Severe vesicoureteral reflux and chronic renal failure: a condition peculiar to male gender? Data from the ItalKid Project

The Role of Endoscopic Treatment in the Management of Grade V Primary Vesicoureteral Reflux

OBJECTIVES

Although endoscopic treatment provides a high rate of success in children with grades II-IV vesicoureteral reflux (VUR), its role in the management of grade V reflux has been questioned. In this study we reviewed our 21-yr experience of endoscopic treatment in children with grade V primary VUR.

METHODS

We retrospectively reviewed the medical records of 132 children who underwent endoscopic treatment for primary grade V reflux from 1984 to 2004. VUR was unilateral in 39 patients and bilateral in 34, and 59 patients had ipsilateral grade V reflux with a lower grade of VUR on the contralateral side. Endoscopic treatment was performed in a total of 166 grade V ureters; polytetrafluoroethylene was used from 1984 to 2000 and dextranomer/hyaluronic acid from 2001 to 2004. Median follow-up was 12.2 yr and mean follow-up was 13.4 yr.

RESULTS

VUR was completely resolved after first injection in 88 (53%) ureters and downgraded to grade I or II in 26 (15.7%). VUR resolved after a second and third injection in 36 (21.7%) and 10 (6%) of ureters, respectively. Endoscopic treatment failed to correct VUR in 6 (3.6%) ureters, requiring ureteral reimplantation in 5 and nephrectomy in 1. Thirteen patients developed urinary tract infections during the follow-up period, and on investigation 9 ureters (5.4%) had recurrence of VUR. No injection or morbidity related to tissue-augmenting substances was noted in any patient.

CONCLUSION

Endoscopic treatment should be the first-line of treatment in management of grade V vesicoureteral reflux.

Therapy Insight: what nephrologists need to know about primary vesicoureteral reflux

Vesicoureteral reflux (VUR) is the abnormal, retrograde flow of urine from the bladder to the upper urinary tract. This disease affects about 1% of otherwise normal children, 30-50% of those who present with urinary tract infections, and approximately 10% with prenatally diagnosed hydronephrosis. Over the past 50 years, tremendous progress has been made in the diagnosis, treatment and management of VUR. The realization that VUR is probably a component of generalized dysfunction of the lower urinary tract (i.e. dysfunctional elimination syndrome) has further enhanced understanding of the disease. This Review covers basic pathogenesis, diagnosis, management, clinical presentation, and current controversies surrounding VUR.

Endoscopic Treatment of Moderate and High Grade Vesicoureteral Reflux in Infants Using Dextranomer/Hyaluronic Acid

PURPOSE

Renal parenchymal injury in vesicoureteral reflux occurs early, in most patients before age 3 years. It is generally believed that early prevention of urinary tract infections may decrease the amount of renal parenchymal damage. Endoscopic treatment for vesicoureteral reflux has become an established alternative to long-term antibiotic prophylaxis and ureteral reimplantation. We prospectively evaluated the effectiveness and safety of dextranomer/hyaluronic acid copolymer for high grade vesicoureteral reflux in infants.

MATERIALS AND METHODS

A total of 276 infants, including 124 boys and 152 girls, with a median age of 7 months (range 2 to 12) underwent endoscopic treatment for vesicoureteral reflux with dextranomer/hyaluronic acid. Reflux was detected in 225 infants following investigation for urinary tract infection, in 46 following screening for sibling vesicoureteral reflux and in 5 for prenatally diagnosed hydronephrosis. Vesicoureteral reflux was unilateral in 85 infants and bilateral in 191 (467 refluxing ureters). Reflux was grade II in 14 ureters, grade III in 188, grade IV in 248 and grade V in 17. Dimercapto-succinic acid scan was performed in 250 infants and it demonstrated renal scarring in 43 (17.2%).

RESULTS

Vesicoureteral reflux completely resolved in 373 ureters (79.9%) after a single injection of dextranomer/hyaluronic acid and it was downgraded to grade I in 21 (4.4%). Of the ureters 65 (14%) required a second injection and 8 (1.7%) required a third injection to resolve reflux. All patients underwent endoscopic treatment on an outpatient basis. There were no complications except in 1 patient, who was readmitted to the hospital the next day with acute pyelonephritis. Three children had urinary tract infections during followup, of whom 1 was found to have recurrent reflux on investigation.

CONCLUSIONS

Endoscopic treatment with dextranomer/hyaluronic acid is safe and highly effective for eradicating high grade vesicoureteral reflux in infants. Early intervention in infants with high grade reflux may change its natural history and protect against renal scarring.

Prescription of drugs blocking the renin-angiotensin system in Italian children

Little is known about the prescription pattern of antihypertensive drugs for children with impaired kidney function. We have therefore documented the use of antihypertensive drugs in this patient group by evaluating the Italian pediatric population-based registry of patients with chronic kidney disease on conservative treatment (ItalKid) from 1995 to 2003. In 1995, prescriptions written for antihypertensive drugs for use by children were approximately equally divided among drugs blocking the renin-angiotensin system and calcium channel blockers (38 vs. 43% of all prescriptions), followed by beta-blockers and diuretics (15 and 4%, respectively). During subsequent years the proportion of prescriptions for drugs blocking the renin-angiotensin system increased (2003: 61%; p<0.001) and that of calcium channel blockers decreased (2003: 18%, p<0.001). In 1995, blockers of the renin-angiotensin system were prescribed, either as monotherapy or in combination, in 53% of the patients, but the relative frequency of the patients prescribed these drugs increased up to 83% in 2003 (p<0.0005). In conclusion, physicians caring for Italian children with impaired kidney function are increasingly prescribing drugs blocking the renin-angiotensin system.

Endoscopic treatment for high grade vesicoureteral reflux in infants

PURPOSE

Minimally invasive endoscopic treatment for vesicoureteral reflux has become an established alternative to long-term antibiotic prophylaxis and surgical intervention in children. We determined the long-term efficacy and safety of this treatment for high grade reflux in infants.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 411 consecutive infants who underwent endoscopic treatment of grade III to V vesicoureteral reflux between June 1985 and October 2004. A total of 29 patients (7%) were excluded from study because they were lost to followup or the medical records were incomplete. Of the remaining 382 infants, including 203 males, 274 had bilateral and 108 had unilateral vesicoureteral reflux. This represented 642 high grade refluxing units with grade III to V disease in 232, 339 and 71, respectively. A dimercapto-succinic acid scan performed in 312 infants revealed renal scarring in 88 (28%). The tissue augmenting substance used for endoscopic injection was polytetrafluoroethylene and dextranomer/hyaluronic acid copolymer in 432 and 210 ureters, respectively. Endoscopic treatment was done at a median age of 7 months (range 2 months to 1 year). Median followup in these patients was 7 years (range 6 months to 20 years).

RESULTS

Complete resolution of vesicoureteral reflux after a single injection occurred in 443 ureters (69%), including 73% with dextranomer/hyaluronic acid copolymer and 65% with polytetrafluoroethylene. Of the 642 ureters 127 (20%) required more than 1 injection to correct vesicoureteral reflux. In 60 ureters vesicoureteral reflux was downgraded to grade I or II and no further treatment was given, while 12 ureters that failed to respond to endoscopic treatment required open surgical intervention. Only 1 ureter required reimplantation to treat vesicoureteral obstruction.

CONCLUSIONS

Endoscopic correction is a safe, effective, minimally invasive outpatient procedure for high grade vesicoureteral reflux in infants. Early correction of vesicoureteral reflux may provide protection from reflux associated renal damage and prolonged antibiotic use.

Subureteral dextranomer/hyaluronic acid injection as first line treatment in the management of high grade vesicoureteral reflux

PURPOSE

Endoscopic correction of vesicoureteral reflux has become an established alternative to long-term antibiotic prophylaxis and ureteral reimplantation. A number of tissue augmenting substances have been used for the endoscopic correction of vesicoureteral reflux. We prospectively evaluated the effectiveness of dextranomer/hyaluronic acid copolymer (Deflux) as first line treatment for high grade vesicoureteral reflux.

MATERIALS AND METHODS

Between 2001 and 2004, 692 children with a median age of 2.1 years (3 months to 13.7 years) with high grade vesicoureteral reflux underwent endoscopic subureteral injection of Deflux soon after the diagnosis of vesicoureteral reflux was made on the initial voiding cystourethrogram. Vesicoureteral reflux was unilateral in 283 patients and bilateral in 409. Of the 1,101 ureters vesicoureteral reflux was grade II to V in 35 (3.2%), 580 (52.7%), 457 (41.5%) and 29 (2.6%), respectively. The procedure was performed on an outpatient basis. Followup ultrasound and voiding cystourethrogram were performed 3 months after the procedure, and renal and bladder ultrasound was done annually.

RESULTS

Reflux resolved after first, second and third endoscopic Deflux injections in 952 (86.5%), 130 (11.8%) and 19 ureters (1.7%), respectively. Followup ultrasound revealed no evidence of delayed vesicoureteral junction obstruction. Of the patients 18 (2.6%) had urinary tract infection during followup after successful vesicoureteral reflux correction.

CONCLUSIONS

Endoscopic subureteral injection of Deflux is excellent first line treatment in children with high grade vesicoureteral reflux. This 15-minute outpatient procedure is safe and simple to perform, and it can be easily repeated in failed cases.

Predictive factors of chronic kidney disease in severe vesicoureteral reflux

The aim of this retrospective cohort study was to evaluate independent predictive factors of chronic kidney disease (CKD) in children with severe bilateral primary vesicoureteral reflux (VUR). Between 1970 and 2004, 184 patients were diagnosed with VUR (grades III-V) and were systematically followed up at a single tertiary renal unit. CKD was defined as estimated glomerular filtration rate <75 ml/min per 1.73 m2 body surface area in two consecutive examinations. Risk of CKD was analyzed by the Kaplan-Meier method and Cox's regression model. The probability of CKD for patients with bilateral severe reflux was estimated at 15% by 10 years after VUR diagnosis. After adjustment, four variables remained independently associated with CKD during follow-up: age at diagnosis >24 months [relative risk (RR)=4.8, 95% confidence interval (95%CI), 1.8-12.7, P<0.001], VUR grade V (RR=3.5, 95%CI, 1.5-7.9, P=0.002), bilateral renal damage (RR=2.86, 95%CI, 1.3-6.1, P=0.007), and decade of admission after 1990 as a protective factor (RR=0.16, 95%CI 0.06-0.43, P<0.001). A delay in the diagnosis of VUR more than 12 months after urinary tract infection (UTI) was also a predictive factor in an alternative model (RR=2.2, 95%CI, 1.1-6.6, P=0.03). Prognosis regarding renal function was relatively poor after a long-term follow-up of patients with bilateral severe reflux.

Vesicoureteric reflux and urinary tract infection in children

An association between vesicoureteric reflux (VUR) and renal damage was found in 1960. In 1973, the term reflux nephropathy (RN) was first used to describe the renal damage caused by VUR. Follow up studies show that about 10%-20% of children with RN develop hypertension or end stage renal disease. It is now evident that there is a sex difference in the development of RN. In most males with RN, the kidneys are congenitally abnormal. In females it is an acquired condition, the most severe damage being sustained by recurrent urinary tract infections (UTIs). The purpose of current UTI guidelines is to identify VUR or any other abnormality of the urinary tract. Since the advent of routine antenatal ultrasonography, there is no longer a need to identify an abnormality of the urinary tract after the first reported UTI. Routine investigations are not required. Recurrent UTIs and a family history of VUR need further evaluation. There is also an urgent need to establish the long term value of prophylactic antibiotics in children with VUR.

Vesicoureteral reflux

Vesicoureteral reflux, the abnormal flow of urine from the bladder into the ureter, is one of the most common congenital anomalies found in children. The association of vesicoureteral reflux with urinary tract infections and renal scarring has important clinical implications. New insights into pathogenesis and new surgical techniques are changing the approach to the management of this disorder.

Gender and vesico-ureteral reflux: a multivariate analysis

The aim of this retrospective cohort study was to describe the characteristics of patients with primary vesico-ureteral reflux (VUR) with special attention to gender-specific differences. Between 1970 and 2004, 735 patients were diagnosed with VUR and were systematically followed in a single tertiary renal unit. The following variables were analyzed: race, age at diagnosis, clinical presentation, weight and height Z-score, unilateral/bilateral reflux, VUR grade, renal damage, severity of renal damage, constipation, and dysfunctional voiding. Comparison of proportion between genders was assessed by the chi-square test with Yates' correction. The logistic regression model was applied to identify independent variables associated with gender. A survival analysis was performed to evaluate VUR resolution. After adjustment, five variables remained independently associated with male gender at baseline: non-white race [Odds ratio (OR) = 1.98, 95% confidence interval (95% CI) 1.33-2.95, P=0.001], moderate/severe grade of reflux (OR=2.16, 95% CI 1.45-3.22, P<0.001), severe renal damage (OR=1.60, 95% CI 1.04-2.52, P=0.04), age at diagnosis <24 months (OR=1.79, 95% CI 1.23-2.60, P=0.002), and antenatal clinical presentation (OR=3.56, 95% CI 1.91-6.63, P<0.001). Follow-up data were available for 684 patients (93%). Median follow-up time was 69 months (range 6 months to 411 months). Girls had a greater risk of urinary tract infection (UTI) during follow-up than boys (OR=1.68, 95% CI 1.18-2.38, P=0.003). There was no difference in progression to chronic renal insufficiency (CRI) between boys (3.8%) and girls (2.4%) during this period of follow-up (OR=1.58, 95% CI 0.59-4.15, P=0.44). Gender as an isolated variable is a poor predictor of clinical outcome in an unselected series of primary reflux. Although boys had a more severe pattern at baseline, girls had a greater risk of dysfunctional voiding and recurrent UTI during follow-up.

Mechanisms of renal damage owing to infection

Urinary tract infection (UTI) is a common bacterial illness in children. It is known to be associated with an increased risk of permanent renal cell damage and scarring which may lead to generation of pathological conditions such as hypertension, pre-eclampsia during pregnancy, renal insufficiency, and end-stage kidney disease. The pathophysiology of renal scarring is still obscure, which makes the prevention of renal damage difficult. During acute infection, there are numerous factors that may contribute to tissue damage. Inflammatory responses are activated by host defense mechanisms as well as by specific bacterial virulence factors. Understanding of these complex mechanisms would be helpful to better identify children at high risk of developing renal scarring following UTI.

Diagnosis and management of pediatric urinary tract infections

Urinary tract infection (UTI) is among the most commonly diagnosed bacterial infections of childhood. Although frequently encountered and well researched, diagnosis and management of UTI continue to be a controversial issue with many challenges for the clinician. Prevalence studies have shown that UTI may often be missed on history and physical examination, and the decision to screen for UTI must balance the risk for missed infections with the cost and inconvenience of testing. Interpretation of rapid diagnostic tests and culture is complicated by issues of contamination, false test results, and asymptomatic colonization of the urinary tract with nonpathogenic bacteria. The appropriate treatment of UTI has been controversial and has become more complex with the emergence of resistance to commonly used antibiotics. Finally, the anatomic evaluation and long-term management of a child after a UTI have been based on limited evidence, and newer studies question some of the tenets of prior recommendations. The goal of this review is to provide an up-to-date summary of the literature with particular attention to practical questions about diagnosis and management for the clinician.

Antibiotics or surgery for vesicoureteric reflux in children

CONTEXT

1-2% of children have vesicoureteric reflux (VUR). VUR occurs in 25-40% of children with acute pyelonephritis. VUR can lead to renal scarring, hypertension, and end-stage renal disease. The best form of treatment for children with VUR is debated: no treatment, long-term antibiotic prophylaxis, surgery, or a combination of antibiotic prophylaxis and surgery. In children with recurrent urinary tract infections (UTIs) and progressive renal damage, despite antibiotic prophylaxis, surgical correction of VUR, especially high-grade VUR, is generally recommended.

STARTING POINT

Danielle Wheeler and colleagues recently did a meta-analysis of ten randomised controlled trials (964 children) to evaluate whether any intervention for VUR is better than no treatment (Cochrane Database Syst Rev 2004; 3: CD001532). The main endpoints were incidence of UTIs, new or progressive renal damage, renal growth, hypertension, and glomerular filtration rate. They concluded that it is uncertain whether the identification of children with VUR is associated with clinically important benefit. The additional benefit of surgery over antibiotics is small. WHERE NEXT? New strategies for management will require a tailored diagnostic and therapeutic approach, including non-invasive or less invasive diagnostic procedures, and a less aggressive therapeutic approach. Whether the common practice of cystourethrography as a first-line investigation is warranted needs evaluation. The goal of paediatricians in the future, to prevent kidney damage, will probably be prevention of renal parenchymal injury and not necessarily the correction of ureterovesical junction anomalies. Because two main clinical pictures of VUR (diagnosed prenatally or postnatally with different age and sex distribution) can be identified, boys and girls will probably be managed differently. The factors responsible for congenital and acquired renal injury in children with VUR need to be studied.