Imaging studies after a first febrile urinary tract infection in young children

The efficacy of ultrasound and dimercaptosuccinic acid scan in predicting vesicoureteral reflux in children below the age of 2 years with their first febrile urinary tract infection

We evaluated the efficacy of dimercaptosuccinic acid (DMSA) scan and ultrasound (US) in comparison with voiding cystourethrography (VCUG) in predicting vesicoureteral reflux (VUR) in children below the age of 2 years. Medical records and radiologic studies of children (<2 years) suffering their first febrile urinary tract infection (UTI) between January 2001 and May 2007 were retrospectively reviewed. We evaluated the sensitivity, specificity, and positive and negative predictive values of US and DMSA scans in diagnosing VUR. Among 220 children with their first febrile UTI, VUR was detected in 67 (30.4%). The detection rate of VUR by US was 41.7% and 86% in the low (I, II) and high grade (III~IV) groups, respectively. Detection rate of VUR by DMSA scan was 37.5% and 88.4% in the low and high grade groups, respectively. Combining US and DMSA scan, we found that the detection rate of high grade VUR was 95.3% and that of low grade was 62.5%. During follow up, most of the low grade VURs with normal DMSA and US scans resolved or were downgraded. Most high grade VURs could be detected by US and DMSA scan, but the prediction rate was not as high in low grade VURs. However, we can anticipate spontaneous improvement without complications in patients with either low or high grade reflux and negative findings on US and DMSA scan.

Renal scintigraphy in children with vesicoureteral reflux

OBJECTIVE

To determine the incidence and pattern of abnormal scintigraphy findings in children with UTI and VUR.

METHODS

Data of 118 children who underwent micturating cystourethrography (MCU) and late Tc-99m dimercaptosuccinic acid (DMSA) scan were evaluated. Findings were categorized under the image appearance and relative kidney uptake (RKU) and related to the grade of VUR, sex and child's age.

RESULTS

MCU revealed VUR (78 unilateral and 40 bilateral) of grades I, II, III, IV and V in 2, 47, 35, 19 and 15 patients respectively. There were 52 children with normal and 66 with abnormal DMSA finding. Scarring rate was significantly associated with high grade VUR (p=0.0023) and male gender ( p=0.0412). Bilateral scarring was seen exclusively in children with bilateral VUR. No significant difference was found between renal scarring and child's age in the same gender group. Poor kidney function was shown in 5 patients.

CONCLUSION

Renal scarring highly correlated with grade of VUR. A strategy to perform MCU only on patients with abnormal DMSA finding is proposed.

Controversies in the management of vesicoureteral reflux: the rationale for the RIVUR study

The current management of vesicoureteral reflux (VUR) focuses on the prevention of urinary tract infections (UTI), with curative surgery being limited to those children that fail conservative measures. This is based on the assumption that UTIs are preventable with the use of prophylatic antibiotics, leading to reduction of renal scarring, and the possibility that VUR in children can resolve spontaneously.

METHODS

Review of the recent literature has demonstrated a growing concern that antibiotic prophylaxis may not lead to prevention of UTIs. Additionally, data indicate that renal scarring may not be preventable with antibiotic prophylaxis or even surgical correction of VUR. An overview of all of the current controversies is presented in this paper.

RESULTS

Does antibiotic prophylaxis lead to reduction in UTIs in children with VUR? To address this question, the National Institutes of Health have developed a randomized placebo-controlled study of children with VUR (the RIVUR Study), identified following the development of a UTI.

CONCLUSIONS

There are far reaching consequences of the results of the RIVUR Study. If antibiotic prophylaxis does not prevent UTI in children with VUR, or lead to reduction in renal scarring, does identification of VUR provide any benefits? Perhaps appropriate treatment of UTI may be all that is necessary for preserving renal function. Final answers will have to wait until the completion of this study.

Implications of 99mTc-DMSA scintigraphy performed during urinary tract infection in neonates

OBJECTIVE

To evaluate prospectively whether normal scintigraphic results during urinary tract infections (UTIs) in neonates were predictive of the absence of dilating vesicoureteral reflux (VUR) (grade > or =III) and permanent renal damage (PRD).

METHODS

Term neonates with a first symptomatic, community-acquired UTI participated in the study. Urinary tract ultrasonography and technetium-99m-labeled dimercaptosuccinic acid ((99m)Tc-DMSA) scintigraphy were performed within 72 hours after diagnosis and voiding cystourethrography within 1 to 2 months. DMSA scintigraphy, to determine the development of PRD, was repeated 6 months after UTI.

RESULTS

Seventy-two neonates (144 renal units) were enrolled. Acute pyelonephritis was diagnosed through early DMSA scintigraphy in 19% of renal units, VUR in 22%, and grade > or =III VUR in 13%. The majority (71%) of renal units with grade > or =III VUR had normal early DMSA scintigraphic results. The sensitivity and specificity of abnormal early DMSA scintigraphic results to predict grade > or =III VUR were 29% (95% confidence interval: 11%-55%) and 82% (95% confidence interval: 74%-88%), respectively. PRD was found in 7% of renal units, all of which had abnormal early DMSA scintigraphic results. PRD was significantly more frequent among renal units with grade > or =III VUR than among nonrefluxing renal units (P < .05).

CONCLUSIONS

Normal early DMSA scintigraphic results for neonates with symptomatic UTIs were helpful in ruling out later development of PRD but were not predictive of the absence of dilating VUR. To rule out dilating VUR, voiding cystourethrography may be required.

Diagnosis and management of vesicoureteral reflux in children

Critical evaluation of previously accepted dogma regarding the evaluation and treatment of vesicoureteral reflux (VUR) has raised significant questions regarding all aspects of VUR management. Whereas the standard of care previously consisted of antibiotic prophylaxis for any child with VUR, it is now unclear which children, if any, truly benefit from antibiotic prophylaxis. Operative intervention for VUR constitutes overtreatment in many children, yet there are limited data available to indicate which children benefit from VUR correction through decreased rates of adverse long-term clinical sequelae. Studies with longer follow-up demonstrate decreased efficacy of endoscopic therapy that was previously hoped to approach the success of ureteroneocystostomy. Prospective studies might identify risk factors for pyelonephritis and renal scarring without antibiotic prophylaxis. Careful retrospective reviews of adults with a history of reflux might allow childhood risk factors for adverse sequelae to be characterized. Through analysis of multiple characteristics, better clinical management of VUR on an individualized basis will become the new standard of care.

Novel biomarkers for the diagnosis of urinary tract infection-a systematic review

Urinary tract infections (UTIs) are associated with significant morbidity. We rely on clinical presentation, urinalysis, and urine culture to diagnose UTI. To differentiate between lower UTI and pyelonephritis, we depend on the clinical presentation. In the extremes of age and in immunocompromised individuals, clinical presentation is often atypical posing a challenge to diagnosis. In the elderly, the high prevalence of asymptomatic bacteriuria is another confounder. We conducted a search of publications to find novel biomarkers to diagnose UTI and to ascertain its severity. We searched PUBMED, MEDLINE and SCOPUS databases for studies pertaining to novel biomarkers and UTI. Two reviewers independently evaluated the methodology of the studies using the STARD (Standards for Reporting of Diagnostic Accuracy) criteria. We have identified procalcitonin as a biomarker to differentiate lower UTI from pyelonephritis in the pediatric age group. Elevated serum procalcitonin levels can result in early and aggressive treatment at the time of presentation. Interleukin 6 has also shown some promise in differentiating between lower UTI and pyelonephritis but needs further validation. Lastly, given the paucity of data in certain subgroups like diabetics, kidney transplant recipients, and individuals with spinal cord injury, further studies should be conducted in these populations to improve diagnostic criteria that will inform clinical management decisions.

Ultrasonography as predictor of permanent renal damage in infants with urinary tract infection

AIM

To evaluate the ability of ultrasound (US) in infants (<1 year) with acute urinary tract infection (UTI), to identify those with permanent renal damage (PRD) at scintigraphy 1 year later.

METHODS

US, dimercaptosuccinic acid scintigraphy and voiding cystourethrography were performed in 191 infants.

RESULTS

US was abnormal in 46 infants (24%). PRD was found in 46 infants (24%); 19 of these had abnormal US (sensitivity 41%). In 145 infants without PRD, 27 had abnormal US (specificity 81%). Dilating reflux or verified obstruction occurred in 21 (11%) infants, of whom 18 (86%) had PRD while 28 of 170 (16%) without such diagnoses had PRD. Of 16 infants with dilating reflux, 9 (sensitivity 56%) had abnormal US and 14 (88%) PRD. Dilatation at US was seen in 27 children; 7 of these had dilating reflux and 5 verified obstruction.

CONCLUSION

US performed in association with acute UTI had limited ability to identify children with PRD at (99m)Tc-dimercaptosuccinic acid (DMSA) 1 year later, although abnormal renal size was a strong indicator of renal damage. The ability of US to identify children with dilating reflux was also limited. However, once detected at US, dilatation of the urinary tract was associated with dilating reflux or obstruction in half of the cases. Our study confirms that dilating reflux and obstruction are strong indicators of PRD but only half of those who developed PRD had such diagnoses.

Age-related renal parenchymal lesions in children with first febrile urinary tract infections

OBJECTIVE

The aim of this study was to define the association between age and the occurrence of acute pyelonephritis and renal scars.

METHODS

Between 1999 and 2002, all children 0 to 14 years of age consecutively seen with a first febrile urinary tract infection were enrolled in the study. (99m)Tc-Dimercaptosuccinic acid renal scintigraphy was performed within 5 days after admission for the detection of renal parenchymal involvement. The presence of vesicoureteral reflux was assessed by using cystography performed 1 month after the infection. If the acute scan results were abnormal, then follow-up (99m)Tc-dimercaptosuccinic acid scanning was performed after 6 months, to assess the frequency of scars.

RESULTS

A total of 316 children were enrolled in the study (190 children <1 year, 99 children 1-4 years, and 27 children 5-14 years of age). (99m)Tc-Dimercaptosuccinic acid scintigraphy revealed that 59% of the children had renal involvement in the acute phase of infection. The frequency of kidney involvement in infants <1 year of age (49%) was significantly lower than that in children 1 to 4 years of age (73%) and >5 years of age (81%). Of the 187 children with positive acute (99m)Tc-dimercaptosuccinic acid scan results, 123 underwent repeat scintigraphy after 6 months. Renal scars were found for 28% of children <1 year, 37% of children 1 to 4 years, and 53% of children 5 to 14 years of age. No significant differences in the frequency of scars and the presence or absence of vesicoureteral reflux were noted.

CONCLUSIONS

Our findings confirm that acute pyelonephritis and subsequent renal scarring occur only in some children with first febrile urinary tract infections. Children <1 year of age with febrile urinary tract infections have a lower risk of parenchymal localization of infection and renal scarring.

Screening young children with a first febrile urinary tract infection for high-grade vesicoureteral reflux with renal ultrasound scanning and technetium-99m-labeled dimercaptosuccinic acid scanning

OBJECTIVE

To evaluate the predictive value of renal ultrasound scanning and 99m-Technetium-dimercaptosuccinic acid (DMSA) scintigraphy for high-grade vesicoureteral reflux (VUR) in young children with a first urinary tract infection (UTI).

STUDY DESIGN

The medical records of children who had been examined with renal ultrasound scanning, DMSA scanning, and voiding cystourethrography (VCUG) were reviewed. The findings of renal ultrasound scanning, DMSA scanning, and their predictive values were evaluated.

RESULTS

Of 699 children, high-grade VUR (grades III-V) was diagnosed in 119 (17.0%). Signs of renal hypodysplasia (OR, 16.15), cyclic dilatation of pelvicaliceal system (OR, 11.73), hydroureter (OR, 4.00) with renal ultrasound scanning, and renal hypodysplasia (OR, 8.78), acute pyelonephritis (OR, 2.76) with DMSA scanning were associated with high-grade VUR. The sensitivities for high-grade VUR of ultrasound scanning alone (67.2%) or DMSA scanning alone (65.5%) were not as good as that of a both-test strategy, which had a sensitivity rate of 83.2%. The negative predictive value of the both-test strategy was 91.5%.

CONCLUSION

Renal ultrasound scanning and DMSA scanning both should be routinely performed in children with a first febrile UTI. VCUG is only indicated when abnormalities are apparent on either ultrasound scanning or DMSA scanning or both.

Procalcitonin as a predictor of renal scarring in infants and young children

The aim of this study was to evaluate the usefulness of procalcitonin (PCT) as a marker of renal scars in infants and young children with a first episode of acute pyelonephritis. Children aged 7 days to 36 months admitted for first febrile urinary tract infection (UTI) to a pediatric emergency department were prospectively enrolled. The PCT concentration was determined at admission. Acute (99m)Tc-dimercaptosuccinic acid (DMSA) scintigraphy was performed within 7 days of admission and repeated 12 months later when abnormal findings were obtained on the first scan. Of the 72 children enrolled in the study, 52 showed signs of acute pyelonephritis (APN) on the first DMSA scan. A follow-up scintigraphy at the 12-month follow-up performed on 41 patients revealed that 14 (34%) patients had developed renal scars; these patients also presented significantly higher PCT values than those without permanent renal lesions [2.3 (interquartile range 1-11.6) vs. 0.5 (0.2-1.4) ng/mL; p = 0.007]. A comparison of the PCT concentration in patients with febrile UTI without renal involvement, with APN without scar development and with APN with subsequent renal scarring revealed a significant increasing trend (p = 0.006, Kruskal-Wallis test). The area under the ROC curve for scar prediction was 0.74 (95% confidence interval 0.61-0.85), with an optimum statistical cut-off value of 1 ng/mL (sensitivity 78.6%; specificity 63.8%). Based on these results, we suggest that serum PCT concentration at admission is a useful predictive tool of renal scarring in infants and young children with acute pyelonephritis.

[Urinary tract infections in children]

Urinary tract infection (UTI) is relatively frequent in children. The younger the child is, the more symptoms are atypical. UTI is often associated with functional or malformative uropathy, such as vesico-ureteral reflux or obstruction. Appropriate imaging studies should be carried out in every infected child. The prognosis of uncomplicated UTI is very good, but is less favorable when the UTI is associated with urological abnormalities. Development of pyelonephritic scars can lead to kidney scarring, for which the occurrence of intrarenal reflux is probably responsible . Short-term treatment is recommended for uncomplicated UTI. Uncomplicated UTI with frequent relapses requires prophylactic chemotherapy; this treatment should also be considered when UTI is associated with vesico-ureteral reflux. Surgery is indicated in the presence of major urological malformations. Whether medical or surgical, the treatment of UTI should be followed by urine cultures whenever the child presents with fever. The antibiotic treatment of acute pyelonephritis must be started immediately, preferentially by intravenous route. A switch to oral treatment can be made after obtaining the results of the antibiogram. UTI represents a major risk in neonates; it should preferably be managed in specialized centers.

Timing of voiding cystourethrography in infants with first time urinary infection

The aim of the study was to evaluate whether the timing of performing a voiding cystourethrography (VCUG) following a first urinary tract infection (UTI) in infants is related to the presence or the severity of vesicoureteral reflux (VUR). A total of 411 children (male 230, female 181) with a first-recognised UTI between ages 15 days and 12 months (median 3 months) underwent a VCUG within 4-81 days (median 9 days) following diagnosis. The presence and the grade of the VUR were compared in two groups: an "early" group in which the VCUG was performed during the first week of the start of treatment and a "late" group in which the examination was performed during the second week or thereafter. The prevalence of VUR in the study cohort was 23.3% (96/411 infants). A VUR was diagnosed in 44 infants in the early group (28%) and in 52 in the late group (21%). Reflux of grade III or higher was seen in 25/44 (57%) of the infants in the early group and in 27/52 (52%) infants in the late group. These differences were not significant. Our results suggest that neither the presence nor the grade of VUR in infants is influenced by the timing of the examination following diagnosis. We therefore recommend that it is better to perform VCUG as soon as possible, provided the inflammation has subsided.

Value of imaging studies after a first febrile urinary tract infection in young children: data from Italian renal infection study 1

OBJECTIVE

We examined the diagnostic accuracy of routine imaging studies (ultrasonography and micturating cystography) for predicting long-term parenchymal renal damage after a first febrile urinary tract infection.

METHODS

This study addressed the secondary objective of a prospective trial evaluating different antibiotic regimens for the treatment of acute pyelonephritis. Data for 300 children < or =2 years of age, with normal prenatal ultrasound results, who completed the diagnostic follow-up evaluation (ultrasonography and technetium-99m-dimercaptosuccinic acid scanning within 10 days, cystography within 2 months, and repeat technetium-99m-dimercaptosuccinic acid scanning at 12 months to detect scarring) were analyzed. Outcome measures were sensitivity, specificity, and negative and positive predictive values for ultrasonography and cystography in predicting parenchymal renal damage on the 12-month technetium-99m-dimercaptosuccinic acid scans.

RESULTS

The kidneys and urinary tracts were mostly normal. The acute technetium-99m-dimercaptosuccinic acid scans showed pyelonephritis in 54% of cases. Renal scarring developed in 15% of cases. The ultrasonographic and cystographic findings were poor predictors of long-term damage, showing minor sonographic abnormalities for 12 and reflux for 23 of the 45 children who subsequently developed scarring.

CONCLUSIONS

The benefit of performing ultrasonography and scintigraphy in the acute phase or cystourethrography is minimal. Our findings support (1) technetium-99m-dimercaptosuccinic acid scintigraphy 6 months after infection to detect scarring that may be related to long-term hypertension, proteinuria, and renal function impairment (although the degree of scarring was generally minor and did not impair renal function) and (2) continued surveillance to identify recurrent urinary tract infections that may warrant further investigation.

[Imaging studies in the first urinary infection with fever in infants: is voiding cystourethrography necessary?]

INTRODUCTION

The presence of vesicoureteral reflux (VUR) in an infant with urinary tract infection (UTI), does not necessarily lead to an acquired renal injury. Only serious reflux can be a factor in fostering its appearance.

OBJECTIVES

To assess whether in infants diagnosed for the first time with a UTI with a fever, a routine initial DMSA can be used as a screening method for detecting severe reflux and replace voiding cystourethrography (VCUG).

PATIENTS AND METHODS

We retrospectively studied 162 infants under 2 years old admitted to our hospital due to having a ITU with fever for the first time (92 males and 70 females). In all cases, a renal ultrasound, DMSA and VCUG had been performed a few days after the diagnosis.

RESULTS

Of the 162 patients, 62 (38 %) had VUR, of which 56 (90 %) were mild and 6 (10 %) were severe. The DMSA was abnormal in 26/100 patients without VUR (26 %), 12/56 with mild VUR (21 %) and 6/6 of those with severe VUR (100 %). DMSA sensitivity for detecting severe reflux was 100 % and specificity was 76 %. The positive predictive value and negative predictive value was 14 % and 100 % respectively. The positive likelihood ratio was 4.17 and the negative likelihood ratio was 0.

CONCLUSIONS

It is unnecessary to carry out VCUG in an infant with an initial UTI, and a negative DMSA.

The value of renal ultrasound in children with a first episode of urinary tract infection

BACKGROUND

Urinary tract infection (UTI) is a common pediatric problem. Guidelines recommend obtaining a renal ultrasonogram (RUS) for young children after a first UTI. Our aim was to assess the value of routine RUS in the management of children hospitalized with a first episode of UTI.

METHODS

We conducted a retrospective review of the medical records of 130 children 12 years of age or younger admitted with a first UTI. Children were excluded if they had a urinary tract abnormality before admission and/or had been treated with an antibacterial agent within 7 days before admission. The yield of RUS was measured by ability to detect renal abnormalities, by the sensitivity and specificity for detecting vesicoureteral reflux (VUR) using voiding cystourethrogram (VCUG) as a gold standard, and by its influence on UTI management.

RESULTS

RUS was conducted in 130 children, but only 118 returned for a VCUG and were included in the study. The findings were positive for VUR in 20 of 40 patients (50%) with a confirmed VUR on VCUG and positive in 18 of 78 patients (23.1%) without VUR on VCUG. Of the 20 patients with a normal RUS who showed VUR, 2 had grade I reflux, 8 had grade II reflux, 7 had grade III reflux and 3 had grade IV reflux. The sensitivity, specificity, positive and negative predictive value of ultrasound in suggesting VUR was 50% and 76.9%, 52.6% and 75%, respectively. Except for one, the result of an abnormal RUS did not alter the management of our patients.

CONCLUSION

The results of our study show that the RUS has a little value in the management of children with a first UTI.

Persistence of Escherichia coli clones and phenotypic and genotypic antibiotic resistance in recurrent urinary tract infections in childhood

We assessed the clonality of consecutive Escherichia coli isolates during the course of recurrent urinary tract infections (RUTI) in childhood in order to compare clonality with phenotypic antibiotic resistance patterns, the presence of integrons, and the presence of the sul1, sul2, and sul3 genes. Altogether, 78 urinary E. coli isolates from 27 children, who experienced recurrences during a 1-year follow-up after the first attack of acute pyelonephritis, were investigated. The MICs of sulfamethoxazole, trimethoprim-sulfamethoxazole (SXT), ampicillin, cefuroxime, cefotaxime, and gentamicin and the presence or absence of the intI gene for class 1 integrons and the sulfamethoxazole resistance-encoding genes sul1, sul2, and sul3 were determined. All E. coli strains were genotyped by pulsed-field gel electrophoresis. There were no significant differences in the prevalences of resistance to beta-lactams and SXT between initial and consecutive E. coli isolates (41 versus 45% and 41 versus 29%, respectively). However, the E. coli strains obtained after SXT administration more frequently carried two or more sul genes than the nonexposed strains (9/21 [43%] versus 11/57 [19%], respectively; P = 0.044). In 78% of the patients, the recurrence of unique clonal E. coli strains alone or combined with individual strains was detected. Phenotypic resistance and the occurrence of sul genes were more stable in clonal strains than in individual strains (odds ratios, 8.7 [95% confidence interval {95% CI}, 1.8 to 40.8] and 4.4 [95% CI, 1.1 to 17.7], respectively). Thus, in children with RUTIs, the majority of E. coli strains from consecutive episodes are unique persisting clones, with rare increases in the initially high antimicrobial resistance, the presence of sul genes, and the presence of integrons.

Antibiotic prophylaxis for childhood urinary tract infection: a national survey

AIMS

To describe attitudes of paediatricians and paediatric nephrologists regarding antibiotic prophylaxis for urinary tract infection (UTI) and determine the factors associated with its use.

METHOD

A self-administered questionnaire was mailed to Canadian paediatricians (1136) and paediatric nephrologists (42).

RESULTS

The response rate was 58.1% (684 physicians); 436 who had made a decision about antibiotic prophylaxis for childhood UTI in the previous year were included in the analysis. Of these, 407 (93.3%) were certified in paediatrics and 29 (6.7%) were paediatric nephrologists. Most respondents prescribed prophylaxis for children with grade III-V vesicoureteral reflux (VUR) (96.5%-98%); 69.8 and 92.8% prescribed it for children with grades I and II VUR, respectively. Factors significantly associated with use of prophylaxis for children with grade I VUR were frequency of decision-making about prophylaxis, city size and province. Fifteen percent of physicians felt that their practice regarding antibiotic prophylaxis for children with VUR was evidence based. A hundred one respondents (24.3%) prescribed prophylaxis for infants with a first febrile UTI in the absence of VUR. Nineteen percent felt that their practice regarding antibiotic prophylaxis for these infants was evidence based. Prescription of prophylaxis for children >12 months with recurrent UTI in the absence of VUR was influenced by frequency of pyelonephritis (88.5% of respondents) and presence of voiding dysfunction (53.8%). Nine percent of physicians felt that their practice for these children was evidence based.

CONCLUSION

Opinions of Canadian paediatricians and paediatric nephrologists regarding antibiotic prophylaxis for UTI in children vary widely, probably because of the paucity of solid evidence about prophylaxis.

Current status of Gil-Vernet trigonoplasty technique

Significant controversy exists regarding vesicoureteral reflux (VUR) management, due to lack of sufficient prospective studies. The rationale for surgical management is that VUR can cause recurrent episodes of pyelonephritis and long-term renal damage. Several surgical techniques have been introduced during the past decades. Open anti-reflux operations have high success rate, exceeding 95%, and long durability. The goal of this article is to review the Gil-Vernet trigonoplasty technique, which is a simple and highly successful technique but has not gained the attention it deserves. The mainstay of this technique is approximation of medial aspects of ureteral orifices to midline by one mattress suture. A unique advantage of Gil-Vernet trigonoplasty is its bilateral nature, which results in prevention from contralateral new reflux. Regarding not altering the normal course of the ureter in Gil-Vernet procedure, later catheterization of and retrograde access to the ureter can be performed normally. There is no report of ureterovesical junction obstruction following Gil-Vernet procedure. Gil-Vernet trigonoplasty can be performed without inserting a bladder catheter and drain on an outpatient setting. Several exclusive advantages of Gil-Vernet trigonoplasty make it necessary to reconsider the technique role in VUR management.

Value of comprehensive renal ultrasound in children with acute urinary tract infection for assessment of renal involvement: comparison with DMSA scintigraphy and final diagnosis

The aim of this study was to evaluate the value of comprehensive renal ultrasound (US), i.e., combining greyscale US and amplitude-coded color Doppler sonography (aCDS), for assessment of urinary tract infection (UTI) in infants and children, compared to (1) (99m)Tc DMSA scintigraphy and (2) final diagnosis. Two hundred eighty-seven children with UTI underwent renal comprehensive US and DMSA scintigraphy. The results were compared with regard to their reliability to diagnose renal involvement, using (1) DMSA scintigraphy and (2) final diagnosis as the gold standard. Sixty-seven children clinically had renal involvement. Sensitivity increased from 84.1% using only aCDS to 92.1% for the combined US approach, using DMSA scintigraphy as the reference standard. When correlated with the final diagnosis, sensitivity for DMSA scintigraphy was 92.5%; sensitivity for comprehensive US was 94.0%. Our data demonstrate an increasing sensitivity using the combination of renal greyscale US supplemented by aCDS for differentiation of upper from lower UTI. Sensitivity for DMSA and comprehensive US was similar for both methods compared to the final diagnosis. Comprehensive US should gain a more important role in the imaging algorithm of children with acute UTI, thereby reducing the radiation burden.

Is antibiotic prophylaxis in children with vesicoureteral reflux effective in preventing pyelonephritis and renal scars? A randomized, controlled trial

OBJECTIVES

There has been intense discussion on the effectiveness of continuous antibiotic prophylaxis for children with vesicoureteral reflux, and randomized, controlled trials are still needed to determine the effectiveness of long-term antibiotics for the prevention of acute pyelonephritis. In this multicenter, open-label, randomized, controlled trial, we tested the effectiveness of antibiotic prophylaxis in preventing recurrence of pyelonephritis and avoiding new scars in a sample of children who were younger than 30 months and vesicoureteral reflux.

METHODS

One hundred patients with vesicoureteral reflux (grade II, III, or IV) diagnosed with cystourethrography after a first episode of acute pyelonephritis were randomly assigned to receive antibiotic prophylaxis with sulfamethoxazole/trimethoprim or not for 2 years. The main outcome of the study was the recurrence of pyelonephritis during a follow-up period of 4 years. During follow-up, the patients were evaluated through repeated cystourethrographies, renal ultrasounds, and dimercaptosuccinic acid scans.

RESULTS

The baseline characteristics in the 2 study groups were similar. There were no differences in the risk for having at least 1 pyelonephritis episode between the intervention and control groups. At the end of follow-up, the presence of renal scars was the same in children with and without antibiotic prophylaxis.

CONCLUSIONS

Continuous antibiotic prophylaxis was ineffective in reducing the rate of pyelonephritis recurrence and the incidence of renal damage in children who were younger than 30 months and had vesicoureteral reflux grades II through IV.

DMSA renal scans and the top-down approach to urinary tract infection

Assessment of first febrile urinary tract infection in young children has usually involved 2 imaging techniques: renal ultrasonogram and voiding cystourethrography. Currently, there is growing interest in using the dimercaptosuccinic acid (DMSA) scan labeled with technetium-99m as an alternative initial study, in the evaluation of UTI. DMSA renal scanning is the most sensitive radiologic study to detect acute pyelonephritis. Early DMSA renal scanning has been called the top-down approach, because the focus is the identification of kidney injury rather than reflux. Positive and negative aspects of DMSA renal scans are discussed by a pediatric urologist.

Prevalence of urinary tract infection in childhood: a meta-analysis

BACKGROUND

Knowledge of baseline risk of urinary tract infection can help clinicians make informed diagnostic and therapeutic decisions. We conducted a meta-analysis to determine the pooled prevalence of urinary tract infection (UTI) in children by age, gender, race, and circumcision status.

METHODS

MEDLINE and EMBASE databases were searched for articles about pediatric urinary tract infection. Search terms included urinary tract infection, cystitis, pyelonephritis, prevalence and incidence. We included articles in our review if they contained data on the prevalence of UTI in children 0-19 years of age presenting with symptoms of UTI. Of the 51 articles with data on UTI prevalence, 18 met all inclusion criteria. Two evaluators independently reviewed, rated, and abstracted data from each article.

RESULTS

Among infants presenting with fever, the overall prevalence (and 95% confidence interval) of UTI was 7.0% (CI: 5.5-8.4). The pooled prevalence rates of febrile UTIs in females aged 0-3 months, 3-6 months, 6-12 months, and >12 months was 7.5%, 5.7%, 8.3%, and 2.1% respectively. Among febrile male infants less than 3 months of age, 2.4% (CI: 1.4-3.5) of circumcised males and 20.1% (CI: 16.8-23.4) of uncircumcised males had a UTI. For the 4 studies that reported UTI prevalence by race, UTI rates were higher among white infants 8.0% (CI: 5.1-11.0) than among black infants 4.7% (CI: 2.1-7.3). Among older children (<19 years) with urinary symptoms, the pooled prevalence of UTI (both febrile and afebrile) was 7.8% (CI: 6.6-8.9).

CONCLUSIONS

Prevalence rates of UTI varied by age, gender, race, and circumcision status. Uncircumcised male infants less than 3 months of age and females less than 12 months of age had the highest baseline prevalence of UTI. Prevalence estimates can help clinicians make informed decisions regarding diagnostic testing in children presenting with signs and symptoms of urinary tract infection.

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.

Imaging in urinary tract infections: current strategies and new trends

The aim of imaging in a child with urinary tract infection (UTI) is to detect abnormalities that require appropriate treatment or findings that can be acted on to prevent development of complications (hypertension, chronic renal failure or pregnancy-related complications). Imaging protocols in pediatric urinary tract infections are evolving. From strategies based on extensive investigations in all children younger than 7 years of age, we are slowly moving to imaging strategies focused on children at risk of developing renal damage and possibly long-term complications. The article provides an overview on urinary tract infections, their complications and the use of imaging in their management. The different imaging strategies in children with UTIs (including the recommendation of excluding from imaging certain groups of patients) still needs full evaluation. It is interesting to note, however, a slow move from wide use of cystography in all children with UTI, which has been standard practice for many years but was probably not based on solid scientific evidence, toward a more focused use of cystograms in specific groups of children.

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.

Imaging and treatment strategies for children after first urinary tract infection

PURPOSE OF REVIEW

To highlight recent controversies regarding the rationale and effectiveness of imaging and treatment strategies for children who experience a first urinary tract infection.

RECENT FINDINGS

The yield of renal ultrasound for children who have had a first urinary tract infection is relatively low, and the most commonly identified abnormalities are of unclear clinical significance. If concerned about renal ultrasound abnormalities, clinicians should not be reassured by a normal late trimester prenatal ultrasound because its negative predictive value is not sufficiently high. Vesicoureteral reflux is neither necessary nor sufficient for developing renal scars. Some pyelonephritis and renal scarring may be related to vesicoureteral reflux that is missed by standard voiding cystourethrogram but detectable during positional instillation of contrast cystography. Dimercaptosuccinic acid scans provide important information about presence of pyelonephritis and renal scars, and have high negative predictive value for ruling out high-grade (III-V) vesicoureteral reflux. Antimicrobial prophylaxis may not be effective for preventing recurrent infections and may result in antimicrobial resistance. Endoscopic therapy (Deflux) has demonstrated moderate success in correcting vesicoureteral reflux, but little is known about its impact on recurrent infection and renal scarring.

SUMMARY

Debate continues about optimal imaging strategies after first urinary tract infection. More research is needed on the effectiveness of interventions designed to prevent recurrent infections and renal scarring.

Normal dimercaptosuccinic acid scintigraphy makes voiding cystourethrography unnecessary after urinary tract infection

OBJECTIVE

To test the hypothesis that infants with dilating vesicoureteral reflux (VUR) have abnormal acute dimercaptosuccinic acid (DMSA) scintigraphy results, as was suggested by an earlier retrospective study.

STUDY DESIGN

We conducted a prospective study of infants <1 year old with first diagnosed symptomatic urinary tract infection at the Children's Hospital of Göteborg, Sweden. Two hundred ninety consecutive children (161 boys and 129 girls) with complete records were examined. Renal ultrasound scanning and DMSA scintigraphy were performed within a few days from diagnosis, and VCU was performed within 2 months.

RESULTS

VUR was found in 52 children, of which 27 had dilating VUR (grade III-V). DMSA scintigraphy results were abnormal in 149 infants (51%), 105 of 238 (44%) without VUR, 18 of 25 (72%) with VUR grade I to II, and 26 of 27 (96%) with VUR grade III to V (P <.001).

CONCLUSION

DMSA scintigraphy results were abnormal in all 27 infants with dilating VUR except 1. This single false-negative finding should be compared with 140 unnecessary VCU investigations. This supports our hypothesis that DMSA scintigraphy results are abnormal when there is dilating VUR. Thus, a normal DMSA scan makes VCU unnecessary in the primary examination of infants with UTI.