Urology Department, Menoufia University, Egypt MP34-9: Acute unilateral ureteric obstruction with high serum creatinine: is it true or false renal impairment ? El-Shazly M, Aziz M Urology Department, Menoufia University, Egypt Introduction: 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. Objective: Our aim is to measure global renal function by measuring estimated renographic GFR to determine if there is a real impairment of renal function or not in this clinical scenario. Patients and methods: It is a prospective study over 3 years (2012-2015). Estimated glomerular filtration rate (eGFR) was measured using DTPA isotope renography on admission. Serum creatinine measurement and DTPA was repeated 2 weeks after intervention or after spontaneous passage of stones. Results: Fifty three patients (all males) were enrolled in the study. The mean serum creatinine on admission was 178.7± 14.83 µmol\L (normal range for males 70-120 µmol\L). The mean estimated renographic GFR (e GFR) on admission was 95.04 ± 15.41 ml \ minute (normal range for males 75-125 ml/minute). The mean serum creatinine after treatment was 107.5 ± 6.5 µmol\L. Estimated GFR after drainage or after passage of stones was 94.45 ± 6.37 ml \ minute. 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 estimated glomerular filtration rate. Renal impairment in these circumstances is not a true impairment.