusion of pulmonary vasculature leads to increased pulmonary capillary pressure, with failure of capillaries and leak of fluid across alveoli.

Risk factors include the following:

• Prior history of HAPE
• Pulmonary hypertension
• Patent foramen ovale
• Male sex
• Cold temperature
• Respiratory infection or disease (eg, chronic obstructive pulmonary disease)
• Intense exercise

With treatment, recovery from HAPE is usually rapid.

Related topics: acute mountain sickness, high-altitude cerebral edema