[1362] Coumadin Overdose Accompanied by Acute Tubular Injury: Pathological Findings in Renal Biopsies

SV Brodsky, A Satoskar, J Chen, G Nadasdy, L Hebert, T Nadasdy. Ohio State University, Columbus, OH; New York Medical College, Valhalla, NY

Background: Warfarin therapy has been associated with microscopic and gross hematuria. However, acute renal injury in these patients has been rarely described.
Design: Herein we report pathological findings in renal biopsies in patients with coumadin overdose and acute renal dysfunction.
Results: Seven renal biopsies from patients on coumadin therapy with gross hematuria were found in our database from 2004 till 2008. Mean age was 65.86.2 years. There were four males and three females. All patients had an increased INR (4.51.5 IU) and elevated serum creatinine (4.20.98 mg/dl)) at the time of biopsy, versus 1.30.41 mg/dl baseline levels. Four patients had proteinuria. Morphologically, all renal biopsies revealed red blood cells (RBC) in Bowman's space, RBC casts in tubules and acute tubular injury (ATI). Patients did not have history of extra-renal causes of ATI or underlying renal diseases resulting in gross hematuria. Hematuria was resolved after normalization of INR. Depletion of vitamin K in mice resulted in hematuria, but no tubular RBC casts and ATI, suggesting that an underlying renal condition is necessary for the development of RBC casts.
Conclusions: Occlusive RBC casts with acute tubular injury is a possible serious complication of a warfarin overdose and physicians should be aware of it.
Category: Kidney (does not include tumors)

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 199, Monday Morning