A 45-year-old man presents with hemoptysis, sinusitis, and rapidly progressive glomerulonephritis. c-ANCA is positive and anti-proteinase 3 (PR3) antibody is elevated. Renal biopsy shows pauci-immune necrotizing glomerulonephritis with crescent formation. What is the most likely diagnosis?
- A Microscopic polyangiitis
- B Eosinophilic granulomatosis with polyangiitis (EGPA)
- C Granulomatosis with polyangiitis (GPA) ✓
- D Polyarteritis nodosa
Correct answer: C. Granulomatosis with polyangiitis (GPA)
Explanation
GPA is associated with c-ANCA/PR3 and characterized by necrotizing granulomatous inflammation of the upper and lower respiratory tract with pauci-immune glomerulonephritis. MPA is typically p-ANCA/MPO positive and lacks granulomatous upper airway disease. EGPA features asthma and eosinophilia. PAN does not involve glomerulonephritis or ANCA.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.