[Acute mountain sickness and high-altitude pulmonary edema. How to protect the mountain climber from the effects of the "altitude haze"].

Acute mountain sickness (AMS) usually occurs after 6-12 hours of acute exposure to altitudes above 2,500 m. If there is no further altitude gain, it normally resolves spontaneously within a day or two. However, it may, in rare cases, progress to life-threatening cerebral edema. High-altitude pulmonary edema (HAPE) is a non-cardiogenic edema that is often preceded by symptoms of AMS. The major preventive measure is slow ascent. Acetazolamide and dexamethasone are effective in preventing AMS, while nifedipine is effective only against HAPE. Immediate descent and/or the administration of oxygen is the treatment of choice for both conditions. If this is not possible, dexamethasone may be given for severe AMS and nifedipine for HAPE.