Staghorn calculus in renal allograft presenting as acute renal failure

Background: Urolithiasis is a rare complication in renal transplant recipients. We report a case of a staghorn calculus occurring in renal allograft, presenting as anuric renal failure with Gram-negative sepsis. Methods and Results: A 48-year-old Caucasian female, with end-stage renal disease due to autosomal dominant polycystic kidney disease, underwent cadaveric renal transplantation in 1986. Sixteen years after transplant, she presented with Gram-negative sepsis with Proteus mirabilis and acute anuric renal failure in the allograft. After undergoing an emergency nephrostomy and treatment of sepsis, a staghorn calculus was subsequently removed by percutaneous nephrolithotomy. Based on the stone analysis and history of urinary tract infections with urease splitting bacteria, the calculus was thought to be infection-induced. Conclusion: Although a rare complication, urolithiasis in an allograft can be associated with significant morbidity. Immediate recognition is critical to restore renal allograft function and to treat associated serious infection in an immunocompromised patient.