Value of screening for vesicoureteral reflux in infants with antenatal hydronephrosis in king abdulaziz medical city-Riyadh

Abdullah Mansour Alsaef; Faisal Alsadoun; Abdullah Alsaif; Emad Masudi; Kamal Ali; Saif Alsaif; Ibrahim Ahmed

doi:10.4103/jcn.JCN_75_18

ORIGINAL ARTICLE

Year : 2019 | Volume : 8 | Issue : 1 | Page : 24-27

Value of screening for vesicoureteral reflux in infants with antenatal hydronephrosis in king abdulaziz medical city-Riyadh

Abdullah Mansour Alsaef¹, Faisal Alsadoun¹, Abdullah Alsaif¹, Emad Masudi¹, Kamal Ali², Saif Alsaif², Ibrahim Ahmed²
¹ Department of Medical Education, Collage of Medicine, King Saud Bin Abdulaziz University for Health Science, Riyadh, Saudi Arabia
² Neonatal Intensive Care Department, King Abdulaziz Medical City, Riyadh, Saudi Arabia

Date of Web Publication

29-Jan-2019

Correspondence Address:
Dr. Abdullah Mansour Alsaef
College of Medicine, King Saud Bin Abdulaziz University for Health Science, Riyadh
Saudi Arabia

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jcn.JCN_75_18

Abstract

Background: Antenatal hydronephrosis (AHN) is diagnosed in 0.5%–1% of pregnancies. Hydronephrosis has many causes, but vesicoureteral reflux (VUR) remains an important cause, as it could lead to serious damage to the kidneys. Screening for VUR by voiding cystourethrogram (VCUG) is done in infants with congenital hydronephrosis to detect VUR that could lead to repeated urinary tract infections (UTIs). Objectives: The aim of the study was to investigate the value of VCUG as a screening tool for VUR in infants with various grades of hydronephrosis. Materials and Methods: This is a retrospective chart review for all infants with antenatal hydronephrosis between January 2010 and December 2015 at King Abdulaziz Medical City-Riyadh. Comparisons were made between hydronephrosis grades and VUR. Differences, therefore, were assessed for statistical significance using Chi-square test as appropriate. Analysis was performed using SPSS version 22. Results: During the study periods, 203 infants (75% of the study population) underwent VCUG. VUR was diagnosed in 21% of all infants who had VCUG. VUR was significantly higher in infants with high grade compared to low-grade hydronephrosis (30% versus 14.40%, P = 0.005). On the other hand, no significant difference found between high-grade hydronephrosis and low-grade hydronephrosis in the severity of VUR (P = 0.169). Meanwhile, high-grade hydronephrosis was significantly more associated with UTI 27.20% (25/92) than low-grade hydronephrosis 14.70% (26/177). Conclusion: Infants with antenatal hydronephrosis (HN) suffer greater morbidity as reflected by the increased incidence of VUR and UTI at follow-up. For high-grade HN, our recommendation clearly goes with the current practice for doing VCUG to all high-grade patients. On the other hand, the risk of VUR and UTI, although higher in infants with high-grade HN is still substantial in infants with low-grade HN. However, it is still controversial to do VCUG for them. Hence, we recommend further big researches about low-grade HN and VCUG to come up with clear conclusion for this HN group.

Keywords: Hydronephrosis, urinary tract infection, vesicoureteral reflux, voiding cystourethrogram

How to cite this article:
Alsaef AM, Alsadoun F, Alsaif A, Masudi E, Ali K, Alsaif S, Ahmed I. Value of screening for vesicoureteral reflux in infants with antenatal hydronephrosis in king abdulaziz medical city-Riyadh. J Clin Neonatol 2019;8:24-7

How to cite this URL:
Alsaef AM, Alsadoun F, Alsaif A, Masudi E, Ali K, Alsaif S, Ahmed I. Value of screening for vesicoureteral reflux in infants with antenatal hydronephrosis in king abdulaziz medical city-Riyadh. J Clin Neonatol [serial online] 2019 [cited 2019 Feb 17];8:24-7. Available from: http://www.jcnonweb.com/text.asp?2019/8/1/24/250984

Introduction

“Antenatal hydronephrosis (ANH) refers to the dilation of the renal pelvis with or without dilation of the renal calyces,”^[1] Antenatal hydronephrosis is diagnosed in 0.5%–1% of pregnancies.^[1] In a meta-analysis published in 2006 including 17 studies, antenatal hydronephrosis was identified in 1.6% of pregnancies.^[2] Similarly, data from a study conducted at King Abdulaziz University found that hydronephrosis occurred in 1.7% of pregnancies.^[3]

There are different causes of antenatal hydronephrosis including vesicoureteral reflux (VUR) ureteropelvic junction obstruction and transient hydronephrosis.^[4] Fetal hydronephrosis is readily diagnosed by prenatal ultrasound as early as 12^th week of gestation.^[5] The diagnosis of hydronephrosis is established if the anteroposterior diameter of the renal pelvis on the second trimester is ≥4 or ≥7 mm in the third trimester.^[6] Hydronephrosis is graded into three grades as mild, moderate, and severe based on the ultrasound result Based on the second trimester, evaluation of the renal pelvis, 4–7 mm dilation is mild, 7–10 mm dilation is moderate, and >10 is severe.^[6]

Voiding cystourethrogram (VCUG) is recognized as the gold standard for VUR diagnosis.^[7] Nevertheless, it is an invasive procedure that has many disadvantages including radiation exposure and the risk of infections. Some studies reported a 12% incidence rate of VUR among infants with ANH screened by VCUG^[8] whereas others have found VUR in only 5% of infants with AHN who had VCUG.^[3] The aim of the study was to investigate the value of VCUG as a screening tool for VUR in infants with various grades of hydronephrosis.

Materials And Methods

A retrospective chart review was conducted for all infants with an antenatal diagnosis of hydronephrosis born between 2010 and 2015 at King Abdulaziz Medical City Riyadh. The infants were identified from a neonatal database, the neonatal unit admission book, and a radiology database. High-grade hydronephrosis (moderate and severe grades) was defined as renal pelvis dilation of >7 mm and infants with >4–7 mm dilatation were diagnosed as having low-grade hydronephrosis (mild grade). Antenatally hydronephrosis grading was defined in the infants depend on the last AP diameter measurements of the renal pelvis antenatally. All infants with antenatal hydronephrosis went to confirmatory US postnatally. VCUG was performed before maternity unit discharge in all infants with postnatal high-grade hydronephrosis while infants with postnatal low-grade hydronephrosis only had VCUG if the abnormality persisted beyond 6 months of age on follow-up renal ultrasound screening (USS) according to the departmental guidelines. VUR grading was defined according to the International Grading of VUR. Low-grade VUR consists of Grades 1 and 2 which defined as reflux present in the ureter only or ureter, pelvis, and calyces without dilation. Where moderate VUR consists of Grade 3, which is mild dilation of the ureter and renal pelvis. High-grade VUR consists of Grades 4 and 5 VUR which are defined as moderate dilation of ureter, renal pelvis, and calyces or gross dilation of all these. The UTI was defined as febrile infection (38 Celsius and above) and positive urine culture.

Data retrieved from the medical records included gender and the results of VCUG. The severity of the VUR and details of urinary tract infection (UTI) episodes were also documented.

Statistical analysis

Comparisons were made between genders, grades of hydronephrosis, and grades of VUR. Differences, therefore, were assessed for statistical significance using Chi-square test as appropriate. P < 0.05 was considered statistically significant. Analysis was performed using SPSS version 22.0 (SPSS, Inc., Chicago, IL, USA).

Ethical approval

The paper has been approved by the Institutional Review Board in King Abdullah International Medical Research Center.

Results

A total of 269 infants with antenatal hydronephrosis were born during the 6-year study period. There were 211 males (78%) and 58 (22%) females. One hundred and seventy-seven infants (65.8%) had low-grade HN, and 92 infants had high-grade HN. Among male infants with ANH, one hundred and thirty had a low-grade HN (61.65%), and 81 had a high-grade HN (38.4%). Similarly, there was a predominance of low-grade HN among females, (81%) compared to high-grade HN (19%) [Table 1]. Of the 92 infants diagnosed with high-grade HN, 85 (92.4%) underwent VCUG. Of those underwent VCUG positive, VUR was diagnosed in 30.6% (26/85). Eighteen infants (69%) had severe VUR, two infants (7%) had moderate VUR, and six infants (23%) were diagnosed with mild VUR on VCUG screening for high-grade HN. On the other hand, VCUG screening was performed in 67.8% (120/177) of infants with low-grade hydronephrosis, and VUR was diagnosed in 14.4% (17/120). The severity of VUR diagnosed in infants with low-grade HN who underwent VCUG screening was similar to that of those with high-grade HN with severe VUR diagnosed in 53%, moderate VUR in 29%, and mild VUR in 18%. The percentage of positive VUR was significantly higher in high grade HN (30.6%) compared to low-grade HN (14.4%) (P = 0.005) [Table 2].

Table 1: Patients gender with the hydronephrosis status

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Table 2: Voiding Cystourethrogram, urinary tract infection and vesicoureteral reflux status with the hydronephrosis status

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UTI was diagnosed in 27.2% of infants with high-grade HN compared to 14.7% in infants with low-grade HN (P = 0.013). In addition, UTI was significantly higher in infants with VUR compared to those with no VUR (35% vs. 20%, P = 0.035) [Table 3].

Table 3: Urinary tract infection with vesicoureteral reflux and gender status

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Discussion

The overall incidence of VUR in live born infants with Antenatal HN, in our series, was 21%, which is higher than what was reported previously locally and globally.^[3],[8] Importantly, we have demonstrated that infants with low-grade HN can suffer chronic morbidity as evidenced the occurrence of VUR and UTI. However, due to the limitation that not all low-grade HN did VCUG, the significant of these percentages is not clear. Antenatally detected HN is recommended to be followed up postnatally by ultrasound.^[9] However, the need for VCUG screening for infants with various grades of HN is controversial,^[10] although some recommends VCUG to all hydronephrosis grades.^[9] Others suggest VCUG screening to be done only for infants with high-grades hydronephrosis.^[8] In our study, VCUG screening was carried out in the neonatal period in 92% of those with high-grade hydronephrosis. This is similar to what was reported from a Canadian study in which VCUG was performed in 98% of the high-grade HN but only 66% of those with low-grade hydronephrosis.^[8]

We have also demonstrated a higher prevalence of lower grades HN compared to higher grades. This is similar to what was reported from a large Canadian study.^[8] In that study, they found that the prevalence of low-grade HN (71.8%) surpassed the high-grade HN (28.1%).^[7] In another international study, the discrepancy between the prevalence of different grades of hydronephrosis was more remarkable.^[11] The study found that the prevalence of low-grade HN (88%) was much greater than the high-grade HN (12%).^[11] We speculate that the higher consanguinity rate in our study population contributed to the higher prevalence of higher grades hydronephrosis.

In our study, we have found a higher incidence of HN among male infants. This is similar to what was reported from two international studies conducted in South Korea and Canada.^[8],[12] Nevertheless, we have not observed significant gender differences in the grade of hydronephrosis and the prevalence of VUR.

In this study, it has been shown that the risk of VUR increases significantly with increasing grade of hydronephrosis. This is in contrast to results from another study which did not show significant differences in the incidence of VUR between high- and low-grades HN.^[8]

Limitations

This study has strengths and some limitations. We report a consecutive series of hydronephrosis infants, who underwent management in a single center with a standardized protocol. The data were collected retrospectively but all the radiology information such as the antenatal USS, postnatal USS, and VCUG results were complete. In addition, we were able to track all episodes of UTI in the cohort. Certain information, such as the details of antenatal USS scans, were missing but we do not feel that this would have impacted in our results. However, 32.2% of low-grade HN subjects were not screened for VUR so this may overestimate the incidence of VUR in low-grade HN. Another limitation that patients with congenital renal anomalies were not excluded from the study.

Conclusion

Infants with antenatal hydronephrosis (HN) suffer greater morbidity as reflected by the increased incidence of VUR and UTI at follow-up. For high-grade HN our recommendation clearly goes with the current practice for doing VCUG to all high-grade patients. On the other hand, the risk of VUR and UTI, although higher in infants with high-grade HN is still substantial in infants with low-grade HN. However, it is still controversial to do VCUG for them. Hence, we recommend further big researches about low-grade HN and VCUG to come up with clear conclusion for this HN group.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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