Acute 99mTc DMSA Scan Predicts Dilating Vesicoureteral Reflux in Young Children With a First Febrile Urinary Tract Infection: A Population-Based Cohort Study

Adherence to the Swedish paediatric guidelines for urinary tract infections

AIM

To audit adherence to the Swedish paediatric guidelines for urinary tract infections (UTIs) in infants. Secondary objectives were to compare findings on imaging performed according to the guidelines with imaging without guideline support and to identify predictors of non-adherence.

METHODS

A prospective multicentre study of infants <1 year treated at paediatric hospitals for their first UTI. Adherence to recommendations was assessed for diagnosis, treatment, and imaging of the urinary tract with a follow-up period of 1 year. Vesicoureteral reflux on voiding cystourethrography and findings on renal scintigraphy according to recommendations were compared to imaging without recommendation.

RESULTS

A total of 1357 infants were included. Adherence to recommended diagnostic procedures, antibiotic treatment, and imaging was 86.1%, 91.0% and 64.2%, respectively. Non-adherence to imaging recommendations was associated with inpatient management and smaller hospitals but was also more often due to excessive rather than refrained imaging.

CONCLUSION

High adherence rates to diagnostic and treatment recommendations indicate careful attention to infant UTI among paediatricians. Lower adherence to imaging recommendations raises concerns regarding the guideline algorithm; particularly, early DMSA scans seem to be challenging for smaller hospitals.

A machine learning algorithm predicting risk of dilating VUR among infants with hydronephrosis using UTD classification

BACKGROUNDS

Urinary Tract Dilation (UTD) classification has been designed to be a more objective grading system to evaluate antenatal and post-natal UTD. Due to unclear association between UTD classifications to specific anomalies such as vesico-ureteral reflux (VUR), management recommendations tend to be subjective.

OBJECTIVE

We sought to develop a model to reliably predict VUR from early post-natal ultrasound.

STUDY DESIGN

Radiology records from single institution were reviewed to identify infants aged 0-90 days undergoing early ultrasound for antenatal UTD. Medical records were reviewed to confirm diagnosis of VUR. Primary outcome defined as dilating (≥Gr3) VUR. Exclusion criteria include major congenital urologic anomalies (bilateral renal agenesis, horseshoe kidney, cross fused ectopia, exstrophy) as well as patients without VCUG. Data were split into training/testing sets by 4:1 ratio. Machine learning (ML) algorithm hyperparameters were tuned by the validation set.

RESULTS

In total, 280 patients (540 renal units) were included in the study (73 % male). Median (IQR) age at ultrasound was 27 (18-38) days. 66 renal units were found to have ≥ grade 3 VUR. The final model included gender, ureteral dilation, parenchymal appearance, parenchymal thickness, central calyceal dilation. The model predicted VUR with AUC at 0.81(0.73-0.88) on out-of-sample testing data. Model is shown in the figure.

DISCUSSION

We developed a ML model that can predict dilating VUR among patients with hydronephrosis in early ultrasound. The study is limited by the retrospective and single institutional nature of data source. This is one of the first studies demonstrating high performance for future diagnosis prediction in early hydronephrosis cohort.

CONCLUSIONS

By predicting dilating VUR, our predictive model using machine learning algorithm provides promising performance to facilitate individualized management of children with prenatal hydronephrosis, and identify those most likely to benefit from VCUG. This would allow more selective use of this test, increasing the yield while also minimizing overutilization.

Whole exome sequencing identifies KIF26B, LIFR and LAMC1 mutations in familial vesicoureteral reflux

Vesicoureteral reflux (VUR) is a common urological problem in children and its hereditary nature is well recognised. However, despite decades of research, the aetiological factors are poorly understood and the genetic background has been elucidated in only a minority of cases. To explore the molecular aetiology of primary hereditary VUR, we performed whole-exome sequencing in 13 large families with at least three affected cases. A large proportion of our study cohort had congenital renal hypodysplasia in addition to VUR. This high-throughput screening revealed 23 deleterious heterozygous variants in 19 candidate genes associated with VUR or nephrogenesis. Sanger sequencing and segregation analysis in the entire families confirmed the following findings in three genes in three families: frameshift LAMC1 variant and missense variants of KIF26B and LIFR genes. Rare variants were also found in SALL1, ROBO2 and UPK3A. These gene variants were present in individual cases but did not segregate with disease in families. In all, we demonstrate a likely causal gene variant in 23% of the families. Whole-exome sequencing technology in combination with a segregation study of the whole family is a useful tool when it comes to understanding pathogenesis and improving molecular diagnostics of this highly heterogeneous malformation.

Diagnostic Value of Urine Ribonuclease 7 (RNase 7) to Creatinine Ratio for Detecting Urinary Tract Infection in Children with Pyuria

Objective Ribonuclease 7 (RNase 7) is one of the members of the antimicrobial peptides playing a role in maintaining urinary tract sterility. We aimed to investigate the predictive value of the urine RNase 7 levels in children with pyuria and associations between RNase 7 and vesicoureteral reflux (VUR) and renal scarring.

Methods This study included 109 children with pyuria (46 febrile urinary tract infections [UTIs], 38 nonfebrile UTIs, and 25 sterile pyuria) whose RNase 7 levels were measured by enzyme-linked immunoassay. The results for urine RNase 7 concentrations were expressed as micrograms per milligrams creatinine.

Results RNase 7/Cr levels were higher in patients with both febrile and nonfebrile UTIs than the patients with sterile pyuria (p = 0.001). RNase 7/Cr had predictive values of diagnosis of febrile and nonfebrile UTIs (cut-off value: 2.92 µg/mg, p = 0.003; cut-off value: 3.67 µg/mg, p < 0.001, respectively). RNase 7/Cr had higher levels in the patients with VUR than without VUR (cut-off value: 4.28 µg/mg, p = 0.037). The patients with renal scarring had higher urine RNase 7/Cr than those without scarring (cut-off value: 4.54 µg/mg, p = 0.041).

Conclusion The evaluation of RNase 7/Cr may help prevent unnecessary and/or inappropriate antibiotic use in children with pyuria. The higher RNase 7 levels in patients with VUR and renal scarring may reflect long-term inflammation or greater inflammatory response during acute infection.

Prediction of Vesicoureteral Reflux by Ultrasonography and Renal Scan in Children

Background. In recent studies, renal ultrasonography and dimercapto-succinic acid (DMSA) scan have a role in predicting vesicoureteral reflux in children with febrile urinary tract infection (UTI). Materials and Methods. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were defined for ultrasonography and DMSA scan to predict vesicoureteral reflux in 70 children with febrile UTI. Results. Renal ultrasonography sensitivity, specificity, PPV, NPV, PLR, and NLR for vesicourethral reflux prediction was 0.57, 0, 1, 0, 0.57, and 0.47 and sensitivity, specificity, PPV, NPV, PLR, and NLR of DMSA scan for predicting vesicourethral reflux was 0.75, 0.9, 0.33, 0.98, 7.5, and 0.27, respectively. Conclusions. Ultrasonography cannot predict the presence of VUR, but DMSA scan has a good sensitivity in this context. Therefore, by observation of DMSA scan results, it can be decided whether to perform VCUG or not.

Management of Vesicoureteral Reflux: What Have We Learned Over the Last 20 Years?

Vesicoureteral reflux (VUR) is associated with increased risks of urinary tract infection, renal scarring and reflux nephropathy. We review advancements over the last two decades in our understanding and management of VUR. Over time, the condition may resolve spontaneously but it can persist for many years and bladder/bowel dysfunction is often involved. Some factors that increase the likelihood of persistence (e.g., high grade) also increase the risk of renal scarring. Voiding cystourethrography (VCUG) is generally considered the definitive method for diagnosing VUR, and helpful in determining the need for treatment. However, this procedure causes distress and radiation exposure. Therefore, strategies to reduce clinicians' reliance upon VCUG (e.g., after a VUR treatment procedure) have been developed. There are several options for managing patients with VUR. Observation is suitable only for patients at low risk of renal injury. Antibiotic prophylaxis can reduce the incidence of UTIs, but drawbacks such as antibiotic resistance and incomplete adherence mean that this option is not viable for long-term use. Long-term studies of endoscopic injection have helped us understand factors influencing use and the effectiveness of this procedure. Ureteral reimplantation is still performed commonly, and robot-assisted laparoscopic methods are gaining popularity. Over the last 20 years, there has been a shift toward more conservative management of VUR with an individualized, risk-based approach. For continued treatment improvement, better identification of children at risk of renal scarring, robust evidence regarding the available interventions, and an improved VUR grading system are needed.

Vesicoureteral Reflux and Renal Scarring in Infants After the First Febrile Urinary Tract Infection

Introduction

The objective of this research was to determine whether vesicoureteral reflux(VUR) was associated with evolution to renal scarring (RS) following a febrile urinary tract infection (UTI) in infants.

Materials and methods

Our research included 100 infants, ages up to 1 year with a first febrile UTI. The diagnostic was based on results of: laboratory findings, ultrasonography (USG), voiding cystourethrography (VCUG) and initial and control renal scintigraphy (DMSA renal scan) withtechnetium^99mTcsuccimer (dimercaptosuccinic acid), to assess the acute pyelonephritis (APN), VUR and RS.

Results

APN was proven with DMSA renal scan in 66 (66%) infants. Twenty-two infants (33.3%) had VUR in-group of patients with APN. On the control DMSA scan, performed 6 months after the first DMSA, the presence of RS was found in 18 (27.27%) infants. In infants with renal scars VUR were discovered in 9 of them (50%).

Conclusions

The pathogenesis of RS after febrile UTI in young children is multifactorial. Children with VUR have an increased risk for APN and RS. However, VUR is not the only precondition for RS. Creating a renal scarring cannot be imagined without the inflammatory process of the upper urinary system. Therefore, early detection and treatment of febrile UTIs in children and identify children at risk for RS are of primary importance.

Shear Wave Elastography in the Evaluation of the Kidneys in Pediatric Patients with Unilateral Vesicoureteral Reflux

OBJECTIVES

To evaluate the ability of shear wave elastography (SWE) to detect renal parenchymal scar formation in patients with vesicoureteral reflux.

METHODS

We prospectively evaluated 49 patients with unilateral grade 2 or higher-degree VUR. All patients underwent dimercaptosuccinic acid (DMSA) scintigraphy for evaluation of the renal parenchymal scar. After the DMSA scan, 2 radiologists, who were blinded to clinical data and each other's measurements, evaluated the kidneys of the patients using SWE. The kidneys were divided into 3 parts: upper pole, middle region, and lower pole, and 3 regions of interest were placed to each part. Shear wave velocity (SWV) values were calculated using meters per second as a unit and recorded for each region. Afterward, SWV values were compared to DMSA results.

RESULTS

There was no significant difference between the observers' mean SWV values of kidneys with VUR without scar formation (mean ± SD, 2.11 ± 0.06 and 2.09 ± 0.05 m/s) and the contralateral normal kidney SVW values (2.11 ± 0.06 and 2.10 ± 0.05 m/s; P = .936 and .724, respectively). We observed a significant difference between the mean SWV values of the kidneys with VUR accompanied by scar formation (2.28 ± 0.10 and 2.27 ± 0.11 m/s) and the mean SWV values of the contralateral normal kidneys (2.09 ± 0.05 and 2.10 ± 0.04 m/s; P < .001 for both observers).

CONCLUSIONS

Shear wave elastography could detect scar tissue in kidneys; however, the variability of the stiffness due to the kidney's complex structure, and variations in blood perfusion and the glomerular filtration rate of the kidney might limit the use of SWE in current clinical diagnostic algorithms for VUR.

Prediction of vesicoureteral reflux in children with febrile urinary tract infection using relative uptake and cortical defect in DMSA scan

BACKGROUND

Vesicoureteral reflux (VUR) is an important urologic anomaly that causes renal injury in children with febrile urinary tract infection (UTI). The present study aimed to evaluate the associations of abnormalities detected on technetium-99m-labeled dimercaptosuccinic acid (DMSA) scans, focusing on the association with VUR of the levels of relative decrease in kidney function and cortical defects after a first febrile UTI in children.

METHODS

All 171 children underwent ultrasonography, DMSA scan and voiding cystourethrography (VCUG). The features of ultrasound and DMSA scans were compared between patients with (n = 48) and without VUR (n = 123). The relative uptake (RU) by each kidney was derived from the absolute value of the differences between the value for RU of radionuclide in the right kidney and that in the left kidney. The extent of cortical defects (ECD) was graded according to the number of compartments that contained cortical defect in both kidneys (right upper/right lower, left upper/left lower). Receiver operating characteristic curves were constructed to examine the diagnostic value of these parameters of ultrasound and DMSA scans for predicting VUR.

RESULTS

The ratio of patients having hydronephrosis on ultrasound or cortical defects on DMSA scan did not differ significantly between VUR and non-VUR groups. However, the absolute values of the RU and the scores for ECD were significantly higher in the VUR group than in the non-VUR group. The area under the curves for these two parameters were higher than those for the presence of hydronephrosis or the presence of cortical defects or both.

CONCLUSION

Decreased relative function and increased extents of cortical defects on DMSA scan may be associated with the presence of VUR. These findings may assist pediatricians to decide whether febrile UTI children need to undergo VCUG.

Delayed diagnosis of primary vesicoureteral reflux in children with recurrent urinary tract infections: Diagnostic approach and renal outcomes

OBJECTIVE

In this study, we aimed to assess renal outcomes of delayed diagnosis of dilating primary vesicoureteral reflux (VUR) following recurrent febrile urinary tract infections (fUTIs) and its diagnostic imaging procedures.

MATERIAL AND METHODS

The medical records of patients who underwent ultrasonography (US), non- acute dimercaptosuccinic acid (Tc-99mDMSA) scintigraphy and voiding cystourethrography (VCUG), and who were older than 2 years at the time of VUR diagnosis were retrospectively reviewed.

RESULTS

A total of 32 children (female, n=27: 84.4%) with a mean age of 7.67±3.34 years at the time of diagnosis of VUR were included in the study. Grade III, IV, V VUR were found in 22%, 69%, and 9% of the patients, respectively. At the time of VUR diagnosis, abnormal US findings were detected in 75% of the cases. Tc-99mDMSA detected abnormalities in 83.9% (7 with a single scar, 7 with multiple lesions, 12 with reduced kidney function) of the patients. Estimated glomerular filtration rate of 3 patients with bilateral grade IV VUR was <75 mL/min/1.73 m². In 5 patients (16%), VUR could not be predicted by US+DMSA scintigraphy (Grade IV VUR in 3 and Grade III in 2 cases ). The sensitivity in predicting VUR was 75.00% (95% CI: 56.60-88.54) and 83.87% (95% CI: 66.27-94.55), respectively, for US alone and combined US+DMSA.

CONCLUSION

VCUG should be performed routinely in addition to US and non-acute DMSA in all children referred with recurrent fUTIs. Awareness of childhood UTI in public and healthcare personnels should be increased in order to refer these patients at a early stage to pediatric urology and nephrology units.

Vitamin D receptor gene (FokI, TaqI, BsmI, and ApaI) polymorphisms in children with urinary tract infection

BACKGROUND

Little is known about the genetic background of urinary tract infection (UTI) in children.

METHODS

In this study, vitamin D receptor (VDR) gene polymorphisms were compared between 60 children with UTI (case group) and 60 healthy children (control group). DNA extraction, polymerase chain reaction, and the restriction fragment length polymorphism methods were used to perform the genetic analysis.

RESULTS

There was a significant difference between the case and control groups for VDR gene, ApaI and Bsml, polymorphisms (P < 0.05). The frequency of VDR Bb, bb, Aa, and aa genotypes, and the b and a alleles in the case group was significantly higher than that in the control group (P < 0.05). A significant difference was also found between lower UTI and acute pyelonephritis groups for the VDR Apal and Bsml genotypes (P < 0.05). There was no significant difference between children with first UTI and those with more than one UTI for VDR gene polymorphisms (P > 0.05).

CONCLUSION

This study showed that there is a significant relationship between VDR gene, Apal and Bsml, polymorphisms and UTI in children. The results indicate that these polymorphisms may play a role in pathogenesis of UTI.

Critical appraisal of the top-down approach for vesicoureteral reflux

Vesicoureteral reflux (VUR) has been linked to recurrent urinary tract infections (UTIs), renal scarring, hypertension, renal insufficiency and end-stage kidney disease. Different imaging strategies have been proposed to approach children presenting with UTI to sort out patients with significant VUR while minimizing patient morbidity, radiation exposure and financial burden. None of these imaging strategies is universally accepted. The“top-down approach” (TDA) aims at restricting the number of voiding cystourethrograms (VCUGs) and its associated morbidity while identifying patients with clinically-significant reflux. In this approach, children presenting with febrile UTIs are acutely investigated with dimercapto-succinic acid (DMSA) renal scans to identify patients with renal parenchymal inflammation. Those with evidence of renal affection are offered VCUG and late DMSA scan to identify VUR and permanent renal scarring, respectively. Although TDA could identify clinically-significant VUR with high sensitivity, it is not without limitations. The approach segregates patients based on the presence of DMSA cortical lesions omitting the morbidity and the economic burden of UTI. Additionally, some of DMSA lesions are attributed to congenital dysplasia and unrelated to UTI. Ionizing radiation exposure, financial costs, limited availability of DMSA scans in the acute setting, variability in interpreting the results and low yield of actionable findings on DMSA scans are some other limitations. In this review, we tried to address the drawbacks of the TDA and reinforce the value of patient-centered approach for VUR.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

Antimicrobial Resistance and Diagnostic Imaging in Infants Younger Than 2 Months Old Hospitalized With a First Febrile Urinary Tract Infection: A Population-based Comparative Study

BACKGROUND

Data on urinary tract infection (UTI) in infants ≤2 months of age are limited. We examined clinical characteristics, antimicrobial resistance, imaging findings and clinical outcomes in infants ≤2 months of age and children 2-24 months of age hospitalized with the first febrile UTI.

METHODS

Children ≤24 months of age hospitalized with their first-diagnosed febrile UTI were prospectively studied. Renal ultrasonography, Tc-dimercaptosuccinic acid scanning and voiding cystourethrography were performed in all children.

RESULTS

Of the 388 children analyzed (255 boys and 133 girls), 61 patients were ≤2 months of age, representing 15.7% of the whole population, whereas 327 patients were 2-24 months of age. Escherichia coli was the predominant bacterium, with similar antimicrobial resistance in the 2 groups, and associated E. coli bacteremia occurred in 9 patients (2.3%). Renal ultrasonography showed abnormal findings in 130 patients (33.5%), but there was no difference in the rate of abnormal findings between the groups. Vesicoureteral reflux (VUR) was present in 130 children (33.5%), including 93 (24%) with grades III-V VUR. VUR was more prevalent in the infants ≤2 months of age (P = 0.007), but there was no difference in the prevalence of grades III-V VUR between the groups. The incidence of renal scarring was 28.6% (111/388), and it did not differ between the groups.

CONCLUSIONS

There are similarities in clinical characteristics, antimicrobial resistance, imaging findings and clinical outcomes after a first UTI between the young infants ≤2 months and children 2-24 months of age. The same guidelines for the diagnosis and management after the first febrile UTI can be applied to children who are ≤24 months of age.

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.

Role of Renal Ultrasonography in Predicting Vesicoureteral Reflux and Renal Scarring in Children Hospitalized with a First Febrile Urinary Tract Infection

BACKGROUND

This study was designed to examine the capability of renal ultrasonography (US) for predicting vesicoureteral reflux (VUR) and renal scarring (RS), and to assess, using initial US, the significant urologic abnormalities that impact on management of children hospitalized with a first febrile urinary tract infection (UTI).

METHODS

Hospitalized children aged ≤ 2 years with a first febrile UTI were prospectively evaluated using imaging studies, including (99m)Tc dimercaptosuccinic acid (DMSA) scan, US, and voiding cystourethrography.

RESULTS

Of the 310 children analyzed (195 boys and 115 girls), 105 (33.9%) had abnormal US. Acute DMSA scans were abnormal in 194 children (62.6%), including 89 (45.9%) with concomitant abnormal US. There was VUR in 107 children (34.5%), including 79 (25.5%) with Grades III-V VUR. The sensitivity and negative predictive values of US were 52.3% and 75.1%, respectively, for Grades I-V VUR and 68.4% and 87.8%, respectively, for Grades III-V VUR. Eighty-five children (27.4%) had RS, including 55 (64.7%) with abnormal US. Of the 105 children with abnormal US, 33 (31.4%) needed subsequent management (surgical intervention, parental counseling, or follow up of renal function). Nephromegaly on initial US and Grades III-V VUR were risk factors of RS.

CONCLUSION

Abnormal US may carry a higher probability of Grades III-V VUR and RS, and can affect subsequent management in a significant number of children. Nephromegaly on initial US and Grades III-V VUR are strongly associated with an increased risk for RS. Thus, US should be performed on children after a first febrile UTI and children with normal US may not require voiding cystourethrography.

Radiologic and clinical evaluation of children with first febrile urinary tract infection

Background and objectives

Accurate diagnosis of acute pyelonephritis (APN) is clinically challenging in young children. The evaluation methods for APN and its major risk factor, vesicoureteral reflux (VUR), have been revised in recent years. The aim of this study was to evaluate the value of different radiologic investigations in children experiencing the first episode of APN.

Materials and methods

This study included 425 children of 2–12 months of age (17.5% male, 82.5% female) with APN. APN was defined as a positive urine culture associated with focal or diffuse decreased cortical uptake and preservation of renal contour indicated by DMSA renal scan.

Results

The mean age at diagnosis was 39.2 ± 1.56 months. The following signs were observed in the patients: fever ≥ 38.5 °C, 66.8%; positive CRP, 85.4%; ESR > 25, 78.6%; and leukocytosis > 13,000/mm³, 53.4%.

Pyelocalyceal fullness and increased parenchymal echogenicity were the most common renal ultrasonography findings, and ultrasonography had 34% sensitivity and 53% specificity for these two findings. DMSA scan and ultrasound findings of APN were not significantly correlated (P = .112).

VUR was found in 42.2% of patients. DMSA scanning was not reliable for the diagnosis of VUR (P = .956), with 42% sensitivity and specificity.

VUR was identified in 42.7% of patients by ultrasound (P = .001), and the diagnostic rate was related to the VUR severity. Ultrasound had 42.7% sensitivity and 27% specificity for the diagnosis of VUR.

Conclusion

Determination of inflammatory markers is recommenced for the evaluation of children with APN. In addition, normal ultrasound is a valuable imaging tool for excluding high grade VUR.

Predictive risk factors in childhood urinary tract infection, vesicoureteral reflux, and renal scarring management

Approaches to the management of children with urinary tract infection (UTI), vesicoureteral reflux (VUR), and renal scars have been challenged and have become controversial over the past decade. It is difficult to determine when, how, and which patients will benefit from the diagnosis and management of this condition. Therefore, the issues of diagnostic imaging, observation, follow-up, and intervention tend to be decided more on a case-by-case basis, rather than by using an algorithm. Over the past few years, there have been advances in the identification of risk factors that predispose patients with UTI to present with VUR, to develop recurrent UTIs and renal scars, to have deteriorating renal function, to show VUR improvement and/or spontaneous resolution, and to be candidates for and benefit from early surgical intervention.

Comparison of procalcitonin and different guidelines for first febrile urinary tract infection in children by imaging

BACKGROUND

We examined the ability of a procalcitonin (PCT) protocol to detect vesicoureteral reflux (VUR) and renal scarring (RS), evaluated procedural costs and radiation burden, and compared four representative guidelines for children with their first febrile urinary tract infection (UTI).

METHODS

Children aged ≤2 years with their first febrile UTI who underwent renal ultrasonography (US), acute and late technetium-99m ((99m)Tc)-dimercaptosuccinic acid scan, and voiding cystourethrography were prospectively studied. The representative guidelines applied in a retrospective simulation included the American Academy of Pediatrics (AAP), National Institute of Clinical Excellence, top-down approach (TDA), and Italian Society of Pediatric Nephrology (ISPN). These were compared in terms of ability to detect abnormalities, procedural costs and radiation.

RESULTS

Of 278 children analyzed, 172 (61.9%) had acute pyelonephritis. There was VUR in 101 (36.3%) children, including 73 (26.3%) with grades III-V VUR. RS was identified in 75 (27.0%) children. To detect VUR, TDA and PCT had the highest sensitivity for grades I-V VUR (80.2%) and III-V VUR (94.5%), respectively, whereas AAP had the highest specificity for I-V VUR (77.4%) and III-V VUR (78.0%), respectively. TDA and PCT had the highest sensitivity (100%) for detecting RS. The highest cost and radiation dose was associated with TDA, whereas AAP had the least expenditure and radiation exposure. By multivariate analysis, PCT and VUR, especially grades III-V, were independent predictors of RS.

CONCLUSIONS

There is no perfect guideline for first febrile UTI children. The PCT protocol has good ability for detecting high-grade VUR and RS. If based on available imaging modalities and reducing cost and radiation burden, clinical suggestions in the AAP guidelines represent a considerable protocol.

Accuracy of early DMSA scan for VUR in young children with febrile UTI

OBJECTIVE

To evaluate the accuracy of an acute (99m)Tc-dimercaptosuccinic acid (DMSA) scan in predicting dilating vesicoureteral reflux (VUR) among young children with a febrile urinary tract infection (UTI).

METHODS

The medical records of children (≤ 2 years of age), presenting with febrile UTI between January 2000 and December 2011, were retrospectively reviewed.

RESULTS

A total of 523 children were included in this study, of whom 397 children (75.9%) had abnormal DMSA results and 178 children (34.0%) were identified as VUR on micturating cystourethrography (MCU). Among all the patients, the number of children with dilating VUR was 151 (28.9%). The rate of abnormal results on DMSA for the dilating VUR group was significantly higher than the rates for the non-VUR and low-grade VUR groups (P < .01). In the <6 months age group and ≥ 6 months age group, the sensitivities of DMSA in predicting dilating VUR were 96.15% and 100.0%, respectively, the negative predictive values were 97.26% and 100.0%, respectively, and the negative likelihood ratios were 0.0911 and 0.0000, respectively.

CONCLUSION

For children ≤ 2 years of age with a febrile UTI, an acute DMSA scan is valuable in the exclusion of dilating VUR. The likelihood of the presence of dilating VUR on MCU is rather low when the result of DMSA is negative. DMSA should be conducted to assess the need for an MCU.