A 70-year-old man undergoes coronary angiography. Three weeks later he has livedo reticularis over both legs, bluish discolouration of the toes, abdominal pain, and a creatinine that has risen from 1.1 to 4.0 mg/dL. Total count shows eosinophils 1800/mm3, ESR is 80 mm/hr, and complement C3 is low. Urinalysis is bland. The most likely diagnosis is:

• A Contrast-induced acute tubular necrosis
• B Cholesterol crystal embolisation syndrome ✓
• C Acute interstitial nephritis from antibiotics
• D ANCA-associated vasculitis

Explanation

Cholesterol crystal embolisation follows instrumentation of atherosclerotic arteries, with a typical lag of days to weeks before skin findings, renal failure, eosinophilia, and low complement appear. The delayed onset distinguishes it from contrast nephropathy, which peaks within 48 to 72 hours and then recovers. Bland urine with systemic signs separates it from AIN, and the low complement plus livedo argues against ANCA vasculitis, where complement is usually normal.

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

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Written and medically reviewed by the StethoPrep medical team.