A 50-year-old woman has granulomatous vasculitis involving the aorta and its major branches with elevated ESR, asymmetric arm blood pressure, and absent radial pulse. Biopsy of temporal artery is normal. The most likely diagnosis and the key distinguishing feature from giant cell arteritis (GCA) is:

• A Takayasu arteritis — affects large vessels (aorta and major branches) in women <50 years; GCA affects medium vessels in older (>50 years) ✓
• B Polyarteritis nodosa — affects medium arteries; ANCA-positive in 50%
• C Giant cell arteritis — cannot be distinguished; temporal artery biopsy should be repeated
• D Kawasaki disease — primarily affects young children and coronary arteries

Explanation

Takayasu arteritis (pulseless disease) classically affects women of Asian descent under 50 years and involves the aorta, its main branches, and pulmonary arteries, causing narrowing/occlusion ('pulseless' features, arm claudication, unequal BP). GCA (temporal arteritis) affects patients >50 years and involves superficial temporal artery, ophthalmic artery (causing blindness), and vertebral artery — temporal artery biopsy is positive. Both are granulomatous large vessel vasculitides, but age of onset and vessel distribution distinguish them definitively.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.