Slow Symptom Resolution of Acute Altitude Illness Upon Rapid Descent

Hill, Adam D. Slow symptom resolution of acute altitude illness upon rapid descent. High Alt Med Biol. 00:00–00, 2026.—Acute mountain sickness (AMS) effects roughly one-quarter to more than three-quarters of persons travelling to elevations greater than 2,500 m. Treatment relies primarily on descent or a stoppage of further ascent (with or without pharmacologic therapy) to allow for acclimatization. In the latter approach, acclimatization as heralded by improvement of symptoms can take anywhere from 12 hours to 4 days. The timeline for symptom resolution when descent takes place, however, is not clearly defined. A case is presented of a hiker who suffered from persistent symptoms of AMS for nearly 24 hours despite descending rapidly to sea level.