There are inherent risks in traveling at high altitude. The information provided here is designed for educational use only and is not a substitute for specific training or experience. Princeton University and the author assume no liability for any individual’s use of or reliance upon any material contained or referenced herein. This paper is prepared to provide basic information about altitude illnesses for the lay person. Medical research on high altitude illnesses is always expanding our knowledge of the causes and treatment. When going to altitude it is your responsibility to learn the latest information. The material contained in this article may not be the most current.HACE is the result of swelling of brain tissue from fluid leakage. Symptoms can include headache, loss of coordination (ataxia), weakness, and decreasing levels of consciousness including, disorientation, loss of memory, hallucinations, psychotic behavior, and coma. It generally occurs after a week or more at high altitude.
Severe instances can lead to death if not treated quickly. Immediate descent is a necessary life-saving measure (2,000 - 4,000 feet [610-1,220 meters]). There are some medications that may be prescribed for treatment in the field, but these require that you have proper training in their use. Anyone suffering from HACE must be evacuated to a medical facility for proper follow-up treatment.
Watch out for the fellow who talks about putting things in order! Putting things in order always means getting other people under your control.
-- Denis Diderot (1713 - 1784), Supplement to Bougainville's 'Voyage,' 1796