The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection

Could prophylactic antibiotics be stopped in patients with history of vesicoureteral reflux?

OBJECTIVE

To compare the incidence and type of urinary tract infection (UTI) in patients with primary vesicoureteral reflux (VUR) diagnosed after a febrile UTI while they were on prophylactic antibiotics (PA) and after stopping PA.

MATERIALS AND METHODS

Criteria to discontinue PA were: no UTI during 12+ or more months on PA, old enough to communicate UTI symptoms, potty trained and absence of risk factors for UTI. Patients with at least 1 year of follow up without PA were included (n=77). We recorded: age at which PA was indicated and stopped, time on and off PA, incidence and type of UTI (cystitis vs acute pyelonephritis (APN)), and renal scan results.

RESULTS

PA was started and stopped at a mean age of 18.5 and 61 months, respectively. Mean time on PA was 39 months (range 12-95): 25 patients had 44 UTI episodes (0.17 episodes/patient/year), and 31 (70%) of them were APN. Mean time of antibiotics was 44.5 months (range 12-162): 13 patients had 24 UTI episodes (0.08 episodes/patient/year), eight (33%) of which were APN (P<0.05). A renal scan was performed in 71 patients after the index infection and repeated in 12. Two patients lost renal function while still on PA.

CONCLUSION

Discontinuing PA in patients with history of VUR is a safe practice and should be considered as a management option.

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.

Imaging studies for first urinary tract infection in infants less than 6 months old: can they be more selective?

This retrospective study aimed to evaluate the applicability of the selective approach of imaging infants < 6 months old with urinary tract infection (UTI) according to the UTI guidelines of the National Institute for Health and Clinical Excellence (NICE) 2007. Infants < 6 months old with their first UTI from January 2001 to December 2006 having undergone an ultrasound examination of the urinary tract, a micturating cystourethrogram, and a late di-mercaptosuccinic acid (DMSA) scan, were included. Their condition was evaluated against a set of risk features according to the UTI guidelines. Those having any one of these were classified as atypical and those having none as typical. There were 134 infants reviewed, with a typical (98 infants) to atypical (36 infants) ratio of 2.7 to 1. Girls were found to be relatively more represented in the atypical group [male (M):female (F) = 1.3:1] than in the typical group (M:F = 4.4:1) (P < 0.004). There were significantly more infants with abnormal micturating voiding cystourethrograms (MCUGs) (P = 0.007), more refluxing ureters (P < 0.001) and more significant vesico-ureteral reflux (VUR) (>/= grade III) (P = 0.013) in the atypical group than in the typical group; while there was no significant difference in ultrasound (US) and DMSA scan findings between the two groups. In the atypical group there was no difference in imaging studies (and, thus, the results) between the conventional practice and the NICE UTI recommendation. In the typical group, if the recommendations of the guidelines had been followed (i.e. only those with abnormal US would have been further investigated), 25 refluxing ureters and 22 scarred kidneys would have been left undiagnosed. In conclusion, application of the suggested selective imaging approach would leave a significant number of VUR and renal scars undiagnosed, and it may not be an optimal practice for infants less than 6 months old with their first UTI. The best approach remains to be clarified.

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.

Sensitivity of ultrasonography in detecting renal parenchymal defects: 6 years' follow-up

While (99m)Tc-dimercaptosuccinic acid (DMSA) scanning is still considered the most accurate method for the assessment of renal parenchymal defects (RPDs), our study 6 years previously suggested that ultrasonography (US) could be a safe and efficient substitute for this purpose, provided that it is reliably performed and that renal function parameters are followed. By comparison of the original and follow-up study data from 67 children, the accuracy of our recommendations was re-evaluated. US was performed and renal function parameters investigated and correlated to the DMSA scans from the original study. US identified all six patients with clinically significant RPD and 52/61 with clinically insignificant RPDs, seen on the DMSA scans. Twenty two out of 22 severe RPDs, 21/23 moderate RPDs and 20/40 mild RPDs seen on the DMSA scans were detected by US. In ten cases normal US findings from the original study were rendered abnormal, correlating well with the DMSA scans with respect to RPD localization and kidney size. These results further support our previous suggestion that US is a safe and harmless alternative to DMSA scanning in the detection and follow-up of RPDs. While it cannot be excluded that small RPDs missed on the initial US might 'develop' clinical significance in later life, children with normal findings on initial US should have another sonogram done, at the shortest a year later, together with an investigation of renal function parameters.

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.

Reflux nephropathy

Vesicoureteral reflux may be associated with abnormalities of the renal parenchyma. The purpose of this review is to define what the parenchymal abnormalities are histologically, what their etiologies may be, how they are identified and what their long-term clinical impact may be. Two categories are recognized, renal dysplasia and post-infection, chronic pyelonephritis. The diagnostic gold standard is microscopic evaluation of biopsy specimens but renal scintigraphy can be used in the diagnosis of renal dysplasia versus chronic pyelonephritis. Potential long-term sequelae of reflux nephropathy include hypertension and renal insufficiency although these may occur infrequently. A review of the current literature is provided.

Randomized Intervention for Children With Vesicoureteral Reflux (RIVUR): background commentary of RIVUR investigators

Because of the frequency of urinary tract infections in children, off-label use of antimicrobial prophylaxis is often the usual treatment of children with vesicoureteral reflux, and such use is increasingly being called into question; hence, a definitive study to determine the value of antimicrobial prophylaxis with regard to the recurrence of urinary tract infection and the incidence of renal scarring is essential. The currently recommended follow-up procedures (repeated urine cultures, renal and genitourinary imaging, antimicrobial therapy and prophylaxis, as well as other factors including cleanliness, adequate bladder and bowel emptying, and compliance with protocols) are expensive (in terms of time, attention to detail, and cost) and cumbersome. Such recommendations should be evidence-based.

Magnetic resonance urography in children

Magnetic resonance (MR) urography is a powerful tool that fuses anatomic information with functional data in a single test without the use of ionizing radiation. This article provides an overview of the technical aspects of MR urography and common clinical applications, such as the evaluation of hydronephrosis, reflux nephropathy, and renal dysplasia.

Randomised trial of oral versus sequential intravenous/oral cephalosporins in children with pyelonephritis

The hypothesis was tested that oral antibiotic treatment in children with acute pyelonephritis and scintigraphy-documented lesions is equally as efficacious as sequential intravenous/oral therapy with respect to the incidence of renal scarring. A randomised multi-centre trial was conducted in 365 children aged 6 months to 16 years with bacterial growth in cultures from urine collected by catheter. The children were assigned to receive either oral ceftibuten (9 mg/kg once daily) for 14 days or intravenous ceftriaxone (50 mg/kg once daily) for 3 days followed by oral ceftibuten for 11 days. Only patients with lesions detected on acute-phase dimercaptosuccinic acid (DMSA) scintigraphy underwent follow-up scintigraphy. Efficacy was evaluated by the rate of renal scarring after 6 months on follow-up scintigraphy. Of 219 children with lesions on acute-phase scintigraphy, 152 completed the study; 80 (72 females, median age 2.2 years) were given ceftibuten and 72 (62 females, median age 1.6 years) were given ceftriaxone/ceftibuten. Patients in the intravenous/oral group had significantly higher C-reactive protein (CRP) concentrations at baseline and larger lesion(s) on acute-phase scintigraphy. Follow-up scintigraphy showed renal scarring in 21/80 children treated with ceftibuten and 33/72 with ceftriaxone/ceftibuten (p = 0.01). However, after adjustment for the confounding variables (CRP and size of acute-phase lesion), no significant difference was observed for renal scarring between the two groups (p = 0.2). Renal scarring correlated with the extent of the acute-phase lesion (r = 0.60, p < 0.0001) and the grade of vesico-ureteric reflux (r = 0.31, p = 0.03), and was more frequent in refluxing renal units (p = 0.04). The majority of patients, i.e. 44 in the oral group and 47 in the intravenous/oral group, were managed as out-patients. Side effects were not observed. From this study, we can conclude that once-daily oral ceftibuten for 14 days yielded comparable results to sequential ceftriaxone/ceftibuten treatment in children aged 6 months to 16 years with DMSA-documented acute pyelonephritis and it allowed out-patient management in the majority of these children.

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.

Evaluation of reflux nephropathy, pyelonephritis and renal dysplasia

MR urography has the potential to significantly improve our understanding of the relationship between reflux nephropathy, pyelonephritis, vesicoureteric reflux and renal dysplasia. MR urography utilizes multiple parameters to assess both renal anatomy and function and provides a more complete characterization of acquired and congenital disease. Pyelonephritis and renal scarring can be distinguished by assessing the parenchymal contours and signal intensity. Characteristic imaging features of renal dysplasia include small size, subcortical cysts, disorganized architecture, decreased and patchy contrast enhancement as well as a dysmorphic pelvicalyceal system. Because of its ability to subdivide and categorize this heterogeneous group of disorders, it seems inevitable that MR urography will replace DMSA renal scintigraphy as the gold standard for assessment of pyelonephritis and renal scarring. MR urography will contribute to our understanding of renal dysplasia and its relationship to reflux nephropathy.

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.

How has research changed my practice in the last 5 years?

You can't teach old dogs new tricks. Teaching middle-aged dogs new tricks is hard enough. They tend to stick to particular styles of attacking the postman that over the years have proved pretty reliable, often choosing to ignore new findings, or simply failing to keep up with progress in current discussions on, say, the old trouser versus postbag debate. Some unsettling papers are even asking whether dogs really need to attack postmen at all.

Urinary tract infection in the newborn: clinical and radio imaging studies

The objective of this study was to assess clinical characteristics and results of radio imaging studies and compare community-acquired urinary tract infection (UTI) with nosocomial UTI in 301 neonates with UTI consecutively admitted to 28 neonatal units in Spain over 3 years (community-acquired UTI, n = 250; nosocomial UTI, n = 51). UTI was diagnosed in the presence of symptoms of infection together with any colony growth for a single pathogen from urine obtained by suprapubic aspiration, or >or=10(4) CFU/ml for a single pathogen from urine obtained by urethral catheterization. Abnormal renal ultrasound was present in 37.1% of cases (34% in community-acquired UTI and 54.5% in nosocomial UTI, P < 0.01). The voiding cystourethrography (VCUG) showed vesicoureteral reflux (VUR) in 27% of cases (23.8% in community-acquired UTI and 48.6% in nosocomial UTI, P < 0.01). In patients with abnormal renal ultrasound and VUR, renal scan with dimercaptosuccinic acid (DMSA) performed early after UTI revealed cortical defects in 69.5% of cases. However, in patients with abnormal renal ultrasound and normal VCUG, DMSA also revealed cortical defects in 39% of cases. The absence of VUR in neonates with UTI and abnormal renal ultrasound does not exclude the presence of cortical defects suggestive of pyelonephritis.

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.

Renal infection and vesico-ureteric reflux

Urinary tract infection (UTI) is a common disease of childhood. The investigation of UTI in children has been the subject of debate and controversy for many years. Most workers agree that the first imaging modality to be used should be an ultrasound examination to exclude obstruction, structural abnormalities, and renal calculi. The role of (99m)Tc dimercaptosuccinic acid scintigraphy (DMSA) in the diagnosis of acute pyelonephritis is becoming increasingly important. Many argue that if the DMSA study is normal at the time of acute UTI, no further investigation is required because the kidneys have not been involved and thus there will be no late sequelae. Others use the acute DMSA study to determine the intensity of antibiotic therapy. The importance of the role of vesico-ureteric reflux (VUR) is being debated. Some workers will only proceed to cystography to detect VUR if the DMSA study is abnormal, whereas others advocate a more aggressive approach. VUR can be identified by a variety of radiological and scintigraphic techniques. Although the radiological cystogram is the gold standard and is essential in the first UTI in a male patient, to exclude the presence of posterior urethral valves, radionuclide cystograms are advantageous in other situations. Suprapubic cystography techniques have been described to overcome the trauma of urethral catheterization but have not been widely accepted.

Imaging strategies for vesicoureteral reflux diagnosis

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

Ordering of renal tract imaging by paediatricians after urinary tract infection

AIM

To describe paediatricians' reported ordering of renal tract imaging of children following urinary tract infection.

METHODS

This is a piloted self-administered survey. A total of 354 randomly sampled practising paediatricians in Australia participated in the survey. The survey included 12 clinical scenarios that varied with age, gender and fever. Respondents indicated their likelihood of ordering renal ultrasound, micturating cystourethrogram (MCU) and dimercaptosuccinic acid scan (DMSA) from 0 to 100%.

RESULTS

Response rate was 74.6% (264/354). For all clinical scenarios the median probability of ordering an ultrasound was 100% with little variability. For children aged 2 months, likelihood of ordering an MCU was 100%, with little variability, but was 70% for 3-year-olds with fever (45% without fever), and 5% for 6-year-olds with very large variability. Median likelihood of ordering a DMSA was 80% at 2 months, 60% at 3 years and 20% at 6 years (40%, 15%, 5% without fever, respectively). Variability was large for all scenarios and DMSA ordering. Child gender did not influence ordering practices.

CONCLUSIONS

Renal tract imaging practice across paediatricians shows consistent, approximately 100% use of the least invasive modality, ultrasound. In contrast, there is considerable variation in the reported ordering of the more invasive tests MCU and DMSA. Doctors order these tests more in younger children and when fever is present.

[Evaluation of renal lesions using 99mTc-DMSA in children with urinary tract infection and the relation with vesicoureteral reflux]

OBJECTIVE

Paediatric patients with urinary tract infection (UTI) have risk of developing renal scarrings. Although it is known that vesicoureteral reflux (VUR) predisposes to UTIs and it seems to have an important role in the development of renal lesions, some recent published studies question that relation. The aim of the study was to evaluate renal scarring by using renal scintigraphy 99mTc-DMSA and see the relation with or without the presence of VUR.

MATERIAL AND METHODS

We evaluated retrospectively a total of 230 patients (460 renal units), mean age: 11 months (range: 12d-5y), with UTI probed by urinoculture. All were studied with voiding cistourethrography (MCU) to evaluate the presence or absence of VUR. Patients were evaluated with 99mTc-DMSA scan 6 months after UTI to determine if UTI caused renal scarring.

RESULTS

Renal scans with 99mTc-DMSA 6 months post-infection were abnormal in 62 renal units, affecting 54 patients (23 %). From all patients studied, 110 were diagnosis of VUR being affected 161 renal units, 43 of them (27 %) presented renal scarrings. From the remaining 120 patients without VUR that is 240 renal units, 19 of them (8 %) presented parenchymatous damage.

CONCLUSION

Renal scarring resulting from UTI are in some cases related to VUR, but sometimes are caused by the infection itself. Not all patients with VUR develop renal lesions, and neither the presence of VUR always predispose children to renal lesions. MCU and direct isotopic cystography are useful for diagnosis of VUR but we shouldn't avoid 99mTc-DMSA scan in the management of children with UTI.

Vesicoureteral reflux increases the risk of renal scars: a study of unilateral reflux

The aim of this study was to assess the impact of vesicoureteral reflux (VUR) on renal scar following acute pyelonephritis by comparing the refluxing renal units with nonrefluxing renal units in children with unilateral primary VUR. Forty-eight children with unilateral primary VUR diagnosed after the first pyelonephritis were enrolled. Mean age of patients was 1.0+/-1.6 years (29 boys and 19 girls). All patients underwent renal ultrasonography and renal 99 m-technetium dimercaptosuccinic acid (DMSA) scan within three days following the diagnosis of pyelonephritis, and voiding cystourethrography (VCU) was performed soon after fever subsided and the infection was controlled. The DMSA scan was rechecked six months after the initial study when the first scan showed a renal defect. The first DMSA showed renal defects in 34 (70.8%) out of 48 of the refluxing renal units and in 13 (27.1%) out of 48 of the nonrefluxing renal units (P<0.01, OR: 6.54). At six months after the infection, 23 (47.9%) out of 48 refluxing renal units and seven (14.6%) out of 48 nonrefluxing renal units had renal scars on DMSA scan (P<0.01, OR: 5.39). The prevalence of renal scars did not vary significantly according to the grade of VUR. The CRP level on admission was significantly higher in patients with acute renal defect and scar. In conclusion, VUR increases the risk of post-pyelonephritic renal scars in children.

Acute urinary tract infection--evaluation and treatment

PURPOSE OF REVIEW

The evaluation and management of urinary tract infections in infants and children is undergoing changes due to the impact of evidence-based studies and new technology.

RECENT FINDINGS

The uncircumcised male infant is at increased risk for a urinary tract infection, but there is marked difference in the frequency of circumcision carried out to lower the risk of infection in the United States compared with Europe. Commentaries presenting different interpretations of the current data make for interesting reading and present the many sides of this issue. Vesicoureteric reflux, previously viewed as the major risk factor for acquired renal damage, now shares this role with nonreflux nephropathy. Procalcitonin has been evaluated as a biochemical tool to identify patients at risk for kidney damage, with dimercaptosuccinic acid scintigraphy as the reference method to detect renal scarring.

SUMMARY

The previously accepted concept that vesicoureteric reflux as detected radiologically is almost always the key factor in acquired renal injury secondary to a urinary tract infection is no longer accepted. Current studies show that nonreflux nephropathy occurs as often as reflux nephropathy. There is now a question of the value of imaging studies designed to identify vesicoureteric reflux and of the use of suppressive antibiotics for vesicoureteric reflux. There exist useful evidence-based studies for antibiotic therapy for upper and lower tract urinary tract infections, but no such data are available for guidance in selecting imaging studies for the infant or child with a first febrile urinary tract infection.

Can we predict vesicoureteric reflux?

Commentary on the paper by Leroy et al (see page 241)