Journals | Policy | Permission

World Journal of Nephrology & Urology

Original Article

Volume 5, Number 3, September 2016, pages 51-53

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

Elevated serum creatinine is used as a marker of impaired renal function [1]. Acute rise of serum creatinine indicates acute kidney injury (AKI) [2]. Acute bilateral ureteric obstruction is a common cause of AKI due to decreased glomerular filtration rate (GFR) and renal plasma flow with decrease of the optimal function of both kidneys [3]. Acute unilateral ureteral obstruction (AUUO) is a common presentation in clinical practice and mostly due to obstructing ureteric stone [4]. In AUUO, elevated serum creatinine is considered by some as AKI and consequently, urgent intervention is usually performed and conservative medical expulsive therapy (MET) is not recommended [5]. Urine has high levels of creatinine (20 - 25 mg/kg/day, roughly 1,575 mg/day for a 70-kg male) [6]. As high as 18% of AUUO may present with urine extravasation due to increased intrapelvic pressure. Absorption of extravasated urine or obstructed urine in AUUO into circulation elevates serum creatinine levels [7, 8]. Recently, published animal study proved that in AUUO, back flow of obstructed urine into venous and lymphatic vessels causes elevation of serum creatinine. Accordingly, this rise of serum creatinine is considered a false renal impairment (pseudo renal failure) due to absorption of obstructed urine with its high creatinine levels [9].

Renal function can be estimated through measurement of GFR. This can be done through different methods as measurement of intrinsic creatinine clearance, from serum creatinine using the Cockcroft-Gault equation and through isotope renography using Tc-99m-DTPA [1, 10]. In AUUO, high serum creatinine may affect estimation of renal function and GFR using either intrinsic creatinine clearance or from serum creatinine using the Cockcroft-Gault equation. However, estimation of GFR using Tc-99m-DTPA does not need blood or urine sampling and will not be affected by the rise of serum creatinine in this clinical scenario [11].

To our knowledge, there is no clinical study in the literature to prove or disprove this hypothesis.

Our aim was to measure global renal function by measuring eGFR to determine if there is a real impairment of renal function or not.

It is a prospective study over 3 years (2012 - 2015). It included patients from 25 to 45 years old. All patients with unilateral ureteric obstruction with normal contralateral kidney and high serum creatinine > 140 mmol/L were included in our study. Patients with known previous renal impairment and contralateral hydronephrosis or medically diseased kidney were excluded from the study. All patients were diagnosed by abdominal ultrasonography and non-contrast computed tomography (CT). Demographic variables and preoperative routine laboratory tests including serum creatinine were recorded. eGFR was measured using Tc-99m-DTPA isotope renography on admission. Serum creatinine measurement and Tc-99m-DTPA were repeated 2 weeks after intervention or after spontaneous passage of stones. Patients meeting the criteria for MET were given standard treatment in the form of NSAIDs and α-blockers till spontaneous passage of stone or intervention was indicated. Surgical intervention was done either due to failed MET or other causes like persistent pain or patient preference. Surgical intervention was done in the form of ureteral stenting with or without stone extraction.

Statistical analysis was done using paired samples test to compare creatinine and eGFR before and after relief of obstruction.

We declare that we acted ethically regarding research involving human participants and informed consent. Approval of institutional board review was taken.

Fifty-three patients (all males) were enrolled in the study. The mean age was 36.43 ± 9.2 years. Obstruction was on the right side in 27 patients (50.9%). Thirty-seven patients had mild hydronephrosis (69.8%) and 16 patients had moderate hydronephrosis (30.2%). Forty-one patients had stone in the lower ureter (77.3%), seven patients (13.2%) had stone in middle third ureter and five patients (9.5%) had stone in the upper ureter. The mean stone size was 9.1 ± 5.3 mm (range from 4 to 15 mm). Twenty patients (37.8%) had stone < 6 mm. Thirty-three patients (62.2%) had stones more than 6 mm. The mean serum creatinine on admission was 178.7 ± 14.83 µmol/L (normal range for males: 70 - 120 µmol/L). The mean serum creatinine after treatment was 107.5 ± 6 µmol/L. Differences in mean serum creatinine in admission and after passage of stone or treatment were statistically significant (P < 0.05). Thirteen patients passed stones on MET without intervention. Thirty-one patients underwent double J insertion and nine patients underwent ureteroscopy with removal or disintegration. The mean eGFR on admission was 95.04 ± 15.41 mL/min (normal range for males: 75 - 125 mL/min). The mean eGFR after drainage or after passage of stones was 94.45 ± 6.37 mL/min. This difference was statistically insignificant (P > 0.05) (Table 1). The mean hospital stay was 2.5 ± 1.5 days.

Click to view

Table 1. Clinical and Radiological Findings

AUUO is a common clinical scenario. It is commonly due to obstructing stone, less commonly due to trauma, iatrogenic, malignancy or endometriosis [12, 13]. AUUO may be associated with a rise in serum creatinine levels, which raises the concern for AKI secondary to the obstruction. Urgent intervention in the form of ureteric stenting, percutaneous nephrostomy insertion or urgent ureteroscopy is often recommended [14]. It is commonly explained by urologist to be caused by use of NSAIDs, dehydration or due to renin angiotensin effect [15]. Such impairment if true will be detected through measurement of GFR. Measurement of GFR using Tc-99m-DTPA is commonly used and does not need blood or urine sampling [11]. There is a growing evidence from literature that renal impairment in AUUO is due to absorption of obstructed urine with its high creatinine back to systemic circulation. This is considered false renal impairment with normal GFR [9]. In our study, we measured renal function through measurement of eGFR using Tc-99m-DTPA. From our results, differences between eGFR on admission and after passage of stone or relieve of obstruction were non-significant. Our results support the hypothesis of false impairment in this clinical scenario. This may change practice in the future as there is no need to embark to urgent intervention and so, continuing MET is justifiable. Larger well-designed studies may be needed in the future to draw firm conclusion.

Rise of serum creatinine in patients with AUUO is not associated with decreased renographic eGFR. Our data suggest that renal impairment in these circumstances is not a true impairment.

Conflicts of Interest

The authors declare that they have no conflicts of interest.

1. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.
   doi
2. Bellomo R, Kellum JA, Ronco C. Acute kidney injury. Lancet. 2012;380(9843):756-766.
   doi
3. Klahr S. Urinary tract obstruction. Semin Nephrol. 2001;21(2):133-145.
   doi pubmed
4. Picozzi SC, Marenghi C, Casellato S, Ricci C, Gaeta M, Carmignani L. Management of ureteral calculi and medical expulsive therapy in emergency departments. J Emerg Trauma Shock. 2011;4(1):70-76.
   doi pubmed
5. Nakada SY, Hsu THS. Campbell, Campbell-Walsh urology / editor-in-chief, Alan J. Wein ; [editors, Louis R. Kavoussi ... et al.]. 10th ed. Philadelphia, PA: Elsevier Saunders. 2012:1163-1164.
6. Azotemia. http://emedicine.medscape.com/article/238545-overview.
7. Kosehan D, Akin K, Topcu A, Koktener A, Cakir B, Teksam M. Spontaneous urinary extravasation: detection rate with 64-row multidetector computed tomography in patients presenting with acute abdomen. Emerg Radiol. 2013;20(4):273-277.
   doi pubmed
8. Hinman F, Jr. Peripelvic extravasation during intravenous urography, evidence for an additional route for backflow after ureteral obstruction. J Urol. 1961;85:385-395.
9. Rosenzweig B, Pinthus JH, Kleinmann N, Joffe E, Erlich T, Fridman E, Winkler H, et al. The relative contribution of urine extravasation to elevate plasma creatinine levels in acute unilateral ureteral obstruction. Can Urol Assoc J. 2015;9(7-8):E428-433.
   doi pubmed
10. Itoh K. Comparison of methods for determination of glomerular filtration rate: Tc-99m-DTPA renography, predicted creatinine clearance method and plasma sample method. Ann Nucl Med. 2003;17(7):561-565.
    doi pubmed
11. Prigent A, Cosgriff P, Gates GF, Granerus G, Fine EJ, Itoh K, Peters M, et al. Consensus report on quality control of quantitative measurements of renal function obtained from the renogram: International Consensus Committee from the Scientific Committee of Radionuclides in Nephrourology. Semin Nucl Med. 1999;29(2):146-159.
    doi
12. Singh I, Strandhoy JW, Assimos DG. Campbell-Walsh Urology. 10th ed. Wein AJ, Kavoussi LR, Novick AC, Partin AW, Peters CA, editors. Philadelphia, PA: Elsevier Saunders; 2012:1087-1088.
    doi
13. Choi JI, Yoo JG, Kim SJ, Lee HN, Kim MJ. Acute Renal Failure due to Obstructive Uropathy Secondary to Ureteral Endometriosis. Case Rep Obstet Gynecol. 2015;2015:761348.
14. Turk C, Knoll T, Petrik A, Sarica K, Skolarikos A, Straub M, Seitz C. Guidelines on Urolithiasis. uroweb.org/wp-content/uploads/22-Urolithiasis_LR.pdf.
15. Al-Ani A, Al-Jalham K, Ibrahim T, Majzoub A, Al-Rayashi M, Hayati A, Mubarak W, et al. Factors determining renal impairment in unilateral ureteral colic secondary to calcular disease: a prospective study. Int Urol Nephrol. 2015;47(7):1085-1090.
    doi pubmed

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

World Journal of Nephrology and Urology is published by Elmer Press Inc.