A 42-year-old man presents to the pulmonary clinic with a three-week history of worsening cough, wheezing, and shortness of breath. He has a history of moderate persistent asthma since childhood, which is usually well-controlled on a medium-dose inhaled corticosteroid and long-acting beta-agonist combination. Over the past month, his symptoms have escalated despite adherence to his inhaler, and he reports coughing up firm, brownish “plugs” of mucus. He also notes low-grade fevers and malaise. He denies any recent travel, sick contacts, or changes to his home environment. He does not smoke and has no other medical conditions.

He appears mildly distressed and has an occasional loose cough. He is afebrile. His blood pressure is 128/78 mmHg, with a heart rate of 92 bpm, a respiratory rate of 18 breaths per minute, and an oxygen saturation of 95% on ambient air.