Frontiers in Neuroscience

It is now generally accepted that acute mountain sickness (AMS) is caused by a mild form of high-altitude cerebral edema (HACE). In susceptible individuals AMS may progress to a lethal form of HACE and/or high-altitude pulmonary edema (3). Two hypotheses have been promulgated to account for HACE: the vasogenic edema hypothesis and the cytotoxic edema hypothesis (3,4). Since cerebral energetics are unchanged during AMS-HACE in an experimental sheep model (7), evidence favors the view that HACE is vasogenic in nature, although cytotoxic edema has not been ruled out specifically.