Double Whammy: Pigment Nephropathy and Warfarin-related Nephropathy As Aetiology for Acute Kidney Injury in a Patient With Mechanical Heart Valves

It is well known that patients with mechanical heart valves may develop sheer stress related hemolysis and consequent pigment related nephropathy. Warfarin Related Nephropathy (WRN) is a relatively new entity and defined as Acute Kidney Injury (AKI) in the setting of an INR of > 3.0 excluding other obvious etiologies. A biopsy diagnosis of WRN is conducted when red blood cell casts are noted filling and blocking the tubules; additionally, glomerular hemorrhage may be observed. We describe a patient with mechanical heart valves on oral anticoagulation who developed both pigment nephropathy and WRN causing AKI.