Acute Unilateral Ureteric Obstruction in Young Men With High Serum Creatinine: Is It True or False Renal Impairment?

Background: Acute unilateral ureteric obstruction, with normal contralateral kidney, is occasionally accompanied by a rise of serum creatinine. Urgent drainage is usually performed to restore normal renal function. However, there is a growing evidence in literature that this rise of serum creatinine is false (pseudo renal failure) due to absorption of urine with its high creatinine. This is possibly through back flow into venous and lymphatic vessels. This hypothesis can render urgent intervention in these circumstances unnecessary. Our aim was to measure global renal function by measuring estimated renographic glomerular filtration rate (GFR) to determine if there is a real impairment of renal function or not in this clinical scenario. Methods: It is a prospective study over 3 years (2012 - 2015). All patients with acute unilateral ureteric obstruction due to ureteric stones with normal contralateral kidney and high serum creatinine > 140 mmol/L were included in our study. All patients were diagnosed by abdominal ultrasonography and non-contrast computed tomography (CT). Estimated GFR (eGFR) was measured using DTPA isotope renography on admission. Serum creatinine measurement and DTPA were repeated 2 weeks after intervention or after spontaneous passage of stones. Results: Fifty-three patients (all males) were enrolled in the study. The mean age was 36.43 ± 9.2 years. The mean serum creatinine on admission was 178.7 ± 14.83 µmol/L (normal range for males: 70 - 120 µmol/L). The mean eGFR on admission was 95.04 ± 15.41 mL/min (normal range for males: 75 - 125 mL/min). Thirteen patients passed stones on medical expulsive therapy without intervention. Thirty-one patients underwent double J insertion and nine patients underwent ureteroscopy with stones removal or disintegration. The mean serum creatinine after treatment was 107.5 ± 6.5 µmol/L. The mean eGFR after drainage or after passage of stones was 94.45 ± 6.37 mL/min. The difference between eGFR on admission and eGFR after passage of stones or after intervention was statistically insignificant (P > 0.05). Conclusions: Rise of serum creatinine in patients with acute unilateral ureteric obstruction is not associated with decreased renographic eGFR. Renal impairment in these circumstances is not a true impairment. World J Nephrol Urol. 2016;5(3):51-53 doi: http://dx.doi.org/10.14740/wjnu276w