Microscopic hematuria is a frequently encountered clinical problem in kidney graft recipients. The causes vary and could be benign or malignant. Differential diagnosis is difficult but imperative for patient with chronic relapsing hematuria and graft survival. We evaluated the renal recipients who developed hematuria treated with a defined algorithm.
Materials & methods:
We evaluated 1,300 renal transplant recipients who underwent renal transplantation from March 1, 1992 to December 31, 2002. Plain radiography, sonography, and cystoscopic examination were performed sequentially to evaluate these patients. Graft biopsy was performed in patients with negative results after taking those studies.
The mean duration after transplantation was 40.81±14.5 months (6-118 months). Microscopic hematuria was developed in 245 recipients. In 99 recipients, hematuria was transitory and spontaneously cleared-up within 3 months. We tried to identify the causes of hematuria in 136 recipients with persisting condition. The known causes of hematuria were urolithiasis in 16, benign bladder mucosal bleeding in 5, bladder cancer in 5 and kidney cancer from the original kidney in 2. Graft kidney biopsy was performed in 108 patients and the results were as follows: chronic rejection in 31, IgA nephropathy in 18, cyclosporine toxicity in 15, acute rejection in 7, focal segmental glomerulosclerosis in 5, other glomerulonephritis in 3, and tubular atrophy and interstitial fibrosis in 19 patients. No pathological diagnosis could be made in 10 patients. Combined pathologic findings were detected in 17 patients.
The causes of hematuria after kidney transplantation varied from benign to malignant disease. When ultrasonographic and/or cystoscopic examination could not determine the cause, graft biopsy should be performed to identify the intra- and extra-graft causes of hematuria.