Polyarteritis nodosa (PAN) characteristically spares which type of vessels, differentiating it from other forms of systemic vasculitis?

• A Large elastic arteries
• B Medium-sized muscular arteries
• C Coronary arteries
• D Pulmonary arteries and glomerular capillaries (no lung or kidney glomerular involvement) ✓

Explanation

PAN is a necrotizing vasculitis of medium-sized muscular arteries with characteristic sparing of the pulmonary vasculature and glomerular capillaries. Renal involvement is through arterial (not glomerular) disease, causing renovascular hypertension and infarcts rather than glomerulonephritis. This contrasts with ANCA-associated vasculitides (GPA, MPA, EGPA) which frequently involve the lungs and cause glomerulonephritis. Hepatitis B is an important association.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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