Development of new renal scars: a collaborative study

[Imaging in children and adolescents with urinary tract infections]

CLINICAL/METHODOLOGICAL PROBLEM

Urinary tract infections are among the most common infectious diseases in childhood. The task of imaging is to detect predisposing factors, such as urinary transport disorders, vesicoureteral reflux, as well as complications such as abscesses or pyonephrosis in addition to possible morphological changes of the kidneys and the draining urinary tract during an infection.

STANDARD RADIOLOGICAL PROCEDURES

The initial diagnostic imaging technique is generally sonography. For the diagnosis of vesicoureteral reflux, voiding urosonography or alternatively radiological voiding cystourethrography are used. Further diagnostic workup may include scintigraphy, magnetic resonance imaging (MRI) or, in exceptional cases, computed tomography (CT).

RECOMMENDATION FOR PRACTICE

In children and adolescents, it is of particular importance to avoid recurrent urinary tract infections and their sequelae. This requires precise imaging diagnostics, which must be performed with special consideration of radiation protection.

Vesicoureteral reflux is associated with increased risk of chronic kidney disease: A nationwide cohort study

The association between vesicoureteral reflux (VUR) and chronic kidney disease (CKD) risk remains unestablished. We investigated the incidence of CKD in children with VUR in Taiwan and evaluated whether they had a higher risk of CKD than the general population. A nationwide population-based cohort study was conducted among children with VUR identified using Taiwan's National Health Insurance Research Database from 2000 to 2013. VUR was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes. We identified the children with VUR and randomly selected comparison children according to a 1:1 ratio, matching them by age, gender, index year and comorbidity using data from the National Health Insurance Research Database. In total, 8648 children with VUR and 8648 comparison children were included. All children were followed from the study date until a diagnosis of CKD, termination of insurance, or the end of 2013. Cox proportional hazards regressions were performed to compare the hazard ratios for CKD between the 2 cohorts. Incident cases of CKD were identified. After adjustment for potential confounders, the study cohort was independently associated with a higher risk of CKD (adjusted hazard ratio, 3.78; 95% confidence interval, 2.10-7.18). This population-based cohort study indicated that children with VUR have a higher risk of CKD than those without VUR.

Genetic Evaluation of E. coli Strains Isolated from Asymptomatic Children with Neurogenic Bladders

This study was conducted to describe the genetic profiles of E. coli that colonize asymptomatic pediatric neurogenic bladders. E. coli was isolated from 25 of 80 urine samples. Patients were excluded if they presented with symptomatic urinary tract infection or received treatment with antibiotics in the preceding three months. Multiplex PCR was performed to determine E. coli phylotype (A, B1, B2, and D) and the presence of seven pathogenicity islands (PAIs) and 10 virulence factors (VFs). E. coli strains were predominantly of the B1 and B2 phylotype, with few strains in the A or D phylotype. The PAIs IV₅₃₆, I_CFT073, and II_CFT073 had the highest prevalence: 76%, 64%, and 48%, respectively. The PAIs II₅₃₆, I_J96, and II_J96 were less prevalent: 28%, 20%, and 24%, respectively. The most prevalent VF was vat (40%), while the least prevalent VFs were sfa (8%) and iha (12%). None of the strains carried the VF fyuA, which is very common in uropathogenic E. coli (UPEC). The genetic profiles of E. coli in this cohort seem to be more similar to UPEC than to commensal E. coli. However, they appear to have reduced virulence potential that allows them to colonize asymptomatically.

Persistence and recurrence of vesicoureteric reflux in children after endoscopic therapy - implications of a risk-adapted follow-up

Introduction

There is no well-defined follow-up scheme available to reliably detect persistent or recurrent vesicoureteric reflux (VUR) after endoscopic therapy (ET), but also to reduce postoperative invasive diagnostics in these children.

Our aim was the evaluation of possible predictors of persistence and recurrence of VUR, in order to elaborate and test a risk-adapted follow-up regimen.

Material and methods

92 patients (85/92%f, 7/8%m, age 2.99y) underwent direct isotope cystography (DIC) three months after ET. Persistent or recurrent VUR, scarring on dimercaptosuccinic acid (DMSA) scans and further fUTIs after therapy (follow-up 24.6 m) were documented and analysed.

Results

VUR persistence 3 months after ET was found in 11 (11.9%) patients; recurrent VUR in 4 (4.3%) patients. Scarring on preoperative DMSA and dilating VUR (°III and °IV) were significantly associated with recurrent VUR. If only children with preoperative positive DMSA scan or dilating VUR would have undergone DIC, only 58/92 DICs (64%) would have been necessary. Only 45.5% of otherwise detected VURs would have been identified using this risk-adapted strategy.

Conclusions

Limiting invasive follow-up diagnostics (VCUG) and, therewith, the radiation burden in a predefined group of patients at risk for persistence or recurrence of VUR is not recommended, due to the significant chance of missing persistent or new onset contralateral VUR. Therefore, we recommend a routine follow-up VCUG after ET. Further prospective scientific efforts to evaluate new, alternative factors influencing persistence and recurrence of VUR, in order to establish an effective follow-up strategy, are warranted.

The results of different diagnostic imaging studies used in children with urinary tract infection

Urinary tract infections (UTI) can cause significant renal scarring, which can be complicated by hypertension and renal impairment. This study describes the outcome of different imaging modalities in children with UTI and its relation to age, sex and type of UTI. Our objective was to describe the frequencies of different imaging studies, which were used to investigate children with UTI at King Fahad Hospital (KFH) between the years 2003 and 2008. This is a descriptive study of all children presenting with UTI at KFH from 2003 to 2008. The study population, 100 children , were divided into 3 age groups; first group (> 1 month to 2 years); second group (> 2 to 5 years) , third group (> 5 to 12 years). All enrolled children were confirmed to have had UTI via urinary cultures. Ninety seven (97%) patients underwent renal ultrasonography (US), 77 (77%) had a 99mTc-dimercaptosuccinic acid (DMSA) scan within 2 months of presentation, and 60 (60%) patients underwent micturating cystourethrogram (MCUG), mainly those with an abnormal DMSA scan. A total of 100 patients screened, 10 (10%) were males and 90 (90%) were females, first age group constituted 10%, second age group was 25% , third age groups was 65%. E-coli was isolated in 84% of patients, 60% had recurrent UTI, 45% had pyelonephritis, 48.4% had abnormal renal US, 61% had an abnormal DMSA scan, and 26.6% had abnormal MCUG. UTI can cause significant morbidity in children if not managed properly. Imaging studies are useful in identifying children who require advanced medical intervention; however, such studies should be performed only when indicated.

Antibiotics for acute pyelonephritis in children

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infections in infants. The most severe form of UTI is acute pyelonephritis, which results in significant acute morbidity and may cause permanent kidney damage. There remains uncertainty regarding the optimum antibiotic regimen, route of administration and duration of treatment. This is an update of a review that was first published in 2003 and updated in 2005 and 2007.

OBJECTIVES

To evaluate the benefits and harms of antibiotics used to treat children with acute pyelonephritis. The aspects of therapy considered were 1) different antibiotics, 2) different dosing regimens of the same antibiotic, 3) different duration of treatment, and 4) different routes of administration.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register, CENTRAL, MEDLINE, EMBASE, reference lists of articles and conference proceedings without language restriction to 10 April 2014.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic agents, routes, frequencies or durations of therapy in children aged 0 to 18 years with proven UTI and acute pyelonephritis were selected.

DATA COLLECTION AND ANALYSIS

Four authors independently assessed study quality and extracted data. Statistical analyses were performed using the random-effects model and the results expressed as risk ratio (RR) for dichotomous outcomes or mean difference (MD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

This updated review included 27 studies (4452 children). This update included evidence from three new studies, and following re-evaluation, a previously excluded study was included because it now met our inclusion criteria.Risk of bias was assessed as low for sequence generation (12 studies), allocation concealment (six studies), blinding of outcome assessors (17 studies), incomplete outcome reporting (19 studies) and selective outcome reporting (13 studies). No study was blinded for participants or investigators. The 27 included studies evaluated 12 different comparisons. No significant differences were found in duration of fever (2 studies, 808 children: MD 2.05 hours, 95% CI -0.84 to 4.94), persistent UTI at 72 hours after commencing therapy (2 studies, 542 children: RR 1.10, 95% CI 0.07 to 17.41) or persistent kidney damage at six to 12 months (4 studies, 943 children: RR 0.82, 95% CI 0.59 to 1.12) between oral antibiotic therapy (10 to 14 days) and intravenous (IV) therapy (3 days) followed by oral therapy (10 days). Similarly, no significant differences in persistent bacteriuria at the end of treatment (4 studies, 305 children: RR 0.78, 95% CI 0.24 to 2.55) or persistent kidney damage (4 studies, 726 children: RR 1.01, 95% CI 0.80 to 1.29) were found between IV therapy (three to four days) followed by oral therapy and IV therapy (seven to 14 days). No significant differences in efficacy were found between daily and thrice daily administration of aminoglycosides (1 study, 179 children, persistent clinical symptoms at three days: RR 1.98, 95% CI 0.37 to 10.53). Adverse events were mild and uncommon and rarely resulted in discontinuation of treatment.

AUTHORS' CONCLUSIONS

This updated review increases the body of evidence that oral antibiotics alone are as effective as a short course (three to four days) of IV antibiotics followed by oral therapy for a total treatment duration of 10 to 14 days for the treatment of acute pyelonephritis in children. When IV antibiotics are given, a short course (two to four days) of IV therapy followed by oral therapy is as effective as a longer course (seven to 10 days) of IV therapy. If IV therapy with aminoglycosides is chosen, single daily dosing is safe and effective. Insufficient data are available to extrapolate these findings to children aged less than one month of age or to children with dilating vesicoureteric reflux (grades III-V). Further studies are required to determine the optimal total duration of antibiotic therapy required for acute pyelonephritis.

Hypertension in pediatric patients with renal scarring in association with vesicoureteral reflux

OBJECTIVE

To examine the reflux nephropathy rate and severity as well as the hypertension rate in pediatric patients with vesicoureteral reflux (VUR).

METHODS

The study included 240 patients with VUR. Renal scarring (RS) was demonstrated by renal parenchymal examination using technetium-99m-labeled dimercaptosuccinic acid (99mTc-DMSA) scintigraphy. Office measurements of arterial blood pressure and ambulatory blood pressure monitoring (ABPM) of VUR patients were done during the follow-up period.

RESULTS

Follow-up was a mean duration of 24 months. Rates of RS and hypertension increased parallel to increases in the degree of VUR. A gradual elevation in hypertension rates was evident during the follow-up period. All patients with hypertension had RS. Severe RS in 56 patients was associated with increasing blood pressure readings by 24-hour ABPM or office measurements in 19 patients (33.9%). ABPM measurements enabled us to detect additional patients compared with office measurements alone.

CONCLUSION

Hypertension is a serious complication in children with reflux nephropathy and is associated with the severity of RS and VUR grade. ABPM seems to be superior over office measurements of blood pressure in identifying patients with hypertension.

Abnormal dimercaptosuccinic Acid scan may be related to persistence of vesicoureteral reflux in children with febrile urinary tract infection

PURPOSE

This study assessed whether (99m)technetium dimercaptosuccinic acid (DMSA) scintigraphy used for the assessment of renal sequelae after febrile urinary tract infection (UTI) has any prognostic value for outcome measurement of vesicoureteral reflux (VUR) by retrospectively evaluating the correlation between abnormal DMSA scintigraphy results and persistence of VUR in children with febrile UTI.

MATERIALS AND METHODS

The medical records of 142 children (57 boys, 85 girls) admitted with febrile UTI from January 2004 to December 2006 and who were followed up for more than 1 year were retrospectively reviewed. At the initial and follow-up visits, renal ultrasound and DMSA scans were performed within 7 days from the diagnosis and voiding cystourethrography (VCUG) was performed within 1 month in all case and follow-up evaluations.

RESULTS

The children's mean age was 4.8±3.6 years (range, 0.3 to 14 years). The mean follow-up was 28.2±4.8 months. At the initial examination, VUR was more often associated with an abnormal DMSA scan result (83.3%) than with a normal DMSA scan result (16.7%, p=0.02). The frequency of VUR with an abnormal DMSA scan during acute UTI was significantly higher than the frequency of VUR with a normal DMSA scan (38.8% vs, 25.8%, respectively, p=0.004). Also, high-grade VUR was associated with an abnormal DMSA scan result (32.5%) more often than with a normal DMSA scan result (0%, p=0.01). Children with an abnormal DMSA scan had a lower resolution rate of VUR (17.5%) than did children with a normal DMSA scan (75.0%) at the follow-up VCUG (p=0.02).

CONCLUSIONS

An abnormal result on a DMSA scan during febrile UTI is associated with high-grade and persistent VUR. DMSA scans performed during febrile UTI are useful in reflux resolution in childhood.

The KIDSTEM European Research Training Network: Developing a Stem Cell Based Therapy to Replace Nephrons Lost through Reflux Nephropathy

The incidence and prevalence of end stage renal disease (ESRD) continues to grow worldwide at a rate that is far in excess of the growth rate of the general population. In children and young adults the most common cause of ESRD is vesicoureteric reflux (VUR), a condition where urine from the bladder re-enters the kidney, predisposing to pyelonephritis, renal scarring, and in the most severe cases, ESRD. However, there is usually a time-window of several years from initial diagnosis of VUR to the development of ESRD, which presents an opportunity to design therapies aimed at preventing disease progression by repairing renal tissue before it becomes nonfunctional. Advances in our understanding of kidney development coupled with recent progress in stem cell science and tissue engineering, present an unprecedented opportunity to design a stem cell-based therapy for this clinical problem. KIDSTEM will investigate the properties of several different stem cell types (kidney stem cells, embryonic stem cells, amniotic fluid stem cells and mesenchymal stem cells) to determine which is most appropriate for the generation of functional renal tissue promoted by specifically designed biomaterials to facilitate the generation of functional nephrons.

Acute phase 99mTc-dimercaptosuccinic acid scan in infants with first episode of febrile urinary tract infection

BACKGROUND

99mTc-dimercaptosuccinic acid (DMSA) scan is the golden standard for the diagnosis of acute pyelonephritis and renal scaring. We investigated the use of acute phase DMSA scan in infants presented promptly to the hospital because of the first episode of their febrile urinary tract infection (UTI).

METHODS

Ninety-eight infants with microbiologically confirmed first episode of febrile UTI were studied. DMSA scans were carried out within 7 days in these infants after admission. Infants with an abnormal acute DMSA scan underwent a second DMSA scan 6-12 months later.

RESULTS

Overall, acute DMSA scan was abnormal in 16 (16.3%) of the 98 patients. There were no differences in sex, age, fever over 38.5°C, blood inflammation indices, or evidence of vesicoureteral reflux (VUR) between patients with normal and abnormal acute DMSA scan (P>0.05). However, infants with grade III to V VUR as well as those with delayed treatment presented significantly increased renal involvement by acute DMSA scan (P<0.05). The sensitivity and specificity of abnormal acute DMSA scan to predict grade III to V VUR were 50% and 88% respectively. Its positive and negative likelihood ratios were 4.16 and 0.57, respectively. Of 16 children with abnormal initial DMSA scan results, 14 underwent a second DMSA scan. Follow-up DMSA scans were normal in 12 of the 14 children.

CONCLUSIONS

Parenchymal damage found in a minority of infants with febrile UTI presented promptly to the hospital. Acute phase DMSA scan should be carried out only in selected patients. An abnormal acute DMSA scan is a moderate predictor for dilated VUR and its ability to exclude VUR is restricted.

Persistent renin-angiotensin system activation after anti-reflux surgery and its management

PURPOSE

To study renin-angiotensin system activation and the role of angiotensin-converting enzyme inhibition (ACE-I) after anti-reflux surgery.

MATERIAL AND METHODS

Thirty nine children underwent anti-reflux surgery for high grades of primary VUR. Plasma renin activity (PRA), urinary microalbumin, renal scars, split renal function (SRF), glomerular filtration rate (GFR), serum creatinine, blood pressure and episodes of breakthrough urinary tract infection were monitored in the early (5.9 ± 3.9; range 3-9 months) and late (27.1 ± 6.5; range 15-36 months) postoperative phase, before and after therapy with ACE-I (mean period 13.6 ± 2.5; range 10-24 months).

RESULTS

The early postoperative improvement in renal parameters (rise in SRF and GFR by 11.2% and 7.3%, respectively, and fall in PRA by 68.8%), was not sustained subsequently (minimal improvement in SRF, 7.4%, and GFR, 0.14%, was accompanied by a rise in PRA by 92.3%). After ACE-I therapy, improvement was noted in SRF and GFR by 0.5% and 7.5%, respectively, and there was a fall in urinary microalbumin by 52.3%.

CONCLUSIONS

Significant down regulation of rennin-angiotensin system activation and the accompanying improvement in renal function seen early after surgery is not sustained during follow up. ACE-I aids renal recovery.

A guideline for the inpatient care of children with pyelonephritis

BACKGROUND AND OBJECTIVES

Febrile urinary tract infections and pyelonephritis are common in children and frequently lead to hospitalization for management, especially in the child who appears toxic. The American Academy of Pediatrics (AAP) practice parameter on the diagnosis, treatment and evaluation of the initial urinary tract infection in febrile infants and young children provides experience and evidence-based guidelines for the practitioner caring for children between the ages of 2 months to 2 years. No established guideline exists for older children and the AAP guideline does not specifically focus on inpatient care.

METHODS

We conducted a comprehensive review of recently published literature and practice guidelines to develop a consensus on the inpatient diagnosis and management of children with pyelonephritis.

RESULTS

Eight recommendations are proposed for the diagnosis and management, including revised guidelines for the imaging studies postpyelonephritis on the basis of current best evidence.

CONCLUSION

Proper diagnosis of pyelonephritis, timely initiation of appropriate therapy and identification of children at risk for renal injury will help to reduce immediate as well as long-term complications due to chronic kidney disease.

Length of intravenous antibiotic therapy and treatment failure in infants with urinary tract infections

OBJECTIVE

The goal was to determine the association between short-duration (< or =3 days) and long-duration (> or =4 days) intravenous antibiotic therapy and treatment failure in a cohort of young infants hospitalized with urinary tract infections (UTIs).

METHODS

We conducted a retrospective cohort study of infants <6 months of age who were hospitalized with UTIs between 1999 and 2004 at 24 children's hospitals in the Pediatric Health Information System. Our main model adjusted for all covariates, propensity scores, and clustering according to hospital to evaluate the effect of short versus long courses of inpatient intravenous antibiotic therapy on treatment failure, defined as readmission because of UTI within 30 days.

RESULTS

Of the 12,333 infants who met the inclusion criteria, 240 (1.9%) experienced treatment failure. The treatment failure rates were 1.6% for children who received short-course intravenous antibiotic treatment and 2.2% for children who received long-course treatment. Treatment courses varied substantially across hospitals and with patient-level characteristics. After multivariate adjustment, including propensity scores, there was no significant association between treatment group and outcomes, with an odds ratio for long versus short treatment of 1.02 (95% confidence interval: 0.77-1.35). Known presence of genitourinary abnormalities, but not age, predicted treatment failure.

CONCLUSIONS

Treatment failure for generally healthy young infants hospitalized with UTIs is uncommon and is not associated with the duration of intravenous antibiotic treatment. Treating more infants with short courses of intravenous antibiotic therapy might decrease resource use without affecting readmission rates.

A survey of the management of urinary tract infection in children in primary care and comparison with the NICE guidelines

BACKGROUND

The aim of this study was to establish current practices amongst general practitioners in the West of Ireland with regard to the investigation, diagnosis and management of urinary tract infection (UTI) in children and to evaluate these practices against recently published guidelines from the National Institute for Health and Clinical Excellence (NICE).

METHODS

A postal survey was performed using a questionnaire that included short clinical scenarios. All general practices in a single health region were sent a questionnaire, cover letter and SAE. Systematic postal and telephone contact was made with non-responders. The data was analysed using SPSS version 15.

RESULTS

Sixty-nine general practitioners were included in the study and 50 (72%) responded to the questionnaire. All respondents agreed that it is important to consider diagnosis of UTI in all children with unexplained fever. Doctors accurately identified relevant risk factors for UTI in the majority (87%) of cases. In collecting urine samples from a one year old child, 80% of respondents recommended the use of a urine collection bag and the remaining 20% recommended collection of a clean catch sample. Respondents differed greatly in their practice with regard to detailed investigation and specialist referral after a first episode of UTI. Co-amoxiclav was the most frequently used antibiotic for the treatment of cystitis, with most doctors prescribing a five day course.

CONCLUSIONS

In general, this study reveals a high level of clinical knowledge amongst doctors treating children with UTI in primary care in the catchment area of County Mayo. However, it also demonstrates wide variation in practice with regard to detailed investigation and specialist referral. The common practice of prescribing long courses of antibiotics when treating lower urinary tract infection is at variance with NICE's recommendation of a three day course of antibiotics for cystitis in children over three months of age when there are no atypical features.

P-fimbriated Escherichia coli in adults with renal scarring and pyelonephritis

The commonest organism in urinary tract infections (UTI) is Escherichia coli. Pyelonephritogenic E.coli strains possess P-fimbriae which firmly attach to uroepithelial cells by recognition of a carbohydrate structure, alpha-D-Galp-(1-4)-beta-D-Galp, which is confined within all glycosphingolipids related to the human P-blood group antigens. Several investigators have studied virulence properties of E.coli and host resistance in relation to UTI. Uroepithelial cells from children and women with recurrent UTI have an increased capacity to bind E.coli. In contrast to previous studies the present one deals with patients with renal scarring, who constitute the major risk group among patients with UTI. P-fimbriae mediated binding to uroepithelial cells was studied and the risk of recurrent UTI in patients with renal scarring was determined. Ninety per cent of the E.coli isolates from female patients with acute non-obstructive pyelonephritis in this study possess P-fimbriae (I). The fecal E.coli colonies obtained from these patients were P-fimbriated in 55% compared to 11% of the fecal E.coli colonies from healthy controls. The P-blood group distribution in 56 female patients with renal scarring and a history of febrile UTI was the same as in a control group of 39 healthy subjects (II). A history of recurrent and/or early infections did not increase the percentage of the P1 blood group phenotype. Forty-nine female patients with renal scarring were prospectively investigated for the incidence of symptomatic UTI in relation to fecal colonization with P-fimbriated E.coli (III). Fifty-three per cent of the patients had altogether 65 episodes of symptomatic UTI during the three-year follow-up (0.036 infections per month). Eight patients (16%) had nine attacks of acute pyelonephritis and 4/5 of the tested E.coli strains from these patients were P-fimbriated. No relationship was demonstrated between the presence of P-fimbriated E.coli in the fecal flora and the development of subsequent acute pyelonephritis. The binding of P-fimbriated E.coli to uroepithelial cells from 19 female patients with renal scarring was studied with the fluorescence-activated cell sorting (FACS) analysis (IV). The uroepithelial cells from the patients with renal scarring exhibited a significantly higher binding capacity (p less than 0.01) than uroepithelial cells from healthy controls. Furthermore, uroepithelial cells from the patients with renal scarring and kidney insufficiency had a higher availability of P-fimbriae receptors on their uroepithelial cells than cells obtained from patients with renal scarring and normal renal function (r = -0.75, p less than 0.001) (V).(ABSTRACT TRUNCATED AT 400 WORDS)

Vesicoureteric reflux is not a benign condition

Renal parenchymal defects may be congenital, usually associated with dilated vesicoureteric reflux (VUR), or they may appear in previously normal kidneys and be caused by reflux nephropathy due to VUR combined with urinary tract infection (UTI). A piglet model defined that the 70% of children with VUR and vulnerable pyramids would scar rapidly with their first UTI. Because most defects are present at first imaging after a UTI, and from the lack of benefit from apparently reasonable clinical interventions, many now believe that most defects are congenital, their association with VUR being a shared dysplasia rather than causal. Consequently, guidelines now argue for less assiduous management. These conclusions ignore adult human transplant evidence, adult pig studies, and clinical anecdotes, which indicate that scars may develop in infant kidneys quicker than urine culture can confirm the diagnosis, and that reflux nephropathy has no age limit. Its rarity over 4 years suggests that most vulnerable children develop scars before then, despite all medical efforts. I argue that preventing such scarring will require better diagnosis of infant UTI, quicker treatment, reliable imaging of scars and VUR, and subsequent protection until VUR resolves. To make a difference, we need more assiduous management, not less, and cannot afford to consider VUR to be a benign condition.

Imaging in childhood urinary tract infections: time to reduce investigations

The correct protocol for investigating urinary tract infections (UTI) is unknown but remains a hotly debated topic. The main objective in investigating children with UTI is to prevent the long-term complications of developing hypertension, chronic kidney disease (CKD) and/or pregnancy complications. However, the prognosis for childhood UTI remains good, with low long-term risks, from epidemiological studies, of developing these sequelae. Although childhood UTI is common, the occurrence of CKD and the likelihood that acute pyelonephritis will cause renal damage progressing to CKD are rare. We studied the current literature on investigations of childhood UTI and propose a protocol for carrying out selected investigations in high-risk children. By identifying this group of children with increased risk of having an abnormal urinary tract that warrant investigation, we recommend that targeting investigations to specific children (as opposed to protocol-based investigations of all children with UTI), will be clinically safe and effective and will avoid the unnecessary distress and cost of invasive investigations.

Antibiotics for acute pyelonephritis in children

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infection in infants. The most severe form of UTI is acute pyelonephritis, which results in significant acute morbidity and may cause permanent renal damage. Published guidelines recommend treatment of acute pyelonephritis initially with intravenous (IV) therapy followed by oral therapy for seven to 14 days though there is no consensus on the duration of either IV or oral therapy.

OBJECTIVES

To determine the benefits and harms of different antibiotic regimens for the treatment of acute pyelonephritis in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, reference lists of articles and conference proceedings without language restriction. Date of most recent search: December 2006.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic agents, routes, frequencies or durations of therapy in children aged 0 to 18 years with proven UTI and acute pyelonephritis were selected.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or mean difference (WMD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Twenty three studies (3295 children) were eligible for inclusion. No significant differences were found in persistent renal damage at 6 months (2 studies, 424 children: RR 0.87, 95% CI 0.35 to 2.16) or in duration of fever (2 studies, 693 children: WMD 1.54, 95% CI -1.67 to 4.76) between oral antibiotic therapy (10 to 14 days) and IV therapy (3 days) followed by oral therapy (10 days). Similarly no significant differences in persistent renal damage (3 studies, 341 children: RR 1.13, 95% CI 0.86 to 1.49) were found between IV therapy (3 to 4 days) followed by oral therapy and IV therapy for 7 to 14 days. No significant differences in efficacy were found between daily and thrice daily administration of aminoglycosides (1 study, 179 children, persistent symptoms at 3 days: RR 1.98, 95% CI 0.37 to 10.53).

AUTHORS' CONCLUSIONS

These results suggest that children with acute pyelonephritis can be treated effectively with oral antibiotics (cefixime, ceftibuten and amoxycillin/clavulanic acid) or with short courses (2 to 4 days) of IV therapy followed by oral therapy. If IV therapy is chosen, single daily dosing with aminoglycosides is safe and effective. Studies are required to determine the optimal total duration of therapy.

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.

Does early treatment of urinary tract infection prevent renal damage?

OBJECTIVE

Therapeutic delay has been suggested as the most important factor that is likely to have an effect on the development of scarring after acute pyelonephritis. However, this opinion has not been supported by prospective studies, so we tested it.

METHODS

In a prospective clinical study, we evaluated whether the time interval between the onset of the renal infection and the start of therapy correlates with the development of acute inflammatory changes and the subsequent development of renal scars, documented by dimercaptosuccinic acid scintigraphy. A total of 278 infants (153 male and 125 female) aged 0.5 to 12.0 months with their first urinary tract infection were enrolled in the study.

RESULTS

The median time between the onset of infection and the institution of therapy was 2 days (range: 1-8 days). Renal inflammatory changes were documented in 57% of the infants. Renal defects were recorded in 41% of the patients treated within the first 24 hours since the onset of fever versus 75% of those treated on day 4 and onward. Renal scarring was developed in 51% of the infants with an abnormal scan in the acute phase of infection. The frequency of scarring in infants treated early and in those whose treatment was delayed did not differ, suggesting that once acute pyelonephritis has occurred, ultimate renal scarring is independent of the timing of therapy. Acute inflammatory changes and subsequent scarring were more frequent in the presence of vesicoureteral reflux, especially that which is high grade. However, the difference was not significant, which suggests that renal damage may be independent of the presence of reflux.

CONCLUSIONS

Early and appropriate treatment of urinary tract infection, especially during the first 24 hours after the onset of symptoms, diminishes the likelihood of renal involvement during the acute phase of the infection but does not prevent scar formation.

Medical management of vesicoureteral reflux--quiz within the article. Don't overlook placebos

Vesicoureteral reflux (VUR) in children is associated with increased risk of urinary tract infection (UTI). Recurrent UTI in the presence of the VUR is believed to cause renal scarring, which carries a risk of subsequent hypertension, toxemia of pregnancy, and significant renal damage, including end-stage renal disease. The natural history of VUR is to improve or resolve completely with time in most of the patients. The traditional management consists of prompt treatment of UTI, long-term anti-microbial prophylaxis until the VUR resolves, or surgical intervention in those with persistent high grade VUR, recurrent UTI in spite of prophylaxis with anti-microbial agent, allergy to anti-microbial agents, and patient/parent non-compliance with the medical management. Voiding dysfunction and constipation play an important role, and their diagnosis and appropriate management helps reduce the frequency of UTI and promote the resolution of the VUR. Patients with renal scarring need to be monitored for potential complications such as hypertension, proteinuria, and progression of the renal damage. In patients with hypertension and/or proteinuria, angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) are the drugs of choice, because of their reno-protective properties. Recent studies have revealed that there is no convincing evidence that UTI in the presence of VUR predicts renal injury or that the use of long-term anti-microbial prophylaxis or surgical intervention prevents renal scarring or its progression. However, until proven otherwise by a prospective, placebo-controlled, randomized study, it is advisable to err on the side of caution and consider VUR and UTI risk factors for renal scarring and treat each patient on individual basis.

Infections and vesicoureteral reflux

Vesicoureteral reflux (VUR) is a common condition in children. It may cause and maintain urinary tract infections, eventually leading to progressive renal damage and end-stage renal disease. Ideally, VUR should be detected and treated before renal scarring occurs. Although fetal hydronephrosis on antenatal ultrasound may be the first indicator, the role of further diagnostic investigations in these newborns is still controversial. Because VUR is an inherited condition, offspring of women with a family history of VUR and urinary tract infection should be screened closely for early detection of VUR. Once diagnosed, however, the optimal management of VUR (i.e. medical or surgical treatment) remains controversial. Evidence-based treatment recommendations, like the American Urological Association guidelines, may aid physicians in their therapeutic decision making, but cannot replace personal experience or surgical skill.

Applying the ALARA concept to the evaluation of vesicoureteric reflux

The voiding cystourethrogram (VCUG) is a widely used study to define lower urinary tract anatomy and to diagnose vesicoureteric reflux (VUR) in children. We examine the technical advances in the VCUG and other examinations for reflux that have reduced radiation exposure of children, and we give recommendations for the use of imaging studies in four groups of children: (1) children with urinary tract infection, (2) siblings of patients with VUR, (3) infants with antenatal hydronephrosis (ANH), and (4) children with a solitary functioning kidney. By performing examinations with little to no radiation, carefully selecting only the children who need imaging studies and judiciously timing follow-up examinations, we can reduce the radiation exposure of children being studied for reflux.

Renal and Bladder Functional Status at Diagnosis as Predictive Factors for the Outcome of Primary Vesicoureteral Reflux in Children

PURPOSE

We studied the relationship between renal and bladder functional status at diagnosis and spontaneous resolution of reflux in young children with primary vesicoureteral reflux.

MATERIALS AND METHODS

Children with grade III or greater vesicoureteral reflux were recruited for the study. At entry each patient underwent voiding cystourethrogram, renal ultrasound, isotope renogram, and natural filling and conventional filling urodynamic studies. Patients were then divided into 4 groups-group 1 had normal renal and bladder function, group 2 had abnormal renal and normal bladder function, group 3 had normal renal and abnormal bladder function, and group 4 had abnormal renal and bladder function. Correlation between renal and bladder functional status with reflux resolution at a minimum followup of 24 months was evaluated.

RESULTS

A total of 82 patients (mean age 3.8 years) were prospectively evaluated and followed. There were 18 patients (13 males and 5 females) in group 1, 19 (13 and 6) in group 2, 19 (18 and 1) in group 3 and 26 (22 and 4) in group 4. Complete resolution of vesicoureteral reflux occurred in 17 patients (94%) in group 1 and 7 (37%) in group 2. None of the patients from group 3 or group 4 achieved complete vesicoureteral reflux resolution. Reflux grade remained unchanged in 15 patients (79%) in group 3 and 20 (77%) in group 4.

CONCLUSIONS

Resolution of vesicoureteral reflux significantly correlated with renal and bladder functional status at diagnosis. Normal renal and bladder function at diagnosis is highly predictive of complete resolution of vesicoureteral reflux, whereas abnormal renal and bladder function is prognostic for persistence of reflux.

Pediatric urinary tract infections

Pediatric urinary tract infections are common. These infections have been recognized as a source of acute morbidity and long-term medical consequences in adulthood. There are various risk factors and clinical presentations in children with urinary tract infections. The main objectives in management include prompt diagnosis, appropriate antimicrobial therapy, identification of anatomic anomalies, and, in select patients, long-term follow-up.

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.

Prise en charge des pyélonéphrites aiguës du nourrisson de plus de 3 mois et de l'enfant : enquête effectuée parmi les services d'urgences pédiatriques d'Île de France en 2004

OBJECTIVES

To describe the different modalities of ambulatory management of acute pyelonephritis in patients older than 3 months of age in paediatric emergency units of the Ile de France region in 2004.

METHODS

Between October 2003 and April 2004, referents of 39 paediatric emergency units of the Ile de France region were questioned through a written questionnaire concerning the management of acute pyelonephritis: in or outpatient modalities, antibiotic regimen (molecule and route of administration), investigations and follow-up.

RESULTS

Thirty-one questionnaires (79.5%) were returned and analysed. A written protocol was available in 60% of the units. Outpatient management was performed in 24/31 centres. Young age, poor clinical tolerance, urological abnormalities and social difficulties were the major contra-indications for such management. Ultrasonic echography at diagnosis (within 24 h) was performed in 50% of the units. Antibiotics were started using IV route in 18/24 units (75%) and ceftriaxone and aminoside were respectively prescribed in 100% and 29.4% of the units for a duration of 1 to 5 days before switching to the oral route. Antibiotherapy was started orally in 6 units and cefixime was chosen by 5 of them. Follow-up consultations were scheduled in 100% of the units but with various delay after initiation of the treatment. The total duration of treatment was mostly 10 days and oral prophylactic antibiotherapy was prescribed by 10/24 centres after completion of the treatment. Cystoureterography was systematically realized by 83.3% of the units.

CONCLUSIONS

Despite important differences in the management of acute pyelonephritis in Ile-de-France, a majority of the units follows similar therapeutic modalities. In the absence of consensus, new recommendations are necessary concerning the management of pyelonephritis in infants and children in France.

May we go on with antibacterial prophylaxis for urinary tract infections?

Recurrent urinary tract infections (UTIs), with or without vesicoureteric reflux (VUR), are by far the most frequent reason for long-term antibacterial prophylaxis in infants and children today. However, the strategies of antibacterial prophylaxis for the prevention of recurrent urinary tract infection are no longer universally accepted. In infants and children at risk, the benefits of antibacterial prophylaxis definitively are not yet proven by evident data. To put antibacterial prophylaxis in its place, risk groups for recurrent symptomatic infections, ascending UTI and permanent renal damage have to be defined and the efficacy of prophylaxis in these groups has to be proved by prospective randomised studies. Nevertheless, until the results of these studies are available, antibacterial prophylaxis will remain one of the most frequently practised methods to protect risk patients from pyelonephritic damage and UTI recurrences.

Kidney length and scarring in children with urinary tract infection: importance of ultrasound scans

BACKGROUND

Many studies have demonstrated that dimercaptosuccinic acid (DMSA) scintigraphy is the most sensitive diagnostic method in the identification of irreversible renal lesions (scars) in children with previous episodes of acute pyelonephritis (APN). This study assessed the reliability of ultrasound in identifying reflux nephropathy in children with acute pyelonephritis with or without vesicoureteric reflux (VUR).

METHODS

Eighty children (45 female and 35 male, age range 5 months to 10 years, average age 2 years 1 month) with a positive history for at least one episode of APN participated in this study. All children underwent voiding cystourethrography, DMSA scintigraphy 4 to 8 months after the most recent episode of APN, and an ultrasound test evaluation less than 2 months after DMSA scintigraphy.

RESULTS

Voiding cystourethrograms showed VUR in 52 children (68%); 13 of these were bilateral, for a total of 65 refluxing kidney units of the 154 (42%) evaluated; DMSA scintigram was normal for 108 of 154 kidneys (70%). Of the 65 kidneys with VUR, DMSA scintigram displayed normal findings in 29 cases (45%) and pathologic findings in 36 (55%). In the 79 nonrefluxing kidneys, DMSA scintigram was normal in 69 cases (87%). The relative risk of scarring in VUR kidneys is 2.6. The ultrasound study recorded a maximum longitudinal diameter between the 5th and 95th percentiles in 80 of 89 (81%) kidneys without VUR and in 21 of 65 (32%) with VUR. A significant correlation was found between maximum longitudinal diameters and DMSA scintigraphic findings in kidneys with VUR and those without VUR, respectively.

CONCLUSION

This study establishes that ultrasound scans, by means of a simple and reproducible measurement technique, maximum longitudinal diameter, have a predictive value with regard to the presence of scars, with few exceptions. This finding, in our opinion, could lead to a decrease in the number of invasive procedures, in particular DMSA scan, in patients with APN.

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.

[Vesicorenal reflux]

For vesicorenal reflux an incidence of 16 to 17% is described. In 85% girls are affected except in the antenately detected reflux. Ascending infections are the pathomechanism. A reflux can be diagnosed in up to 70% of children with febrile urinary tract infection. The probability of spontaneous maturation is highest in low grade and unilateral reflux as well as during the first year of life. During time to maturation antibiotic prophylaxis can avoid urinary tract infections (conservative treatment). Break-through infections, high grade reflux, loss of kidney function, associated malformations and bad patients compliance represent indications for operative reflux repair. Surgery should more often be considered in girls (higher risk for urinary tract infections, pregnancy). Success rates of reflux surgery are high (>90%). Endoscopy is quoted to be an alternative, however, success rates are lower and long-term results of the new substances are still lacking.

Antibiotics for acute pyelonephritis in children

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infection in infants. The most severe form of UTI is acute pyelonephritis, which results in significant acute morbidity and may cause permanent renal damage. Published guidelines recommend treatment of acute pyelonephritis initially with intravenous (IV) therapy followed by oral therapy for seven to 14 days though there is no consensus on the duration of either IV or oral therapy.

OBJECTIVES

To determine the benefits and harms of different antibiotic regimens for the treatment of acute pyelonephritis in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, reference lists of articles and abstracts from conference proceedings without language restriction. Date of most recent search: June 2004.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic agents, routes, frequencies or durations of therapy in children aged 0 to 18 years with proven UTI and acute pyelonephritis were selected.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes or weight mean difference (WMD) for continuous data with 95% confidence intervals (CI).

MAIN RESULTS

Eighteen trials (2612 children) were eligible for inclusion. No significant differences were found in persistent renal damage at six months (one trial, 306 infants: RR 1.45, 95% CI 0.69 to 3.03) or in duration of fever (WMD 0.80, 95% CI -4.41 to - 6.01) between oral cefixime therapy (14 days) and IV therapy (three days) followed by oral therapy (10 days). Similarly no significant differences in persistent renal damage (three trials, 315 children: RR 0.99, 95% CI 0.72 to 1.37) were found between IV therapy (3-4 days) followed by oral therapy and IV therapy for 7-14 days. In addition no significant differences in efficacy were found between daily and thrice daily administration of aminoglycosides (one trial, 179 children, persistent symptoms at three days: RR 1.98, 95% CI 0.37 to 10.53).

AUTHORS' CONCLUSIONS

These results suggest that children with acute pyelonephritis can be treated effectively with oral cefixime or with short courses (2-4 days) of IV therapy followed by oral therapy. If IV therapy is chosen, single daily dosing with aminoglycosides is safe and effective. Trials are required to determine the optimal total duration of therapy and if other oral antibiotics can be used in the initial treatment of acute pyelonephritis.

ABNORMAL DIMERCAPTO-SUCCINIC ACID SCANS PREDICT AN INCREASED RISK OF BREAKTHROUGH INFECTION IN CHILDREN WITH VESICOURETERAL REFLUX

PURPOSE

The management of high grade vesicoureteral reflux remains controversial, with breakthrough infections being an indication for surgical repair. We sought to determine if technetium dimercapto-succinic acid (DMSA) scan could help predict which children are at risk for breakthrough urinary tract infection.

MATERIALS AND METHODS

A retrospective review was performed on children presenting with a febrile urinary tract infection and prenatal hydronephrosis who were found to have vesicoureteral reflux and underwent a DMSA scan. Reflux was tabulated according to the highest grade. DMSA results were graded as 0-normal, no parenchymal or size defects, grade 1-focal parenchymal defects or less than a quarter of a renal unit involved, or grade 2-severe defects to include at least half of a renal unit, bilateral defects or unilateral atrophy.

RESULTS

A total of 120 consecutive patients were evaluated. An abnormal DMSA scan was documented in 57 (33 females and 24 males), and 35 with grade 1 and 22 with grade 2 defects. Of the patients 53 females and 10 males had a normal scan. Of the 57 children with an abnormal DMSA scan 6% presented with grades 1 and 2 vesicoureteral reflux, 24% with grade 3, 38% with grade 4 and 26% with grade 5. Of the children with grades 3 to 5 reflux 60% had a subsequent breakthrough infection. Of the 63 children with a normal DMSA scan 11% presented with grade 1 reflux, 28% with grade 2, 48% with grade 3, 11% with grade 4 and 2% with grade 5. Of these children 5 had a subsequent breakthrough infection.

CONCLUSIONS

An abnormality on DMSA scan in the presence of grade 3 to 5 reflux correlates with a greater chance of having a breakthrough infection (60%). We conclude that children with grade 3 to 5 vesicoureteral reflux and an abnormal DMSA scan are at increased risk for breakthrough urinary tract infection.

Persistent renal cortical scintigram defects in children 2 years after urinary tract infection

BACKGROUND

Renal cortical scintigraphic studies challenge the role of vesicoureteric reflux in renal scar development, emphasizing instead the part played by acute pyelonephritis.

OBJECTIVE

To determine the prevalence of renal cortical defects in a child cohort 2 years after the child's first diagnosed urinary tract infection and to analyze the relationship of these defects with acute illness variables, primary vesicoureteric reflux and recurrent infections.

MATERIALS AND METHODS

In a prospective cohort study, 193 children younger than 5 years with their first proven urinary tract infection underwent renal sonography, voiding cystourethrogram, and renal cortical scintigraphy within 15 days of diagnosis. Two years later, 150 of the 193 children, or 77.7%, had a further renal cortical scintigram, including 75, or 86.2%, of the 87 children who had acute scintigraphic defects. The relationship of cortical defects to age, gender, pre-treatment symptom duration, hospitalization, presence and grade of vesicoureteric reflux, and recurrent urinary tract infections was evaluated.

RESULTS

Overall, 20 of the 150 (13.3%; 95% confidence interval (CI) 8.3, 19.8) children had persistent defects 2 years after infection. This included 20 of 75 (26.7%; 95% CI 17.1, 38.1) with initially abnormal scintigrams. No new defects were detected. Although acute defects were more common in the young, those with persistent defects were older (median ages 16.4 vs. 6.8 months, P=0.004) than those with transient abnormalities. After adjustment for age, persistent defects were no longer associated with gender and were not predicted by acute illness variables, primary vesicoureteric reflux or recurrent infections.

CONCLUSIONS

Renal cortical scintigraphic defects persisted in approximately one-quarter of young children after their first proven urinary tract infection. The associated clinical features, however, failed to predict scar formation. It is possible that some of the scintigraphic defects preceded the infection by arising from either previously undiagnosed acute pyelonephritis or from underlying congenital dysplasia. The etiology of scars may be best addressed by determining whether prevention of urinary tract infections from birth avoids post-natal scar acquisition or extension.

Utility of follow-up renal sonography in children with vesicoureteral reflux and normal initial sonogram

OBJECTIVE

The purpose of this study was to determine the value of follow-up renal sonography in children who presented with urinary tract infection and were found to have a voiding cystogram diagnosis of vesicoureteral reflux while having a normal initial renal sonogram.

METHODS

We retrospectively reviewed the medical records of 64 consecutive children who presented for follow-up renal sonography with a voiding cystogram diagnosis of vesicoureteral reflux and a normal initial sonogram conducted as part of the routine evaluation after urinary tract infection. Data recorded included gender, age, initial grade of reflux, time to follow-up sonogram, and abnormalities on follow-up sonogram. Children with conditions that may predispose to vesicoureteral reflux were excluded.

RESULTS

Children who were studied (7 boys, 57 girls) ranged in age from 1 month to 10 years, 10 months (mean: 35.6 months; median: 24 months). Ninety-four (73.4%) of 128 renal units demonstrated vesicoureteral reflux on voiding cystogram; 89 (94.7%) of 94 of them were grade 1 to 3. The mean time to follow-up was 22 months (range: 4 months to 5 years, 2 months; median: 18 months). All 128 (95% confidence interval: 0%-2.8%) renal units were normal on follow-up sonography.

CONCLUSION

Routine performance of repeat sonography seems unnecessary among children, particularly girls, with low- to medium-grade vesicoureteral reflux, who have had a previous normal sonogram and no conditions that predispose to vesicoureteral reflux.