Primary vesicoureteric reflux and renal damage in the first year of life

Prevalence of Risk Factors of Urinary Tract Infections in Infants and Children in Arak, Iran: A Cross-sectional Study

Background: Urinary tract infection (UTI) is one of the most common childhood infections. Urinary tract infections are divided into simple and complex types. If the bladder infection is not treated, it can cause secondary kidney infections, such as acute pyelonephritis, which can lead to kidney scar or permanent kidney damage. A significant percentage of patients of any age are re-infected after antimicrobial treatments during the first six months after the first period of UTI. Objectives: This research aimed to investigate the risk factors affecting UTI in infants and children hospitalized in Arak Amir Kabir Hospital in 2017-2018 to prevent UTI and its secondary complications. Methods: In this cross-sectional study, the data collection tool was a validated questionnaire to gather the child's demographic characteristics, including age, sex, type of nutrition, circumcision, age of circumcision, as well as information about fetal birth weight, chronic maternal diseases such as diabetes and stress, and residence place. The content validation method was used to determine the validity of the checklist, and the test-retest was used for reliability. Data were analyzed by SPSS version 22 software. Results: Sixty four percent of children had the normal ultrasound, while 22% had hydronephrosis and nephrolithiasis on ultrasound. The average thickness and size of the right kidney were 71.75 and 9.11, and those of the left kidney were 9.11 and 9.50, respectively. The most common microorganism was Escherichia coli. Conclusions: Given the importance of prevention and timely diagnosis and treatment of UTI to prevent kidney injuries, it is necessary to find UTI risk factors as the first step to preventing children from secondary kidney injuries.

Antibiotic prophylaxis for prevention of urinary tract infections in the first year of life in children with vesicoureteral reflux diagnosed in the workup of antenatal hydronephrosis: a systematic review

BACKGROUND

Children with antenatal hydronephrosis (ANH) diagnosed with postnatal asymptomatic vesicoureteral reflux (VUR) are thought to be at higher risk of urinary tract infection (UTI). As such, continuous antibiotic prophylaxis (CAP) is empirically recommended until age of toilet training; however, there are limited data to support this. The objective of this systematic review was to summarize the existing data and compare UTI rates in infants with asymptomatic VUR on CAP during the first year of life, to those not on CAP. Secondary objectives were to determine associated risk factors with UTI development.

METHODS

A systematic search of all relevant studies and abstracts was conducted using 4 electronic databases by utilizing appropriate key words by an expert hospital librarian. Eligible studies included children with prenatal hydronephrosis, asymptomatic VUR with or without CAP, and reported on development of UTI in the first year.

RESULTS

Of 6903 citations screened, 18 were selected, giving a total population of 829 (69.4% male, median age 57 days) who met the inclusion criteria. Most studies were retrospective and of low-quality evidence. Overall, 15.4% of patients developed at least one breakthrough UTI and females had a higher risk of UTI (odds ratio (OR) 2.3, 95% CI 1.1-4.7). Comparison with children not taking CAP was not readily reported, and meta-analysis could not be completed.

CONCLUSIONS

Randomized controlled trials and standardized reporting of clinical variables are required to understand the protective effect of antibiotic prophylaxis in this cohort.

The prevalence of kidney scarring due to urinary tract infection in Iranian children: a systematic review and meta-analysis

INTRODUCTION

Urinary tract infection is one of the most common diseases in childhood, and can lead to severe complications such as renal scarring in case of lack of diagnosis and timely treatment.

OBJECTIVE

The aim of this study was to investigate the prevalence of kidney scarring caused by urinary tract infection in Iranian children by meta-analysis.

STUDY DESIGN

English -language databases including Science Direct, PubMed, Scopus, Web of Science, and Springer, and Persian -language sites including SID, Magiran, Iranmedex, and Medlib, and the Google Scholar search engine were searched by in March 2018 using MeSH keywords. The heterogeneity of studies was studied using the I2 index. Data were analyzed using STATA software, version 15.1.

RESULTS

In 18 studies, the prevalence of kidney scarring from urinary tract infections in Iranian children was 31% (95% confidence intervalCI: 22%-39%), (which was 14% in girls and 23% in boys. Also, the prevalence of kidney scar in children with urinary reflux was 47% and in children without urinary reflux was 12%. The most common symptom of the renal scar was fever in 61%, followed by urinary reflux in 45% (unilateral in 42% and bilateral in 30%). Also, the prevalence of mild, moderate, and severe reflux, respectively, was 31%, 27%, and 13%. Meta-regression also showed that the prevalence of kidney scar due to urinary tract infections had no significant relationship with the number of samples and years of research (P > 0.05).

DISCUSSION AND CONCLUSION

About one-third of Iranian children suffering from urinary tract infections had kidney scarring, so that the prevalence is lower in girls than in boys. Also, the prevalence of renal scarring in children with urinary reflux is about four times higher than that in children without urinary reflux.

Developmental pathology of congenital kidney and urinary tract anomalies

Congenital anomalies of the kidneys or lower urinary tract (CAKUT) are the most common causes of renal failure in children and account for 25% of end-stage renal disease in adults. The spectrum of anomalies includes renal agenesis; hypoplasia; dysplasia; supernumerary, ectopic or fused kidneys; duplication; ureteropelvic junction obstruction; primary megaureter or ureterovesical junction obstruction; vesicoureteral reflux; ureterocele; and posterior urethral valves. CAKUT originates from developmental defects and can occur in isolation or as part of other syndromes. In recent decades, along with better understanding of the pathological features of the human congenital urinary tract defects, researchers using animal models have provided valuable insights into the pathogenesis of these diseases. However, the genetic causes and etiology of many CAKUT cases remain unknown, presenting challenges in finding effective treatment. Here we provide an overview of the critical steps of normal development of the urinary system, followed by a description of the pathological features of major types of CAKUT with respect to developmental mechanisms of their etiology.

Vesicoureteral Reflux in Pediatric Age: Where are we Today?

Although the diagnosis of vesicoureteral reflux and of reflux nephropathy is a well-established and shared procedure, its treatment nowadays is still very controversial. New developments on the knowledge of pathophysiology of renal damage associated to reflux opened the way towards a different diagnostic work-up and different therapeutic approaches.

Recently, the “top-down” diagnostic approach has gained wider interest, versus the “down-top” protocol. The attention has recently focused on the renal parenchyma damage and less interest has been given to the presence and the radiological degree of vesicoureteral reflux.

The review criteria were based on an in-depth search of references conducted on PubMed, using the terms “vesicoureteral reflux”, “children”, “incidence”, “etiology”, “diagnosis”, “treatment” and “outcomes”. The selection of the papers cited in this review was influenced by the content and the relevance to the points focused in the article.

Conservative approaches include no treatment option with watchful waiting, long-term antibiotic prophylaxis and bladder rehabilitation. The operative treatment consists of endoscopic, open, laparoscopic and robotic procedures to stop the refluxing ureter.

No final consensus has been achieved in literature yet, and further studies are necessary in order to better define the subset of children at risk of developing progression of renal damage.

This review aims to clarify the diagnostic management and the urological-nephrological treatment of reflux in pediatric age, on the basis of a review of the best-published evidence.

Evolution and prognosis value of intrarenal reflux

PURPOSE

The aim of this study was to evaluate the prognostic significance of intrarenal reflux (IRR) regarding urinary tract infection (UTI), renal scarring and spontaneous resolution after 3 years of follow up.

PATIENTS AND METHODS

33 patients (42 refluxing units) with IRR were compared to 27 children (44 refluxing units) with high-grade vesicoureteral reflux (VUR) without IRR (controls) matched for gender, age and VUR grade. All patients received antibiotic prophylaxis during observation and antireflux surgery was performed in children with recurrent UTI. DMSA scan was performed at study entry, and 18 and 36 months.

RESULTS

DMSA scores at entry showed a higher proportion of moderate and severe damage in the IRR group (25/42) compared to the control group (16/44) (Chi squared, P < 0.03). During follow up the incidence of UTI was similar in the two groups, as well as the stability of DMSA scintigraphy and the rate of spontaneous disappearance of the reflux. A similar proportion of patients underwent surgery (18/33 patients with IRR and 13/27 control patients; Chi squared, not significant).

CONCLUSIONS

Under medical management, the prognosis for IRR is not different from high-grade VUR without IRR. The presence of IRR does not justify more aggressive management than a high-grade VUR without IRR.

Primary Vesico-Ureteral Reflux: Comparison of Factors between Infants and Children

Purpose

The association of age, sex and renal parenchymal damage (RPD) in vesicoureteral reflux (VUR) is well known. We compared various factors between infants and children in a cohort of patients with primary VUR.

Materials and Methods

Medical records of 147 patients diagnosed as VUR between 1997 and 2010 were reviewed. Of these children 91 (61.9%) were boys and 56 (38.1%) were girls. 99 (67.3%) of the 147 patients were younger (Group 1), and 48 (32.7%) were older than 1 year (Group 2). The impact of patient's gender and age as well as VUR grade on RPD were analyzed in each patient. The Fisher's exact test and chi square test was done with SPSS ver. 12.0 (SPSS Inc., Chicago, IL, USA).

Results

VUR was unilateral in 88 patients (59.9%) and bilateral in 59 patients (40.1%). Abnormal renal scan was found in 78 (37.7%) renal units. The incidence of VUR was significantly higher in male in group 1 (p<0.01) and in female in group 2 (p<0.01). The incidence of abnormal renal scan was significantly higher in intermediate and high grade VUR comparing low grade VUR in group 1 (p=0.042). In both group, abnormal renal scan didn't show any difference between male and female statistically (p>0.05).

Conclusions

Our data showed that VUR in infant was significantly higher in male than in female, whereas VUR in children was significantly higher in female. This may be due to that characteristic of a population where neonatal circumcision is not a common procedure in infant and urinary tract infections are more common in female children. Further study may be needed to identify gender difference in RPD in infant with high grade reflux.

Vesicoureteral reflux

Vesicoureteral reflux (VUR), the retrograde flow of urine from the bladder toward the kidney, is common in young children. About 30% of children with urinary tract infections will be diagnosed with VUR after a voiding cystourethrogram. For most, VUR will resolve spontaneously; 20% to 30% will have further infections, but few will experience long-term renal sequelae. Developmentally, VUR arises from disruption of complex signaling pathways and cellular differentiation. These mechanisms are probably genetically programmed but may be influenced by environmental exposures. Phenotypic expression of VUR is variable, ranging from asymptomatic forms to severe renal parenchymal disease and end-stage disease. VUR is often familial but is genetically heterogeneous with variability in mode of inheritance and in which gene, or the number of genes, that are involved. Numerous genetic studies that explore associations with VUR are available. The relative utility of these for understanding the genetics of VUR is often limited because of small sample size, poor methodology, and a diverse spectrum of patients. Much, if not all, of the renal parenchymal damage associated with end-stage disease is likely to be congenital, which limits the opportunity for intervention to familial cases where risk prediction may be available. Management of children with VUR remains controversial because there is no strong supportive evidence that prophylactic antibiotics or surgical intervention improve outcomes. Furthermore, well-designed genetic epidemiological studies focusing on the severe end of the VUR phenotype may help define the causal pathway and identify modifiable or disease predictive factors.

Which cystography in the diagnosis and grading of vesicoureteral reflux?

The gold standard procedure for the evaluation of vesicoureteral reflux (VUR) is the radiographic voiding cystourethrography (VCUG); direct radionuclide voiding cystography (DRVC) is an alternative method for detecting VUR. A new imaging procedure, voiding urosonography (VUS) with contrast medium, has recently been introduced. We have carried out a comparative study of these three techniques in 157 patients (aged 6 weeks-4.7 years). VUS showed the presence of VUR in 91 of 311 renal units; VCUG detected reflux in 64 of 233 renal units, and the DRVC in 23 of 78 renal units. VCUG and VUS were compared in 118 patients, and both procedures showed the same grade of reflux in 56 refluxing units (kappa value 0.92); in six cases the reflux grade was greater at VUS than at VCUG. Seven cases of reflux detected by VUS were not identified on VCUG. VCUG did not show a grade of VUR that was higher than in VUS in any patient. In the identification of 4 degrees-5 degrees grade reflux, the sensitivity of VUS reached 100%. VUS and DRVC were found to be equally effective in the detection of VUR (kappa value 0.85). In conclusion, we found that VUS is a useful method for the diagnosis and grading of patients with VUR.

Antenatal hydronephrosis and the risk of pyelonephritis hospitalization during the first year of life

OBJECTIVES

To assess the risk of hospitalization for pyelonephritis within the first year of life among infants with and without antenatal hydronephrosis.

METHODS

A retrospective cohort analysis was performed using linked birth-hospital discharge records from Washington State for 1987 to 2002 to evaluate the risk of hospitalization in the first year of life for pyelonephritis among infants with and without hydronephrosis. Eligible infants had mothers who had prenatal ultrasound screening. A total of 522 singleton infants with antenatal hydronephrosis (International Classification of Diseases, Ninth Revision code 753.2) at the birth hospitalization were identified. For comparison, 2610 singletons without hydronephrosis were selected. We screened hospital discharge records for 1 year after delivery to identify hospitalizations for pyelonephritis and estimate the relative risk (RR) among infants with and without hydronephrosis.

RESULTS

Five percent of infants with antenatal hydronephrosis and 1% of those without had pyelonephritis-related hospitalizations in their first year (RR 11.8, 95% confidence interval [CI] 6.8 to 20.5). Among girls the RR was 36.3 (95% CI 10.6 to 124.0); among boys it was 5.3 (95% CI 2.2 to 13.1). In infants with hydronephrosis, girls were more likely to be hospitalized with pyelonephritis (odds ratio 2.9, 95% CI 1.2 to 6.9).

CONCLUSIONS

Infants with antenatal hydronephrosis are nearly 12 times more likely to have pyelonephritis-related hospitalizations in the first year of life. This association is stronger in girls. Parents and healthcare providers of infants with this diagnosis should be vigilant for the signs and symptoms of urinary tract infections.

Imaging strategies for vesicoureteral reflux diagnosis

The prevalence of vesicoureteral reflux (VUR), although reported to be low in the general population, is high in children with urinary tract infection (UTI), first degree relatives of patients with known VUR and children with antenatal hydronephrosis. In addition, it has been shown that VUR and UTIs are associated with renal scarring, predisposing to serious long-term complications, i.e., hypertension, chronic renal insufficiency and complications of pregnancy. Therefore, diagnostic imaging for the detection of VUR in the high-risk groups of children has been a standard practice. However, none of these associations has been validated with controlled studies, and recently the value of identifying VUR after a symptomatic UTI has been questioned. In addition, several studies have shown that renal damage may occur in the absence of VUR. On the other hand, some patients, mainly males, may have primary renal damage, associated with high-grade VUR, without UTI. Recently, increasing skepticism has been noted concerning how and for whom it is important to investigate for VUR. It has been suggested that the absence of renal lesions after the first UTI in children may rule out VUR of clinical significance and reinforces the redundancy of invasive diagnostic techniques. Therefore, the priority of imaging strategies should focus on early identification of renal lesions to prevent further deterioration.

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.

First urinary tract infection in neonates, infants and young children: a comparative study

In an attempt to evaluate first urinary tract infection (UTI) in neonates and infants, we estimated retrospectively in 296 patients (62 neonates and 234 infants) clinical and laboratory findings, occurrence of vesicoureteral reflux (VUR), urinary tract abnormalities and pyelonephritis. First UTI occurred more often in male than female neonates, whereas male and female infants/young children were affected at an equal rate. The pathogens isolated in urine cultures of neonates and infants did not statistically significantly differ (P>0.05); Escherichia coli predominated. Gram-negative bacteria other than E. coli affected boys more often than girls (P=0.0022). Fever was the most frequent symptom. Neonates had lower-grade fever of shorter duration than infants (P<0.05). The incidence of reflux and urinary tract abnormalities did not differ between neonates and infants, male and female neonates and infants (P>0.05). Pyelonephritis affected neonates and infants at an equal rate; it was more prevalent among female patients (P=0.038) and patients with VUR or urinary tract abnormalities other than VUR (P<0.0001). Neonates with reflux were more often affected by Gram-negative bacteria other than E. coli than were neonates without reflux (P=0.0008).

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.

Clinical course of 735 children and adolescents with primary vesicoureteral reflux

The purpose of this retrospective cohort study was to report the clinical course of children with primary vesicoureteral reflux (VUR). Between 1970 and 2004, 735 patients were diagnosed with VUR and were systematically followed in a single tertiary renal unit. Patients were followed up for a mean time of 76 months (6 months to 411 months). The events of interest were reflux resolution, renal damage, urinary tract infection (UTI), chronic kidney disease (CKD), and hypertension. Survival analysis was performed in order to evaluate reflux resolution and CKD. Renal damage was detected at admission in 319 patients (43.4%). Continuous low-dose antibiotic prophylaxis was administered to 624 patients (91.2%); 499 (73%) patients subsequently had no UTI or fewer than three episodes. The median time of persistence of reflux according to Kaplan-Meier analysis was 38 months for grade I/II [95% confidence interval (95% CI), 33-43], 98 months for grade III (95% CI, 78.5-105), and 156 months for grade IV/V (95% CI, 122-189). Twenty patients (3%) developed hypertension. It was estimated that the probability of CKD was 5% at 10 years after diagnosis of VUR; for children diagnosed after 1990 the probability of CKD was only 2%. Renal function impairment occurred in patients with severe bilateral reflux or in patients with contralateral renal hypoplasia. There has been an improvement of prognosis for patients diagnosed in the past 15 years.

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.

Clinical course of prenatally detected primary vesicoureteral reflux

The purpose of this study was to report the clinical course of medium-long-term follow-up of children with prenatally detected vesicoureteral reflux (VUR). Between 1986 and 2004, 53 (41 males) children with VUR detected by investigation of prenatal hydronephrosis were followed up for a mean time of 66 months (range: 6-200 months). Newborns were investigated by ultrasound, voiding cystourethrogram (VCUG) and DMSA scan. Follow-up clinical visits were performed at 6-month intervals. After 24 months patients were investigated by conventional VCUG or direct isotope cystogram. Survival analysis was performed in order to evaluate the resolution of the reflux. Differences between subgroups (mild vs moderate/severe reflux) were assessed by the two-sided log rank test. Thirty (58%) infants presented bilateral VUR, for a total of 83 renal units. There was a predominance of severe reflux (54%). Renal damage was detected in 33.7% of the units on first renal scan. There was a significant correlation between severe reflux and renal damage scars (RR=3.4, 95% confidence interval [CI], 1.4-8, p=0.002). Forty-seven patients were treated with continuous prophylaxis. One patient developed systolic hypertension. Urinary tract infection occurred in 12 (25%) children conservatively managed. VUR resolution was evaluated in 56 renal units. Spontaneous resolution was observed in 25 units (45%). At 48 months after diagnosis, 75% of the cases of mild reflux (I-III) and 37% of severe reflux (IV-V) had resolved (log-rank, 5.6, p=0.017). There was an improvement of nutritional parameters between admission and the end of follow-up. In conclusion, the clinical course of prenatally detected VUR followed up on a medium-long-term basis is relatively benign. Our study corroborates the results obtained in other series of infants with reflux that emphasized the heterogeneity of this disorder.

[Neonatal pelvic ectasia: long-term outcome and association with ureterovesical anomalies]

OBJECTIVE

To analyze the outcome of neonatal pelvic ectasia (PE) and the association between this entity and vesicoureteral reflux and/or other urinary tract abnormalities.

PATIENTS AND METHODS

We performed a retrospective study of 255 children (205 boys, 50 girls) with an ultrasonographic diagnosis of PE in the first month of life. The initial ultrasonographic examination was indicated by urinary tract infection in 30 neonates, abnormalities in the prenatal ultrasonographic examination in 150 and by other reasons in 75. Pelvic ectasia was classified in four stages according to anteroposterior pelvic diameter: I < 1 cm, II 1-1.5 cm, III 1.6-2 cm, and IV > 2 cm.

RESULTS

Pelvic ectasia was bilateral in 153 children (60 %) and unilateral in 102 (left side in 81.4 % and right side in 18.6 %). Stage I was found in 75.49 %, stage II in 20.34 %, stage III in 3.9 % and stage IV in 0.24 %. The mean follow-up was 32.6 +/- 25.2 months. At the end of the first year, the results of renal ultrasound were normal in 70.2 % of left-sided PE and in 55.9 % of right-sided PE, but 46 patients (18 %) showed worsening of PE between the first and second ultrasound scans. Voiding cystourethrography was performed in 79.6 % of the children and some abnormalities were found in 50 (24.6 %): urethral dilatations in two patients and vesicoureteral reflux in 48. No correlation was found between vesicoureteral reflux and the degree of ectasia (74 % had an anteroposterior diameter of < or = 1 cm). Urinary tract infection was present in 24.3 % of the children and 13 required surgery (eight pyeloplasties, four urethral reimplantations and two resections of type III urethral valves).

CONCLUSIONS

Neonatal PE was more prevalent in boys (4:1) and was more frequently located on the left side in both sexes. Associated vesicourethral reflux was found in 23.64 % with no correlation between the degree of dilation and the presence or degree of reflux. Consequently, cystourethrography should be performed in any child with pelvic ectasia, regardless of stage, side or sex.

The role of imaging in urinary tract infections

The aim of imaging in urinary tract infections (UTI) is to detect conditions that must be corrected to avoid imminent deterioration of kidney function, or to prevent recurrent infections and long-term kidney damage. The most threatening conditions are obstruction of an infected upper tract and abscesses of the genitourinary system. An image-guided percutaneous drainage can be lifesaving. The role of imaging in small children with UTI is controversial in terms of the importance of anatomical and functional disorders in relation to the preventive measures to be taken. In newborns identified with hydronephrosis during pregnancy or by neonatal screening, vesicoureteral reflux (VUR) and renal scarring are congenital and not caused by infection. Most of these patients are males and the VUR is of a higher grade than VUR detected in girls after the first UTI. Imaging in children with UTI should only be ordered after a thorough evaluation of the risk of renal damage and the benefits of preventive measures. In adult females, no imaging is necessary in cystitis, while ultrasonography and plain films are recommended in acute pyelonephritis. Since uncomplicated UTI in men is rare, diagnostic imaging should be started early to rule out complicating factors in the urinary tract. In prostatitis, vesiculitis, epididymitis and orchitis the role of imaging is to rule out abscess formation and testicular malignancies.

Predictive risk factors for chronic renal failure in primary high-grade vesico-ureteric reflux

OBJECTIVE

To evaluate and define the risk factors predictive of chronic renal failure (CRF) in children with severe bilateral primary vesico-ureteric reflux (VUR), observed within the first year of life and with a long follow-up.

PATIENTS AND METHODS

The study comprised 50 patients presenting with grade 3-5 bilateral VUR diagnosed in the first year of life; 12 were suspected prenatally and confirmed shortly after birth, before any urinary tract infection (UTI). The mean (range) follow-up was 6.3 (1-16) years. The variables considered within the first year of life were: gender, prenatal diagnosis with no UTI, number of febrile UTIs, serum creatinine and urea nitrogen levels, metabolic acidosis, proteinuria, 24-h urine output, hypertension, bilateral renal length on ultrasonography and renal scarring on renal scintigraphy. CRF was defined as a creatinine clearance of <80 mL/min/1.73 m(2) at the last follow-up. The results were assessed using univariate and multivariate analyses (backward-stepwise multiple regression) of the selected variables.

RESULTS

CRF was detected at the last follow-up in 27 patients (54%), all boys, while renal function was normal in 23 (46%; seven girls). None of the 12 patients with prenatal diagnosis had UTI, but six had CRF. Febrile UTI was the presenting symptom in 38 (76%) patients and 17 (34%) of them had renal scarring. There was no significant difference between the prenatally detected VUR and febrile UTI group in the outcome as CRF. The univariate and multiple regression analysis showed that the first serum creatinine threshold of >6 mg/L before 1 year old was the most significant risk factor for CRF (P < 0.001; odds ratio 1.25).

CONCLUSIONS

Children with primary bilateral high-grade VUR and a serum creatinine of > 6 mg/L in the first year of life have a significant risk of developing CRF in the long-term. Prenatal diagnosis and postnatal febrile UTI do not modify the outcome for renal function.

Renal damage in vesico-ureteric reflux

OBJECTIVE

To detect the different extent of renal parenchymal involvement in primary vesico-ureteric reflux (VUR), and to evaluate the relationship between VUR grade, patient age and different patterns of parenchymal damage.

PATIENTS AND METHODS

This blinded retrospective study included 197 consecutive children (mean age 4.26 years, range 1 month to 13 years) with primary VUR detected by voiding cysto-urethrography (VCUG), 99mTc-dimercaptosuccinic acid (DMSA; 120 MBq/1.73 m2) renal scintigraphy, with scanning for 3 h after intravenous injection. An abnormal DMSA scan was classified into three subtypes: cortical defects as a single scar (SS), multiple cortical scarring (MS) and diffuse reduced uptake with small renal size. Renal absolute uptake (AU), and split-kidney relative uptake were evaluated in refluxing and nonrefluxing renal units, and correlated with parenchymal damage and patient age. Student's t-test and the chi-square test were used for the statistical analysis.

RESULTS

In all, 282 refluxing and 112 nonrefluxing units were assessed. Renal damage was detected in 188 of 282 units with VUR (67%) and in 18 of 112 (16%) contralateral nonrefluxing kidneys. The mean AU was 18.7% in kidneys with VUR and 29% in nonrefluxing units (P < 0.001). The mean (SD) AU decreased from lower to higher grades of VUR, i.e. grade 0 VUR (group A), 28.97 (9.71); grade 1-3 (group B), 21.28 (8.33); grade 4-5 (group C), 14.78 (8.02). The differences were statistically significant (A vs B, B vs C, both P < 0.001). Renal damage was differently distributed in the three groups: 69 of 109 kidneys (63%) in group C (MS prevalent), 39 of 173 (22.5%) in group B (SS prevalent) and 17 of 112 (15.2%) in group A. There was no significant difference in the distribution of renal damage subtypes in patients aged < or > 2 years (SS 19.6% vs 17.9%, MS 29.6% vs 30.1%, small size 48.2% vs 46.3%). The VUR was severe (group C) in 65% of patients aged < 2 years and in 46% aged > 2 years (chi-square, P = 0.016).

CONCLUSIONS

VUR is commonly associated with renal damage. Age (< or > 2 years) did not significantly influence the kidney lesion subtype. Reduced parenchymal function (AU) progressively decreased with the severity of VUR. Focal MS, reduced size and relative uptake were significantly more common in severe VUR, leading to multifocal lesions and hypo-dysplasia. Renal scarring was present in up to 15% of contralateral nonrefluxing kidneys. Severe VUR behaved differently from lesser VUR in the renal scan parenchymal uptake.

Antenatal Hydronephrosis: Negative Predictive Value of Normal Postnatal Ultrasound—a 5-year Study

AIM

To determine whether normal postnatal ultrasound, as part of a strict screening protocol for the detection and follow-up of antenatal hydronephrosis, effectively excludes the majority of babies with congenital urinary tract abnormalities that would otherwise present with a urinary tract infection.

MATERIALS AND METHODS

We retrospectively reviewed all babies who had postnatal follow-up of antenatally detected hydronephrosis over a 5-year period at our institution, a district general Trust with a specialist paediatric unit. We then studied all babies presenting with urinary tract infection before their first birthday to our institution over the same period. By cross-referencing these two study groups we were able to determine which babies developed a urinary tract infection having been previously discharged after normal postnatal ultrasound.

RESULTS

Four hundred and twenty-five babies had postnatal follow-up of antenatal hydronephrosis. Of these, 284 were investigated with ultrasound alone. In the same 5-year period, 230 babies presented with urinary tract infection before their first birthday. Only three of these babies had been previously discharged after normal postnatal ultrasound. The negative predictive value of a normal postnatal ultrasound was therefore 98.9% (281/284) for babies who subsequently presented with a urinary tract infection before their first birthday.

CONCLUSION

Careful antenatal and postnatal ultrasound with strict protocols is effective in detecting congenital renal tract abnormalities. Infants discharged after normal postnatal ultrasound are highly unlikely to still have an undetected urinary tract abnormality. We suggest that all babies with antenatal hydronephrosis are started on prophylactic antibiotics at birth, pending further investigation. All babies without features of severe obstruction antenatally should have their postnatal ultrasound delayed for a month. We recommend selective use of micturating cystourethrogram (MCUG), and delaying this investigation until the baby is 3 to 4 months old to allow for spontaneous resolution of vesicoureteric reflux. We do not believe that all babies with antenatal hydronephrosis require MCUG, providing a clear protocol is followed.

Urinary diversion in infants with primary high-grade vesicoureteric reflux, urinary sepsis and renal function impairment

INTRODUCTION

General consensus on the optimal treatment of septic infants with primary high-grade vesicoureteric reflux (VUR) and renal function impairment has not been reached. Our study aims at evaluating the role of temporary urinary diversion.

MATERIALS AND METHODS

Twenty male infants, affected by sepsis and primary high-grade VUR, underwent urinary diversion in 1996-2001 because of estimated risk of renal function deterioration, due to non-compliance with the antibiotic treatment. Plasmatic creatinine clearance, ultrasonography, micturition cystography and scintigraphy were evaluated.

RESULTS

Creatinine clearance was abnormal in 13 infants on admission, in 10 after urinary diversion and in 6 after second surgery. Renal damage (focal or diffuse) was evident in 16 patients, without modifications after surgery. No patient developed urinary tract infections (UTI). Vesicostomy was done in 12 cases, ureterostomy in 8. Nephrectomy was performed in 3 cases with poor renal function, and ureteroneocystostomy in 17.

CONCLUSIONS

Urinary diversion in septic infants with high-grade VUR can represent an alternative approach to the conservative or surgical treatment in selected patients presenting risk of renal function impairment. This procedure allowed an easy management of UTI without worsening of renal function while waiting for a better anatomical status to perform reconstructive surgery.

Vesicoureteric reflux and reflux nephropathy

Reflux nephropathy i.e. renal scarring associated with vesico-ureteric reflux (VUR) and urinary tract infection (UTI) was originally considered an acquired disease. The renal scarring seems to get worse with recurrent urine infections especially in the young. Therefore, in the past much effort was undertaken to correct the VUR surgically and minimize the number of recurrent urinary tract infections by antibiotic prophylaxis with the hope of reducing if not arresting the onset of complications that follow i.e. hypertension and renal failure. However, it is now becoming clear that reflux nephropathy encompass at least two major categories of disease; "acquired" renal scarring secondary to UTI and VUR predominantly affecting females and "congenital" scarring with dysplastic features associated with prenatal VUR but with no infection and predominantly affecting boys. The latter is much less common but is disproportionately represented in the group of patients with reflux nephropathy that go on to develop renal failure. Unfortunately, the susceptibility to renal scarring, the onset of hypertension and progression to renal failure seems to be significantly influenced by genetic factors and hence measures undertaken to prevent recurrence of UTI may not change the ultimate outcome although it will certainly improve the comfort of the individual. Therefore, the extensive investigation and management routines adopted today in these children may not be cost-effective in preventing end stage renal disease in VUR. The progression to renal failure, however, can be delayed but not halted with adequate control of high blood pressure and hence the need for life long follow-up.

Antenatal hydronephrosis: evaluation and outcome

We present a comprehensive and current review of the etiology, evaluation, treatment, and outcome of antenatal hydronephrosis. When a diagnosis of antenatal hydronephrosis is made, many questions regarding pregnancy, prenatal care, intervention, and what may be expected after birth are raised. Debate and controversy exist on the diagnosis and subsequent evaluation and management of the child with antenatal hydronephrosis. A review of the literature and our own experience with antenatal hydronephrosis are presented in order to guide the physician who is caring for mother and child.

Diagnosis and imaging in urinary tract infections

The aim of imaging in urinary tract infection is to detect conditions that must be treated in order to avoid immediate deterioration or recurrences, and probable long-term kidney damage. In newborns identified with hydronephrosis during pregnancy or by neonatal screening, vesicoureteral reflux and renal scarring are congenital and not caused by infection. Most of these patients are male and the vesicoureteral reflux is of a higher grade than that detected in girls having had urinary tract infection. In children with urinary tract infection, several authors advocate a more selective policy and recommend imaging only in those children who are at risk for developing renal damage. In adult females no imaging is necessary in cystitis, whereas ultrasonography and plain films are recommended in acute pyelonephritis. Because uncomplicated urinary tract infection in men is rare, diagnostic evaluation including imaging should be started early in order to rule out complicating factors within the urinary tract. The role of imaging in prostatitis, vesiculitis, epididymitis and orchitis is primarily to rule out abscess formation, but also to exclude testicular malignancies.