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

Is technetium-99m dimercaptosuccinic acid renal scintigraphy available for predicting vesicoureteral reflux in children with first febrile urinary tract infection under the age of 24 months?

OBJECTIVE

Vesicoureteral reflux (VUR) is a common complication after urinary tract infection (UTI) and can lead to irreversible renal scar. Voiding cystourethrogram is the most reliable technology to detect VUR and its severity, but it is restricted in children's examinations for various shortcomings. This study aimed to evaluate and compare the efficiency of Tc-99m DMSA renal scintigraphy and conventional ultrasonography (USG) in predicting VUR with the gold standard of cystourethrogram results.

METHODS

This retrospective study consisted of 285 first febrile UTI children under the age of 24 months who completed inflammatory indicator examinations, USG, Tc-99m DMSA renal scintigraphy and underwent cystourethrography after controlling infection with prophylactic antibiotics. The efficiency of Tc-99m DMSA renal scintigraphy and USG in predicting VUR was calculated and compared.

RESULTS

Abnormal USG (40.23% vs. 21.72%, P = 0.001) and Tc-99m DMSA renal scintigraphy results (87.36% vs. 71.72%, P = 0.004) were more common in VUR children. The sensitivity of USG in predicting VUR was only 40.23%, whereas the sensitivity and negative predictive value of Tc-99m DMSA renal scintigraphy reached 87.63 and 83.58%, respectively. Tc-99m DMSA renal scintigraphy had a higher efficacy than USG in predicting high-grade reflux kidneys (73.87% vs. 33.33%; P < 0.001), but there was no significant difference in predicting low-grade reflux kidneys ( P = 0.703).

CONCLUSION

Tc-99m DMSA renal scintigraphy had a significant higher efficiency in predicting VUR (a common cause of renal scarring, detected on DMSA) in first febrile urinary tract infection children under the age of 24 months as compared with USG, especially in high-grade reflux.

Guidelines for the medical management of pediatric vesicoureteral reflux

Urinary tract infection is a bacterial infection that commonly occurs in children. Vesicoureteral reflux is a major underlying precursor condition of urinary tract infection, and an important disorder in the field of pediatric urology. Vesicoureteral reflux is sometimes diagnosed postnatally in infants with fetal hydronephrosis diagnosed antenatally. Opinions vary regarding the diagnosis and treatment of vesicoureteral reflux, and diagnostic procedures remain debatable. In terms of medical interventions, options include either follow‐up observation in the hope of possible spontaneous resolution of vesicoureteral reflux with growth/development or provision of continuous antibiotic prophylaxis based on patient characteristics (age, presence/absence of febrile urinary tract infection, lower urinary tract dysfunction and constipation). Furthermore, there are various surgical procedures with different indications and rationales. These guidelines, formulated and issued by the Japanese Society of Pediatric Urology to assist medical management of pediatric vesicoureteral reflux, cover the following: epidemiology, clinical practice algorithm for vesicoureteral reflux, syndromes (dysuria with vesicoureteral reflux, and bladder and rectal dysfunction with vesicoureteral reflux), diagnosis, treatment (medical and surgical), secondary vesicoureteral reflux, long‐term prognosis and reflux nephropathy. They also provide the definition of bladder and bowel dysfunction, previously unavailable despite their close association with vesicoureteral reflux, and show the usefulness of diagnostic tests, continuous antibiotic prophylaxis and surgical intervention using site markings.

National Imaging and Antibiotic Practice Patterns in Children Presenting With Urinary Tract Infection to Community Practices: Little Impact From the American Academy of Pediatrics Guidelines?

Our objective was to use community-based, national databases to evaluate diagnostic imaging and antibiotic prophylaxis practice patterns before and after the release of the 2011 American Academy of Pediatrics guidelines for acute febrile urinary tract infection. Using the National Ambulatory and Hospital Ambulatory Medical Care Surveys, urinary tract infection encounters were identified for patients aged 2 months to 18 years. Primary outcomes were utilization of antibiotics (as proxy for prophylaxis) and diagnostic imaging during encounters. Weighted multivariate logistic regression models were used to examine the association between time period (before and after 2011) and each of the primary outcomes. Among 8 588 035 weighted encounters, adjusting for covariates, there was insufficient evidence to suggest a difference between time periods for antibiotic utilization (odds ratio = 0.66, P = .12) or diagnostic imaging (odds ratio = 1.16, P = .56). Thus, we did not find evidence of changes in antibiotic utilization or diagnostic imaging practice patterns after the release of the 2011 American Academy of Pediatrics guidelines.

Antibiotics for performing voiding cystourethrogram: a randomised control trial

OBJECTIVE

To assess whether antibiotic reduces voiding cystourethrogram (VCUG)-associated urinary tract infection (UTI).

DESIGN

Open-labelled randomised controlled trial.

SETTING

Tertiary paediatric nephrology centre.

PATIENTS

120 children (age 2 months-5 years) undergoing VCUG.

INTERVENTIONS

Children were randomised into group A (antibiotic, n=72) or group B (no antibiotic, n=48) in 3:2 ratio. Group A received oral antibiotic (cephalexin if <6 months or co-trimoxazole if >6 months old) a day prior to VCUG and continued for 1 day post VCUG.

MAIN OUTCOME MEASURES

The main outcome measure is incidence of VCUG-associated UTI. Urine was checked on day 3 after VCUG and UTI was defined as significant growth of a single organism in a symptomatic child.

RESULTS

The median age was 8 months (IQR 13 months) with 68% male. Indication for undertaking VCUG was history of UTI (first UTI in infancy=43, recurrent UTI=49) and congenital anomaly of kidney and urinary tract without any UTI (n=28). Post-VCUG UTI was significantly higher among group B in comparison to group A (17% (n=8) vs 1.4% (n=1); p=0.01, OR=14.2 (95% CI 1.7 to 117)). Multivariate binary logistic regression analysis found an abnormal pre-VCUG ultrasound scan to be a significant independent risk factor for post-VCUG UTI (p=0.02, OR=9.51, 95% CI 1.43 to 63.4). The number needed to treat with antibiotic to prevent one post-VCUG UTI was 6.5, which reduced to 4 if only the group with abnormal pre-VCUG ultrasound scan was included.

CONCLUSIONS

Antibiotic significantly reduces post-VCUG-acquired UTI especially in those with abnormal ultrasound scans.

TRIAL REGISTRATION NUMBER

Clinical Trial Registry of India: CTRI/2017/03/00824.

Yield of Imaging Performed as per Indian Society of Pediatric Nephrology Guidelines in Children with Urinary Tract Infection

OBJECTIVE

To assess yield of imaging performed as per Indian Society of Pediatric Nephrology (ISPN) urinary tract infection (UTI) guideline.

METHODS

Ultrasonography (USG), voiding cystourethrography (VCUG) and dimercaptosuccinic-acid (DMSA) scintigraphy were performed in 183 children (age 0-5y) with first episode (age 0-1y) of UTI or recurrent (age <5y) UTI, as per ISPN recommendations.

RESULTS

Significant abnormalities were detected in 110 (63%), with vesicoureteric reflux (VUR) grades 3-5 in 31% and renal scars in 43%. Combined USG and DMSA had a negative predictive value of 94% for significant VUR.

Conclusion

ISPN guideline resulted in a high yield of detection of significant abnormalities.

Selective imaging modalities after first pyelonephritis failed to identify significant urological anomalies, despite normal antenatal ultrasounds

AIM

We investigated the consequences of applying different imaging guidelines for urological anomalies after first pyelonephritis in children with normal routine antenatal ultrasounds.

METHODS

The cohort comprised 472 children treated for their first culture-positive pyelonephritis and investigated with ultrasound and renal scintigraphy. We excluded patients with known urological anomalies and patients born before routine antenatal ultrasound. We followed the cohort for a median of 5.7 years (3.1-10.1 years) by reviewing their medical reports.

RESULTS

Urological anomalies were diagnosed in 95 patients. Dilated vesicoureteral reflux (VUR) was the predominant finding (n = 29), including nine who initially had surgery. Using imaging guidelines from the American Academy of Pediatrics would have missed 11 urological patients, including two with initial surgery, and avoided 339 scintigraphies. Using the European Association of Paediatric Urology guidance would have missed three urological patients, one with initial surgery, and avoided 46 scintigraphies. Investigating patients under two years with ultrasound and scintigraphy, and just ultrasound in children over two years, would have identified all patients initially treated with surgery and avoided 65 scintigraphies.

CONCLUSION

Dilated VUR was the dominant anomaly in a cohort with first time pyelonephritis and normal antenatal ultrasound. The optimal imaging strategy after pyelonephritis must be identified.

Dimercaptosuccinic acid scan or ultrasound in screening for vesicoureteral reflux among children with urinary tract infections

BACKGROUND

There is considerable interest in detecting vesicoureteral reflux (VUR) because its presence, especially when severe, has been linked to an increased risk of urinary tract infections and renal scarring. Voiding cystourethrography (VCUG), also known as micturating cystourethrography, is the gold standard for the diagnosis of VUR, and the grading of its severity. Because VCUG requires bladder catheterisation and exposes children to radiation, there has been a growing interest in other screening strategies that could identify at-risk children without the risks and discomfort associated with VCUG.

OBJECTIVES

The objective of this review is to evaluate the accuracy of two alternative imaging tests - the dimercaptosuccinic acid renal scan (DMSA) and renal-bladder ultrasound (RBUS) - in diagnosing VUR and high-grade VUR (Grade III-V VUR).

SEARCH METHODS

We searched MEDLINE, EMBASE, BIOSIS, and the Cochrane Register of Diagnostic Test Accuracy Studies from 1985 to 31 March 2016. The reference lists of relevant review articles were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We considered published cross-sectional or cohort studies that compared the results of the index tests (DMSA scan or RBUS) with the results of radiographic VCUG in children less than 19 years of age with a culture-confirmed urinary tract infection.

DATA COLLECTION AND ANALYSIS

Two authors independently applied the selection criteria to all citations and independently abstracted data. We used the bivariate model to calculate summary sensitivity and specificity values.

MAIN RESULTS

A total of 42 studies met our inclusion criteria. Twenty studies reported data on the test performance of RBUS in detecting VUR; the summary sensitivity and specificity estimates were 0.44 (95% CI 0.34 to 0.54) and 0.78 (95% CI 0.68 to 0.86), respectively. A total of 11 studies reported data on the test performance of RBUS in detecting high-grade VUR; the summary sensitivity and specificity estimates were 0.59 (95% CI 0.45 to 0.72) and 0.79 (95% CI 0.65 to 0.87), respectively. A total of 19 studies reported data on the test performance of DMSA in detecting VUR; the summary sensitivity and specificity estimates were 0.75 (95% CI 0.67 to 0.81) and 0.48 (95% CI 0.38 to 0.57), respectively. A total of 10 studies reported data on the accuracy of DMSA in detecting high-grade VUR. The summary sensitivity and specificity estimates were 0.93 (95% CI 0.77 to 0.98) and 0.44 (95% CI 0.33 to 0.56), respectively.

AUTHORS' CONCLUSIONS

Neither the renal ultrasound nor the DMSA scan is accurate enough to detect VUR (of all grades). Although a child with a negative DMSA test has an < 1% probability of having high-grade VUR, performing a screening DMSA will result in a large number of children falsely labelled as being at risk for high-grade VUR. Accordingly, the usefulness of the DMSA as a screening test for high-grade VUR should be questioned.

Accuracy of ultrasonography in predicting vesicoureteral reflux in children: A meta-analysis

OBJECTIVE

The aim of this study was to assess the existing evidence on the accuracy of renal and bladder ultrasonography in predicting vesicoureteral reflux in children with first urinary tract infection.

MATERIALS AND METHODS

The CENTRAL, MEDLINE, Embase and Web of Science data sources were searched. A random effects meta-analysis was conducted.

RESULTS

Fourteen studies, involving 3544 participants, fulfilled the inclusion criteria. The risk of bias and concern regarding applicability were considered high in four studies. The pooled sensitivity was 0.37 [95% confidence interval (CI) 0.34 to 0.40], specificity 0.81 (95% CI 0.80 to 0.83), positive likelihood ratio 2.0 (95% CI 1.61 to 2.50), negative likelihood ratio 0.75 (95% CI 0.65 to 0.86), diagnostic odds ratio 3.03 (95% CI 2.10 to 4.37) and area under the curve 0.72.

CONCLUSION

There is no evidence that renal and bladder ultrasonography should be recommended as a test to predict a vesicoureteral reflux in children with their first urinary tract infection.

Paediatric urinary tract infections: a retrospective application of the National Institute of Clinical Excellence guidelines to a large general practitioner referred historical cohort

BACKGROUND

The National Institute for Clinical Excellence (NICE) is a United Kingdom nondepartmental public body accountable to the Department of Health. Before the introduction of the NICE guidelines in the United Kingdom most children younger than 1 year of age had a urinary tract ultrasound, cyclic micturating cystourethrogram and dimercaptosuccinic acid scintigraphy, the latter delayed 6 months post infection. Children older than 1 year had a urinary tract ultrasound only, and further imaging if necessary.

OBJECTIVE

Identify who would have been investigated had the NICE imaging strategy been used and who would not. Compare the diagnostic yield and patient outcome with the previous imaging protocol using our prospectively collected historical data.

MATERIALS AND METHODS

We applied the new imaging strategy to a historic cohort of 934 patients with a urinary tract infection (UTI) referred by general practitioners to a specialist children's hospital between 1996 and 2002.

RESULTS

Of the 934 patients referred, 218 would have been investigated according to the NICE guidelines. In total, there were 105 patients with abnormal imaging findings, and 44 of these (42%) would have been investigated under the NICE guidelines.

CONCLUSION

Applying the NICE guidelines to children presenting with UTI will reduce the number imaged by 77% and will lead to missed identification of 58% of imaging abnormalities in the group. The majority of these abnormalities may be important. While supporting conservative investigation protocols, we are concerned that many abnormalities might go undetected.

Voiding cystourethrography is mandatory in infants with febrile urinary tract infection

Vesicoureteral reflux (VUR) is common condition in infants with febrile urinary tract infections (UTIs). Both VUR and febrile UTIs are risk factors for renal scars, characterized by glomerular hypertrophy with global or segmental sclerosis as cardinal features in pathology. Because renal scars may cause hypertension or chronic kidney diseases in later life, voiding cystourethrography (VCUG) has been mandatory for infants following their first febrile UTIs to identify VUR. However, increasing evidence suggests that the presence of VUR may not represent a direct risk factor for renal scars, which has led to an increase in the use of a stratified approach, in which VCUG is not performed for all patients. This study was conducted to verify whether the stratified approach is justified to identify infants at risk for renal scarring. The medical records of 306 infants with first febrile UTIs (median age, 4 months; 0-72 months) were reviewed. VUR was detected in 40.4% (67/166) of patients by the non-stratified approach, in which VCUG was performed in all patients. In contrast, VUR was identified in only 27.1% (38/140) of patients by the stratified approach, in which VCUG was performed only in the patients with high risk of developing renal scars. This difference in the discovery rate was significant (p = 0.02). Renal bladder ultrasonography had the sensitivities of as low as 45.7% and 52.9% in detecting VUR and in predicting renal scarring assessed by renal scintigraphy, respectively. In conclusion, VCUG should be performed in all infants after their first febrile UTIs.

Genome-guided insights into the versatile metabolic capabilities of the mercaptosuccinate-utilizing β-proteobacterium Variovorax paradoxus strain B4

Variovorax paradoxus B4 is able to utilize 2-mercaptosuccinate (MS) as sole carbon, sulfur and energy source. The whole genome of V. paradoxus B4 was sequenced, annotated and evaluated with special focus on genomic elements related to MS metabolism. The genome encodes two chromosomes harbouring 5 795 261 and 1 353 255 bp. A total of 6753 putative protein-coding sequences were identified. Based on the genome and in combination with results from previous studies, a putative pathway for the degradation of MS could be postulated. The putative molybdopterin oxidoreductase identified during transposon mutagenesis probably catalyses the conversion of MS first into sulfinosuccinate and then into sulfosuccinate by successive transfer of oxygen atoms. Subsequently, the cleavage of sulfosuccinate yields oxaloacetate and sulfite, while the latter is oxidized to sulfate. The expression of the putative molybdopterin oxidoreductase was induced by MS, but not by gluconate, as confirmed by reverse transcriptase polymerase chain reaction. Further, in silico studies combined with experiments and comparative genomics revealed high metabolic diversity of strain B4. It bears a high potential as plant growth-promoting bacterium and as candidate for degradation and detoxification of xenobiotics and other hardly degradable substances. Additionally, the strain is of special interest for production of polythioesters with sulfur-containing precursors as MS.

NICE guidelines for imaging studies in children with UTI adequate only in boys under the age of 6 months

PURPOSE

The purpose of this study was to evaluate the applicability of the National Institute for Health and Clinical Excellence (NICE) guidelines for imaging studies in children under the age of three with first urinary tract infection (UTI).

METHODS

In our cohort of 112 patients, we gathered data regarding the occurrence of indications for ultrasonography (US) and voiding cystourethrography (VCUG) according to the NICE guidelines, dimercaptosuccinic acid (DMSA) scintigraphy examinations, UTI recurrence, antimicrobial prophylaxis (AMP), anti-reflux procedures, and other urological procedures.

RESULTS

If the NICE guidelines had been applied, 13 of the 25 patients (52 %) with vesicoureteral reflux (VUR), including 6 of the 12 patients (50 %) with dilating VUR and 3 of the 4 patients who underwent endoscopic anti-reflux treatment, would have been missed, and a negative VCUG would have been avoided in 25 of the 42 patients (60 %) with no VUR. None of the missed diagnoses occurred in the younger boys' group.

CONCLUSION

Based on these preliminary analyses, we feel that the NICE guidelines for imaging studies in children under 3 years old with UTI may be applicable to clinical use only in boys under 6 months of age. For other patients the guidelines were unsuccessful.

[Diagnostics and therapy of urinary tract infections]

In infants and young children, urinary tract infections (UTI) often present with unspecific symptoms. Appropriate techniques of urine sampling play an important role for accurate microbiological diagnosis. In infants urine sampling by bladder puncture or transurethral catheter is recommended. In young infants with suspected pyelonephritis, calculated antibiotic treatment should be initiated parenterally with a combination of a third generation cephalosporin or an aminoglycoside with ampicillin. After the age of 3-6 months group 3 oral cephalosporins can be used in uncomplicated pyelonephritis. With the first febrile UTI early sonography is recommended to provide information about renal parenchymal involvement and to exclude malformations of the kidneys and urinary tract. Strategies for the recognition of vesicoureteral reflux and renal damage are under discussion. Recently published guidelines by the American Academy of Pediatrics for the diagnosis and management of UTI in febrile children and infants aged 2-24 months will most likely influence the still pending German guidelines.

Incidence of abnormal imaging and recurrent pyelonephritis after first febrile urinary tract infection in children 2 to 24 months old

PURPOSE

The AAP (American Academy of Pediatrics) no longer recommends voiding cystourethrogram in children 2 to 24 months old who present with a first urinary tract infection if renal-bladder ultrasound is normal. We identified factors associated with abnormal imaging and recurrent pyelonephritis in this population.

MATERIALS AND METHODS

We retrospectively evaluated children diagnosed with a first episode of pyelonephritis at age 2 to 24 months using de-identified electronic medical record data from an institutional database. Data included age at first urinary tract infection, gender, race/ethnicity, need for hospitalization, intravenous antibiotic use, history of abnormal prenatal ultrasound, renal-bladder ultrasound and voiding cystourethrogram results, urinary tract infection recurrence and surgical intervention. Risk factors for abnormal imaging and urinary tract infection recurrence were analyzed by univariate logistic regression, the chi-square test and survival analysis.

RESULTS

We identified 174 patients. Of the 154 renal-bladder ultrasounds performed 59 (38%) were abnormal. Abnormal prenatal ultrasound (p = 0.01) and the need for hospitalization (p = 0.02) predicted abnormal renal-bladder ultrasound. Of the 95 patients with normal renal-bladder ultrasound 84 underwent voiding cystourethrogram. Vesicoureteral reflux was more likely in patients who were white (p = 0.003), female (p = 0.02) and older (p = 0.04). Despite normal renal-bladder ultrasound, 23 of 84 patients (24%) had dilating vesicoureteral reflux. Of the 95 patients with normal renal-bladder ultrasound 14 (15%) had recurrent pyelonephritis and 7 (7%) went on to surgical intervention.

CONCLUSIONS

Despite normal renal-bladder ultrasound after a first pyelonephritis episode, a child may still have vesicoureteral reflux, recurrent pyelonephritis and the need for surgical intervention. If voiding cystourethrogram is deferred, parents should be counseled on these risks.

Pediatric urinary tract infection: does the evidence support aggressively pursuing the diagnosis?

The epidemiology of pediatric fever has changed considerably during the past 2 decades with the development of vaccines against the most common bacterial pathogens causing bacteremia and meningitis. The decreasing incidence of these 2 conditions among vaccinated children has led to an emphasis on urinary tract infection as a remaining source of potentially hidden infections in febrile children. Emerging literature, however, has led to questions about both the degree and nature of the danger posed by urinary tract infection in nonverbal children, whereas the aggressive pursuit of the diagnosis consumes resources and leads to patient discomfort, medical risks, and potential overdiagnosis. We review both early and emerging literature to examine the utility and efficacy of early identification and treatment of urinary tract infection in children younger than 24 months. We conclude that in well children of this age, it may be reasonable to withhold or delay testing for urinary tract infection if signs of other sources are apparent or if the fever has been present for fewer than 4 to 5 days.

Managing urinary tract infections

Urinary tract infections (UTI) are common in childhood. Presence of pyuria and bacteriuria in an appropriately collected urine sample are diagnostic of UTI. The risk of UTI is increased with an underlying urological abnormality such as vesicoureteral reflux, constipation, and voiding dysfunction. Patients with acute pyelonephritis are at risk of renal scarring and subsequent complications such as hypertension, proteinuria with and without FSGS, pregnancy-related complications and even end-stage renal failure. The relevance and the sequence of the renal imaging following initial UTI, and the role of antimicrobial prophylaxis and surgical intervention are currently undergoing an intense debate. Prompt treatment of UTI and appropriate follow-up of those at increased risk of recurrence and/or renal scarring are important.

Common childhood bacterial infections

Children with infectious diseases are commonly encountered in primary care settings. Identification of the subset of patients with bacterial infections is key in guiding the best possible management. Clinicians frequently care for children with infections of the upper respiratory tract, including acute otitis media, otitis externa, sinusitis, and pharyngitis. Conjunctivitis is not an uncommon reason for office visits. Bacterial pneumonia, urinary tract infections, and gastroenteritis are regularly seen. Over the last decade, a growing number of children have had infections of the skin and soft tissue, driven by the increased prevalence of infections caused by methicillin-resistant Staphylococcus aureus. The following review addresses the epidemiology and risk factors for specific infections and examines the clinical presentation and selection of appropriate diagnostic methods in such conditions. Methods to prevent these bacterial infections and recommendations for follow-up are suggested. Management of these infections requires that antimicrobial agents be used in a judicious manner in the outpatient setting. Such antibiotic therapy is recommended using both available clinical evidence and review of disease-specific treatment guidelines.

Febrile urinary tract infection, vesicoureteral reflux, and renal scarring: current controversies in approach to evaluation

The ideal approach to the radiological evaluation of children with urinary tract infection (UTI) is in a state of confusion. The conventional bottom-up approach, with its focus on the detection of upper and lower urinary tract abnormalities, including vesicoureteral reflux, has been challenged by the top-down approach, which focuses on confirming the diagnosis of acute pyelonephritis before more invasive imaging is considered. Controversies abound regarding which approach may best assess the ultimate risk for reflux-related renal scarring. Evolving practices motivated by the emerging evidence, the desire to minimize unnecessary interventions, as well as improve compliance with recommended testing, have added to the current controversies. Recent guideline updates and ongoing clinical trials hopefully will help in addressing some of these concerns.

Imaging strategy for infants with urinary tract infection: a new algorithm

PURPOSE

We analyzed clinical data for prediction of permanent renal damage in infants with first time urinary tract infection.

MATERIALS AND METHODS

This population based, prospective, 3-year study included 161 male and 129 female consecutive infants with first time urinary tract infection. Ultrasonography and dimercapto-succinic acid scintigraphy were performed as acute investigations and voiding cystourethrography within 2 months. Late scintigraphy was performed after 1 year in infants with abnormality on the first dimercapto-succinic acid scan or recurrent febrile urinary tract infections. End point was renal damage on the late scan.

RESULTS

A total of 270 patients had end point data available, of whom 70 had renal damage and 200 did not. Final kidney status was associated with C-reactive protein, serum creatinine, temperature, leukocyturia, non-Escherichia coli bacteria, anteroposterior diameter on ultrasound and recurrent febrile urinary tract infections. In stepwise multiple regression analysis C-reactive protein, creatinine, leukocyturia, anteroposterior diameter and non-E.coli bacteria were independent predictors of permanent renal damage. C-reactive protein 70 mg/l or greater combined with anteroposterior diameter 10 mm or greater had sensitivity of 87% and specificity of 59% for renal damage. An algorithm for imaging of infants with first time urinary tract infection based on these results would have eliminated 126 acute dimercapto-succinic acid scans compared to our study protocol, while missing 9 patients with permanent renal damage.

CONCLUSIONS

C-reactive protein can be used as a predictor of permanent renal damage in infants with urinary tract infection and together with anteroposterior diameter serves as a basis for an imaging algorithm.

Evaluating different imaging strategies in children after first febrile urinary tract infection

We conducted a retrospective multicenter review to estimate the prevalence of urological abnormalities in Chinese children with first febrile urinary tract infection (UTI) and to evaluate the selective imaging strategy recommended by the NICE guideline for detecting underlying abnormalities. Atypical UTI was defined as in the NICE UTI guideline. Overall, 576 boys and 244 girls aged below 24 months were reviewed. All underwent ultrasound (US) and micturating cystourethrogram (MCUG) and 612 underwent DMSA scans. US was abnormal in 73 (8.9%) and vesicoureteral reflux was shown in 195 patients (23.8%). A total of 126 patients were considered to have remediable urological abnormalities requiring additional surgical or medical interventions. The NICE guideline yielded excellent negative predictive values (NPV) of 100-94.4% in girls but 91% in boys. If all boys underwent US and DMSA and only those with atypical UTI or abnormal US or DMSA proceeded to MCUG, then the NPV increased to 95.2% and 97.4% for boys aged below and above 6 months, respectively. These revised strategies would substantially save invasive studies-DMSA and MCUG in 27 and 74% of girls aged below and above 6 months, respectively, or MCUG in 23 and 59% of boys aged below and above 6 months, respectively.

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.