Acute medical problems in the Himalayas outside the setting of altitude sickness.

Well-recognized medical threats at high altitude (>2,500 m) include acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Thousands of travelers in the Himalayas are exposed annually to these often life-threatening syndromes. Their recognition and treatment has advanced considerably in recent years. In the Himalayas, we frequently see acute medical problems outside the setting of AMS and the two types of altitude edemas. Many of these other conditions are also hypoxia related and sometimes may mimic the classic high altitude illnesses of AMS, HAPE, and HACE. Although the vast majority of these medical problems are neurological, pulmonary and other organ system dysfunction also occur. These "non-high altitude sickness" disease entities in persons who sojourn to remote mountainous environments are reviewed in this paper to enhance their recognition, diagnosis, and treatment.