Cortical scintigraphy in the evaluation of renal parenchymal changes in children with pyelonephritis

SNMMI procedure standard/EANM practice guideline on pediatric [99mTc]Tc-DMSA renal cortical scintigraphy: an update

The Society of Nuclear Medicine and Molecular Imaging (SNMMI), founded in 1954, is an international scientific and professional organization with a purpose to promote the science, technology, and practical application of nuclear medicine. The European Association of Nuclear Medicine (EANM), founded in 1985, is a nonprofit professional medical association with a purpose to facilitate international communication among individuals in nuclear medicine pursuing clinical and academic excellence. Members of the SNMMI and EANM are physicians, technologists, and scientists who specialize in the research and practice of nuclear medicine. The SNMMI and EANM will periodically publish new guidelines for nuclear medicine practice to further advance the science of nuclear medicine and improve patient care. Existing standards/guidelines will be reviewed for revision or renewal, as appropriate. Each standard/guideline, representing a policy statement by the SNMMI/EANM, has undergone a thorough review, and represents an expert consensus. The SNMMI and EANM recognize that the safe and effective use of diagnostic nuclear medicine imaging requires specific training and skills, as described in each document. These standards/guidelines are educational resources designed to assist practitioners in providing appropriate nuclear medicine care for patients. They are consensus documents, and are not mandatory provisions or requirements of practice. They are not intended, nor should they be used, to establish a legal standard of care. For these reasons and those set forth below, the SNMMI and the EANM cautions against the use of these standards/guidelines in litigation procedures that call into question the clinical decisions of a practitioner. The ultimate judgment regarding the appropriateness and propriety of any specific procedure or course of action must be made by medical professionals, taking into account the unique context of each case. Thus, there is no implication that action differing from what is detailed in these standards/guidelines, on its own, is below the standard of care. On the contrary, a conscientious practitioner may responsibly adopt a course of action different from that set forth in the standards/guidelines when, based on the reasonable judgment of the practitioner, such course of action is warranted based on the condition of the patient, limitations of available resources, or advances in knowledge or technology subsequent to publication of the standards/guidelines. Practicing medicine involves not only the science, but also the art of dealing with the prevention, detection, diagnosis, and treatment of disease. The variety and complexity of human conditions make it impossible for general guidelines to consistently allow for an accurate diagnosis to be reached or a specific treatment response to be predicted. Therefore, it should be recognized that adhering to these standards/guidelines does not ensure a successful outcome. All that should be expected is that a practitioner follows a reasonable course of action based on their level of training, the current landscape of knowledge, the resources at their disposal, and the needs/context of the particular patient being treated. The purpose of this document is to provide nuclear medicine physicians, radiologists, and other clinicians with guidelines for the recommendation, performance and interpretation of 99mTc-dimercaptosuccinic acid renal cortical scintigraphy ([99mTc] Tc-DMSA scintigraphy) in pediatric patients. These recommendations represent the expert opinions of experienced leaders in this field, and these recommendations are not all supported by a high level of evidence. Further studies are required to have evidence-based recommendations for the application of [99mTc] Tc-DMSA renal cortical scintigraphy in pediatrics. This guideline summarizes the views of the SNMMI Renal Cortical Scintigraphy in Children Working Group and the EANM Pediatrics Committee. It reflects recommendations for which the SNMMI and EANM cannot be held responsible. The recommendations should be taken into context of good practice of nuclear medicine and do not substitute for national and international legal or regulatory provisions.

Pediatric Nephro-Urology: Overview and Updates in Diuretic Renal Scans and Renal Cortical Scintigraphy

Nuclear medicine offers several diagnostic scans for the evaluation of congenital and acquired conditions of the kidneys and urinary track in children. Tc-99m-MAG 3 diuretic renal scans are most commonly used in the evaluation and follow up of urinary track dilatations. They provide functional information on the differential renal function and on drainage quality which is allows distinction between obstructed and non-obstructed kidneys and the need for surgical correction vs conservative management in kidneys with impaired drainage. Standardized imaging and processing protocols are essential for correct interpretation and for meaningful comparisons between follow up scans. Different approaches and conceptions led to some contradicting recommendations between SNMMI and EANM guidelines on diuretic renography in children which caused confusion and to the emergence of self-made institutional protocols. In Late 2018 the two societies published joint procedural guidelines on diuretic renography in infants and children which hopefully will end the confusion. Tc-99m DMSA scans provide important information about the function of the renal cortex allowing detection of acute pyelonephritis, renal scars dysplasia and ectopy as well as accurate determination of the differential renal function. They are commonly used in the evaluation of children with urinary tract infections and affect clinical management. A standardized imaging and processing protocol improves the diagnostic accuracy of these studies. SPECT or pinhole images should be a routine part of the imaging protocol. This is one of the recommendations in the new EANM and SNMMI procedural guidelines for renal cortical scintigraphy in children available online on the SNMMI website and is under publication. This article provides an overview on the clinical role of diuretic renography and cortical scintigraphy in children and describes the imaging protocols focusing on the new recommendations in the procedural guidelines.

Clinical and Epidemiological Analysis of Children's Urinary Tract Infections in Accordance with Antibiotic Resistance Patterns of Pathogens

The study was conducted to analyze urinary tract infections (UTI) in children by considering epidemiology and antibiotic resistance patterns of pathogens in accordance with inflammatory parameters. The research included 525 patients who demonstrated 627 episodes of UTI. The increasing resistance of bacteria was observed over the years covered by the study (p < 0.001). There was a significant increase of resistance to amoxicillin with clavulanic acid (p = 0.001), gentamicin (p = 0.017) and ceftazidime (p = 0.0005). According to the CART method, we managed to estimate C-reactive protein (CRP), procalcitonin (PCT) and white blood cell (WBC) values, in which antibiotic sensitivity was observed. In children with CRP > 97.91 mg/L, there was a high percentage of sensitive cases to amoxicillin with clavulanic acid (87.5%). Values of WBC above 14.45 K/µL were associated with E. coli more sensitivity to ampicillin. 100% of children with CRP > 0.42 mg/L and PCT ≤ 6.92 ng/mL had confirmed sensitivity to cefuroxime. Concerning sensitivity to gentamicin, the most optimal cut-off point of WBC was >7.80 K/µL, while in the case of nitrofurantoin, it was CRP value > 0.11 mg/L (which was presented in 98.50% of children). These results may guide us with antibiotic therapy and help to inhibit increasing antibiotic resistance.

New strategy of color and power doppler sonography combined with DMSA in the assessment of acute pyelonephritis in infants

Background

The purpose of this study was to evaluate the clinical value of color and power doppler sonography (CPDS) when combined it with 99mTc-dimercaptosuccinic acid scintigraphy (DMSA) in assessment of acute pyelonephritis (APN) in infants.

Methods

A total of 79 children with APN admitted to our hospital from June 2016 to Jan 2019 were enrolled, including 52 boys and 27 girls, age range 1 month to 3 years old. All cases followed the diagnostic criteria for acute pyelonephritis and excluded anatomical abnormalities of urinary system. All 79 patients were examined by urinary ultrasonography (US), CPDS, and DMSA within 48 h of fever and analyzed the clinical value of combining the two methods in the assessment of APN in infants.

Results

Among 79 children, urinary ultrasonography revealed 2 cases of renal cortical echo changes, both located in the upper pole of the kidney, 24 cases of kidney enlargement, and 1 case of left kidney shrinkage. Ninety-five kidneys were shown to be diseased with DMSA, while 105 kidneys abnormal by CPDS. The sensitivity of CPDS was 69.4%, and the specificity was 38.1%. In children younger than 6 months, the sensitivity of CPDS was 56.9%, which was 84.2% in childeren between 6 months to 1 year, and 94.4% from 1 to 3 years old, respectively. The corresponding specificity of CPDS was 44.1, 26.7, and 35.7%. There was no significant correlation between CPDS levels and DMSA positive results. The abnormal rate of intermediate part in the kidneys was significantly lower than that in the upper and lower poles. Children with abnormal CPDS have a greater risk of renal scarring(p < 0.05).

Conclusion

Abnormalities detected by CPDS in a cohort of infants with APN poorly correlated with DMSA findings. But the sensitivity of CPDS is highly age-related, it can be used as a non-invasive helpful tool for early diagnosis of acute pyelonephritis in infants older than 6 months old.

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.

99mTc-dimercaptosuccinic acid scan versus MRI in pyelonephritis: a meta-analysis

PURPOSE

Tc-dimercaptosuccinic acid (DMSA) scan is the current gold standard in detecting parenchymal changes, particularly scarring, in pyelonephritis. Recently, magnetic resonance imaging (MRI) is gaining popularity in the diagnosis of pyelonephritis. The aim of this study is to perform a meta-analysis on studies directly comparing MRI to DMSA scan in patients with pyelonephritis.

MATERIALS

Systematic searches of PUBMED and EMBASE databases were performed to extract studies comparing MRI and DMSA scan in patients with pyelonephritis. The relevance of articles was assessed by two authors according to predefined inclusion and exclusion criteria. The pooled estimates of the sensitivities of MRI and DMSA scan were computed using random-effects meta-analysis model following DerSimonian and Laird's method. Subgroup analysis and publication bias were performed.

RESULTS

Seven studies were included (164 patients). Using random effect model, the pooled estimate of the sensitivities of MRI and DMSA scan were 0.62 (95%CI: 0.44 - 0.77) and 0.59 (95%CI: 0.48 - 0.70), respectively. The pooled estimates of sensitivities of MRI and DMSA scan for acute pyelonephritis were 0.73 (95%CI: 0.49- 0.89) and 0.66 (95%CI: 0.56 - 0.75), respectively, and for scar detection were 0.48 (95%CI: 0.31- 0.66), and 0.50 (95%CI: 0.30 - 0.71), respectively.

CONCLUSION

The overall sensitivities of MRI and DMSA scan were equivalent in detecting parenchymal changes in pyelonephritis. MRI and DMSA scan appeared to be equivalent to scar detection. In a small number of studies, MRI appeared to be better than the DMSA scan in acute pyelonephritis but this should be further studied in a larger number of patients.

Relationship of Urinary Tract Infection to Lower Urinary Tract Dysfunction and Kidney Scar Formation in Children

Background:

Urinary tract infection (UTI) is the most common infection during childhood. Lower urinary tract dysfunction (LUTD) is a broad term that indicates an abnormal voiding pattern in a child without anatomical and neurological impairment. The purpose of this study was to determine the relationship between UTI and LUTD.

Methods:

This study was conducted at the Children Medical Center Hospital in 2014–2016. The inclusion criteria of this study were at least one UTI confirmed by a positive urine culture and active urine analysis in children who were well toilet-trained previously. Complete physical examination of the genitourinary and skeletal systems was performed to identify patients with anomalies in these systems. The patients with genitourinary system anomalies and obvious and prediagnosed neurological defects of the urinary system such as neurogenic bladder were excluded from the study. To confirm the presence of LUTD, the scoring system of Akbal et al. was applied.

Results:

A total of 260 patients including 9.2% of males and 90.8% of females were included in this study. The prevalence of LUTD was 63.8% (166 cases) in these patients. In this study, the prevalence of LUTD in patients with a single episode of UTI was 50.5%, while in patients with recurrence of UTI it was 88.9%. In patients with unilateral kidney scar formation, 90.9% had a recurrence of UTI (P = 0.003) which shows a strong correlation of unilateral scar formation with recurrence of UTI.

Conclusions:

These data suggest that there is a significant relationship between UTI and LUTD in children, so evaluation of voiding dysfunction is necessary in this group. With early diagnosis and appropriate treatment, we can reduce the possible serious and permanent sequels of LUTD in patients with UTIs.

Fever duration during treated urinary tract infections and development of permanent renal lesions

OBJECTIVE

To assess the effect of the duration of fever after the initiation of treatment (FAT) of febrile urinary tract infections (UTI) on the development of permanent renal lesions based on dimercaptosuccinic acid (DMSA) scintigraphy findings. To evaluate the FAT contribution to permanent renal lesion formation in relation to fever before treatment initiation (FBT), the presence of vesicourinary reflux (VUR), age and severity of infection.

METHODS

The inpatient records of 148 children (median age: 2.4 months (11 days to 24 months)) with a first episode of UTI during a 3-year period were analysed. DMSA findings, and clinical and laboratory parameters were evaluated.

RESULTS

Among the study population, 34/148 (22.97%) children had permanent renal lesions on the DMSA scan 6 months after a single episode of UTI. Twenty-three children (15.5%) had mild, 10 (6.7%) had moderate and 1 (0.6%) child had severe lesions on the DMSA. FAT prolongation >/48 hours was associated with older age (p=0.01) and increased absolute neutrophil count (p=0.042). The likelihood of lesions was significantly increased when FAT was ≥48 hours (R²=0.043, p=0.021). On multiple regression analysis, with the addition of FBT>/72 hours (0.022), the presence of VUR (p<0.001), C-reactive protein (p=0.027) and age (p=0.031), the effect of FAT on lesion development disappeared (p=0.15).

CONCLUSIONS

Prolongation of FAT≥48 hours of febrile UTI in children <2 years significantly contributes to the development of permanent renal lesions. However, delay in treatment initiation >/72 hours, the presence of VUR, older age and infection severity seem to be more significant predictors of the development of renal lesions.

Risk factors for urinary tract infection in children with urinary urgency

Purpose

To identify which independent variable would be strong predictor of febrile urinary tract infection (UTI) in children and adolescents with overactive bladder.

Materials and Methods

A search was made of the institute's database for all patients diagnosed with overactive bladder over the preceding four years. Children and adolescents under 18 years of age with overactive bladder and no neurological or anatomical alterations of the lower urinary tract were included in the study. The independent variables were: sex, age, ethnicity (Brazilians of African descendence/others), the presence of urinary urgency, daytime incontinence, enuresis, frequent urination, infrequent voiding (≤3 voids/day), nocturia, holding maneuvers, straining to void, intermittent urinary flow, constipation and encopresis. An analysis was conducted to identify patients with febrile UTI and subsequently determine predictors of this condition. Univariate and multivariate analyses were performed.

Results

Overall, 326 patients (214 girls/112 boys) were evaluated. The mean age of the patients was 7.7±3.19 years (± standard deviation). The incidence of febrile UTI was 39.2%. Being female and infrequent voiding were factors significantly associated with febrile UTI, both in the univariate and multivariate analyses.

Conclusions

These results show that being female and infrequent voiding constituted significant risk factors for a diagnosis of febrile UTI in these children.

Procalcitonin: The marker of pediatric bacterial infection

Timely recognition of systemic bacterial infections in pediatric care setting is the basis for effective treatment and control. This review provides an overview of procalcitonin (PCT) as an early marker for the detection of severe, invasive bacterial infection in children. Almost all articles on biochemical property and clinical studies in PubMed and Scopus databases regarding their use in pediatric infections and the use of PCT as a marker of bacterial infections were examined. Various methods and analyzers are currently available for the evaluation of PCT. Employment of PCT in the identification of neonatal bacterial infection is a complex process in some conditions. Age specific cut-off, underlying syndrome, and maternal antibiotics usage should be considered when PCT is to be applied in neonates. PCT might be false-negative in these conditions. However, if used appropriately, it can lead to a higher specificity than other immunologic markers. Due to its correlation with the severity of infection, PCT can consequently be used as a prognostic indicator especially for sepsis and urinary tract infection. It is, therefore, a practical supplementary means for the identification of bacterial infections in pediatric health settings.

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.

Mean platelet volume in young children with urinary tract infection

Mean platelet volume (MPV) has not yet been well-established in urinary tract infection (UTI). The purpose of this study was to evaluate the role of MPV as an acute phase reactant in children with UTI. Data from 118 young children (<2 years) with UTI between 2012 and 2013 were grouped as acute pyelonephritis (APN) and lower UTI according to the dimercaptosuccinic acid (DMSA) scan abnormalities. MPV, platelet distribution width (PDW) platelet count, and other infection markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], and C-reactive protein [CRP]) were measured. WBC (P = 0.001), ESR (P = 0.005), CRP (P < 0.001) and MPV levels (P = 0.011) were significantly higher in the APN group than those in the lower UTI group. MPV positively correlated with PDW, CRP and negatively with platelet count. Multiple logistic regression analyses showed that CRP and MPV were independent predictive factors for APN patients. However, the area under the Receiver Operating Characteristic (ROC) curve analysis for MPV was lower than CRP. Our results suggest that MPV can be an inflammatory marker in UTI, but the predictive value of MPV was not superior to CRP in the diagnosis of APN.

The lectin like domain of thrombomodulin is involved in the defence against pyelonephritis

Pyelonephritis, a common complication of urinary tract infections, is frequently associated with kidney scarring and may lead to end-stage renal disease. During bacterial infections inflammatory and coagulation pathways and their mutual interaction are playing pivotal roles in the host response. Given that thrombomodulin (TM) is crucially involved in the interplay between coagulation and inflammation, we aimed to investigate the roles of its EGF and lectin-like domains in inflammation during acute pyelonephritis. Indeed, the EGF-like and the lectin-like domains of TM, are especially known to orchestrate inflammation and coagulation in different ways. Acute pyelonephritis was induced by intravesical inoculation of 1 × 10(8) CFU of uropathogenic Escherichia coli in two strains of TM transgenic mice. TM(pro/pro) mice carry a mutation in the EGF-like domain making them unable to activate protein C, an anticoagulant and anti-inflammatory protein. TM(LeD/LeD) mice lack the lectin-like domain of TM, which is critical for its anti-inflammatory and cytoprotective properties. Mice were sacrificed 24 and 48 h after inoculation. Bacterial loads, the immune response and the activation of coagulation were evaluated in the kidney and the bladder. TM(LeD/LeD) mice showed elevated bacterial load in bladder and kidneys compared to WT mice, whereas TM(pro/pro) had similar bacterial load as WT mice. TM(LeD/LeD) mice displayed a reduced local production of pro-inflammatory cytokines and neutrophil renal infiltration. Activation of coagulation was comparable in TM(LeD/LeD) and WT mice. From these data, we conclude that the lectin-like domain of thrombomodulin is critically involved in host defence against E. coli induced acute pyelonephritis.

Risk Factors for Recurrent Urinary Tract Infection and Renal Scarring

OBJECTIVES

To identify risk factors for recurrent urinary tract infection (UTI) and renal scarring in children who have had 1 or 2 febrile or symptomatic UTIs and received no antimicrobial prophylaxis.

METHODS

This 2-year, multisite prospective cohort study included 305 children aged 2 to 71 months with vesicoureteral reflux (VUR) receiving placebo in the RIVUR (Randomized Intervention for Vesicoureteral Reflux) study and 195 children with no VUR observed in the CUTIE (Careful Urinary Tract Infection Evaluation) study. Primary exposure was presence of VUR; secondary exposures included bladder and bowel dysfunction (BBD), age, and race. Outcomes were recurrent febrile or symptomatic urinary tract infection (F/SUTI) and renal scarring.

RESULTS

Children with VUR had higher 2-year rates of recurrent F/SUTI (Kaplan-Meier estimate 25.4% compared with 17.3% for VUR and no VUR, respectively). Other factors associated with recurrent F/SUTI included presence of BBD at baseline (adjusted hazard ratio: 2.07 [95% confidence interval (CI): 1.09-3.93]) and presence of renal scarring on the baseline (99m)Tc-labeled dimercaptosuccinic acid scan (adjusted hazard ratio: 2.88 [95% CI: 1.22-6.80]). Children with BBD and any degree of VUR had the highest risk of recurrent F/SUTI (56%). At the end of the 2-year follow-up period, 8 (5.6%) children in the no VUR group and 24 (10.2%) in the VUR group had renal scars, but the difference was not statistically significant (adjusted odds ratio: 2.05 [95% CI: 0.86-4.87]).

CONCLUSIONS

VUR and BBD are risk factors for recurrent UTI, especially when they appear in combination. Strategies for preventing recurrent UTI include antimicrobial prophylaxis and treatment of BBD.

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.

Is Imaging Time Between two Tc 99m DMSA Scans Sufficient for Reporting as Renal Parenchymal Scarring? Healed Parenchymal Renal Defect After 6 Years

We aimed to report a healed renal parenchymal defect after 6 years in a 9-year-old girl who was being followed for recurrent urinary tract infection (UTI). The first UTI was at the age of two. She was being followed with ultrasonography, urine analysis and urine culture since the first UTI. Technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy was repeated four times up to the present day. She had a renal parenchymal defect reported as parenchymal scarring, which healed 6 years after the first DMSA scintigraphy.

Conflict of interest:None declared.

Urinary tract infection in infants: a single-center clinical analysis in southern Taiwan

BACKGROUND

This study summarized the epidemiology, etiology, and susceptibility of pathogens to antibiotics, and specific characteristics in infants aged less than 4 months diagnosed with urinary tract infection in the past decade in Taiwan.

METHODS

The medical charts of patients aged less than 4 months admitted for urinary tract infection to Kaohsiung Veterans General Hospital between January 2001 and December 2009 were retrospectively reviewed.

RESULTS

A total of 132 patients, with male predominance (68.9%), were enrolled. The top three pathogens were similar to those identified in previous studies in Taiwan. The most common pathogen, Escherichia coli (85.3%), was resistant to ampicillin (75.9%), followed by sulfamethoxazole/trimethoprim (31.7%), and cefazolin (28.5%). Dimercaptosuccinic acid (DMSA) renal scan revealed 34.5% positive findings, while the vesicoureteral reflux (VUR) rate was 37.8% by direct radionuclide voiding cystography and/or voiding cysto-urethrography. Positive DMSA findings significantly correlated with VUR (p<0.001) and higher C-reactive protein level (p<0.05).

CONCLUSIONS

E coli was the most common pathogen in the present cohort, and the top three pathogens were similar to those found in general pediatric population in Taiwan. VUR was the most common genitourinary tract anomaly in this age group. Positive DMSA was well correlated with VUR and higher C-reactive protein level.

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.

Effect of partial ureteral obstruction and bacterial virulence on the occurrence of renal scarring in a mouse model

OBJECTIVE

To evaluate the effect of the infection and the obstruction of urinary tract on renal parenchyma, we developed a model of ascending urinary infection in mice with partial unilateral obstructive uropathy.

METHODS

Six week-old CBA/J mice were operated on to perform a right partial ureteral obstruction and challenged transurethrally with Escherichia coli CFT073 (high virulent strain) or E. coli Mez (low virulent strain). Level of infection of urine and kidneys, score of inflammation and fibrosis of kidneys, and kidney weight ratio (KWR) in the short and long term were studied.

RESULTS

At short-term (72 hours) experimentation, partial ureteral obstruction does not influence the level of kidney infection in terms of bacterial count, and the score of inflammation regardless of whether a virulent or low virulent strain was used. At long-term (42 days) experimentation, E. coli Mez was eliminated from all mice kidneys, but CFT073 persisted in almost all; obstruction did not influence the level of kidney infection with CFT073 but a significant difference of KWR and the inflammation and fibrosis score between obstructed and unobstructed kidneys was found (P = .0078; P = .036, respectively). Although the E. coli Mez strain did not persist in renal parenchyma, severe damage of the renal parenchyma was observed.

CONCLUSION

The proposed model is similar to the obstructive uropathy in children in which ureteral obstruction is present before the onset of infection. The association of obstruction and urinary infection impairs kidney growth and favors the occurrence of renal damage.

Acute phase 99mTc-dimercaptosuccinic acid scan in infants with first episode of febrile urinary tract infection

BACKGROUND

99mTc-dimercaptosuccinic acid (DMSA) scan is the golden standard for the diagnosis of acute pyelonephritis and renal scaring. We investigated the use of acute phase DMSA scan in infants presented promptly to the hospital because of the first episode of their febrile urinary tract infection (UTI).

METHODS

Ninety-eight infants with microbiologically confirmed first episode of febrile UTI were studied. DMSA scans were carried out within 7 days in these infants after admission. Infants with an abnormal acute DMSA scan underwent a second DMSA scan 6-12 months later.

RESULTS

Overall, acute DMSA scan was abnormal in 16 (16.3%) of the 98 patients. There were no differences in sex, age, fever over 38.5°C, blood inflammation indices, or evidence of vesicoureteral reflux (VUR) between patients with normal and abnormal acute DMSA scan (P>0.05). However, infants with grade III to V VUR as well as those with delayed treatment presented significantly increased renal involvement by acute DMSA scan (P<0.05). The sensitivity and specificity of abnormal acute DMSA scan to predict grade III to V VUR were 50% and 88% respectively. Its positive and negative likelihood ratios were 4.16 and 0.57, respectively. Of 16 children with abnormal initial DMSA scan results, 14 underwent a second DMSA scan. Follow-up DMSA scans were normal in 12 of the 14 children.

CONCLUSIONS

Parenchymal damage found in a minority of infants with febrile UTI presented promptly to the hospital. Acute phase DMSA scan should be carried out only in selected patients. An abnormal acute DMSA scan is a moderate predictor for dilated VUR and its ability to exclude VUR is restricted.

Discordant findings on dimercaptosuccinic acid scintigraphy in children with multi-detector row computed tomography-proven acute pyelonephritis

PURPOSE

The diagnosis of acute pyelonephritis (APN) is often difficult, as its clinical and biological manifestations are non-specific in children. If not treated quickly and adequately, however, APN may cause irreversible renal damage, possibly leading to hypertension and chronic renal failure. We were suspecting the diagnostic value of (99m)Tc-dimercaptosuccinic acid (DMSA) scan by experiences and so compared the results of DMSA scan to those of multi-detector row computed tomography (MDCT).

METHODS

We retrospectively selected and analyzed 81 patients who were diagnosed as APN by MDCT during evaluation of their acute abdomen in emergency room and then received DMSA scan also for the diagnostic work-up of APN after admission. We evaluated the results of imaging studies and compared the diagnostic value of each method by age groups, <2 years (n=45) and ≥2 years (n=36).

RESULTS

Among total 81 patients with MDCT-proven APN. DMSA scan was diagnostic only in 55 children (68%), while the remaining 26 children (32%) showed false negative normal findings. These 26 patients were predominantly male with average age of 21 months and most of them, 19 (73.1%) were <2 years of age.

CONCLUSION

DMSA scan has obvious limitation compared to MDCT in depicting acute inflammatory lesions of kidney in children with APN, especially in early childhood less than 2 years of age. MDCT showed hidden lesions of APN, those were undetectable through DMSA scan in children.

Risk of renal scarring in children with a first urinary tract infection: a systematic review

BACKGROUND

To our knowledge, the risk of renal scarring in children with a urinary tract infection (UTI) has not been systematically studied.

OBJECTIVE

To review the prevalence of acute and chronic renal imaging abnormalities in children after an initial UTI.

METHODS

We searched Medline and Embase for English-, French-, and Spanish-language articles using the following terms: "Technetium (99m)Tc dimercaptosuccinic acid (DMSA)," "DMSA," "dimercaptosuccinic," "scintigra*," "pyelonephritis," and "urinary tract infection." We included articles if they reported data on the prevalence of abnormalities on acute-phase (≤15 days) or follow-up (>5 months) DMSA renal scans in children aged 0 to 18 years after an initial UTI. Two evaluators independently reviewed data from each article.

RESULTS

Of 1533 articles found by the search strategy, 325 full-text articles were reviewed; 33 studies met all inclusion criteria. Among children with an initial episode of UTI, 57% (95% confidence interval [CI]: 50-64) had changes consistent with acute pyelonephritis on the acute-phase DMSA renal scan and 15% (95% CI: 11-18) had evidence of renal scarring on the follow-up DMSA scan. Children with vesicoureteral reflux (VUR) were significantly more likely to develop pyelonephritis (relative risk [RR]: 1.5 [95% CI: 1.1-1.9]) and renal scarring (RR: 2.6 [95% CI: 1.7-3.9]) compared with children with no VUR. Children with VUR grades III or higher were more likely to develop scarring than children with lower grades of VUR (RR: 2.1 [95% CI: 1.4-3.2]).

CONCLUSIONS

The pooled prevalence values provided from this study provide a basis for an evidence-based approach to the management of children with this frequently occurring condition.

Procalcitonin as a marker of severe bacterial infection in children in the emergency department

Procalcitonin, the prohormone of calcitonin, is a relatively new and innovative marker of bacterial infection that has multiple potential applications in the pediatric emergency department. In healthy individuals, circulating levels of procalcitonin are generally very low (<0.05 ng/mL), but in the setting of severe bacterial infection and sepsis, levels can increase by hundreds to thousands of fold within 4 to 6 hours. Although the exact physiologic function of procalcitonin has not been determined, the consistent response and rapid rise of this protein in the setting of severe bacterial infection make procalcitonin a very useful biomarker for invasive bacterial disease. In Europe, serum procalcitonin measurements are frequently used in the diagnosis and the management of patients in a variety of clinical settings. To date, the use of procalcitonin has been limited in the United States, but this valuable biomarker has many potential applications in both the pediatric emergency department and the intensive care unit. The intent of this article is to review the history of procalcitonin, describe the kinetics of the molecule in response to bacterial infection, describe the laboratory methods available for measuring procalcitonin, examine the main causes of procalcitonin elevation, and evaluate the potential applications of procalcitonin measurements in pediatric patients.

Update on childhood urinary tract infection and vesicoureteral reflux

Urinary tract infection (UTI) is a leading cause of serious bacterial infection in young children. Vesicoureteral reflux (VUR), a common pediatric urologic disorder, is believed to predispose to UTI, and both are associated with renal scarring. The complex interaction of bacterial virulence factors and host defense mechanisms influence renal damage. However, some renal parenchymal abnormalities associated with VUR are noninfectious in origin. Long-term, renal parenchymal injury may be associated with hypertension, pregnancy complications, proteinuria, and renal insufficiency. Optimal management of VUR and UTI is controversial because of the paucity of appropriate randomized controlled trials; there is a need for well-designed studies. The recently launched Randomized Intervention for children with VesicoUreteral Reflux (RIVUR) study hopefully will provide insight into the role of antimicrobial prophylaxis of UTI in children with VUR.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Urine macrophage migration inhibitory factor (MIF) in children with urinary tract infection: a possible predictor of acute pyelonephritis

Macrophage migration inhibitory factor (MIF) is an important pro-inflammatory cytokine expressed at sites of inflammation. We have assessed this factor (MIF) in urinary tract infections with the aim of determining a non-invasive and sensitive method to differentiate upper and lower renal involvement. Thirty-three pediatric patients with urinary track infection (25 with acute pyelonephritis, eight with acute cystitis) and 40 healthy subjects were recruited for this prospective case-control study. Pyelonephritis was differentiated from cystitis by dimercaptosuccinic acid (DMSA) scan. Urinary MIF concentration was determined using an enzyme-linked immunosorbent assay method. The urine MIF/creatinine (Cr) ratio was significantly higher in pyelonephritis patients than in those with acute cystitis and the control group (P < 0.001). The optimal cut-point of 4.90 pg/micromol Cr for the urine MIF/Cr ratio has the potential to be a biomarker for distinguishing patients with acute pyelonephritis from those with acute cystitis. Determination of the urinary MIF was also useful in selecting the patients at risk of permanent renal damage. Of those patients with pyelonephritis, based on the DMSA scan at the time of infection, scarring on follow-up DMSA scan 9-12 months later occurred in patients with the highest urinary MIF/Cr ratios. We conclude that the urine MIF/Cr ratio is a sensitive test for differentiating acute pyelonephritis from acute cystitis and also for detecting children with acute pyelonephritis who are at a higher risk for permanent renal scars in the future.

The presence of urinary nitrites is a significant predictor of pediatric urinary tract infection susceptibility to first- and third-generation cephalosporins

BACKGROUND

Previous studies in adults have refuted the use of nitrites as a predictor of bacterial resistance to both trimethoprim-sulfamethoxazole and cephalosporins. Some centers now consider first-line outpatient therapy with an oral third-generation cephalosporin appropriate for young children.

OBJECTIVE

The objective of this study was to determine if nitrite-negative pediatric urinary tract infections (UTIs) were more likely than nitrite-positive UTIs to be resistant to cephalosporins. This may enable physicians to adjust antimicrobial therapy before patients leave the Emergency Department (ED) to avoid the complications of ineffectively treated pediatric UTIs.

METHODS

A retrospective chart review examined, over a 9-month period, 173 pediatric patients who were diagnosed with a clinical UTI in the ED and who also had a positive urine culture and a recorded dipstick at the time of visit. The chi-squared test and Fisher's exact test were used to compare nitrite-negative vs. nitrite-positive UTIs for resistance to third-generation cephalosporins and other empiric antimicrobials.

RESULTS

For third-generation cephalosporins, 1.4% of nitrite-positive UTIs were resistant, whereas 14.4% of nitrite-negative UTIs were resistant (95% confidence interval [CI] -0.22 to -0.05). For first-generation cephalosporins, 8.4% were resistant in the nitrite-positive group, compared to 22.2% in the nitrite-negative group (95% CI -0.24 to -0.03).

CONCLUSION

The absence of urinary nitrites is a significant indicator for potential resistance to cephalosporins in pediatric UTIs. Due to low levels of pediatric UTI resistance, cephalosporins continue to represent useful empiric therapy in the general pediatric population. However, in high-risk patients, physicians may opt to alter their empiric choice of antibiotic based on the presence of urinary nitrites.

Prospective, randomized trial comparing short and long intravenous antibiotic treatment of acute pyelonephritis in children: dimercaptosuccinic acid scintigraphic evaluation at 9 months

OBJECTIVE

We report a prospective, randomized, multicenter trial that compared the effect of 3 vs 8 days of intravenous ceftriaxone treatment on the incidence of renal scarring at 6 to 9 months of follow-up in 383 children with a first episode of acute pyelonephritis.

METHODS

After initial treatment with intravenous netilmicin and ceftriaxone, patients were randomly assigned to either 5 days of oral antibiotics (short intravenous treatment) or 5 days of intravenous ceftriaxone (long intravenous treatment). Inclusion criteria were age 3 months to 16 years and first acute pyelonephritis episode, defined by fever of >38.5 degrees C, C-reactive protein level of >20 mg/L, and bacteriuria at >10(5)/mL. All patients underwent 99m technetium-dimercaptosuccinic acid scintigraphy 6 to 9 months after inclusion. A total of 548 children were included, 48 of whom were secondarily excluded and 117 of whom were lost to follow-up or had incomplete data; therefore, 383 children were eligible, 205 of them in the short intravenous treatment group and 178 in the long intravenous treatment group.

RESULTS

At inclusion, median age was 15 months, median duration of fever was 43 hours, and median C-reactive protein level was 122 mg/L. A total of 37% (143 of 383) of patients had a vesicoureteral reflux grades 1 to 3. Patient characteristics at inclusion were similar in both groups, except for a significantly higher proportion of girls in the short intravenous treatment group. The frequency of renal scars at scintigraphy was similar in both groups. Multivariate analysis demonstrated that renal scars were significantly associated with increased renal height at initial ultrasound and with the presence of grade 3 vesicoureteric reflux.

CONCLUSIONS

The incidence of renal scars was similar in patients who received 3 days compared 8 days of intravenous ceftriaxone. Increased renal height at initial ultrasound examination and grade 3 vesicoureteric reflux were significant risk factors for renal scars.

The clinical spectrum of acute 'uncomplicated' pyelonephritis from an emergency medicine perspective

Acute uncomplicated pyelonephritis (APN) is a complex clinical entity, which is defined differently based on clinical or imaging criteria. The aim of this study was to describe the clinical and radiological presentation of APN-upper urinary tract infection (UTI) cases observed between May 2005 and June 2006 and hospitalised in the Emergency Medicine ward of San Luigi Hospital, Orbassano, Turin, Italy. All patients underwent imaging scans and were differentiated on the basis of parenchymal involvement. Of around 45000 patient visits to the emergency room between May 2005 and June 2006, 23 patients were diagnosed as having uncomplicated upper UTI (all female, age 15-57 years). Renal parenchymal involvement was confirmed by imaging in 16 cases (69.6%). The imaging spectrum ranged from a small single lesion to large multiple defects; on admission, 2 cases had no pain and 2 had no fever; lower urinary tract symptoms were present in only 13 patients (7 with parenchymal involvement). All patients with parenchymal involvement had at least one sign of systemic inflammation-infection. Most patients (15) had taken antibiotics before hospitalisation; consequently, urine cultures were negative in 21 cases (14 cases with positive imaging (87.5%)). The data from patients with and without parenchymal involvement overlapped, the only difference being a higher prevalence of high CRP levels in cases with parenchymal involvement.

Imaging in childhood urinary tract infections: time to reduce investigations

The correct protocol for investigating urinary tract infections (UTI) is unknown but remains a hotly debated topic. The main objective in investigating children with UTI is to prevent the long-term complications of developing hypertension, chronic kidney disease (CKD) and/or pregnancy complications. However, the prognosis for childhood UTI remains good, with low long-term risks, from epidemiological studies, of developing these sequelae. Although childhood UTI is common, the occurrence of CKD and the likelihood that acute pyelonephritis will cause renal damage progressing to CKD are rare. We studied the current literature on investigations of childhood UTI and propose a protocol for carrying out selected investigations in high-risk children. By identifying this group of children with increased risk of having an abnormal urinary tract that warrant investigation, we recommend that targeting investigations to specific children (as opposed to protocol-based investigations of all children with UTI), will be clinically safe and effective and will avoid the unnecessary distress and cost of invasive investigations.

Imaging and treatment strategies for children after first urinary tract infection

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Risk factors for renal scarring in children and adolescents with lower urinary tract dysfunction

Risk factors for renal scarring in children with lower urinary tract dysfunction (LUTD) were evaluated. The medical records of 120 patients were assessed concerning gender, presence of vesicoureteric reflux (VUR), bladder capacity, detrusor overactivity, residual urine, febrile urinary tract infection (UTI), bacteriuria, constipation, detrusor sphincter incoordination (DSI), high detrusor pressure at maximal cystometric capacity (PMCC), low compliance, and thickness and trabeculation of the bladder wall. Renal scarring was diagnosed by (99m)technetium-dimercaptosuccinic acid renal scan (DMSA). Renal scarring was detected in 38 patients (31%). VUR, UTI, decreased bladder capacity, urinary residue, and trabeculated and thick bladder wall were associated with scarring at univariate analysis. Multivariate analysis showed VUR (P < 0.0001) as the independent risk factor for renal scarring. Thickness of the bladder wall was a marginal risk factor (P = 0.07). Although UTI was not a risk factor, it was associated with VUR (P = 0.03). In our analysis, VUR was the main risk factor; however, renal scarring was probably due to multifactorial causes, as VUR was associated with UTI.

Does early treatment of urinary tract infection prevent renal damage?

OBJECTIVE

Therapeutic delay has been suggested as the most important factor that is likely to have an effect on the development of scarring after acute pyelonephritis. However, this opinion has not been supported by prospective studies, so we tested it.

METHODS

In a prospective clinical study, we evaluated whether the time interval between the onset of the renal infection and the start of therapy correlates with the development of acute inflammatory changes and the subsequent development of renal scars, documented by dimercaptosuccinic acid scintigraphy. A total of 278 infants (153 male and 125 female) aged 0.5 to 12.0 months with their first urinary tract infection were enrolled in the study.

RESULTS

The median time between the onset of infection and the institution of therapy was 2 days (range: 1-8 days). Renal inflammatory changes were documented in 57% of the infants. Renal defects were recorded in 41% of the patients treated within the first 24 hours since the onset of fever versus 75% of those treated on day 4 and onward. Renal scarring was developed in 51% of the infants with an abnormal scan in the acute phase of infection. The frequency of scarring in infants treated early and in those whose treatment was delayed did not differ, suggesting that once acute pyelonephritis has occurred, ultimate renal scarring is independent of the timing of therapy. Acute inflammatory changes and subsequent scarring were more frequent in the presence of vesicoureteral reflux, especially that which is high grade. However, the difference was not significant, which suggests that renal damage may be independent of the presence of reflux.

CONCLUSIONS

Early and appropriate treatment of urinary tract infection, especially during the first 24 hours after the onset of symptoms, diminishes the likelihood of renal involvement during the acute phase of the infection but does not prevent scar formation.

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.

Resolution of cortical lesions on serial renal scans in children with acute pyelonephritis

BACKGROUND

The ideal time for distinguishing a renal scar from acute inflammatory lesions by renal DMSA scintigraphy remains controversial.

OBJECTIVE

To determine the time needed for resolution of lesions after acute pyelonephritis.

MATERIALS AND METHODS

A total of 105 children with acute pyelonephritis underwent renal sonography, voiding cystourethrography and baseline DMSA scintigraphy. Two subsequent scans were performed during the 6th and 12th months in patients with abnormal findings on the previous scan.

RESULTS

The baseline DMSA scintigraphy revealed cortical lesions in 37 patients. At 6 months, 13 patients (38.2%) were found to have cortical lesions. At 12 months, 6 patients (17.6%) were found to have persistent renal cortical lesions. The resolution rates for lesions detected on the first scan were 61.8% and 82.4% on the 6- and 12-month scans, respectively. Vesicoureteric reflux, and bilaterality or multifocality were not relevant for resolution of lesions. Female gender seemed to be associated with a higher persistence rate.

CONCLUSIONS

The renal cortical defects present at 6 months have a high rate of resolution later during follow-up. DMSA scintigraphy performed 12 months after the infection provides more reliable data regarding persistence of renal cortical lesions.

First urinary tract infection in neonates, infants and young children: a comparative study

In an attempt to evaluate first urinary tract infection (UTI) in neonates and infants, we estimated retrospectively in 296 patients (62 neonates and 234 infants) clinical and laboratory findings, occurrence of vesicoureteral reflux (VUR), urinary tract abnormalities and pyelonephritis. First UTI occurred more often in male than female neonates, whereas male and female infants/young children were affected at an equal rate. The pathogens isolated in urine cultures of neonates and infants did not statistically significantly differ (P>0.05); Escherichia coli predominated. Gram-negative bacteria other than E. coli affected boys more often than girls (P=0.0022). Fever was the most frequent symptom. Neonates had lower-grade fever of shorter duration than infants (P<0.05). The incidence of reflux and urinary tract abnormalities did not differ between neonates and infants, male and female neonates and infants (P>0.05). Pyelonephritis affected neonates and infants at an equal rate; it was more prevalent among female patients (P=0.038) and patients with VUR or urinary tract abnormalities other than VUR (P<0.0001). Neonates with reflux were more often affected by Gram-negative bacteria other than E. coli than were neonates without reflux (P=0.0008).