Early discontinuation of antibiotic prophylaxis in patients with persistent primary vesicoureteral reflux initially detected during infancy: outcome analysis and risk factors for febrile urinary tract infection

Contemporary Management of Urinary Tract Infections in Children

Purpose of Review

Urinary tract infection (UTI) in children is a major source of office visits and healthcare expenditure. Research into the diagnosis, treatment, and prophylaxis of UTI has evolved over the past 10 years. The development of new imaging techniques and UTI screening tools has improved our diagnostic accuracy tremendously. Identifying who to treat is imperative as the increase in multi-drug-resistant organisms has emphasized the need for antibiotic stewardship. This review covers the contemporary management of children with UTI and the data-driven paradigm shifts that have been implemented into clinical practice.

Recent Findings

With recent data illustrating the self-limiting nature and low prevalence of clinically significant vesicoureteral reflux (VUR), investigational imaging in children has become increasingly less frequent. Contrast-enhanced voiding urosonogram (CEVUS) has emerged as a useful diagnostic tool, as it can provide accurate detection of VUR without the need of radiation. The urinary and intestinal microbiomes are being investigated as potential therapeutic drug targets, as children with recurrent UTIs have significant alterations in bacterial proliferation. Use of adjunctive corticosteroids in children with pyelonephritis may decrease the risk of renal scarring and progressive renal insufficiency. The development of a vaccine against an antigen present on Escherichia coli may change the way we treat children with recurrent UTIs.

Summary

The American Academy of Pediatrics defines a UTI as the presence of at least 50,000 CFU/mL of a single uropathogen obtained by bladder catheterization with a dipstick urinalysis positive for leukocyte esterase (LE) or WBC present on urine microscopy. UTIs are more common in females, with uncircumcised males having the highest risk in the first year of life. E. coli is the most frequently cultured organism in UTI diagnoses and multi-drug-resistant strains are becoming more common. Diagnosis should be confirmed with an uncontaminated urine specimen, obtained from mid-stream collection, bladder catheterization, or suprapubic aspiration. Patients meeting criteria for imaging should undergo a renal and bladder ultrasound, with further investigational imaging based on results of ultrasound or clinical history. Continuous antibiotic prophylaxis is controversial; however, evidence shows patients with high-grade VUR and bladder and bowel dysfunction retain the most benefit. Open surgical repair of reflux is the gold standard for patients who fail medical management with endoscopic approaches available for select populations.

Girls and renal scarring as risk factors for febrile urinary tract infection after stopping antibiotic prophylaxis in children with vesicoureteral reflux

PURPOSE

To clarify the incidence of and risk factors for febrile urinary tract infection in children with persistent vesicoureteral reflux (VUR) after the discontinuation of continuous antibiotic prophylaxis (CAP), retrospective chart review was performed.

PATIENTS AND METHODS

Among children with primary VUR at 10 years of age or younger at presentation, those who had persistent VUR despite conservative management with CAP and who were subsequently followed after discontinuation of CAP were included. Kaplan-Meier curve and Cox's proportional hazard regression model were used for evaluation of the incidence of and risk factors for febrile urinary tract infection (fUTI) after stopping CAP.

RESULTS

Among 144 children (99 boys and 45 girls), fUTI developed in 34. The 5-year fUTI-free rate after discontinuation of CAP was 69.4%. On multivariate analyses, girls (p = 0.008) and abnormalities on nuclear renal scans (p = 0.0019), especially focal defect (p = 0.0471), were significant factors for fUTI. Although the fUTI-free rate was not different between children who had no or 1 risk factor, it was significantly lower in children with 2 risk factors than in those with no or 1 risk factor.

CONCLUSIONS

The present study revealed that girls and abnormal renal scan, especially focal defect, are risk factors for fUTI. Active surveillance without CAP for persistent VUR seems to be a safe option for children with no or 1 risk factor. Prophylactic surgery or careful conservative follow-up may be an option for girls with abnormal renal scan results if VUR persists under CAP.

Guidelines for the medical management of pediatric vesicoureteral reflux

Urinary tract infection is a bacterial infection that commonly occurs in children. Vesicoureteral reflux is a major underlying precursor condition of urinary tract infection, and an important disorder in the field of pediatric urology. Vesicoureteral reflux is sometimes diagnosed postnatally in infants with fetal hydronephrosis diagnosed antenatally. Opinions vary regarding the diagnosis and treatment of vesicoureteral reflux, and diagnostic procedures remain debatable. In terms of medical interventions, options include either follow‐up observation in the hope of possible spontaneous resolution of vesicoureteral reflux with growth/development or provision of continuous antibiotic prophylaxis based on patient characteristics (age, presence/absence of febrile urinary tract infection, lower urinary tract dysfunction and constipation). Furthermore, there are various surgical procedures with different indications and rationales. These guidelines, formulated and issued by the Japanese Society of Pediatric Urology to assist medical management of pediatric vesicoureteral reflux, cover the following: epidemiology, clinical practice algorithm for vesicoureteral reflux, syndromes (dysuria with vesicoureteral reflux, and bladder and rectal dysfunction with vesicoureteral reflux), diagnosis, treatment (medical and surgical), secondary vesicoureteral reflux, long‐term prognosis and reflux nephropathy. They also provide the definition of bladder and bowel dysfunction, previously unavailable despite their close association with vesicoureteral reflux, and show the usefulness of diagnostic tests, continuous antibiotic prophylaxis and surgical intervention using site markings.

Pediatric voiding cystourethrography: An essential examination for urologists but a terrible experience for children

Voiding cystourethrography is the most important fluoroscopic examination in pediatric urology for the investigation of lower urogenital tract diseases, such as vesicoureteral reflux or urethral stricture. However, this invasive procedure imposes a significant burden on children and their parents, and recently there has been a paradigm shift in the diagnosis and treatment of vesicoureteral reflux. In the 2011 revision, the American Academy of Pediatrics guidelines on urinary tract infection recommended abandoning routine voiding cystourethrography after the first febrile urinary tract infection. In 2014, the randomized intervention for children with vesicoureteral reflux study recommended discontinuation of routine continuous antibiotic prophylaxis for vesicoureteral reflux. The time is now ripe to radically reconsider indications for voiding cystourethrography and the procedure itself.

Postnatal imaging of prenatally detected hydronephrosis-when is voiding cystourethrogram necessary?

OBJECTIVE

To evaluate whether grade 4-5 vesicoureteral reflux (VUR) can be predicted from renal ultrasound (RUS) findings and perform voiding cystourethrograms (VCUGs) only on high-risk patients.

METHODS

The RUS and VCUG images of infants with prenatally detected hydronephrosis admitted to our institution between 2003 and 2013 were re-evaluated. The UTI episodes were collected retrospectively from patient journals. Patients with complex urinary tract anomalies were excluded.

RESULTS

One hundred eighty, 44 female and 136 male, patients (352 renal units (RU)), 23 (30 RU) of them having grade 4-5 VUR, were included. The median age of the patients at the time of the RUS was 1.3 (0.1-3.0) months and the median follow-up time was 2.0 (0.1-11.2) years. In multivariate analysis, a visible ureter (OR 12.72; CI 5.33-32.04, p < 0.001) and shorter renal length (OR 2.67; CR 1.50-4.86, p < 0.001) in RUS predicted grade 4-5 VUR while a visible ureter predicted UTIs (OR 5.75; CI 2.59-12.66, p < 0.001). A three-grade risk score for high-grade VUR was developed based on the RUS findings and the patients were categorized into low-, intermediate-, and high-risk groups. The incidence of grade 4-5 VUR was 2.9% in the low-risk, 12.2% in the intermediate-risk, and 52.2% in the high-risk group. The sensitivity and specificity for detecting grade 4-5 VUR were 79 and 82%, respectively.

CONCLUSIONS

In patients with antenatally detected hydronephrosis, a visible ureter and reduced renal length in RUS are significant risk factors for high-grade VUR. A RUS-based risk scoring would probably reduce the proportion of unnecessary VCUGs.

National Trends in the Management of Primary Vesicoureteral Reflux in Children

PURPOSE

In September 2011 the AAP (American Academy of Pediatrics) released updated guidelines for the evaluation of children 2 to 24 months old with a febrile urinary tract infection. We documented the impact of the guideline on diagnosis and surgical management of vesicoureteral reflux at U.S. children's hospitals. We hypothesized that voiding cystourethrogram studies and the vesicoureteral reflux treatment rate decreased concurrent with the national guideline release.

MATERIALS AND METHODS

The Pediatric Health Information System was queried for children (younger than 18 years) with primary vesicoureteral reflux and their antireflux surgical history from January 2004 to June 2015. Voiding cystourethrogram orders were recorded. Interrupted time series analysis quantified trends surrounding several seminal vesicoureteral reflux publications (2007) and guideline publication (2011).

RESULTS

A total of 43,341 voiding cystourethrogram encounters (male 23,946 [55.3%]) were identified for patients at a median age of 3 months (IQR 1-20). For all children monthly voiding cystourethrogram orders increased (+1.0 to +1.6 encounters per month, p <0.034) to September 2011, then sharply declined by 106 encounters per month from September to October 2011 (p <0.001) then did not change significantly (p=0.096, R²=0.79). For those children 2 to 24 months old with a urinary tract infection (3,379 records; male 1,384 [41.0%], median age 4 months [IQR 3-7]) voiding cystourethrograms gradually increased from January 2007 to September 2011 (+0.1 encounters per month, p=0.036), then similarly decreased by 21 encounters per month from September to October 2011 (p <0.001), then did not change significantly (p=0.064, R²=0.78). Overall 28,484 procedures for primary vesicoureteral reflux were identified (male 5,950 [20.9%], median age 4.8 years [IQR 2.5-7.2]). Total surgical procedures did not change significantly until October 2011, then declined (-1.5 procedures per month, p <0.001, R²=0.66).

CONCLUSIONS

The number of voiding cystourethrograms ordered nationally in all children and those with a urinary tract infection decreased sharply with the 2011 AAP urinary tract infection guideline release and did not change thereafter. A steady decline in procedures for primary vesicoureteral reflux occurred after October 2011.

Incidence of urinary tract infections in infants with antenatally diagnosed hydronephrosis-A retrospective single center study

OBJECTIVE

To evaluate the incidence of urinary tract infections (UTIs) in infants with antenatal hydronephrosis (AHN).

MATERIALS AND METHODS

A cohort of AHN patients admitted to our institution between 2003 and 2013 were identified. Altogether 192 patients with nonrefluxing hydronephrosis (HN, n=135), nonrefluxing hydroureteronephrosis (HUN, n=21), or vesicoureteral reflux (VUR, n=36) were identified. Patients with complex anomalies or neonatal decompression of the urinary tract were excluded. Information about UTIs diagnosed among the AHN patients was collected and compared with data from 58 controls.

RESULTS

During the median follow-up time of 2.6 (0.3-11.2) years, 24 (13%) patients (15 (10%) males and 9 (19%) females) and 2 (3%) controls experienced at least one UTI (p=0.033). Eighteen (69%) UTIs were febrile. The males had the first UTI at significantly younger age than the females (0.3, 0.0-1.7years vs. 1.0, 0.4-4.8years, p=0.010). UTI was detected in 15 (63%) patients with grade 4-5 VUR, in 8 (6%) patients with HN, and in one (5%) patient with HUN (p-values <0.001, 0.726 and >0.999 against the controls). None of the patients with grade≤3 VUR had UTI. Fifty-eight percent of the patients with UTI were on antimicrobial prophylaxis. In five (12%) cases UTI appeared within one week after voiding cystourethrography (VCUG).

CONCLUSIONS

Infants with AHN and grade 4-5 VUR had the highest risk of UTI. UTIs tented to be more common in females than in males; however, males experienced UTI at younger age than females. VCUG caused UTI in 2.3% in our material.

LEVEL OF EVIDENCE

III.

Vesicoureteral reflux: From prophylaxis to surgery

Vesicoureteral reflux (VUR) is one of the most common pathologies encountered in pediatric urology. Better understanding of the evolution of VUR and new endoscopic surgical techniques in the last decades have led to major changes in the management of this pathology. However, the treatment algorithm remains complex and is composed of a wide variety of options, from active surveillance to surgical treatment. Herein, we propose to review treatment options for VUR in order to help clinicians make the right treatment decision for the right patient.

Vesicoureteral Reflux Index: Predicting Primary Vesicoureteral Reflux Resolution in Children Diagnosed after Age 24 Months

PURPOSE

The Vesicoureteral Reflux Index is a validated tool that reliably predicts spontaneous resolution of reflux or at least 2 grades of improvement for patients diagnosed before age 24 months. We evaluated the Vesicoureteral Reflux Index in children older than 2 years.

MATERIALS AND METHODS

Patients younger than 18 years who were diagnosed with primary vesicoureteral reflux after age 24 months and had undergone 2 or more voiding cystourethrograms were identified. Disease severity was scored using the Vesicoureteral Reflux Index, a 6-point scale based on gender, reflux grade, ureteral abnormalities and reflux timing. Proportional subdistribution hazard models for competing risks identified variables associated with resolution/improvement at different time points.

RESULTS

A total of 21 males and 250 females met inclusion criteria. Mean ± SD age was 4.0 ± 2.1 years and patients had a median vesicoureteral reflux grade of 2. The Vesicoureteral Reflux Index score improved by 1 point in 1 patient (100%), 2 points in 25 (67.6%), 3 points in 48 (37%), 4 points in 18 (21.4%) and 5 to 6 points in 4 (18.2%). Female gender (p = 0.005) and vesicoureteral reflux timing (late filling, p = 0.002; early/mid filling, p <0.001) independently predicted nonresolution. Median resolution time based on Vesicoureteral Reflux Index score was 2 months or less in 15.6% of patients (95% CI 11.0-13.8), 3 months in 34.7% (95% CI 25.4-44.1), 4 months in 55.9% (95% CI 40.1 to infinity) and 5 months or more in 30.3% (95% CI 29.5 to infinity). High grade (IV or V) reflux was not associated with resolution at any point. Ureteral abnormalities were associated with lack of resolution in the first 12 to 18 months (HR 0.29, 95% CI 0.29-0.80) but not in later followup. Vesicoureteral Reflux Index scores of 3, 4 and 5 were significantly associated with lack of resolution/improvement compared to scores of 2 or less (p = 0.031).

CONCLUSIONS

The Vesicoureteral Reflux Index reliably predicts primary vesicoureteral reflux improvement/resolution in children diagnosed after age 24 months. Spontaneous resolution/improvement is less likely as Vesicoureteral Reflux Index score and time from diagnosis increase.

Long-term impact of unilateral hypo/dysplastic kidney in infants with primary vesicoureteral reflux

INTRODUCTION

Renal abnormality is not a rare finding in infants with primary VUR. The pathophysiology of the renal abnormality is considered to be congenital or acquired. Congenital hypo/dysplastic kidney is a common finding in infants with primary VUR, especially in boys. However, the long-term impact of unilateral hypo/dysplastic kidney has not been elucidated. The aim of the current study is to clarify the long-term impact of unilateral hypo/dysplastic kidney with primary vesicoureteral reflux diagnosed in infancy.

MATERIAL AND METHODS

The medical records of patients with primary VUR detected in infancy with unilateral hypo/dysplastic kidney on initial nuclear renal scan (<40% relative renal function) and no scar on the contralateral kidney were reviewed retrospectively. Among them, 29 patients who were followed for more than 5 years were included in this study. Their clinical outcomes including chronic kidney disease (CKD) stage using estimated glomerular filtration rate (GFR) and the incidences of hypertension and proteinuria were analyzed.

RESULTS

Mean age at final visit was 12.4 years (range 5.9-22.2). Estimated GFR was evaluated in 26 patients at a mean age of 12.0 years (5.9-22.2). CKD stage was 1 in all. According to the guidelines of the Japanese Society of Hypertension, while none exceeded the standard level of systolic blood pressure (BP), two patients slightly exceeded the standard level of diastolic BP. In addition, no significant proteinuria was detected in all patients, although microalbuminemia was detected in 7.7% of patients.

DISCUSSION

The prognosis of reflux nephropathy depends on the remnant renal tissue mass, that is, the number of normal nephrons. The normal congenital solitary kidney is reported to be hyperplastic with normal-sized glomeruli rather than hypertrophic ones with larger nephrons, and to have better long-term outcome regarding renal function. Accordingly, we speculated that patients with unilateral hypo/dysplastic kidney would have a similar number of nephrons to those without hypo/dysplastic kidney who have no or minimal scar as far as the contralateral kidney is well preserved. Long-term outcome of the current retrospective study was consistent with our speculation in terms of estimated GFR, proteinuria, or hypertension.

CONCLUSIONS

The present study demonstrated that significant clinical findings related to unilateral hypo/dysplastic kidney detected in infancy were rarely observed in the long term. Accordingly, unilateral hypo/dysplastic kidney seems to be a benign condition. To confirm this finding, further follow-up of these patients is necessary.

Urinary microprotein concentrations in the long-term follow-up of dilating vesicoureteral reflux patients who underwent medical or surgical treatment

PURPOSE

This study examined the relationship between urinary microprotein concentrations and renal functional parameters in children with dilating (grade III-V) vesicoureteral reflux (VUR) who underwent either medical or surgical treatment.

METHODS

All 44 dilating VUR patients who were followed for 4 years were screened for inclusion in this study. The patients' clinical features and clinical outcomes, as well as the urinary activities of albumin (ALB), transferrin (TRF), immunoglobulin G (IgG), alpha-1-microglobulin (α1-MG), and N-acetyl-β-glucosaminidase (NAG), were retrospectively analyzed.

RESULTS

High values of NAG, α1-MG, IgG, TRF, and ALB were noted in 73.33, 58.33, 43.33, 24.14, and 53.33 % of patients, respectively, at the first examination. Cystatin C, eGFR, and urinary microprotein levels were associated with a good prognosis after 4 years of follow-up. No differences in recurrent UTI, cystatin C concentration, most microprotein/creatinine (Cr) ratios, eGFR, or ΔGFR4 % were found between the groups. High levels of urinary proteins were found in 2.38-9.52 % of cases after 4 years of follow-up. ALB/Cr, IgG/Cr, and α1-MG/Cr levels were positively correlated with 99mTc-dimercaptosuccinic acid (DMSA) grade, and α1-MG excretion was inversely correlated with eGFR.

CONCLUSIONS

The levels of microprotein were elevated at diagnosis in a higher proportion of patients than for the other markers examined. At long-term follow-up, the reflux level had decreased or completely resolved in all patients, and the proportions of microproteins that were elevated were significantly reduced. Renal impairment measured by eGFR and DMSA grade was related to increased urinary α1-MG levels.