Urinary tract infections in children: knowledge updates and a salute to the future.

UNLABELLED: 1. Evaluating and treating bladder and bowel dysfunction are critical in reducing the risk of urinary tract infections (UTIs). 2. The pathogenesis of Escherichia coli infections reveals that quiescent intracellular reservoirs may be antibiotic-protected sources of recurrent infections. OBJECTIVES: 1. Review the documentation of UTI and the importance of the urine culture. 2. Understand the controversy over imaging and management of febrile UTIs in children. 3. Recognize the risk factors for recurrent UTIs and strategies for intervention. 4. Update information on the pathogenesis of E coli UTIs.

Comparison of standard, prone and cine MRI in the evaluation of tethered cord.

BACKGROUND: Tethered cord syndrome (TCS) is defined by abnormal traction on the spinal cord that confines its movement. Surgical cord release usually stops neurological deterioration; therefore, early and accurate neuroradiological diagnosis is important. Supine MRI is the imaging modality of choice, but prone MRI and cine MRI can demonstrate cord movement. OBJECTIVE: We compared the diagnostic accuracies of standard MRI, prone MRI and cine MRI in patients with clinical suspicion of TCS and evaluated inter-reader reliability for MR imaging. MATERIALS AND METHODS: Children who underwent MRI for suspicion of TCS were retrospectively identified. Supine, prone and cine MRI studies were re-read by two pediatric neuroradiologists. Conus level, filum appearance and cord movement were documented. RESULTS: Thirteen of 49 children had tethered cord documented at surgery. Conus level had the highest diagnostic accuracy (sensitivity 69-77%, specificity 94%, positive predictive value 82-83%, negative predictive value 89-92%, correct diagnosis 88-90%) and highest between-reader concordance (98%). Prone and cine MRI did not add to the accuracy of the supine imaging. CONCLUSION: Conus level provides the highest diagnostic accuracy and inter-reader reliability in TCS. Until a larger series is evaluated, it remains questionable whether prone or cine MRI provides enough additional diagnostic information to warrant routine use.

Frequency of Multidrug-Resistant Organisms Cultured From Urine of Children Undergoing Clean Intermittent Catheterization.

BACKGROUND: Children undergoing CIC frequently have positive urine culture results and receive many antimicrobial agents. Subsequently, this population is at high risk for infections caused by antimicrobial-resistant bacteria. Resistant pathogens, such as vancomycin-resistant Enterococcus (VRE), carbapenem-resistant Enterobacteriaceae (CRE), and organisms that produce extended-spectrum ß-lactamases (ESBLs), which are third-generation cephalosporin resistant (3GCR), are of particular concern. METHODS: In this retrospective study, all urine culture results and antimicrobial-susceptibility testing results were obtained between January 2008 and December 2014 from the electronic health record of children ≤18 years of age who were undergoing CIC (n = 14 832). Isolates were identified as VRE, CRE, or 3GCR. Organisms of the same type that were obtained in the same year and with identical antibiotic susceptibilities from the same patient were excluded. Simple linear regression was used to determine the association between year and rates of resistance. RESULTS: A total of 3997 positive culture results were included in this analysis. Of all Enterococcus isolates for which susceptibility results were available, 4.6% were VRE, 11.1% of all isolates that belonged to the Enterobacteriaceae family were 3GCR, and 0.4% of eligible isolates were CRE. There were significantly higher rates of resistance to third-generation cephalosporins and CRE in 2014 than in 2008 (P < .01). Simple linear regression revealed a significant association between year and rate for resistance to third-generation cephalosporins but not for CRE or VRE. The rate of increase in resistance to third-generation cephalosporins in patients who required CIC was higher than that in patients who did not need CIC. CONCLUSIONS: The rate of resistance to third-generation cephalosporins has increased significantly in the past 7 years in children undergoing CIC, which indicates that careful monitoring is warranted for continued increases in antimicrobial-resistant organisms in this unique patient population.

Analyte variations in consecutive 24-hour urine collections in children.

PURPOSE: The metabolic evaluation of children with nephrolithiasis begins with a 24-h urine collection. For adults, the diagnostic yield increases with consecutive collections; however, little is known regarding the variability of multiple 24-h studies in the pediatric population. We sought to evaluate the variability of consecutive 24-h urine collection in children through a multi-institutional study hypothesizing that compared with a single collection, consecutive 24-h urine collections would reveal a greater degree of clinically useful information in the evaluation of children at risk for nephrolithiasis. MATERIALS AND METHODS: Including data from six institutions, we identified children less than 18 years of age considered at risk for recurrent nephrolithiasis, undergoing metabolic evaluation. We evaluated a subset of patients performing two collections with urine creatinine varying by 10% or less during a 7-day period. Discordance between repeat collections based on normative urine chemistry values was evaluated. RESULTS: A total of 733 children met inclusion criteria, and in over a third both urine calcium and urine volume differed by 30% or more between samples. Urine oxalate demonstrated greater variation between collections in children <5 years than among older children (p = 0.030) while variation in other parameters did not differ by age. Discordance between repeat samples based on normative values was most common for urine oxalate (22.5%) and the derived relative supersaturation ratios for both calcium phosphate (25.1%) and calcium oxalate (20.5%). The proportion of discordant samples, based on normative thresholds, as well as variability greater ≥30% and 50%, respectively, are shown in the table. CONCLUSIONS: Our analysis indicates that stone risk in as many as one in four children may be misclassified if normative values of only a single 24-h urine are used. In light of these findings, repeat 24-h urine collections prior to targeted intervention to modify stone risk are advised to increase diagnostic yield in children at risk for nephrolithiasis.

The effect of guar galactomannan and water availability during hydrothermal processing on the hydrolysis of starch catalysed by pancreatic alpha-amylase.

The effects of water-soluble nonstarch polysaccharides (sNSP) on human metabolism are considered to be beneficial because they decrease postprandial glycaemia and insulinaemia following ingestion of starch-rich foods. The mechanisms by which sNSP attenuate the postprandial rise in blood glucose are not well understood but their presence increases the viscosity of gastrointestinal contents, which affects physiological functions, e.g. gastric emptying and peristalsis. Increased viscosity and decreased water activity during hydrothermal treatment of starch could influence alpha-amylase action. Using guar galactomannan as a representative of sNSP, we found that galactomannan has a direct noncompetitive inhibitory effect on alpha-amylase with a K(i) value of approximately 0.5% (3.3 microM). The inhibition is not time dependent and studies suggest direct binding of the enzyme to galactomannan; the resulting galactomannan-amylase complex being inactive. Processing of starch at low water levels greatly affects the catalytic efficiency of alpha-amylase. The Km value for starch heat treated in limited water is raised and kcat is lowered relative to starch gelatinised in excess water. Since galactomannan has no effect on the Km of alpha-amylase, we conclude that the inhibitory action of the polymer is not secondary to a decrease in available water. Neither does it seem to be a consequence of impaired diffusion of enzyme, substrate and products because of an increase in viscosity of the medium.Thus, the effects of sNSP in lowering postprandial glycaemia not only involve modifications of gut physiology, but also include direct inhibition of the first stage in the biochemical degradation of starch.

Angiotensin-converting enzyme genotype and outcome in pediatric IgA nephropathy.

Angiotensin-converting enzyme (ACE) I/D polymorphism has been implicated as a genetic marker for progression of glomerular disease. Studies of ACE genotypes in adults with IgA nephropathy (IgAN) have yielded conflicting results. We performed ACE genotyping on 79 patients with IgAN diagnosed prior to age 18 years who had either progressed to end-stage renal disease (ESRD) or are now more than 5 years post biopsy. Mean follow-up was 14.8 years for those with normal renal function. Forty-three (54.4%) subjects had normal renal function and a normal urinalysis at last evaluation. Sixteen (20%) progressed to ESRD and 1 has chronic renal insufficiency. Kaplan-Meier survival curves for progression to ESRD did not differ significantly for the ACE DD, ID, and II genotype groups (P=0.095, log-rank test). By univariate analysis, presence of hypertension and degree of proteinuria at diagnosis, and unfavorable histology but not ACE genotype, was significantly associated with progression to ESRD. In the Cox proportional hazards model that included grade of proteinuria, the ACE D allele was a significant independent predictor of outcome with a hazard ratio of 2.37 (P=0.031). Our data, while inconclusive, suggest that the ACE D allele may associate with poor outcome in pediatric IgAN.