A 13-year-old girl reports 3 months of pain and fatigue in both forearms after climbing stairs or carrying her school bag. Her brachial pulses are feeble and unequal between the two arms, blood pressure cannot be recorded reliably in either arm, and a soft bruit is audible below the left clavicle. ESR is 55 mm/hr. Which investigation will establish the diagnosis?
- A Duplex ultrasonography of both femoral arteries alone
- B Contrast-enhanced MR angiography of the aorta and its major branches ✓
- C Coronary CT angiography with calcium scoring
- D Nerve conduction study of all four limbs
Correct answer: B. Contrast-enhanced MR angiography of the aorta and its major branches
Explanation
The picture of limb claudication, asymmetric weak brachial pulses, subclavian bruit, and raised ESR in an adolescent girl is Takayasu arteritis, a granulomatous large vessel vasculitis affecting the aorta and its primary branches. Contrast-enhanced MR angiography demonstrates wall thickening, stenoses, occlusions, and aneurysms and is the standard diagnostic study. Femoral duplex alone misses the aortic arch disease, and nerve studies would be normal because the deficit is vascular ischemia, not neuropathy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.