A patient has the following PFT results: FEV1 58% predicted, FVC 82% predicted, FEV1/FVC 54%, TLC 112% predicted, RV 145% predicted. What is the pattern and MOST likely underlying pathology?
- A Restrictive pattern — interstitial lung fibrosis
- B Mixed obstructive-restrictive — cystic fibrosis with fibrosis
- C Obstructive pattern with air trapping — consistent with COPD/emphysema ✓
- D Normal PFT pattern — all values within acceptable range for age
Correct answer: C. Obstructive pattern with air trapping — consistent with COPD/emphysema
Explanation
The pattern shows a reduced FEV1/FVC ratio (< 70%) confirming obstruction, with a supranormal TLC and markedly elevated RV (air trapping), while FVC is relatively preserved. This is classic for emphysema/COPD where alveolar wall destruction causes loss of elastic recoil, dynamic airway collapse, and gas trapping. Restrictive disease (option A) would show reduced TLC and normal or high FEV1/FVC. Mixed disease (option B) would show reduced TLC alongside obstruction. Option D is incorrect given clearly abnormal FEV1/FVC.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.