Three weeks after elective femoropopliteal bypass grafting, a 68-year-old man develops livedo reticularis over both feet and bluish discoloration of two toes. Creatinine has risen in a stepwise fashion from 1.1 to 3.4 mg/dL. Total leukocyte count is elevated with 14 percent eosinophils, and serum complement C3 and C4 are reduced. Which is the most likely cause of his renal failure?

• A Contrast induced nephropathy from preoperative angiography
• B Acute interstitial nephritis from perioperative antibiotics
• C Polyarteritis nodosa involving arcuate arteries
• D Cholesterol crystal embolisation of small renal arteries ✓

Explanation

Blue toes, livedo reticularis, a delayed and stepwise creatinine rise, peripheral eosinophilia, and low complement form the classic picture of atheroembolic (cholesterol crystal emboli) renal disease after arterial instrumentation or surgery. Contrast nephropathy peaks within 48 to 72 hours rather than weeks and does not cause livedo or eosinophilia. Polyarteritis nodosa raises ESR and ANCA may be present but does not classically reduce complement, and antibiotics causing interstitial nephritis do not explain the skin findings.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.