A 40-year-old woman with progressive dyspnoea. HRCT shows diffuse ground-glass opacities with mosaic attenuation and air-trapping on expiratory scans. Pulmonary function tests reveal an obstructive pattern with reduced DLCO. Which diagnosis fits best?
- A Hypersensitivity pneumonitis ✓
- B Idiopathic pulmonary fibrosis
- C Sarcoidosis
- D Pulmonary Langerhans cell histiocytosis
Correct answer: A. Hypersensitivity pneumonitis
Explanation
Hypersensitivity pneumonitis on HRCT shows ground-glass opacities, mosaic attenuation, and air-trapping due to small airway obstruction, with an obstructive PFT pattern and reduced DLCO. IPF shows basal honeycombing with a restrictive pattern. Sarcoidosis shows perilymphatic nodules. PLCH shows upper-lobe cysts and nodules in smokers.
Reference: Webb, Müller, and Naidich: High-Resolution CT of the Lung, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.