COPD USMLE Step 1 Practice Question
A 68-year-old man with a 45-pack-year smoking history presents to clinic with progressive dyspnea on exertion over the past 2 years. He reports a chronic productive cough with clear sputum most mornings. Physical examination reveals decreased breath sounds bilaterally and barrel chest. Spirometry demonstrates FEV1 52% predicted, FEV1/FVC ratio 0.64, and minimal improvement (3% change) following inhaled albuterol. High-resolution CT chest shows diffuse low-attenuation areas without bronchial wall thickening. The patient denies wheezing, seasonal symptoms, or atopic history. Which of the following pathophysiologic mechanisms is primarily responsible for this patient's airflow obstruction?
Answer choices
- ALoss of elastic recoil and destruction of alveolar walls due to emphysematous changesCorrect answer
- BReversible airway smooth muscle constriction responsive to bronchodilators
- CChronic inflammation with eosinophilic infiltration and type 2 helper cell predominance
- DFixed airflow obstruction from mucus hypersecretion and goblet cell metaplasia alone
- EAllergic sensitization with IgE-mediated mast cell degranulation
- FBronchial wall thickening and remodeling from recurrent infections
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