Technical report: urinary tract infections in febrile infants and young children. The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement

Dysfunctional elimination syndrome is a negative predictor for vesicoureteral reflux

PURPOSE

We investigated the likelihood of finding vesicoureteral reflux (VUR) in patients with urinary tract infections (UTIs), accompanied by fever or dysfunctional elimination syndrome (DES).

MATERIALS AND METHODS

Two hundred consecutive voiding cystourethrograms performed in 1997-2002 for a diagnosis of UTI were reviewed. Fever, DES, and the grade and laterality of VUR were recorded. Patients were stratified into two groups by age to allow for assessment of DES symptoms in the older patient population: <2 years (n=68) and > or =2 years (n=132). Ratios were compared using a two-tailed Fisher's exact test.

RESULTS

Of the children> or =2 years old, 64/132 (48%) had VUR. Patients who were non-febrile with DES were less likely than patients who were febrile without DES to have VUR [12/34 (35%) vs 23/34 (68%), P=0.02], whereas the risk of dilating VUR [5/34 (15%) vs 11/34 (32%), P=0.15] and bilateral VUR [4/34 (12%) vs 11/34 (32%), P=0.08] was not statistically different. In febrile patients, the presence of DES was associated with a lower risk of VUR [22/51 (43%) vs 23/34 (68%), P=0.03] and dilating VUR [5/51 (10%) vs 11/34 (32%), P=0.01], but not bilateral VUR [8/51 (16%) vs 11/34 (32%), P=0.11].

CONCLUSIONS

Children with non-febrile UTI and DES have a significantly lower risk of having VUR compared to children with febrile UTI and no DES. Among children with a history of UTI, DES is a negative predictor for VUR.

Pain in infants who are younger than 2 months during suprapubic aspiration and transurethral bladder catheterization: a randomized, controlled study

OBJECTIVE

Proper diagnosis of urinary tract infections depends on obtaining an uncontaminated urine sample for culture. Suprapubic aspiration and transurethral catheterization are the 2 recommended procedures for obtaining specimens for urine culture from young infants. The objective of the current study was to compare the pain that is experienced during these 2 procedures when performed in young infants.

METHODS

A prospective, single-blind, randomized, controlled study was conducted at a university-affiliated hospital in Israel. Institutional Research Ethics Board approved the study. Infants who were 0 to 2 months of age and presented to the emergency department with fever and therefore required urine collection for culture were randomly assigned evenly into 2 sample collection groups: suprapubic aspiration or transurethral catheterization. Patients were excluded when they were born prematurely or had had a previous sepsis workup or other painful procedures or an anomaly of the urogenital system or abdominal wall. Eutectic mixture of local anesthetic cream that contained lidocaine and prilocaine was applied 1 hour before the procedure. The urethra was catheterized using a 5-Fr latex-free feeding tube that was lubricated with sterile water-soluble jelly that contained 2% lidocaine hydrochloride. Pediatric residents who were experienced with the procedures performed both suprapubic aspiration and transurethral catheterization. The parents were instructed to use any comfort strategies that they wished, including verbal or physical comforting and pacifiers. Pain during collection was assessed on a 100-mm visual analog scale by a nurse and a parent. In addition, the infant's upper part of the body was videotaped during the procedure. An investigator, who was blinded to the procedure, assigned a point score according to the Douleur Aigue du Nouveaune neonatal acute pain scale. For ensuring a successful blinding process, the following steps were taken. First, camera recording started 30 seconds before the procedure to prevent the possibility of distinguishing between the procedures on the basis of their duration. Second, the physician and the nurse were asked not to speak during the procedure to avoid revealing the nature of the procedure. Third, the person who videotaped the procedure watched the tape before it was analyzed to ensure the impossibility of identifying the procedure from the tape. The Student's t test was used to compare the groups. The primary outcome was the mean Douleur Aigue du Nouveaune score. Secondary outcomes were the mean visual analogue scale for pain as estimated by the parents and by the nurse. We estimated that 25 patients would be needed in each group to detect a difference in the mean Douleur Aigue du Nouveaune score of at least 2 points with a power of 80% and alpha of .05.

RESULTS

The study was conducted between April 1, 2004, and April 30, 2005. Fifty-eight infants were recruited; 29 were randomly assigned to suprapubic aspiration, and 29 were randomly assigned to transurethral catheterization. Seven infants were excluded because of consent withdrawal (3 patients), because of technical difficulties during videotaping (3 patients), or because the child voided during the procedure (1 patient). Twenty-seven infants in the suprapubic aspiration group and 24 in the transurethral catheterization group completed the study. All male infants were circumcised. An adequate urine sample was obtained in 18 (66%) of 27 patients in the suprapubic aspiration group and in 20 (83.3%) of 24 in the transurethral catheterization group. The mean Douleur Aigue du Nouveaune score was significantly higher in patients who were randomly assigned to suprapubic aspiration compared with patients who were randomly assigned to transurethral catheterization (7 and 4.5, respectively). The differences in Douleur Aigue du Nouveaune score also were significant in a subgroup analysis of boys and girls. Mean visual analogue scale scores by parents was higher in the suprapubic aspiration group compared with transurethral catheterization (63 +/- 27 mm vs 46 +/- 26, respectively). Similarly, mean visual analogue scale scores by nurses was higher in the suprapubic aspiration group compared with transurethral catheterization (3 +/- 18 mm vs 43 +/- 25 mm, respectively).

CONCLUSIONS

In infants who are younger 2 months, suprapubic aspiration is more painful than transurethral catheterization. Health professionals should consider these differences when choosing a method for obtaining a urine sample from young infants.

Urinary tract infections in children with congenital adrenal hyperplasia

OBJECTIVE

To investigate the incidence of urinary tract infections (UTIs) in children with congenital adrenal hyperplasia (CAH), and to determine whether there was a correlation between UTIs and the timing and type of genital surgery in girls.

STUDY DESIGN

Medical records of patients with CAH < or = 15 years were reviewed. A parent questionnaire regarding history of UTIs was completed.

RESULTS

Seventy-one patients with classic CAH (41 girls, 30 boys) aged 8.3 +/- 4.2 years were identified. Thirty-five (85%) girls had undergone feminizing genitoplasty at 1.1 +/- 0.8 years, while six (15%) had not. History of UTI was reported in nine (12.6%) patients (one boy, eight girls). In seven of the eight girls, genital surgery had been performed and all UTIs occurred after surgery. One UTI was reported in a girl who had not undergone surgery. No correlation was found between UTIs and the type of genital surgery.

CONCLUSION

The incidence of UTIs in children with CAH is similar to that in the general population. Although preliminary, our results do not suggest an increased risk of UTIs if surgery is delayed.

Prise en charge des pyélonéphrites aiguës du nourrisson de plus de 3 mois et de l'enfant : enquête effectuée parmi les services d'urgences pédiatriques d'Île de France en 2004

OBJECTIVES

To describe the different modalities of ambulatory management of acute pyelonephritis in patients older than 3 months of age in paediatric emergency units of the Ile de France region in 2004.

METHODS

Between October 2003 and April 2004, referents of 39 paediatric emergency units of the Ile de France region were questioned through a written questionnaire concerning the management of acute pyelonephritis: in or outpatient modalities, antibiotic regimen (molecule and route of administration), investigations and follow-up.

RESULTS

Thirty-one questionnaires (79.5%) were returned and analysed. A written protocol was available in 60% of the units. Outpatient management was performed in 24/31 centres. Young age, poor clinical tolerance, urological abnormalities and social difficulties were the major contra-indications for such management. Ultrasonic echography at diagnosis (within 24 h) was performed in 50% of the units. Antibiotics were started using IV route in 18/24 units (75%) and ceftriaxone and aminoside were respectively prescribed in 100% and 29.4% of the units for a duration of 1 to 5 days before switching to the oral route. Antibiotherapy was started orally in 6 units and cefixime was chosen by 5 of them. Follow-up consultations were scheduled in 100% of the units but with various delay after initiation of the treatment. The total duration of treatment was mostly 10 days and oral prophylactic antibiotherapy was prescribed by 10/24 centres after completion of the treatment. Cystoureterography was systematically realized by 83.3% of the units.

CONCLUSIONS

Despite important differences in the management of acute pyelonephritis in Ile-de-France, a majority of the units follows similar therapeutic modalities. In the absence of consensus, new recommendations are necessary concerning the management of pyelonephritis in infants and children in France.

A head-to-head comparison: "clean-void" bag versus catheter urinalysis in the diagnosis of urinary tract infection in young children

OBJECTIVE

To compare the validity of the urinalysis on clean-voided bag versus catheter urine specimens using the catheter culture as the "gold" standard.

STUDY DESIGN

This is a cross-sectional study of 303 nontoilet-trained children under age 3 years at risk for urinary tract infection (UTI) who presented to a children's hospital emergency department. Paired bag and catheter specimens were obtained from each child and sent for dipstick and microscopic urinalysis. Sensitivity and specificity were compared using McNemar's chi2 test for paired specimens and the ordinary chi2 test for unpaired comparisons.

RESULTS

The bag dipstick was more sensitive than the catheter dipstick for the entire study sample: 0.85 (95% confidence interval [CI]=0.78 to 0.93) versus 0.71 (95% CI=0.61 to 0.81), respectively. Both bag and catheter dipstick sensitivities were lower in infants < or =90 days old (0.69 [95% CI=0.44 to 0.94] and 0.46 [95% CI=0.19 to 0.73], respectively) than in infants >90 days old (0.88 [95% CI=0.81 to 0.96] and 0.75 [95% CI=0.65 to 0.86], respectively). Specificity was consistently lower for the bag specimens than for the catheter specimens: 0.62 (95% CI=0.56 to 0.69) versus 0.97 (95% CI=0.95 to 0.99), respectively.

CONCLUSIONS

Urine collection methods alter the diagnostic validity of urinalysis. These differences have important implications for the diagnostic and therapeutic management of children with suspected UTI.

Diagnosing symptomatic urinary tract infections in infants by catheter urine culture

BACKGROUND

Diagnosing infantile urinary tract infection (UTI) is difficult due to contamination during urine collection. Catheterization is convenient but diagnostic criteria (colony-forming units per millilitre (CFU/mL)) is controversial, especially in uncircumcised males.

OBJECTIVES

To study the value of catheter urine cultures in terms of likelihood ratios (LRs), sensitivity, specificity, positive and negative predictive values of different CFU/mL in uncircumcised boys and girls.

METHODS

Infants aged 1-18 months who had catheter urine cultures from July 1999 to June 2002 were reviewed to decide if they had symptomatic UTI (group A) or not (group B). Urinary tract infection was confirmed if patients had a positive urine culture plus acute fever, pyuria, positive leucocyte esterase and nitrite tests and good response to antibiotics, with pyelonephritic evidence on early dimercaptosuccinic acid (DMSA) scans in doubtful cases. Group B included infants with negative urine culture results, and those with positive results but were asymptomatic and admitted for micturating cystourethrogram.

RESULTS

Nine hundred and fifty-two patients were studied (492 boys, 460 girls; 212 in group A, 740 in group B). No single cut-off CFU/mL has high sensitivity and specificity to simultaneously diagnose and exclude UTI. The CFU counts of 100-10(3), 10(3)-10(4), 10(4)-10(5) and >10(5) were associated with LRs of 0.11, 0.45, 1.52 and 20.5, respectively in uncircumcised boys, and with LRs of 1.39, 2.49, 8.95 and 18.8, respectively in girls. The LR for mixed growths was 0.21.

CONCLUSION

Unlike suprapubic tap urine, catheter urine culture has to be interpreted against the clinical context or pretest probability and in terms of probability. In the scenario of a febrile infant where the pretest probability of UTI was about 5%, UTI was highly likely if counts exceeded 10(5)/mL, and unlikely if counts were below 10(4)/mL in uncircumcised boys. In female infants, UTI was highly likely if counts were >10(4) CFU/mL, but lower counts could not exclude UTI.

Compliance with guidelines for the medical care of first urinary tract infections in infants: a population-based study

BACKGROUND

No population-based studies have examined the degree to which practice parameters are followed for urinary tract infections in infants.

OBJECTIVE

To describe the medical care of children in their first year of life after a first urinary tract infection.

METHODS

Using Washington State Medicaid data, we conducted a retrospective cohort study of children with a urinary tract infection during their first year of life to determine how many of these children received recommended care based on the most recent guidelines from the American Academy of Pediatrics. Recommended care included timely anatomic imaging, timely imaging for reflux, and adequate antimicrobial prophylaxis. Multivariate logistic-regression models were used to evaluate if hospitalization for first urinary tract infection, young age at time of diagnosis, gender, race, primary language of parents, having a managed care plan, and rural location of household residence were associated with recommended care.

RESULTS

Less than half of all children diagnosed with a urinary tract infection in their first year of life received the recommended medical care. Children who were hospitalized for their first urinary tract infection were significantly more likely than children who were not hospitalized to receive anatomic imaging (relative risk [RR]: 1.38; 95% confidence interval [CI]: 1.20-1.57) and imaging for reflux (RR: 1.62; 95% CI: 1.34-1.90).

CONCLUSIONS

There is poor compliance with guideline-recommended care for first urinary tract infections in infants in a Medicaid population. Given the trend toward increased outpatient management of urinary tract infections, increased attention to outpatient imaging may be warranted.

Defining urinary tract infection in the critically ill child

OBJECTIVE

To define urinary tract infections in critically ill children in the intensive care unit setting for the purpose of surveillance of infection, enrollment of children in sepsis trials, and for trials of therapy and prevention.

DESIGN

Summary of the literature with review and consensus by experts in the field.

RESULTS

A variety of definitions, only some of which have been validated for use in children, were identified. The Centers for Disease Control criteria for the definition of nosocomial infection have been used to establish surveillance data for inter-institutional comparison. Validated definitions for the febrile child were identified. Using the known characteristics of symptoms, signs, and laboratory criteria for urinary tract infections, definitions for definite, possible, and probable urinary tract infection were derived.

CONCLUSIONS

Definitions for definite, probable, and possible urinary tract infection were achieved by consensus that can be used for surveillance and enrolment in sepsis trials. Future research should determine the utility of these definitions in the critically ill child and adapt them accordingly.

Rapid tests and urine sampling techniques for the diagnosis of urinary tract infection (UTI) in children under five years: a systematic review

BACKGROUND

Urinary tract infection (UTI) is one of the most common sources of infection in children under five. Prompt diagnosis and treatment is important to reduce the risk of renal scarring. Rapid, cost-effective, methods of UTI diagnosis are required as an alternative to culture.

METHODS

We conducted a systematic review to determine the diagnostic accuracy of rapid tests for detecting UTI in children under five years of age.

RESULTS

The evidence supports the use of dipstick positive for both leukocyte esterase and nitrite (pooled LR+ = 28.2, 95% CI: 17.3, 46.0) or microscopy positive for both pyuria and bacteriuria (pooled LR+ = 37.0, 95% CI: 11.0, 125.9) to rule in UTI. Similarly dipstick negative for both LE and nitrite (Pooled LR- = 0.20, 95% CI: 0.16, 0.26) or microscopy negative for both pyuria and bacteriuria (Pooled LR- = 0.11, 95% CI: 0.05, 0.23) can be used to rule out UTI. A test for glucose showed promise in potty-trained children. However, all studies were over 30 years old. Further evaluation of this test may be useful.

CONCLUSION

Dipstick negative for both LE and nitrite or microscopic analysis negative for both pyuria and bacteriuria of a clean voided urine, bag, or nappy/pad specimen may reasonably be used to rule out UTI. These patients can then reasonably be excluded from further investigation, without the need for confirmatory culture. Similarly, combinations of positive tests could be used to rule in UTI, and trigger further investigation.

Can MRI replace DMSA in the detection of renal parenchymal defects in children with urinary tract infections?

BACKGROUND

Renal parenchymal defects may be a consequence of urinary tract infections (UTI) in childhood. MRI is a non-radiation imaging modality compared with DMSA scanning.

OBJECTIVE

To compare DMSA with MRI for the detection of renal parenchymal defects in children presenting for radiological investigation after a first UTI.

MATERIALS AND METHODS

Both DMSA and MRI were performed at the same appointment in 37 children (aged 4 months-13 years; mean 4.5 years) with a history of UTI. Both planar and SPECT DMSA were performed. MRI of the kidneys employed axial and coronal T1-, T2- and fat-saturated T1-weighted (T1-W) sequences. Some children had imaging after IV contrast medium.

RESULTS

The coronal fat-saturated T1-W sequence was the best sequence and it detected all the findings on MRI. MRI had a sensitivity of 77% and a specificity of 87% for the detection of a scarred kidney using DMSA as the gold standard. MRI diagnosed pyelonephritis in two children that had been interpreted as scarring on DMSA.

CONCLUSIONS

Renal MRI using a single, coronal, fat-saturated T1-W sequence is a rapid, accurate and minimally invasive technique for the detection of renal scarring that does not employ ionizing radiation.

Timing of follow-up voiding cystourethrogram in children with primary vesicoureteral reflux: development and application of a clinical algorithm

BACKGROUND AND OBJECTIVES

Of children diagnosed with urinary tract infection, 30% to 40% have primary vesicoureteral reflux (VUR). For the majority of these children, treatment involves long-term prophylactic antibiotics (ABX) and a periodic voiding cystourethrogram (VCUG) until resolution of VUR as detected by VCUG. Radiation exposure and considerable discomfort have been associated with VCUG. To date, no clear guidelines exist regarding the timing of follow-up VCUGs. The objective of this study was to develop a clinically applicable algorithm for the optimal timing of repeat VCUGs and validate this algorithm in a retrospective cohort of children with VUR.

METHODS

Based on previously published data regarding the probability of resolution of VUR over time, a decision-tree model (DTM) was developed. The DTM compared the differential impact of 3 timing schedules of VCUGs (yearly, every 2 years, and every 3 years) on the average numbers of VCUGs performed, years of ABX exposure, and overall costs. Based on the DTM, an algorithm optimizing the timing of VCUG was developed. The algorithm then was validated in a retrospective cohort of patients at an urban pediatric referral center. Data were extracted from the medical records regarding number of VCUGs, time of ABX prophylaxis, and complications associated with either. VUR in patients in the cohort was grouped into mild VUR (grades I and II and unilateral grade III for those < or =2 years old), and moderate/severe VUR (other grade III and grade IV). Kaplan-Meier survival curves were created from the cohort data. From the survival curves, the median times to resolution of VUR were determined for the cohort, and these times were compared with the median times to VUR resolution of the data used for the DTM. The numbers of VCUGs performed, time of ABX exposure, and costs in the cohort were compared with those that would have occurred if the algorithm had been applied to both mild and moderate/severe VUR groups.

RESULTS

Using an algorithm that results in a recommendation of VCUGs every 2 years in mild VUR would reduce the average number of VCUGs by 42% and costs by 33%, with an increase in ABX exposure of 16%, compared with a schedule of yearly VCUGs. For moderate/severe VUR, a VCUG performed every 3 years would reduce the average number of VCUGs by 63% and costs by 51%, with an increase in ABX exposure of 10%. Applying this algorithm to the retrospective cohort consisting of 76 patients (between 1 month and 10 years old) with primary VUR would have reduced overall VCUGs by 19% and costs by 6%, with an increase in ABX exposure of 26%. The patterns of VUR resolution, age distribution, and prevalence of severity of VUR were comparable between previously published results and the retrospective cohort.

CONCLUSIONS

Delaying the schedule of VCUG from yearly to every 2 years in children with mild VUR and every 3 years in children with moderate/severe VUR yields substantial reductions in the average numbers of VCUGs and costs, with a modest subsequent increase in ABX exposure.

Using value of information analysis to inform publicly funded research priorities

INTRODUCTION

The purpose of this article is to demonstrate the application and feasibility of using value of information analysis to help set priorities for research as part of the UK National Health Service (NHS) Health Technology Assessment Programme. Probabilistic decision analysis and value of information methods were applied to a research topic under consideration by the National Coordinating Centre for Health Technology Assessment (NCCHTA), in the UK. The case study presented considers whether long-term, low-dose antibacterial treatment of recurrent urinary tract infections (UTIs) in children is effective and cost effective compared with short-term antibacterial therapy.

METHODS

A probabilistic decision-analytic model was developed, within which evidence from published sources was synthesised. Eight subgroups were considered and defined in terms of sex and presence of vesico-ureteral reflux (VUR). Costs were assessed from an NHS perspective, and benefits were expressed as quality-adjusted life-years (QALYs). Simulation methods were used to determine the probability that alternative therapies would be cost effective at a range of threshold values that the NHS may attach to an additional QALY. Value of information analysis was used to quantify the cost of uncertainty associated with the decision about which therapy to adopt, which indicates the maximum value of future research. The feasibility and practicality of using value of information methods to help inform research prioritization was evaluated.

RESULTS

At a threshold value for an additional QALY of 30,000 pound , long-term antibacterial treatment may be regarded as cost effective for all eight patient groups. There was, however, substantial uncertainty surrounding the choice of antibacterial.

DISCUSSION/CONCLUSION

The use of value of information methods was feasible and could inform research prioritization for the NHS. In the context of this specific decision faced by the NHS, the results show that long-term low-dose antibacterials for preventing recurrent UTIs may be cost effective, based on current evidence. However, the analysis suggests that further primary research with longer follow-up may be worthwhile, particularly for girls with no VUR.

Urinary tract infection in children: etiology and epidemiology

The urinary tract is a relatively common site of infection in infants and young children. Urinary tract infection (UTI) may result in significant acute morbidity, as well as longterm medical complications. Recent advances elucidating the pathogen-host interaction have broadened the understanding of the pathogenesis and clinical progression of pediatric UTI. This article focuses on the epidemiology and pathogenesis of pediatric UTI, and briefly discusses UTI-related complications.

Utility of follow-up renal sonography in children with vesicoureteral reflux and normal initial sonogram

OBJECTIVE

The purpose of this study was to determine the value of follow-up renal sonography in children who presented with urinary tract infection and were found to have a voiding cystogram diagnosis of vesicoureteral reflux while having a normal initial renal sonogram.

METHODS

We retrospectively reviewed the medical records of 64 consecutive children who presented for follow-up renal sonography with a voiding cystogram diagnosis of vesicoureteral reflux and a normal initial sonogram conducted as part of the routine evaluation after urinary tract infection. Data recorded included gender, age, initial grade of reflux, time to follow-up sonogram, and abnormalities on follow-up sonogram. Children with conditions that may predispose to vesicoureteral reflux were excluded.

RESULTS

Children who were studied (7 boys, 57 girls) ranged in age from 1 month to 10 years, 10 months (mean: 35.6 months; median: 24 months). Ninety-four (73.4%) of 128 renal units demonstrated vesicoureteral reflux on voiding cystogram; 89 (94.7%) of 94 of them were grade 1 to 3. The mean time to follow-up was 22 months (range: 4 months to 5 years, 2 months; median: 18 months). All 128 (95% confidence interval: 0%-2.8%) renal units were normal on follow-up sonography.

CONCLUSION

Routine performance of repeat sonography seems unnecessary among children, particularly girls, with low- to medium-grade vesicoureteral reflux, who have had a previous normal sonogram and no conditions that predispose to vesicoureteral reflux.

Urinary tract infections in infants and children

This article discusses urinary tract infections in infants and children. The following areas are explored: epidemiology, clinical manifestations, diagnosis, management, imaging, outcome, and prevention.

Imaging studies after a first febrile urinary tract infection in young children

BACKGROUND

Guidelines from the American Academy of Pediatrics recommend obtaining a voiding cystourethrogram and a renal ultrasonogram for young children after a first urinary tract infection; renal scanning with technetium-99m-labeled dimercaptosuccinic acid has also been endorsed by other authorities. We investigated whether imaging studies altered management or improved outcomes in young children with a first febrile urinary tract infection.

METHODS

In a prospective trial involving 309 children (1 to 24 months old), an ultrasonogram and an initial renal scan were obtained within 72 hours after diagnosis, contrast voiding cystourethrography was performed one month later, and renal scanning was repeated six months later.

RESULTS

The ultrasonographic results were normal in 88 percent of the children (272 of 309); the identified abnormalities did not modify management. Acute pyelonephritis was diagnosed in 61 percent of the children (190 of 309). Thirty-nine percent of the children who underwent cystourethrography (117 of 302) had vesicoureteral reflux; 96 percent of these children (112 of 117) had grade I, II, or III vesicoureteral reflux. Repeated scans were obtained for 89 percent of the children (275 of 309); renal scarring was noted in 9.5 percent of these children (26 of 275).

CONCLUSIONS

An ultrasonogram performed at the time of acute illness is of limited value. A voiding cystourethrogram for the identification of reflux is useful only if antimicrobial prophylaxis is effective in reducing reinfections and renal scarring. Renal scans obtained at presentation identify children with acute pyelonephritis, and scans obtained six months later identify those with renal scarring. The routine performance of urinalysis, urine culture, or both during subsequent febrile illnesses in all children with a previous febrile urinary tract infection will probably obviate the need to obtain either early or late scans.

Is bag urine culture useful in monitoring urinary tract infection in infants?

OBJECTIVES

We studied the false-positive rate of bag urine cultures in diagnosing bacteriuria in infants and examined the factors responsible for contamination.

METHODS

One hundred asymptomatic patients with previous urinary tract infections (UTI; age range 5-23 months; sex ratio M : F 73:27) were screened by bag urine cultures and confirmed by suprapubic aspiration or catheterization. Those producing contaminated and clean samples were interviewed with a standard questionnaire.

RESULTS

Sixty patients had insignificant growth and 40 had doubtful or mixed growth. After further interview and instructions, the latter group produced a second bag urine sample with negative results in 23 and positive results in 17. Among the latter, UTI was confirmed in five and excluded in 12 cases. The false-positive rate of first urine collection was 36.8%. Comparing patients with contaminated urine to those with negative urine samples, we found the former were associated with waiting for more than one void to complete urine collection, and with uncircumcised boys. Other factors did not reach statistical significance. Proper counselling and repeating a second culture reduced the overall false-positive rate to 12.6%.

CONCLUSION

In our population, the contamination rate of one bag urine culture was 36.8%, which is unacceptable and alternative methods need to be sought. Contamination was associated with improper collection procedures and with uncircumcised boys. Proper instructions and doing a second urine culture reduced the overall rate to 12.6%, but at the expense of delaying diagnosis and treatment.

Pediatric urinary tract infection

UTIs are common in children. They may present with a range of severity from cystitis to febrile UTI or pyelonephritis. The presentation may be vague and have nonspecific symptoms. Therefore, a UTI should be considered in all children with a fever in whom other sources have been excluded. Treatment depends on the age, location of infection, and degree of illness in the child. Sick children and infants less than 3 months should be treated as inpatients, and healthy children and older infants may be treated as outpatients. Urinalysis provides presumptive evidence of infection, whereas urine culture is definitive. Close follow-up and outpatient evaluations are needed to prevent long-term consequences of infection.

Urinary tract infections in children younger than 5 years of age: epidemiology, diagnosis, treatment, outcomes and prevention

Although the true incidence of urinary tract infections (UTIs) in children is difficult to estimate, they are one of the most common bacterial infections seen by clinicians who care for young children. Except for the first 8 to 12 weeks of life, when infection of the urinary tact may be secondary to a haematogenous source, UTI is believed to arise by the ascending route after entry of bacteria via the urethra. Enterobacteriaceae are the most common organisms isolated from uncomplicated UTI. Infection with Staphylococcus aureus is rare in children without in-dwelling catheters or other sources of infection, and coagulase-negative staphylococci and Candida spp. are associated with infections after instrumentation of the urinary tract. The diagnosis of UTI in young children is important as it is a marker for urinary tract abnormalities and, in the newborn, may be associated with bacteraemia. Early diagnosis is critical to preserve renal function of the growing kidney. A urine specimen for culture is necessary to document a UTI in a young child. Prior to culture, urinalysis may be useful to detect findings supporting a presumptive diagnosis of UTI. The goals of the management of UTI in a young child are: (i) prompt diagnosis of concomitant bacteraemia or meningitis, particularly in the infant; (ii) prevention of progressive renal disease by prompt eradication of the bacterial pathogen, identification of abnormalities of the urinary tract and prevention of recurrent infections; and (iii) resolution of the acute symptoms of the infection. Delay in initiation of the antibacterial therapy is associated with an increased risk of renal scarring. The initial choice of antibacterial therapy is based on the knowledge of the predominant pathogens in the patient's age group, antibacterial sensitivity patterns in the practice area, the clinical status of the patient and the opportunity for close follow-up. Imaging studies to detect congenital or acquired abnormalities are recommended following the first UTI in all children aged <6 years. Patients with significant urinary tract abnormalities and/or frequent symptomatic UTI may benefit from prophylactic antibacterials. The main long term consequence of UTI is renal scarring which may lead to hypertension and end-stage renal disease. Prevention of recurrent UTI focuses on detection, and correction if possible, of urinary tract abnormalities. Interventions that have been associated with a decrease in symptomatic UTI in children with a history of recurrent UTI include relief of constipation and voiding dysfunction.

The epidemiology and clinical presentation of urinary tract infections in children younger than 2 years of age

UTI in young infants generally presents with fever. Among the youngest infants, boys and girls are equally affected. The incidence of UTI in uncircumcised boys is comparable with that in girls, whereas the rate in circumcised boys is much lower. Based on gender and race, white girls have the highest incidence of UTI. A full understanding of the epidemiology of UTI is complicated by the presence of asymptomatic bacteriuria and by incomplete evidence regarding the significance of scarring and the risk of sequelae.