Warfarin-related Nephropathy – a Case Report on Renal Biopsy and Review of the Literature

Warfarin-related nephropathy (WRN) is a recently recognized condition in patients with chronic kidney disease (CKD). WRN is clinically detected as an episode of unexplained acute kidney injury (AKI). It is defined as a serum creatinine (sCR) increase >0.3 mg/dL (26.5 μmol/L) within one week of an international normalized ratio (INR) measurement >3.0 in a patient treated with warfarin without clinical evidence of hemorrhage. Therefore, warfarin therapy can result in AKI by causing glomerular hemorrhage and renal tubular obstruction by red blood cell casts. WRN appears to accelerate the rate of CKD progression and increase the risk of death in susceptible patients. We report on renal biopsy in a patient on warfarin therapy with unexplained AKI and hematuria associated with increased INR. We would like to stress the necessity of an interdisciplinary approach to patients on warfarin therapy.