A previously healthy, 16-year-old Guatemalan girl presents to the emergency department (ED) with a 1-month history of dyspnea on exertion. These episodes are associated with an intermittent cough, occasional fever, dizziness, and a 17-pound weight loss. She had an episode of syncope 3 months prior to presentation, and occasional hemoptysis that resolved 2 weeks ago. She denies chills, orthopnea, shortness of breath at rest, vision changes, chest pain, or palpitations. She returned home from a small town in Guatemala 1 month ago, after living there for 1 year.