Barak Rosenzweig1, Jehonathan H Pinthus2, Nir Kleinmann1, Erel Joffe3, Tomer Erlich1, Eddie Fridman4, Harry Winkler1, Yoram Mor1, Jacob Ramon1, Zohar A Dotan1. 1. Department of Urology, The Chaim Sheba Medical Center, Tel Hashomer, Ramat-Gan, Sackler School of Medicine, Tel-Aviv University, Israel; 2. Department of Surgery, Division of Urology, McMaster University, Hamilton, ON; 3. School of Biomedical Informatics, University of Texas Health Science Center, Houston, TX; 4. Department of Pathology, The Chaim Sheba Medical Center, Tel Hashomer, Ramat-Gan, Sackler School of Medicine, Tel-Aviv University, Israel.
Abstract
INTRODUCTION: Rising levels of plasma creatinine in the setting of acute unilateral ureteral obstruction (AUUO) often reflects acute renal failure, mandating kidney drainage. We hypothesize that re-absorption of peri-renal urine extravasation (PUE), a common result of UUO, contributes significantly to the elevation in plasma creatinine, rendering the latter an inaccurate benchmark for renal function. We explored this hypothesis in a rat model of AUUO and PUE. METHODS: In total, 20 rats were equally divided into 4 groups. Groups 1 and 2 underwent unilateral ligation of the ureter with infiltration of rat's urine (index group) or saline (control) into the peri-renal space. Two additional control groups underwent peri-renal injection of either urine or saline without AUUO. Plasma creatinine levels were determined immediately prior to the procedure (T0), and hourly for 3 hours (T1, T2 and T3). Renal histology was investigated after 3 hours. RESULTS: Rats in the index group had a significantly greater increase in plasma creatinine levels over 3 hours compared to all other groups (p < 0.05). At T3, average plasma creatinine levels for the index group increased by 96% (0.49 ± 0.18 mg/dL) compared to 46% (0.23 ± 0.06 mg/dL increase) in the AUUO and saline group, and less than 15% rise in both the non-obstructed control groups. Our study limitations includes lack of spontaneous PUE and intraperitoneal surgical approach. CONCLUSIONS: Absorption of peri-renal urine in the presence of AUUO is a significant contributor to rising plasma creatinine levels, beyond those attributable to the obstruction alone, and may overestimate the extent of the true renal functional impairment.
INTRODUCTION: Rising levels of plasma creatinine in the setting of acute unilateral ureteral obstruction (AUUO) often reflects acute renal failure, mandating kidney drainage. We hypothesize that re-absorption of peri-renal urine extravasation (PUE), a common result of UUO, contributes significantly to the elevation in plasma creatinine, rendering the latter an inaccurate benchmark for renal function. We explored this hypothesis in a rat model of AUUO and PUE. METHODS: In total, 20 rats were equally divided into 4 groups. Groups 1 and 2 underwent unilateral ligation of the ureter with infiltration of rat's urine (index group) or saline (control) into the peri-renal space. Two additional control groups underwent peri-renal injection of either urine or saline without AUUO. Plasma creatinine levels were determined immediately prior to the procedure (T0), and hourly for 3 hours (T1, T2 and T3). Renal histology was investigated after 3 hours. RESULTS:Rats in the index group had a significantly greater increase in plasma creatinine levels over 3 hours compared to all other groups (p < 0.05). At T3, average plasma creatinine levels for the index group increased by 96% (0.49 ± 0.18 mg/dL) compared to 46% (0.23 ± 0.06 mg/dL increase) in the AUUO and saline group, and less than 15% rise in both the non-obstructed control groups. Our study limitations includes lack of spontaneous PUE and intraperitoneal surgical approach. CONCLUSIONS: Absorption of peri-renal urine in the presence of AUUO is a significant contributor to rising plasma creatinine levels, beyond those attributable to the obstruction alone, and may overestimate the extent of the true renal functional impairment.