Does Prior Respiratory Infection Increase the Risk of High-Altitude Pulmonary and Cerebral Edema? A Case Report

Femling, Jon K., Peter S. Figueiredo, Aaron J. Reilly, Jason D. Williams, Trevor J. Mayschak, Erik R. Swenson, Steven D. Landspurg, and Beth A. Beidleman. Does prior respiratory infection increase the risk of high-altitude pulmonary and cerebral edema? A case report. <i>High Alt Med Biol.</i> 26:411-415, 2025.-Inadequate time to acclimatize to the lower partial pressure of oxygen at high altitude (HA) can result in one or more forms of acute altitude illness: acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE). AMS is common while HAPE and HACE are exceptionally rare, particularly below 4,000 m. Severe AMS can be debilitating while both HAPE and HACE are potentially deadly if untreated. Cases of HAPE at altitudes <4,000 m have been linked to a preceding, or concurrent, respiratory infection (RI), which may augment susceptibility. This case report details a timeline of continuous physiological monitoring, including heart rate and peripheral oxygen saturation, during active ascent and 42-hour exposure to 3,600 m from an individual diagnosed with HAPE/HACE. The case occurred during a military research study providing a homogenous cohort (<i>n</i> = 37) to compare data. Nocturnal oxygen saturation was poor and deteriorated during the stay. The case reported the most severe AMS symptoms on surveys without vocalized complaints. The case presented the classical symptoms of HACE (ataxia and confusion) by the second morning at HA. An underlying RI was discovered that may have increased his susceptibility to HAPE, and subsequently to HACE, at relatively low altitude.