ANCA-associated vasculitis is classified based on ANCA specificity and clinical pattern. Which vasculitis is most strongly associated with anti-myeloperoxidase (MPO-ANCA / p-ANCA)?

• A Granulomatosis with polyangiitis (GPA)
• B Eosinophilic granulomatosis with polyangiitis (EGPA)
• C Polyarteritis nodosa (PAN)
• D Microscopic polyangiitis (MPA) ✓

Explanation

Microscopic polyangiitis (MPA) is predominantly associated with anti-MPO antibodies (p-ANCA pattern), causing pauci-immune necrotizing glomerulonephritis and pulmonary capillaritis without granuloma formation. GPA is more strongly associated with anti-PR3 (c-ANCA) and causes granulomatous inflammation of upper/lower respiratory tract plus glomerulonephritis. EGPA has mixed ANCA associations and features asthma plus eosinophilia. PAN is ANCA-negative and spares small vessels.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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