COPD USMLE Step 1 Practice Question
A 33 year old man has progressive dyspnea and decreased exercise tolerance. He has never smoked. Physical examination shows hyperresonance to percussion and decreased breath sounds. His father died of cirrhosis in his forties. Imaging shows basilar predominant emphysematous change. Which of the following is the most likely underlying mechanism?
Answer choices
- AInhaled silica causing activation of alveolar macrophages
- BAutoimmune destruction of alveolar basement membrane collagen
- CDefect in chloride transport causing mucus plugging
- DBronchiolar smooth muscle hypertrophy due to atopy
- ELoss of antiprotease activity leading to uninhibited elastase in the lungCorrect answer
- FImpaired surfactant production leading to increased alveolar surface tension and collapse
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