MOUNTAINEERS have from time to time reported cases of rapid death attributed to pneumonia, occurring most often in healthy, active persons engaged in strenuous activity at altitudes from 14,000 feet upward. Most of the reports, by nonmedical authors, have appeared in lay publications. The course of the disease has been too fulminating and has not responded to adequate antibiotics to be typical of pneumonia. Consequently, some physician climbers have suspected another cause such as acute pulmonary edema.In 1959 I had the unusual opportunity of seeing such a case within reach of hospital facilities, and this single case is presented . . .