ABSTRACT
The defining environmental features at high altitude are the decline in barometric pressure and the subsequent decrease in the ambient partial pressure of oxygen, important changes that set in motion an array of physiologic responses. In conjunction with the increase in physical activity that often takes place with mountain travel, these environmental changes have the potential to cause a variety of other medical problems in the absence of appropriate preventive measures, including hypothermia, frostbite and nonfreezing cold injury, heat-related illness, and injuries related to excess ultraviolet radiation. This chapter describes each of these entities in greater detail, with particular emphasis on their pathophysiology and risk factors, clinical presentation, strategies for prevention and treatment, and expected outcomes. While often associated with exposure to subfreezing temperatures, hypothermia can develop with ambient temperatures >0°C, at any time of the year, and in any climate provided certain environmental factors, such as exposure to wind and rain, and behavioral factors are in place.
