HAPE and HACE

Q: High altitude pulmonary edema (HAPE) occurs due to? (select one)

A) hypoxic pulmonary vasoconstriction

B) hypoxic pulmonary vasodilatation

Answer: A

The most common cause of death in HAPE is noncardiogenic pulmonary edema. High altitude hypoxia leads to pulmonary vasoconstriction resulting in pulmonary edema.

It starts with nonproductive cough and shortness of breath (SOB) on exertion while walking uphill. It progressively culminates into productive pink, frothy sputum, and hemoptysis. Progressively, SOB stays on even at rest or walking on flat surface.

Generally, it takes about 48 to 96 hours to be evident after arriving at a high altitude, and symptoms tend to occur more at night! 

If untreated, or without de-escalation, to the lower altitude, it progresses to high-altitude cerebral edema (HACE).

#pulmonary

#neurology

References:

1. Dunham-Snary KJ, Wu D, Sykes EA, et al. Hypoxic Pulmonary Vasoconstriction: From Molecular Mechanisms to Medicine. Chest 2017; 151:181.

2. Bärtsch P, Swenson ER. Acute high-altitude illnesses. N Engl J Med 2013; 369:1666.