Elsevier

Journal of Pediatric Urology

Volume 7, Issue 6, December 2011, Pages 612-615
Journal of Pediatric Urology

Relationships among vesicoureteric reflux, urinary tract infection and renal injury in children with non-neurogenic lower urinary tract dysfunction

https://doi.org/10.1016/j.jpurol.2011.05.002Get rights and content

Abstract

Objective

To determine the relationship between vesicoureteric reflux (VUR), urinary tract infection (UTI), renal damage and the pattern of non-neurogenic lower urinary tract dysfunction (LUTD), and to reveal the possible risk factors for renal damage in children with LUTD.

Methods

For the years 2004–2010, demographic, clinical, laboratory and urodynamic study reports of children with LUTD were retrospectively reviewed.

Results

Of 96 patients, there were diagnosed 70 with overactive bladder (OAB), 8 pure dysfunctional voiding (DV) and 18 OAB plus DV. The rate of VUR, UTI and renal damage in patients with OAB plus DV and pure DV was higher than in patients with OAB alone. VUR was significantly higher among the patients who had UTI. Renal scarring was detected in 25 patients, of whom 78% had OAB plus DV and 75% DV. The presence of VUR was associated with a significant increase in the rate of renal damage, and dilating reflux caused significantly greater damage compared to non-dilating reflux.

Conclusion

OAB plus DV and DV are major risk factors for VUR, UTI and renal damage. The presence of VUR in children with LUTD plays an important role with regard to UTI and renal damage, with dilating VUR a major risk factor associated with renal damage.

Introduction

Non-neuropathic or non-anatomic lower urinary tract dysfunction (LUTD) is related to a delay in the maturation of neurological control of the lower urinary tract or abnormal behavior acquired during the training period of urinary sphincter control [1]. LUTD represents a disturbance of the lower urinary tract dynamics affecting detrusor and ureterotrigonal structure. Increased intravesical pressures in children with LUTD cause distortion of the ureterotrigonal junction and predispose to vesicoureteric reflux (VUR) [2].

Even though the association of VUR, urinary tract infection (UTI) and renal injury is well known [3], current opinion is that VUR alone is not sufficient to cause renal injury. It has been reported that there are close links among VUR, UTI and LUTD [4]. Recurrent UTI has been shown to be higher in VUR patients with LUTD than in VUR children without such dysfunction [5], [6]. The children with VUR in association with LUTD may be at increased risk for renal damage given their increased risk of developing UTI. In addition, LUTD plays an important role in renal damage without VUR, so-called non-refluxing pyelonephritis [7]. Although, the many characteristics of the relationships among LUTD, VUR and renal injury have been recently recognized, studies continue to reveal more information.

The aim of this retrospective study was to identify the possible risk factors for renal scarring and the characteristics related to VUR among patients diagnosed with non-neurogenic LUTD.

We retrospectively examined the medical records of patients with non-neurogenic LUTD seen in our outpatient clinic between 2004 and 2010. Neurologically normal children without any urogenital disorder except VUR were included in the study. Urogenital anatomic conditions (e.g. posterior urethral valve, ureterocele) and anorectal malformations were excluded from the study. The study population consisted of 96 children (71 girls and 25 boys) all of whom were toilet trained. The mean age at admission was 7.9 ± 2.4 years. The initial evaluation of all patients included a detailed history, voiding diary and clinical examination. A complete urologic investigation, including urinanalysis and culture, voiding cystourethrography (VCUG), renal ultrasound, technetium 99m-dimercapto-succinic acid (DMSA) renal scan and urodynamic studies (UDS), was performed in all patients. On DMSA renal scan, hypoactive areas, contour defects, renal atrophy and diffuse scarring were defined as renal damage.

UTI was diagnosed by history, clinical symptoms and urine culture. There were caes of recurrent (two or more episodes) febrile UTI among these patients. They also had symptoms or signs suggesting UTI, such as fever, pain, dysuria, nausea, vomiting and smelly urine. Prophylactic antibiotics were started for patients with VUR.

A history of constipation was defined as a stool frequency of less than three times per week, with or without encopresis.

The definitions and methods for UDS suggested by the International Children’s Continence Society were used [8]. UDS, including initial uroflowmetry, calculation of residual urine, saline cystometry with simultaneous monitoring of total intravesical, intrarectal and subtracted detrussor pressures, and surface pelvic floor electromyography during bladder filling and voiding, were performed in all patients while they were awake and seated. At least two repeat fillings were performed in each study. Overactive detrusor contraction was defined as any involuntary increase in detrusor pressure greater than 15 cm H2O in consecutive filling cycles. Any sphincter activity during voiding resulting in a decrease or an interruption of urinary flow was diagnosed as dysfunctional voiding (DV) [8].

VUR was graded according to the International Reflux Study Classification. Patients with grades III, IV, V and bilateral were defined as dilating, while grades I and II were categorized as non-dilating reflux. The distribution of demographic, clinical and urodynamic parameters was compared between the groups.

Data were analyzed with commercially available statistical software (SPSS® version 11.5). Mean, standard deviation and percentages were used for descriptive statistics. Group comparisons were performed using the independent t-test for continuous data, Mann–Whitney U-test for non-continuous data, and the Chi-square test were used for categorical data. A P value of ≤0.05 was considered statistically significant.

Section snippets

Results

Urgency, urinary incontinence and holding maneuvers were detected in 62 (64.5%), 52 (54.1%) and 46 (47.9%) patients, respectively, as the lower urinary tract symptoms. Of 96 patients, 45 (46.8%) had a recurrent UTI history. When girls and boys were compared, the rate of girls with a UTI was significantly higher (63% vs 37%, P < 0.001). According to the results of UDS and clinical data, 70 patients were diagnosed (73%) with overactive bladder (OAB). While DV was accompanied by OAB in 18 patients

Discussion

The factors affecting the presence of VUR, UTI and renal damage in children with idiopathic LUTD are still not understood completely. It has been revealed that LUTD may cause VUR and UTI, and may produce a urinary tract anatomy similar to that associated with neurogenic bladder abnormalities or obstruction [4], [6], [9], [10].

Idiopathic LUTD represents a disturbance of the lower urinary tract dynamics affecting urine storage or emptying without neurological or anatomical abnormalities. OAB,

Conclusions

In this series, OAB was the most common pattern of LUTD and could be associated with DV. OAB plus DV and pure DV were the main risk factors for VUR, UTI and renal damage. The presence of VUR in children with LUTD plays an important role with regard to UTI and renal damage. Moreover, dilating VUR is a major risk factor associated with renal damage.

Conflict of interest

None.

Funding

None.

References (24)

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