Relationship among vesicoureteral reflux, P-fimbriated Escherichia coli, and acute pyelonephritis in children with febrile urinary tract infection

Imaging Diagnosis of Major Kidney and Urinary Tract Disorders in Children

Background and Objectives: Diagnostic imaging is essential for evaluating urinary tract disorders, offering critical insights into renal pathology. This review examines the strengths, limitations, and clinical applications of various imaging modalities, with a focus on pediatric populations. Materials and Methods: A narrative review was conducted, synthesizing current literature on ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and voiding cystourethrography (VCUG). Relevant studies were selected based on diagnostic accuracy, clinical utility, and safety considerations. Results: US is the preferred first-line imaging due to its safety, accessibility, and cost-effectiveness. CT excels in detecting renal calculi, trauma, and malignancies but is limited by radiation exposure. MRI offers superior soft tissue contrast without radiation but is costly and often requires sedation. Nuclear medicine evaluates renal function and scarring, while VCUG remains the gold standard for diagnosing vesicoureteral reflux and posterior urethral valves. Conclusions: Imaging modalities are vital for diagnosing and managing urinary tract disorders, with selection based on clinical needs, patient age, and safety. Ultrasound is the primary choice for its non-invasiveness and cost-effectiveness, while CT, MRI, nuclear medicine, and VCUG provide essential structural and functional insights. A balanced approach ensures accuracy while minimizing patient risk, especially in pediatrics.

Parental Knowledge and Awareness of Childhood Urinary Tract Infections: A Cross Sectional Survey

Background

Parent's misconceptions or lack of knowledge about childhood urinary tract infections (UTIs) can negatively impact their children's health. Therefore, the present study aimed to determine the childhood urinary tract infections awareness and understanding among parents in Saudi Arabia.

Patients and Methods

An online validated cross-sectional survey of parents in Saudi Arabia was conducted from August to September 2021. Study participants who met the inclusion criteria were selected using a convenience sampling technique. A questionnaire with two domains was used to assess parental awareness of childhood urinary tract infection symptoms, complications, treatment, prevention, epidemiology, and diagnosis. The total childhood urinary tract infections awareness scores were classified into three categories: low awareness, moderate awareness, and high awareness. Descriptive statistics were used to determine the data distribution. A chi-square test was used to evaluate the relationship between parental awareness about urinary tract infections in children and other variables. Statistical significance was established at 0.05.

Results

Of the 1688 parents who completed the survey, 1289 (76.4%) were female, 1581 (93.7%) were married, and 1161 (68.8) had a university degree. Parent's total awareness scores were high; however, individual domain scores indicate a moderate level of knowledge. Statistically significant relationship were observed between total awareness and gender, occupation, and level of educational level ((P=0.004, P=0.001, P=0.007, respectively). Another statistically significant relationship was noted between the history of urinary tract infections and awareness of disease prevention (P=0.009).

Conclusion

In Saudi Arabia, parental knowledge about childhood urinary tract infections is moderate to high. However, future studies are needed to investigate gender, educational, and occupational variations in childhood UTI knowledge among parents in Saudi Arabia.

Procalcitonin, C-reactive protein, and erythrocyte sedimentation rate for the diagnosis of acute pyelonephritis in children

BACKGROUND

In children with urinary tract infection (UTI), only those with pyelonephritis (and not cystitis) are at risk for developing long-term renal sequelae. If non-invasive biomarkers could accurately differentiate children with cystitis from children with pyelonephritis, treatment and follow-up could potentially be individualized. This is an update of a review first published in 2015.

OBJECTIVES

The objectives of this review were to 1) determine whether procalcitonin (PCT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) can replace the acute DMSA scan in the diagnostic evaluation of children with UTI; 2) assess the influence of patient and study characteristics on the diagnostic accuracy of these tests, and 3) compare the performance of the three tests to each other.

SEARCH METHODS

We searched MEDLINE, EMBASE, DARE, Web of Science, and BIOSIS Previews through to 17th December 2019 for this review. The reference lists of all included articles and relevant systematic reviews were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We only considered published studies that evaluated the results of an index test (PCT, CRP, ESR) against the results of an acute-phase ⁹⁹Tc-dimercaptosuccinic acid (DMSA) scan (conducted within 30 days of the UTI) in children aged 0 to 18 years with a culture-confirmed episode of UTI. The following cut-off values were used for the primary analysis: 0.5 ng/mL for procalcitonin, 20 mg/L for CRP and 30 mm/hour for ESR.

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 pooled random-effects pooled sensitivity and specificity values.

MAIN RESULTS

A total of 36 studies met our inclusion criteria. Twenty-five studies provided data for the primary analysis: 12 studies (1000 children) included data on PCT, 16 studies (1895 children) included data on CRP, and eight studies (1910 children) included data on ESR (some studies had data on more than one test). The summary sensitivity estimates (95% CI) for the PCT, CRP, ESR tests at the aforementioned cut-offs were 0.81 (0.67 to 0.90), 0.93 (0.86 to 0.96), and 0.83 (0.71 to 0.91), respectively. The summary specificity values for PCT, CRP, and ESR tests at these cut-offs were 0.76 (0.66 to 0.84), 0.37 (0.24 to 0.53), and 0.57 (0.41 to 0.72), respectively.

AUTHORS' CONCLUSIONS

The ESR test does not appear to be sufficiently accurate to be helpful in differentiating children with cystitis from children with pyelonephritis. A low CRP value (< 20 mg/L) appears to be somewhat useful in ruling out pyelonephritis (decreasing the probability of pyelonephritis to < 20%), but unexplained heterogeneity in the data prevents us from making recommendations at this time. The procalcitonin test seems better suited for ruling in pyelonephritis, but the limited number of studies and the marked heterogeneity between studies prevents us from reaching definitive conclusions. Thus, at present, we do not find any compelling evidence to recommend the routine use of any of these tests in clinical practice.

Prevention of Renal Scarring in Acute Pyelonephritis by Probiotic Therapy: an Experimental Study

We evaluated the protective effects of probiotic administration as a prophylaxis treatment and immediately after fever onset in increasing the immune response and decreasing the renal scarring in a rat model of acute pyelonephritis. Twenty-four rats were apportioned to three groups. In GI (n = 8), the rats were injected with direct inoculation of Escherichia coli into the right kidney. In GII (n = 8), the rats received a probiotic regimen 1 month before E. coli injection and the probiotic regimen was continued for the next 2 months. In GIII (n = 8), the probiotic regimen was started just after E. coli injection and was continued for 2 months. Technetium-99m-DMSA renal scan, histopathological evaluations, concentrations of CA19-9, IgA, blood urea nitrogen (BUN), and creatinine were assessed 1 and 2 months post-injection. It took an average of 4.2 ± 1.1 h between the injection and onset of fever in GI and GII. In GIII, this period was longer (7.5 ± 1.4). Probiotic administration resulted in reduction of interstitial fibrosis and tubular and glomerular atrophy in GII in all follow-ups. Technetium-99m-DMSA renal scan showed that the right kidney reached near the normal cortical integrity (47%) in GII compared to GI (32%) after 2 months of injection. However, the renal integrity did not improve significantly in GIII (41%). In GII, CA19-9 was lower (p < 0.05), while the levels of serum and fecal IgA were higher (p < 0.05). Administration of the probiotic regimen in the rat model may decrease renal damage in pyelonephritis. In spite of better results in the prophylactic group compared to the treatment group, no strong evidence was found to prove the advantage of its prophylactic application over the treatment administration.

Molecular Epidemiology of Extraintestinal Pathogenic Escherichia coli

Extraintestinal pathogenic Escherichia coli (ExPEC) are important pathogens in humans and certain animals. Molecular epidemiological analyses of ExPEC are based on structured observations of E. coli strains as they occur in the wild. By assessing real-world phenomena as they occur in authentic contexts and hosts, they provide an important complement to experimental assessment. Fundamental to the success of molecular epidemiological studies are the careful selection of subjects and the use of appropriate typing methods and statistical analysis. To date, molecular epidemiological studies have yielded numerous important insights into putative virulence factors, host-pathogen relationships, phylogenetic background, reservoirs, antimicrobial-resistant strains, clinical diagnostics, and transmission pathways of ExPEC, and have delineated areas in which further study is needed. The rapid pace of discovery of new putative virulence factors and the increasing awareness of the importance of virulence factor regulation, expression, and molecular variation should stimulate many future molecular epidemiological investigations. The growing sophistication and availability of molecular typing methodologies, and of the new computational and statistical approaches that are being developed to address the huge amounts of data that whole genome sequencing generates, provide improved tools for such studies and allow new questions to be addressed.

Top-down approach is possible strategy for predicting breakthrough fUTIs and renal scars in infants

BACKGROUND

Acute-phase technetium-99 m dimercaptosuccinic acid (DMSA) scintigraphy is recommended for initial imaging in children with febrile urinary tract infection (fUTI). Recently, the importance of identifying patients at risk of recurrent fUTI (r-fUTI) has been emphasized. To clarify the effectiveness of DMSA scintigraphy for predicting r-fUTI in infants, we investigated the relationship between defects on DMSA scintigraphy and r-fUTI.

METHODS

Seventy-nine consecutive infants (male: female, 60:19) with fUTI were enrolled in this study. DMSA scintigraphy was performed in the acute phase, and patients with defect underwent voiding cystourethrography and chronic-phase (6 months later) DMSA scintigraphy. Patients were followed on continuous antibiotic prophylaxis (CAP).

RESULTS

Defects on acute-phase DMSA scintigraphy were observed in 32 children (40.5%) of 79. The mean follow-up observation period was 17.0 ± 10.1 months. Four patients had r-fUTI (5%). Two of them had defects on DMSA scintigraphy in both the acute phase and chronic phase, and had bilateral vesicoureteral reflux (VUR) grade IV. Two others had r-fUTI without defects on DMSA and did not have VUR. Twelve patients had defect on chronic-phase DMSA scintigraphy and four of them had no VUR.

CONCLUSIONS

The top-down approach is a possible method for predicting r-fUTI in infants and does not miss clinically significant VUR. Also, given that the prevalence of r-fUTI was 5% regardless of the presence of defects on acute-phase DMSA, then, in conjunction with genital hygiene and CAP, acute-phase DMSA might be unnecessary if chronic-phase DMSA is performed for all patients to detect renal scar.

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.

Drug and Vaccine Development for the Treatment and Prevention of Urinary Tract Infections

Urinary tract infections (UTI) are among the most common bacterial infections in humans, affecting millions of people every year. UTI cause significant morbidity in women throughout their lifespan, in infant boys, in older men, in individuals with underlying urinary tract abnormalities, and in those that require long-term urethral catheterization, such as patients with spinal cord injuries or incapacitated individuals living in nursing homes. Serious sequelae include frequent recurrences, pyelonephritis with sepsis, renal damage in young children, pre-term birth, and complications of frequent antimicrobial use including high-level antibiotic resistance and Clostridium difficile colitis. Uropathogenic E. coli (UPEC) cause the vast majority of UTI, but less common pathogens such as Enterococcus faecalis and other enterococci frequently take advantage of an abnormal or catheterized urinary tract to cause opportunistic infections. While antibiotic therapy has historically been very successful in controlling UTI, the high rate of recurrence remains a major problem, and many individuals suffer from chronically recurring UTI, requiring long-term prophylactic antibiotic regimens to prevent recurrent UTI. Furthermore, the global emergence of multi-drug resistant UPEC in the past ten years spotlights the need for alternative therapeutic and preventative strategies to combat UTI, including anti-infective drug therapies and vaccines. In this chapter, we review recent advances in the field of UTI pathogenesis, with an emphasis on the identification of promising drug and vaccine targets. We then discuss the development of new UTI drugs and vaccines, highlighting the challenges these approaches face and the need for a greater understanding of urinary tract mucosal immunity.

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.

Molecular Epidemiology of Extraintestinal Pathogenic Escherichia coli

Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized E. coli strains that possess the ability to overcome or subvert host defenses and cause extraintestinal disease, are important pathogens in humans and certain animals. Molecular epidemiological analysis has led to an appreciation of ExPEC as being distinct from other E. coli (including intestinal pathogenic and commensal variants) and has offered insights into the ecology, evolution, reservoirs, transmission pathways, host-pathogen interactions, and pathogenetic mechanisms of ExPEC. Molecular epidemiological analysis also provides an essential complement to experimental assessment of virulence mechanisms. This chapter first reviews the basic conceptual and methodological underpinnings of the molecular epidemiological approach and then summarizes the main aspects of ExPEC that have been investigated using this approach.

Incidence of antibiotics resistance among uropathogens in Omani children presenting with a single episode of urinary tract infection

Urinary tract infection (UTI) is one of the most common community-acquired infections. Different organisms can be the cause of UTI in children, with resistance to antibiotics becoming a significant problem in the choice of treatment. Worldwide studies have documented the prevalence of uropathogens in different countries. However, there is no previous study documenting the incidence of different uropathogens in Oman. We aim to report the most common uropathogens and their antibiotic sensitivity patterns in children presenting with documented, single episode UTI at a tertiary hospital in Oman. A retrospective analysis of all Omani children below 14 years who presented with a case of first documented UTI to SQUH between September 2008 and August 2012 was conducted. Data were obtained from the patients' electronic records in the hospital information system. Data were then analyzed using SSPS (Statistical Package for Social Sciences program, Version 20, IBM, Chicago, IL, USA). In the retrospective review of all urine cultures, 438 positive urine cultures were identified. Out of those, 208 (47.5%) belonged to children with their first episode of UTI. Thirty-three patients were excluded and 75 patients were included in the final analysis. Escherichia coli was the most frequently encountered uropathogen in our cohort (69%), followed by Klebsiella pneumoniae infection (17%). Nearly half (46.6%) of these two common organism were resistant to Cotrimoxazole, while 31% of them were resistant to Augmentin. Twenty-four percent of the E. coli and K. pneumoniae strains were resistant to Cefuroxime, and only 10% were resistant to nitrofurantoin. Both Augmentin and Cotrimoxazole should not be the first line antibiotics to treat UTI.

Procalcitonin, C-reactive protein, and erythrocyte sedimentation rate for the diagnosis of acute pyelonephritis in children

BACKGROUND

In children with urinary tract infection (UTI), only those with pyelonephritis (and not cystitis) are at risk for developing long-term renal sequelae. If non-invasive biomarkers could accurately differentiate children with cystitis from children with pyelonephritis, treatment and follow-up could potentially be individualized.

OBJECTIVES

The objectives of this review were to 1) determine whether procalcitonin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) can replace the acute DMSA scan in the diagnostic evaluation of children with UTI; 2) assess the influence of patient and study characteristics on the diagnostic accuracy of these tests, and 3) compare the performance of the three tests to each other.

SEARCH METHODS

We searched MEDLINE, EMBASE, DARE, Web of Science, and BIOSIS Previews for this review. The reference lists of all included articles and relevant systematic reviews were searched to identify additional studies not found through the electronic search.

SELECTION CRITERIA

We only considered published studies that evaluated the results of an index test (procalcitonin, CRP, ESR) against the results of an acute-phase DMSA scan (conducted within 30 days of the UTI) in children aged 0 to 18 years with a culture-confirmed episode of UTI. The following cutoff values were used for the primary analysis: 0.5 ng/mL for procalcitonin, 20 mg/L for CRP and 30 mm/h for ESR.

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 pooled random-effects pooled sensitivity and specificity values.

MAIN RESULTS

A total of 24 studies met our inclusion criteria. Seventeen studies provided data for the primary analysis: six studies (434 children) included data on procalcitonin, 13 studies (1638 children) included data on CRP, and six studies (1737 children) included data on ESR (some studies had data on more than one test). The summary sensitivity estimates (95% CI) for the procalcitonin, CRP, ESR tests at the aforementioned cutoffs were 0.86 (0.72 to 0.93), 0.94 (0.85 to 0.97), and 0.87 (0.77 to 0.93), respectively. The summary specificity values for procalcitonin, CRP, and ESR tests at these cutoffs were 0.74 (0.55 to 0.87), 0.39 (0.23 to 0.58), and 0.48 (0.33 to 0.64), respectively.

AUTHORS' CONCLUSIONS

The ESR test does not appear to be sufficiently accurate to be helpful in differentiating children with cystitis from children with pyelonephritis. A low CRP value (< 20 mg/L) appears to be somewhat useful in ruling out pyelonephritis (decreasing the probability of pyelonephritis to < 20%), but unexplained heterogeneity in the data prevents us from making recommendations at this time. The procalcitonin test seems better suited for ruling in pyelonephritis, but the limited number of studies and the marked heterogeneity between studies prevents us from reaching definitive conclusions. Thus, at present, we do not find any compelling evidence to recommend the routine use of any of these tests in clinical practice.

Gender-based differences in pediatric nuclear medicine

Gender-based differences commonly encountered in pediatric nuclear medicine reflect both basic embryologic differences of the sexes, which are evident from infancy, and evolving physiological changes due to gender, which occur as the pediatric patient grows, undergoes puberty, and matures to adulthood. It is important for a nuclear medicine physician or radiologist to know both the gender and the age of a patient when interpreting her or his studies. It is also important that the reading physician be familiar with the normally evolving physiological changes that are specific for that patient's stage of development. It is particularly important that the reading physician consider such changes when comparing serial studies of the patient that are acquired during the patient's transitions through her or his different significant stages of development. Many pediatric nuclear medicine imaging protocols are modifications or adaptations of the protocols for adult imaging. Physicians reading pediatric studies must routinely incorporate knowledge on age and gender that is relevant to the patient for any given study. The age-defined gender-based subtleties of potential findings in pediatric nuclear medicine studies are often underrecognized. However, they are often of interest and at times important in the workup of both benign entities and pathologic processes of the pediatric patient.

Using intravoxel incoherent motion MR imaging to evaluate cortical defects in the first episode of upper urinary tract infections: preliminary results

PURPOSE

To compare intravoxel incoherent motion diffusion weight imaging IVIM-DWI MRI with DMSA for the evaluation of cortical defect in pediatric upper urinary tract infection (UTI) patients.

MATERIALS AND METHODS

Forty-three kidneys of 22 pediatric patients with the first episode of febrile upper UTI were evaluated. DWI using IVIM model was performed with eight b factors. The presence of cortical defect was evaluated on apparent diffusion coefficient (ADC) map. DMSA was used as the standard of reference. ADC, true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (F) in both defect and nondefect area were calculated and compared.

RESULTS

Cortical defects were detected in 14 kidneys by IVIM-DWI. The sensitivity, specificity, positive predictive value, and negative predictive value of IVIM-DWI MRI for the detection of defects was 93.3%, 100%, 100%, and 96.5%, respectively. Mean values of ADC, D, D*, and F were 1.12 ± 0.15, 1.05 ± 0.10, 33 ± 17 (× 10(-3) mm(2) /s), and 0.14 ± 0.09 in the defect foci. In normal foci, ADC, D, D*, and F were 1.37 ± 0.09, 1.31 ± 0.10, 43 ± 19 (× 10(-3) mm(2) /s), and 0.12 ± 0.04, respectively. ADC and D were significantly lower in defect group than nondefect group (P < 0.01).

CONCLUSION

IVIM-DWI can allow both direct visualization and quantitative measurement of cortical defects.

Issues in febrile urinary tract infection management

Urinary tract infections are common occurrences in the pediatric age group and are a cause of significant morbidity and expense. The understanding of the consequences and sequelae of febrile urinary tract infections led to revision of standard protocols initiated by the American Academy of Pediatrics (AAP) in 1999. A less invasive protocol of radiologic evaluation has been the major outcome of the revised AAP guidelines. Emphasis on prevention of recurrent febrile urinary tract infections has also led to therapeutic programs that are centered less around the use of prophylactic antibiotics than has previously been the practice.

Relationship among bacterial virulence, bladder dysfunction, vesicoureteral reflux and patterns of urinary tract infection in children

PURPOSE

We hypothesized that virulence levels of Escherichia coli isolates causing pediatric urinary tract infections differ according to severity of infection and also among various uropathies known to contribute to pediatric urinary tract infections. We evaluated these relationships using in vitro cytokine interleukin-6 elicitation.

MATERIALS AND METHODS

E. coli isolates were cultured from children presenting with urinary tract infections. In vitro cytokine (interleukin-6) elicitation was quantified for each isolate and the bacteria were grouped according to type of infection and underlying uropathy (neurogenic bladder, nonneurogenic bowel and bladder dysfunction, primary vesicoureteral reflux, no underlying etiology).

RESULTS

A total of 40 E. coli isolates were collected from children with a mean age of 61.5 months (range 1 to 204). Mean level of in vitro cytokine elicitation from febrile urinary tract infection producing E. coli was significantly lower than for nonfebrile strains (p = 0.01). The interleukin-6 response to E. coli in the neurogenic bladder group was also significantly higher than in the vesicoureteral reflux (p = 0.01) and no underlying etiology groups (p = 0.02).

CONCLUSIONS

In vitro interleukin-6 elicitation, an established marker to determine bacterial virulence, correlates inversely with clinical urinary tract infection severity. Less virulent, high cytokine producing E. coli were more likely to cause cystitis and were more commonly found in patients with neurogenic bladder and nonneurogenic bowel and bladder dysfunction, whereas higher virulence isolates were more likely to produce febrile urinary tract infections and to affect children with primary vesicoureteral reflux and no underlying etiology. These findings suggest that bacteria of different virulence levels may be responsible for differences in severity of pediatric urinary tract infections and may vary among different underlying uropathies.

Acute pyelonephritis in adults: a case series of 223 patients

BACKGROUND

Acute pyelonephritis (APN) is a common disease which rarely evolves into abscesses.

METHODS

We prospectively collected clinical, biochemical and radiological data of patients hospitalized with a diagnosis of APN from 2000 to 2008.

RESULTS

Urinary culture was positive in 64/208 patients (30.7%) and blood cultures in 39/182 cases (21.4%). Two hundred and thirteen patients were submitted to computed tomography (CT) or nuclear magnetic resonance (NMR): confirmation of APN was obtained in 196 patients (92%). Among these, 46 (23.5%) had positive urine culture, 31 (15.8%) had positive blood culture and 15 (7.6%) had positive cultures of both urine and blood. In 98 patients, either urine or blood cultures were negative, but CT/NMR were positive for APN. Fifty of the 213 patients submitted to CT/NMR (23.5%) had intrarenal abscesses: only 2 were evidenced by ultrasound examination. No differences were found between patients with positive or negative CT with regards to fever, leucocytosis, C-reactive protein, pyuria, urine cultures and duration of symptoms before hospitalization. No differences were found between patients with or without abscesses with regards to these parameters and risk factors. Patients with abscesses had a longer duration of treatment and hospitalization.

CONCLUSIONS

Our data suggest that in APN it is not always possible to routinely document urinary infection in a clinical setting. This finding could be explained by previous antibiotic treatment, low bacterial growth or atypical pathogens. Systematic CT or NMR is necessary to exclude evolution into abscesses, which cannot be suspected on clinical grounds or by ultrasound examination and may also develop in the absence of risk factors.

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.

Diagnosing Acute Pyelonephritis with CT, Tc-DMSA SPECT, and Doppler Ultrasound: A Comparative Study

Purpose

With growing interest in early imaging, the aim of our study was to define the most practical modality for routine clinical use for the diagnosis of acute pyelonephritis (APN). We compared the sensitivity of enhanced computerized tomography (CT), dimercaptosuccinic acid (DMSA) scintigraphy, and Doppler ultrasonography (DUS) by using clinical findings as the standard of reference.

Materials and Methods

A total of 207 APN patients (191 women, 16 men; mean age, 49.4 years; range, 17-88 years) were enrolled in this study. All the patients underwent imaging modalities during hospitalization. SPECT images were obtained 4 hours after injection of ^99mTc-DMSA. Transverse and coronary CT images were obtained before and after injection of the contrast agent. DUS was performed in the longitudinal, transverse, and coronal planes. All the images were read independently by a single radiologist and a nuclear medicine specialist. The sensitivity of each modality for detecting APN was compared.

Results

CT showed significantly superior sensitivity compared with that of DUS (81.0% vs. 33.3%, respectively, n=147). DMSA scintigraphy also showed significantly superior sensitivity compared with that of DUS (74.7% vs. 33.3%, respectively, n=150). Compared with DMSA scintigraphy, CT showed superior sensitivity, but the difference was not statistically significant (81.0% vs. 74.8%, respectively, n=147, p=0.163).

Conclusions

For cases of clinically suspected APN, CT and DMSA scintigraphy appear to be equally sensitive and reliable for detecting APN, although CT is more practical in various fields. DUS was significantly less sensitive.

The "top-down" approach to the evaluation of children with febrile urinary tract infection

The evaluation of children presenting with urinary tract infection (UTI) has long entailed sonography and cystography to identify all urological abnormalities that might contribute to morbidity. The identification of vesicoureteral reflux (VUR) has been of primary concern since retrospective studies from the 1930s to 1960s established a strong association between VUR, recurrent UTI, and renal cortical scarring. It has been proposed that all VUR carries a risk for renal scarring and, therefore, all VUR should be identified and treated. We will not discuss the controversies surrounding VUR treatment in this review focusing instead on a new paradigm for the evaluation of the child with UTI that is predicated on identifying those at risk for scarring who are most deserving of further evaluation by cystography.

Long-term followup of dextranomer/hyaluronic acid injection for vesicoureteral reflux: late failure warrants continued followup

PURPOSE

Dextranomer/hyaluronic acid injection of ureteral orifices is a popular option in the treatment of vesicoureteral reflux, with success rates ranging from 69% to 89%. We found only 1 study that followed patients beyond the initial postoperative voiding cystourethrogram, which describes a 96% success rate at 2 to 5 years but defines success as "nondilating" reflux. We examined our dextranomer/hyaluronic acid series to evaluate the long-term (1-year) outcome in children who had resolution of reflux on initial postoperative voiding cystourethrography.

MATERIALS AND METHODS

We retrospectively reviewed our dextranomer/hyaluronic acid experience from February of 2002 to December of 2005. We determined initial success on early (6 to 12-week) postoperative voiding cystourethrogram. We then evaluated long-term success by obtaining a voiding cystourethrogram at 1 year postoperatively in patients who were initially cured of reflux. In addition, success rates between the first and second halves of our experience were evaluated to account for surgeon experience and modification of technique.

RESULTS

Our total success rate at initial voiding cystourethrogram was 73% (246 of 337 total ureters). The success rate in the first half of our experience was 65.9% (112 of 170 ureters) and in the second half was 80.2% (134 of 167). A total of 150 ureteral units with initial successful dextranomer/hyaluronic acid treatment were evaluated at 1 year by voiding cystourethrogram. Of these ureters 111 had continued resolution of vesicoureteral reflux, for a long-term success rate of 74%. Including initial postoperative failures, the complete 1-year total success rate was 46.1% (111 of 241 ureters).

CONCLUSIONS

Although the reflux resolution rates at initial postoperative voiding cystourethrogram approach those of open surgery, there is a significant failure rate at 1 year, which warrants long-term followup.

Imaging and treatment strategies for children after first urinary tract infection

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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.

The effects of methylene blue on renal scarring due to pyelonephritis in rats

The aim of this study was to evaluate the efficiency of methylene blue (MB) in preventing renal scar formation after the induction of pyelonephritis (PNP) in a rat model with delayed antimicrobial therapy. An inoculum of the K-12 strain of Escherichia coli was injected into both kidneys. Control groups received isotonic saline instead of bacterial solution. Four equal groups were then formed: the PNP group was untreated and the PNP ciprofloxacin (CIP) treated group was treated only with CIP intraperitoneally (i.p.) starting on the third day following bacterial inoculation. In the PNP (MB)-treated group, MB was given i.p., and in the PNP MB + CIP-treated group, MB + CIP were administered i.p.. In the sixth week following bacterial inoculation, all rats were sacrificed, and both kidneys of the rats in all groups were examined biochemically and histopathologically for renal scarring. Renal scar was significant in the groups treated with MB alone or MB + CIP combination compared with untreated or antibiotic only groups. Delayed treatment with antibiotics had no effect on scarring. These results suggest that the addition of MB to the delayed antibiotic therapy might be beneficial in preventing PNP-induced oxidative renal tissue damage.

Diagnostic significance of clinical and laboratory findings to localize site of urinary infection

The aim of this study was to define in children younger than 2 years of age the diagnostic significance of clinical and laboratory findings to localize site of febrile urinary tract infection. We reviewed the records of 185 children younger than 2 years of age admitted to hospital with febrile urinary tract infection. Patients were divided into having either acute pyelonephritis or acute cystitis according to the presence or absence of acute lesions on dimercaptosuccinic acid (DMSA) renal scintigraphy. Clinical and laboratory [white blood cell count (WBC), urinalysis, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)] findings were compared between the two groups using Student's t test, chi-square test, and multivariate analysis. Patients with pyelonephritis had statistically significant higher age, WBC, ESR, and CRP than those with cystitis. Although the sensitivity of the tests was 80-100%, their specificity was <28%. On multivariate analysis, 33% of patients with cystitis were diagnosed as having pyelonephritis, whereas 22% of those with pyelonephritis were considered to have cystitis. Given the low specificity of clinical findings and available laboratory tests to define the site of urine infection in this age group, we recommend DMSA renal scintigram as the test of choice to make the diagnosis of acute pyelonephritis in these patients.

Accurate diagnosis of acute pyelonephritis: How helpful is procalcitonin?

AIM

This prospective study aimed to investigate the diagnostic value of serum procalcitonin levels in children with acute pyelonephritis documented by Tc-dimercaptosuccinic acid (DMSA) scintigraphy.

METHODS

We compared the symptoms and laboratory findings of fever, vomiting, abdominal/flank pain, leukocyte count, serum C-reactive protein and procalcitonin levels with the results of the DMSA scan obtained within the first 72 h after referral in children who were diagnosed as having acute pyelonephritis. Thirty-three children (31 female and two male) aged 1-11 years (mean 4.42 years) were enrolled in this prospective study.

RESULTS

Twenty-one of 33 patients (64%) had positive DMSA scans. On the scans obtained after 6 months, five of 21 patients (23.8%) had renal scars. No correlation was found between clinical and laboratory parameters, alone or combined with each other, and positive DMSA scans. Serum procalcitonin levels were 0.767+/-0.64 and 1.23+/-1.17 ng . ml in children with normal and positive DMSA scans, respectively. The cut-off value for procalcitonin using receiver operating characteristic analysis was 0.9605 ng . ml, while sensitivity and specificity were 86.4% and 36.4%, respectively. However, if the cut-off value was chosen as 2 ng . ml, the sensitivity increased to 100% while specificity did not change markedly.

CONCLUSION

The serum procalcitonin test, like other commonly used laboratory parameters, e.g. serum C-reactive protein and white blood cell count, was inadequate in distinguishing renal parenchymal involvement in acute febrile urinary tract infections.

[Evidence-based medicine and vesicoureteral reflux]

Vesicoureteral reflux (VUR) remains one of the most controversial subjects in paediatric urology. Much literature has been published on VUR, making the understanding of this anomaly and its treatments quite opaque. Evidence-Based Medicine (EBM) should be helpful to clarify the various VUR approaches contained in the 6224 titles found on Medline using the keywords "vesicoureteral reflux" and "vesicoureteric reflux". These articles were critically reviewed and graded according to EBM scorings, with regard to their methodological designs. This review of VUR literature suggests that most of our knowledge is based on publications with a low level of evidence, and that EBM lacks arguments to support recommendations for VUR diagnostic and treatment. It appears yet that antenatal dilatation of the urinary tract and symptomatic urinary tract infections (UTI) justify VUR screening. Surgery should be discussed in recurrent UTIs or deterioration of renal function. There is no consensus in case of persistent asymptomatic VUR regarding indication and duration of antibio-prophylaxis, and selection of radical treatment.

[Modern imaging technology for childhood urinary tract infection]

Imaging in childhood urinary tract infection (UTI) is still a matter of debate. There are established guidelines, however new knowledge and the changed medical environment have enhanced this ongoing discussion. These new insights have impacted therapy and consequently the imaging algorithm. Modern imaging methods -- particularly MRI and modern ultrasound (US) -- are less invasive with a lower radiation burden. Additionally, it has been shown that VUR is a poor predictor for renal scarring out, which affects long-term results. Furthermore, the majority of UT malformations is depicted by prenatal US. The most crucial aspect of improving long-term outcome appears to be the early and reliable depiction of UTI and effective treatment to prevent renal scarring. This review tries to present this new knowledge and to discuss the potential of modern imaging. Recent changes in imaging algorithms are highlighted and an outcome-oriented algorithm that addresses these recent developments is proposed, without lightly abandoning established standards. It consists of an orienting US and -- for depiction of renal involvement -- amplitude coded color Doppler sonography or renal static scintigraphy (considered the gold standard, particularly for evaluating scars); in future MRI may play a role. Based on this concept, only patients with renal damage as well as patients with complex urinary tract malformations or intractable recurrent UTI may have to undergo VCUG.

Controversies in the diagnosis and management of urinary tract infections in children

Urinary tract infection (UTI) is one of the most common childhood bacterial infections, after upper respiratory tract and middle ear infections. The current goal of management is to prevent detrimental effects of UTI by early detection and treatment. Recommendations for the imaging of children depend upon age at presentation and sex. All children aged <5 years who have had a febrile UTI require a radiologic evaluation to identify any underlying genitourinary pathology. Older children can undergo a more tailored work-up depending on whether there is a febrile UTI or cystitis-type symptoms. Dysfunctional voiding and urge syndrome significantly increase the risk of developing UTIs in children. Vesicoureteral reflux can increase the risk of pyelonephritis and renal scarring in children with UTIs. For the most part, pyelonephritis can be diagnosed on clinical grounds in the majority of patients and a subsequent (99m)Tc-dimercaptosuccinic acid scan can be reserved to identify post-nephritic renal scarring. When renal scarring is identified, the child and parents need to be educated regarding the possibility of hypertension, proteinuria, progressive nephropathy, and the risk of complications in future pregnancies. Treatment of UTI is started in the unwell child before the culture results are available and subsequently changed to culture-specific antimicrobial therapy. A short course of treatment is required for acute uncomplicated UTIs. A child with acute pyelonephritis requires 10-14 days of antibacterial treatment. The oral route in young children often causes vomiting, which implies therapeutic delay, a well known risk factor for scarring.

Pediatric applications of renal nuclear medicine

This review should be regarded as an opinion based on personal experience, clinical and experimental studies, and many discussions with colleagues. It covers the main radionuclide procedures for nephro-urological diseases in children. Glomerular filtration rate can be accurately determined using simplified 2- or 1-blood sample plasma clearance methods. Minor controversies related to the technical aspects of these methods concern principally some correction factors, the quality control, and the normal values in children. However, the main problem is the reluctance of the clinician to apply these methods, despite the accuracy and precision that are higher than with the traditional chemical methods. Interesting indications are early detection of renal impairment, hyperfiltration status, and monitoring of nephrotoxic drugs. Cortical scintigraphy is accepted as a highly sensitive technique for the detection of regional lesions. It accurately reflects the histological changes, and the interobserver reproducibility in reporting is high. Potential technical pitfalls should be recognized, such as the normal variants and the difficulty in differentiating acute lesions from permanent ones or acquired lesions from congenital ones. Although dimercaptosuccinic acid scintigraphy seems to play a minor role in the traditional approach to urinary tract infection, recent studies suggest that this examination might influence the treatment of the acute phase, the indication for chemoprophylaxis and micturating cystography, and the duration of follow-up. New technical developments have been applied recently to the renogram: tracers more appropriate to the young child, early injection of furosemide, late postmicturition and gravity-assisted images and, finally, more objective parameters of renal drainage. Pitfalls mainly are related to the interpretation of drainage on images and curves. Dilated uropathies represent the main indication of the renogram, but the impact of this technique on the management of the child is, in a great number of cases, still a matter of intense controversy. Direct and indirect radionuclide cystography are interesting alternatives to the radiograph technique and should be integrated into the process of diagnosis and follow-up of vesicoureteral reflux.

Molecular epidemiology of extraintestinal pathogenic (uropathogenic) Escherichia coli

Molecular epidemiological analyses of extraintestinal pathogenic Escherichia coli (ExPEC), which are also called "uropathogenic E. coli" since they are the principle pathogens in urinary tract infection, involve structured observations of E. coli as they occur in the wild. Careful selection of subjects and use of appropriate methods for genotyping and statistical analysis are required for optimal results. Molecular epidemiological studies have helped to clarify the host-pathogen relationships, phylogenetic background, reservoirs, and transmission pathways of ExPEC, to assess potential vaccine candidates, and to delineate areas for further study. Ongoing discovery of new putative virulence factors (VFs), increasing awareness of the importance of VF expression and molecular variants of VFs, and growing appreciation of transmission as an important contributor to ExPEC infections provide abundant stimulus for future molecular epidemiological studies. Published by Elsevier GmbH.

Vesicoureteral reflux in adult women with uncomplicated acute pyelonephritis

OBJECTIVES

To evaluate the significance of vesicoureteral reflux (VUR) in adult women with uncomplicated acute pyelonephritis.

METHODS

Eighty-six adult women with uncomplicated acute pyelonephritis were studied from April 1998 to October 2003. They showed no structural urinary tract abnormalities. The mean age of patients was 36.2 years (range, 19 to 54 years). We divided these patients into two groups. In group I (31 patients), we performed a voiding cystourethrogram (VCUG) on the third day of treatment to demonstrate possible transient low-grade VUR during the acute infectious phase. In group II (the remaining 55 patients), we performed VCUG after the seventh day of treatment.

RESULTS

There were only 2 (2.3%) cases of VUR among 86 patients with uncomplicated acute pyelonephritis. No VUR was found in group I, and grade II reflux was found in 2 patients of group II.

CONCLUSIONS

These results indicate that, unlike in children, VUR is not a significant factor causing ascending infection leading to the development of acute pyelonephritis in adult women. Further research is warranted regarding the pathophysiology of ascending infection in the adult population.

Evaluation of acute pyelonephritis with DMSA scans in children presenting after the age of 5 years

It is generally believed that infants are more susceptible to development of renal scarring after pyelonephritis than children over 5 years old. This view has led to differences in investigations and treatment according to age. The aim of this prospective study was to assess the occurrence of renal parenchymal lesion in children over 5 years admitted with a first-time symptomatic urinary tract infection (UTI). Between October 2000 and April 2002, 52 children aged over 5 years who were admitted to our department with probable acute pyelonephritis (APN) and a positive urine culture were included in this study. All children received antibiotics for 14 days. During the acute phase of infection, scintigraphy with technetium-99m-labeled dimercaptosuccinic acid (DMSA) and ultrasonography (US) were done. Voiding cystourethrography (VCUG) was performed in all children early in the course of the illness, generally within 5-7 days of hospitalization. When scintigraphy showed renal parenchymal changes, repeat scintigraphy was done after at least 3 months to assess the progression of renal abnormalities. Of the 52 children with a first-time documented pyelonephritis, cortical scintigraphy showed renal lesion in 41 children (78.8%). US was normal in all children with normal renal scintigraphy, while it detected renal abnormalities in 16 of the 41 (39 %) with abnormal scintigraphy (p <0.0001). Topographic analysis of the 165 focal lesions showed that 42.4% were localized to the upper poles, 17.5% to the middle third, and 40% to the lower poles of the kidneys. Repeat scintigraphy showed persistent lesions corresponding to those on the initial scan in nine (28.2%) of the 32 children. Renal lesions had partly regressed in 23 (71.8%) of the patients who underwent repeat scintigraphy. Vesicoureteral reflux was observed in 13.4% of kidneys and renal parenchymal abnormalities were identified in 71.4% and 72.2% of renal units, respectively, with and without reflux ( p >0.05). In conclusion, our data did not confirm the conventional opinion that the risk of renal scarring after pyelonephritis is low in children over the age of 5 years. Our findings suggest that renal scintigraphy may be a more appropriate method of investigation than VCUG for evaluation of the children over 5 years with acute pyelonephritis. Additionally, the frequency of scintigraphic changes is high, and a strategy based exclusively on ultrasound findings would miss about 61% of the abnormal renal units. We recommend that all children, irrespective of age, will benefit from further investigations that might prevent or limit the development of scarring process and renal complications.

Apport du dosage de la procalcitonine pour le diagnostic de pyélonéphrite aiguë de l'enfant

BACKGROUND

Acute pyelonephritis can induce parenchymal scarring. The aim of this study was to evaluate the usefulness of procalcitonin (PCT) to predict renal involvement in febrile children with urinary tract infection (UTI).

METHODS

In a prospective study serum PCT was measured and compared with others commonly used inflammatory markers in children admitted to the emergency unit with acute pyelonephritis. Renal parenchymal involvement was assessed by a (99 m)Tc-labeled dimercaptosuccinic acid (DMSA) renal scar performed in the first 3 days after the admission.

RESULTS

Among 42 enrolled patients, 19 (45%) had acute renal involvement (Group A) ; 23 (55%) (Group B) had normal DMSA scan (n = 16), or old scarring (n = 4) or various anomalies related to uropathy (n = 3). In group A, the mean PCT level was significantly higher than in the group B (5.4 ng/ml, vs 0.4 ng /ml, p < 10(-5)). In these 2 groups, mean C reactive protein (CRP) levels were 99.1 mg/l and 44.6 mg/l respectively (p < 0.001). For a level of serum PCT > or = 0.5 ng/ml, the sensitivity and specificity to predict the renal involvement were 100% and 87% respectively; for a level> or= 20 mg/l CRP had a sensitivity of 94% but a specificity of 30%.

CONCLUSION

Serum PCT levels were significantly increased in febrile children with UTI when acute renal parenchymal involvement was present. PCT seems a better marker than CRP for the prediction of patients at risk of renal lesions.

Neonates with extra-renal pelvis: the first 2 years

Extra-renal pelvis (ERpel) is a common ultrasonographic finding among neonates who have undergone recurrent ultrasound examinations for a better definition of prenatal renal pelvic dilatation. This study tries to determine whether or not ERpel has important prognostic implications. Seventy-nine neonates (17 female) were examined. All had a diagnosis of prenatal renal pelvis dilatation, which was shown by postnatal ultrasound to be ERpel. Sixty ERpel neonates were examined 1.5 months to 2.5 months after the ultrasound (US) diagnosis by both Tc-99m diethylene triamine penta-acetic acid (DPTA) dynamic renal scanning and (99m)Tc-pertechnetate direct cystography. Clinical assessment, urine cultures and renal ultrasound follow-up were maintained for 2 years. The proportion of urinary tract infections (UTIs) in patients with ERpel was compared with that of the total neonatal and infantile population with normal US scans in the region of our hospital. Associated minor congenital malformations were found in 12 of 79 neonates (15.2%). Four had a family history of ERpel. Among 60 neonates who underwent renal scanning, 36 (60%) were found to have urinary retention in the collecting system. Another nine (15%) had vesico-ureteral (VU) reflux, of which seven had urinary retention. Fifteen (25%) showed normal isotope imaging. Urinary tract infection was diagnosed in 16 ERpel neonates in whom only one exhibited VU reflux (grade 2). The incidence of neonatal UTI in the ERpel group was more than that of either neonatal or infantile UTI in those with normal US scans in the local population (20.2% vs 1.2% and 4.3%, respectively). Fifty-three infants completed a 2-year follow-up. Repeat renal ultrasonography indicated that one infant (1.8%) had developed bilateral hydronephrosis, 12 (22.6%) had unchanged findings, 18 (40%) showed an improvement (decrease of ERpel width or resolution in one side) and, in 22 (41.5%) infants, the condition had resolved. No clinical or kidney function deterioration was observed. Seven patients (13.2%) each had one episode of UTI during the 2-year follow-up period; none of them had VU reflux. Neonatal ERpel is more frequent in male infants. It is associated with greater rates of minor congenital malformations, VU reflux and UTI than in the general population of the same ages. The increased UTI incidence is not attributed to VU reflux.

IMPACT OF VESICOURETERAL REFLUX ON THE SIZE OF RENAL LESIONS AFTER AN EPISODE OF ACUTE PYELONEPHRITIS

PURPOSE

We determined the impact of vesicoureteral reflux (VUR) on the size of renal lesions in children after an episode of acute pyelonephritis.

MATERIALS AND METHODS

A total of 161 children (mean age 2.44 years) with acute pyelonephritis were studied. All had renal lesions on dimercapto-succinic acid scintigraphy done at admission to the hospital. A second dimercapto-succinic acid scan was performed at 3 months. Voiding cystourethrography was done at 6 weeks and VUR was graded I to V. For each renal unit layouts of renal lesions were drawn, and the damage surface was calculated and reported for the total surface of the kidney.

RESULTS

Mean size of acute lesions and scars increased with severity of reflux (p <0.0001), with an important overlap of individual values. Mean size of renal scars in the group of renal units with acute lesions was 5.8% +/- 8.5% in patients without VUR, 9.9% +/- 7.3% in those with grade I reflux, 7.7% +/- 11.0% in those with grade II reflux, 17.7% +/- 14.7% in those with grade III reflux and 17.4% +/- 27.7% in those with grade IV reflux (p <0.001). The size of renal lesions decreased significantly with time. The rate of regression of lesions decreased with increasing reflux. When analyzed according to 3 age groups sizes of scars increased significantly with age.

CONCLUSIONS

VUR has an impact on the size of renal lesions after an episode of pyelonephritis. Children with a grade III or IV reflux are more likely to have larger renal scars. On the other hand, acute lesions of important size may develop even in the absence of VUR.

Renal scintigraphy in children with urinary tract infections

Background/Aim. To determine the incidence of abnormal Technetium Tc 99m Dimercaptosuccinic Acid (Tc99m DMSA) renal scintigraphy findings in the children with urinary tract infection (UTI), and to evaluate the difference between the children with UTI and vesico-ureteral reflux (VUR), and the children with UTI without VUR. Methods. Tc99m DMSA renal scintigraphy was performed in 170 children with UTI, mean age 7.07 years (1 month to 14 years, 137 were girls and 33 were boys). In 88 of the children, VUR was proved by micturating cystouretherography (MCU), while in 82 VUR could not be detected by MCU. VUR was graded in accordance with MCU recommended by the international study of VUR. In 13 of the children the grade of VUR was grade I, in 30 was grade II, in 23 grade III, in 17 grade IV, while the grade V was in 5 of the children. Findings of Tc99m DMSA renal scintigraphy were classified as: 1 - normal, 2 - probably normal, 3 - equivocal, 4 - probably abnormal, and 5 - abnormal. The degree of the significance of the difference of the findings was estimated using ?2, taking p < 0.01 as the limit of statistical significance. Results. Of the total number of 170 studied children, the abnormal findings were detected in 30% (51/170), normal findings in 62% (106/170), and equivocal in 8% (13/170). In the children with UTI and VUR, the incidence of abnormal findings was 49% (43/88), of normal 43% (38/88), and of equivocal findings 8% (7/88). All the children with VUR grade V had the abnormal findings (the incidence of the abnormal findings was 100%). In the children with VUR grade IV, the abnormal findings were 71%. In the children with VUR grade I, 77% of the findings were normal, in the children with VUR grade II, 53% of the findings were normal and in the children with VUR grade III, 30% of the findings of renal scintigraphy were normal. In the children with UTI without VUR, the incidence of abnormal findings was 10% (8/82), of normal findings 83% (68/82), and of equivocal findings 7% (6/82). The incidence of abnormal findings was significantly higher in the children with UTI and VUR than in those with UTI without VUR (p < 0.01). Also, the incidence of the abnormal findings was higher in the children with VUR grades IV and V than in the children with VUR grade I (p < 0.01). Conclusion. DMSA renal scintigraphy in the children with ITU revealed the abnormal findings in 30% of the cases. The incidence of the abnormal findings was significantly higher when VUR was present, as well as if the grade of VUR was higher. Our results confirmed that Tc99m DMSA renal scintigraphy was a very important technique in the evaluation of the children with ITU.

DIMERCAPTO-SUCCINIC ACID SCINTIGRAPHY INSTEAD OF VOIDING CYSTOURETHROGRAPHY FOR INFANTS WITH URINARY TRACT INFECTION

PURPOSE

We study the ability of dimercapto-succinic acid (DMSA) scintigraphy to predict the presence of dilating vesicoureteral reflux (VUR) in infants with urinary tract infection (UTI) to simplify the evaluation protocol.

MATERIALS AND METHODS

A retrospective analysis of the records of 303 children younger than 2 years with initial UTI investigated with DMSA scintigraphy and voiding cystourethrography (VCU) within 3 months after UTI was performed.

RESULTS

In 156 of the 303 children (51%) DMSA scintigraphy showed renal lesions. VUR was found in 80 patients (26%) and VUR grade significantly correlated with the presence of renal lesions. A normal DMSA scintigraphy and dilating VUR (grade III) occurred in 7 infants. At followup after 1 to 2 years, 6 of these 7 patients had normal DMSA scans and 1 had a scarred duplex kidney. VUR resolved spontaneously in 5 and improved spontaneously to grade 1 in 2 patients. None of the 7 children had recurrent UTI.

CONCLUSIONS

DMSA scintigraphy in infants with UTI may replace VCU as a first line investigation. A strategy to perform VCU in only patients with renal lesions is proposed. In this study 147 of 303 VCUs would have been unnecessary as only 1 child with a damaged kidney was missed.

Current diagnosis and management of urinary tract infections in infants and children

The diagnosis and management of urinary tract infections (UTIs) in infants and children poses a unique set of problems, including sterile urine collection in non-toilet-trained children, and recognizing the subtle signs and symptoms of UTIs in infants.

DMSA study performed during febrile urinary tract infection: a predictor of patient outcome?

Technetium-99m dimercaptosuccinic acid (DMSA) study has been advocated as a method for the assessment of renal sequelae after acute febrile urinary tract infection (UTI). However, it is not known whether DMSA scintigraphy performed during acute UTI has any prognostic value for outcome assessment. The objective of this study was to evaluate the usefulness of DMSA scintigraphy performed during UTI as a predictor of patient outcome, to identify children at risk of events [vesico-ureteral reflux (VUR) or recurrent UTI] that may lead to the development of progressive renal damage. One hundred and fifty-two children (including 78 girls) with a mean age of 20 months (range 1 month to 12 years) with first febrile UTI were evaluated by DMSA scintigraphy during acute UTI. After acute UTI, children were explored by voiding cysto-urethrography. Children who presented an abnormal DMSA study, or a normal DMSA study but VUR or recurrent UTI, underwent a DMSA control study 6 months after UTI. Children with VUR were followed up by direct radionuclide cystography. DMSA scintigraphy performed during acute UTI was normal in 112 children (74%). In 95 of these children, follow-up DMSA scintigraphy was not performed owing to a good clinical outcome. In the remaining 17 children, follow-up scintigraphy was normal. Forty children (26%) presented abnormal DMSA study during acute UTI. Twenty-five of them presented a normal follow-up DMSA, and 15 presented cortical lesions. Children with abnormal DMSA had a higher frequency of VUR than children with normal DMSA (48% vs 12%). It is concluded that children with normal DMSA during acute UTI have a low risk of renal damage. Children with normal follow-up DMSA and low-grade VUR have more frequent spontaneous resolution of VUR.