Approach to fatigue Quiz: Ace Your Exams

A 53-year-old man presents to the primary care clinic with progressive fatigue and shortness of breath for the past six months. He was diagnosed with pneumonia four months ago, after which he noticed a persistent cough. He used to be able to run 3 miles a day, but he now has shortness of breath and fatigue while walking up two flights of stairs. He has no other significant past medical history. He has a 32-pack-year smoking history. Temperature is 37.2 °C (99 °F), pulse is 78/min, respiratory rate is 15/min, blood pressure is 124/75 mmHg, and oxygen saturation is 92% on room air. On physical examination, he smells of cigarette smoke. Cardiopulmonary auscultation reveals diffuse wheezing. He has no peripheral edema. Initial laboratory studies show normal complete blood count, thyroid stimulating hormone, and basic metabolic panel. Chest x-ray shows clear lung fields with hyperinflation and flattened diaphragms. Which of the following is the most appropriate next step in management?