Polyarteritis nodosa (PAN) characteristically spares pulmonary vessels and affects medium-sized muscular arteries. ANCA (anti-neutrophil cytoplasmic antibody) serology in PAN is typically:

• A ANCA-negative (PAN is not an ANCA-associated vasculitis) ✓
• B c-ANCA (anti-PR3) positive in >90% of cases
• C p-ANCA (anti-MPO) positive in the majority of cases
• D Both c-ANCA and p-ANCA positive equally

Explanation

Polyarteritis nodosa is NOT an ANCA-associated vasculitis. The ANCA-associated vasculitides are: granulomatosis with polyangiitis (GPA, formerly Wegener — c-ANCA/anti-PR3), eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss — p-ANCA/anti-MPO), and microscopic polyangiitis (MPA — p-ANCA/anti-MPO). PAN affects medium-sized arteries (renal, mesenteric, hepatic), spares pulmonary arteries and glomeruli, and is associated with hepatitis B infection in a subset of cases. ANCA testing in PAN is negative.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.