Reentry High Altitude Pulmonary Edema (HAPE) in High Altitude Residents!

When High Altitude Pulmonary Edema (HAPE) is diagnosed, one often thinks of the diagnosis in relation to patients who have lived long term in low/sea level altitudes coming to high altitudes for the first time. However, a new study conducted by Santosh Baniya based out of the Himalayas suggest there is a subset of HAPE in which long term high altitude residents can fall ill to HAPE upon reentry to high altitudes after even a brief stay at lower altitudes.

Baniya’s study is based off a case report of an otherwise healthy pediatric patient who was diagnosed with HAPE after returning to his village of Manag (3500m) after a winter in Besisahar (760m)- a trip that was done multiple times in his life time with no complications. One change surrounding this diagnosis was a recent construction of a road between the two villages that decreased the usual travel time from a span of several days to a single day. The pathophysiologic explanation behind this phenomenon is thought to be caused by the descent of high altitude residents to lower altitudes, leading to a decrease in the red cell mass and a compensatory rise in plasma volume, which then in turn predisposes an individual to pulmonary edema once they return to high altitudes. Had the patient taken the original route of travel- it is likely that the gradual ascent would’ve allowed his body to acclimate to the altitude change and the red cell mass and plasma levels would’ve adjusted accordingly. However, due to the decrease in overall travel time the excess plasma levels led to pulmonary edema. Manifestation of this included shortness of breath, respiratory distress, and hypoxia (an oxygen saturation of 44% in this case). Treatment included high-flow oxygen, dexamethasone to help with air way swelling, and descent to lower altitudes which resulted in immediate marked improvement.

The remarkable aspect of this case- and the reason it was published- is that the doctors in a high altitude community failed to recognize a condition familiar to medical providers in the mountains here in Colorado. More importantly the clinical symptoms that we describe here are also pertinent to Mountain Resident HAPE and Trauma Related HAPE, which is often misdiagnosed by experts in Denver and other lower altitude communities outside of Colorado. Understanding the prevalence of this phenomenon is of utmost importance as an incorrect diagnosis of influenza, pneumonia or asthma could lead to fatal consequences- as oxygen does not treat these conditions. Proper recognition, diagnosis and treatment with oxygen, rest, and if severe enough, descent into lower altitudes need to be carried out promptly for effective treatment.

 

Garkie Zhu, PA-S3
MCPHS PA Program

Reference:

Baniya, S. (2017). Reentry High Altitude Pulmonary Edema in the Himalayas. High Altitude Medicine & Biology,18(4), 425-427. Retrieved January 23, 2018.

Ebert-Santos, C. (2017). High-Altitude Pulmonary Edema in Mountain Community Residents. HIGH ALTITUDE MEDICINE & BIOLOGY, 18(3), 278-284. Retrieved February 2, 2018.

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