HIGH ALTITUDE CEREBRAL AND PULMONARY EDEMA IN AN ACCLIMATIZED SOLDIER WITH NO CLASSIC SYMPTOMS – A CASE REPORT

Abstract

Acute mountain sickness (AMS) and high altitude cerebral edema (HACE) are considered to represent two points along a single spectrum of disease, with the same underlying pathophysiology. Onset of AMS is usually delayed for 6 to 12 hours following arrival at high altitude, but can occur as rapidly as one to two hours or as late as 24 hours. HACE generally occurs in individuals with AMS and/or high altitude pulmonary edema (HAPE) at elevations over 3000 to 3500 m (9,500 ft.). The hallmarks of HACE are encephalopathic symptoms and signs, including ataxic gait, severe lassitude, and progressive decline of mental function and consciousness (irritability, confusion, impaired mentation, drowsiness, stupor, and finally coma). The onset of encephalopathy and ataxia signifies the transition from AMS to HACE and occurs unpredictably, requiring as long as three days or as little as 12 hours. The patient, a well acclimatized young and fit serving soldier remained asymptomatic for over a month after he climbed gradually to a height of around 15,000 ft from a height of 8,000 ft as per acclimatization protocol. He did not develop classic encephalopathic signs/symptoms of HACE or HAPE as mentioned above. After spending two weeks on the post, he just once recalled the names of his relatives loudly and showed slightly withdrawn behavior from his daily routine. His vital signs and clinical examination was normal and in a very short course of a few hours he developed cardiac arrest. An autopsy performed later on, revealed edema on gross and microscopic examination of the brain and both lung tissues, characteristic of both HACE and HAPE respectively.