Restrictive Lung Disease USMLE Step 1 Practice Question
A 45-year-old woman with a 10-year history of rheumatoid arthritis presents to clinic with progressive dyspnea on exertion and a dry cough over the past 8 months. She reports no fever, chills, or hemoptysis. Vital signs: BP 128/82 mmHg, HR 94 bpm, RR 22/min, SpO2 92% on room air. Physical examination reveals fine late inspiratory crackles at the bilateral lung bases. Chest radiograph shows bilateral lower lobe predominant reticular opacities with traction bronchiectasis. High-resolution CT chest confirms usual interstitial pneumonia (UIP) pattern. Pulmonary function testing demonstrates: FVC 65% predicted, FEV1 68% predicted, FEV1/FVC ratio 88%, DLCO 55% predicted. Which of the following best explains the pathophysiology of her pulmonary disease?
Answer choices
- AImmune-mediated alveolar inflammation with granuloma formation leading to pulmonary fibrosis
- BProgressive fibroblast proliferation and collagen deposition in the alveolar interstitium with heterogeneous lung involvementCorrect answer
- CPredominantly neutrophilic alveolar inflammation with uniform interstitial pneumonitis and preservation of underlying lung architecture
- DEpithelial injury with capillary permeability leading to diffuse alveolar damage and acute respiratory insufficiency
- ESmall airway obstruction with air trapping and emphysematous changes in the pulmonary parenchyma
- FLeft ventricular dysfunction causing pulmonary venous congestion and hydrostatic pulmonary edema
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