A 25-year-old woman presented for pulmonary consultation with a complaint of 18 months of progressive shortness of breath and wheezing. The patient engages in rock climbing, mountaineering, and skiing, and initially experienced dyspnea only with significant exertion at extreme altitude. Over the next several months, however, wheezing and a nonproductive cough developed. Given her history of mild exercise-induced asthma, the patient’s primary care provider recommended treatment with a short-acting bronchodilator. This provided no symptomatic relief.