A 40-year-old non-smoker woman presents with progressive dyspnea and dry cough for 18 months. HRCT shows bilateral ground-glass opacities and reticulation in a peribronchovascular distribution with upper lobe predominance. BAL shows CD4:CD8 ratio of 5.2. She works with birds at home. The diagnosis is:
- A Hypersensitivity pneumonitis (HP) — chronic fibrotic ✓
- B Idiopathic pulmonary fibrosis (IPF/UIP pattern)
- C Non-specific interstitial pneumonia (NSIP)
- D Sarcoidosis
Correct answer: A. Hypersensitivity pneumonitis (HP) — chronic fibrotic
Explanation
Chronic hypersensitivity pneumonitis (bird fancier's lung) presents with upper lobe–predominant fibrosis, peribronchovascular distribution, ground-glass opacities, and a markedly elevated BAL CD4:CD8 ratio (>3.0 suggests HP). Bird antigen exposure is the key precipitant. IPF shows lower-lobe honeycombing with traction bronchiectasis and normal-to-low BAL CD4:CD8 ratio. NSIP shows symmetrical lower-lobe GGO without upper predominance. Sarcoidosis shows CD4:CD8 elevated but typically upper-lobe adenopathy and non-caseating granulomas.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.