Urine testing in young febrile children: a risk-benefit analysis

Urine collection methods and dipstick testing in non-toilet-trained children

Urinary tract infection is a commonly occurring paediatric infection associated with significant morbidity. Diagnosis is challenging as symptoms are non-specific and definitive diagnosis requires an uncontaminated urine sample to be obtained. Common techniques for sampling in non-toilet-trained children include clean catch, bag, pad, in-out catheterisation and suprapubic aspiration. The pros and cons of each method are examined in detail in this review. They differ significantly in frequency of use, contamination rates and acceptability to parents and clinicians. National guidance of which to use differs significantly internationally. No method is clearly superior. For non-invasive testing, clean catch sampling has a lower likelihood of contamination and can be made more efficient through stimulation of voiding in younger children. In invasive testing, suprapubic aspiration gives a lower likelihood of contamination, a high success rate and a low complication rate, but is considered painful and is not preferred by parents. Urine dipstick testing is validated for ruling in or out UTI provided that leucocyte esterase (LE) and nitrite testing are used in combination.

Urinary tract infection in pediatrics: an overview

OBJECTIVE

This review aimed to provide a critical overview on the pathogenesis, clinical findings, diagnosis, imaging investigation, treatment, chemoprophylaxis, and complications of urinary tract infection in pediatric patients.

SOURCE OF DATA

Data were obtained independently by two authors, who carried out a comprehensive and non-systematic search in public databases.

SUMMARY OF FINDINGS

Urinary tract infection is the most common bacterial infection in children. Urinary tract infection in pediatric patients can be the early clinical manifestation of congenital anomalies of the kidney and urinary tract (CAKUT) or be related to bladder dysfunctions. E. coli is responsible for 80-90% of community-acquired acute pyelonephritis episodes, especially in children. Bacterial virulence factors and the innate host immune systems may contribute to the occurrence and severity of urinary tract infection. The clinical presentation of urinary tract infections in children is highly heterogeneous, with symptoms that can be quite obscure. Urine culture is still the gold standard for diagnosing urinary tract infection and methods of urine collection in individual centers should be determined based on the accuracy of voided specimens. The debate on the ideal imaging protocol is still ongoing and there is tendency of less use of prophylaxis. Alternative measures and management of risk factors for recurrent urinary tract infection should be emphasized. However, in selected patients, prophylaxis can protect from recurrent urinary tract infection and long-term consequences. According to population-based studies, hypertension and chronic kidney disease are rarely associated with urinary tract infection.

CONCLUSION

Many aspects regarding urinary tract infection in children are still matters of debate, especially imaging investigation and indication of antibiotic prophylaxis. Further longitudinal studies are needed to establish tailored approach of urinary tract infection in childhood.

Cost-Utility of Antimicrobial Prophylaxis for Treatment of Children With Vesicoureteral Reflux

Objective: Antimicrobial prophylaxis for children with vesicoureteral reflux (VUR) reduces recurrences of urinary tract infection (UTI) but requires daily antimicrobials for extended periods. We used a cost-utility model to evaluate whether the benefits of antimicrobial prophylaxis outweigh its risks and, if so, to investigate whether the benefits and risks vary according to grade of VUR. Methods: We compared the cost per quality-adjusted life-year (QALY) gained in four treatment strategies in children aged <6 years diagnosed with VUR after a first UTI, considering these treatment strategies: (1) prophylaxis for all children with VUR, (2) prophylaxis for children with Grade III or Grade IV VUR, (3) prophylaxis for children with Grade IV VUR, and (4) no prophylaxis. Costs and effectiveness were estimated over the patient's lifetime. We used $100,000/QALY gained as the threshold for considering a treatment strategy cost effective. Results: Based on current data and plausible ranges to account for data uncertainty, prophylaxis of children with Grades IV VUR costs $37,903 per QALY gained. Treating children with Grade III and IV VUR costs an additional $302,024 per QALY gained. Treating children with all grades of VUR costs an additional $339,740 per QALY gained. Conclusions: Treating children with Grades I, II, and III VUR with long-term antimicrobial prophylaxis costs substantially more than interventions typically considered economically reasonable. Prophylaxis in children with Grade IV VUR is cost effective.

Update on the approach of urinary tract infection in childhood

OBJECTIVE

Urinary tract infection (UTI) is the most common bacterial infection in childhood. UTI may be the sentinel event for underlying renal abnormality. There are still many controversies regarding proper management of UTI. In this review article, the authors discuss recent recommendations for the diagnosis, treatment, prophylaxis, and imaging of UTI in childhood based on evidence, and when this is lacking, based on expert consensus.

SOURCES

Data were obtained after a review of the literature and a search of Pubmed, Embase, Scopus, and Scielo.

SUMMARY OF THE FINDINGS

In the first year of life, UTIs are more common in boys (3.7%) than in girls (2%). Signs and symptoms of UTI are very nonspecific, especially in neonates and during childhood; in many cases, fever is the only symptom.

CONCLUSIONS

Clinical history and physical examination may suggest UTI, but confirmation should be made by urine culture, which must be performed before any antimicrobial agent is given. During childhood, the proper collection of urine is essential to avoid false-positive results. Prompt diagnosis and initiation of treatment is important to prevent long-term renal scarring. Febrile infants with UTIs should undergo renal and bladder ultrasonography. Intravenous antibacterial agents are recommended for neonates and young infants. The authors also advise exclusion of obstructive uropathies as soon as possible and later vesicoureteral reflux, if indicated. Prophylaxis should be considered for cases of high susceptibility to UTI and high risk of renal damage.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

Urinary tract infection: clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months

OBJECTIVE

To revise the American Academy of Pediatrics practice parameter regarding the diagnosis and management of initial urinary tract infections (UTIs) in febrile infants and young children.

METHODS

Analysis of the medical literature published since the last version of the guideline was supplemented by analysis of data provided by authors of recent publications. The strength of evidence supporting each recommendation and the strength of the recommendation were assessed and graded.

RESULTS

Diagnosis is made on the basis of the presence of both pyuria and at least 50,000 colonies per mL of a single uropathogenic organism in an appropriately collected specimen of urine. After 7 to 14 days of antimicrobial treatment, close clinical follow-up monitoring should be maintained to permit prompt diagnosis and treatment of recurrent infections. Ultrasonography of the kidneys and bladder should be performed to detect anatomic abnormalities. Data from the most recent 6 studies do not support the use of antimicrobial prophylaxis to prevent febrile recurrent UTI in infants without vesicoureteral reflux (VUR) or with grade I to IV VUR. Therefore, a voiding cystourethrography (VCUG) is not recommended routinely after the first UTI; VCUG is indicated if renal and bladder ultrasonography reveals hydronephrosis, scarring, or other findings that would suggest either high-grade VUR or obstructive uropathy and in other atypical or complex clinical circumstances. VCUG should also be performed if there is a recurrence of a febrile UTI. The recommendations in this guideline do not indicate an exclusive course of treatment or serve as a standard of care; variations may be appropriate. Recommendations about antimicrobial prophylaxis and implications for performance of VCUG are based on currently available evidence. As with all American Academy of Pediatrics clinical guidelines, the recommendations will be reviewed routinely and incorporate new evidence, such as data from the Randomized Intervention for Children With Vesicoureteral Reflux (RIVUR) study.

CONCLUSIONS

Changes in this revision include criteria for the diagnosis of UTI and recommendations for imaging.

Parents' awareness of and knowledge about young children's urinary tract infections

OBJECTIVE

To provide insight into parents' awareness of and knowledge about urinary tract infections (UTIs) in young children.

METHODS

Twenty interviews with parents who had a child recently diagnosed with a UTI were audiotaped, transcribed verbatim, and qualitatively analysed.

RESULTS

Most parents knew the typical symptoms related to UTI. But, according to the parents, neither they nor all general practitioners (GPs) thought of a UTI in case of atypical symptoms. The awareness that UTI can be a serious illness usually came to parents later, partly because health care workers often did not explicitly mention this. According to the parents, health care workers should be more aware of UTIs in children. Parents felt that health education or mass screening might not be desirable because it would increase anxiety or would be perceived as not relevant.

CONCLUSION

Parents could not consistently recognise UTI in their children and were most times unaware of the possible consequences of a UTI. Nevertheless, parents were sceptical about health education and mass screening.

PRACTICE IMPLICATIONS

There seems little scope for health education addressed at parents or screening for UTI in young children. Instead, physicians and nurses should be alert for the possibility of UTIs in young children, and more information should be given once a UTI is diagnosed.

Agreement of decision analyses and subsequent clinical studies in infectious diseases

PURPOSE

Decision analysis techniques can compare management strategies when there are insufficient data from clinical studies to guide decision making. We compared the outcomes of decision analyses and subsequent clinical studies in the infectious disease literature to assess the validity of the conclusions of the decision analyses.

METHODS

A search strategy to identify decision analyses in infectious disease topics published from 1990 to 2005 was developed and performed using PubMed. Abstracts of all identified articles were reviewed, and infectious disease-related decision analyses were retained. Subsequent clinical trials and observational studies that corresponded to these decision analyses were identified using prespecified search strategies. Clinical studies were considered a match for the decision analysis if they assessed the same patient population, intervention, and outcome. Agreement or disagreement between the conclusions of the decision analysis and clinical study were determined by author review.

RESULTS

The initial PubMed search yielded 318 references. Forty decision analyses pertaining to 29 infectious disease topics were identified. Of the 40, 16 (40%) from 13 infectious disease topics had matching clinical studies. In 12 of 16 (75%), conclusions of at least 1 clinical study agreed with those of the decision analysis. Three of the 4 decision analyses in which conclusions disagreed were from the same topic (management of febrile children).

CONCLUSIONS

There was substantial agreement between the conclusions of decision analyses and clinical studies in infectious diseases, supporting the validity of decision analysis and its utility in guiding management decisions.

Kidney length and scarring in children with urinary tract infection: importance of ultrasound scans

BACKGROUND

Many studies have demonstrated that dimercaptosuccinic acid (DMSA) scintigraphy is the most sensitive diagnostic method in the identification of irreversible renal lesions (scars) in children with previous episodes of acute pyelonephritis (APN). This study assessed the reliability of ultrasound in identifying reflux nephropathy in children with acute pyelonephritis with or without vesicoureteric reflux (VUR).

METHODS

Eighty children (45 female and 35 male, age range 5 months to 10 years, average age 2 years 1 month) with a positive history for at least one episode of APN participated in this study. All children underwent voiding cystourethrography, DMSA scintigraphy 4 to 8 months after the most recent episode of APN, and an ultrasound test evaluation less than 2 months after DMSA scintigraphy.

RESULTS

Voiding cystourethrograms showed VUR in 52 children (68%); 13 of these were bilateral, for a total of 65 refluxing kidney units of the 154 (42%) evaluated; DMSA scintigram was normal for 108 of 154 kidneys (70%). Of the 65 kidneys with VUR, DMSA scintigram displayed normal findings in 29 cases (45%) and pathologic findings in 36 (55%). In the 79 nonrefluxing kidneys, DMSA scintigram was normal in 69 cases (87%). The relative risk of scarring in VUR kidneys is 2.6. The ultrasound study recorded a maximum longitudinal diameter between the 5th and 95th percentiles in 80 of 89 (81%) kidneys without VUR and in 21 of 65 (32%) with VUR. A significant correlation was found between maximum longitudinal diameters and DMSA scintigraphic findings in kidneys with VUR and those without VUR, respectively.

CONCLUSION

This study establishes that ultrasound scans, by means of a simple and reproducible measurement technique, maximum longitudinal diameter, have a predictive value with regard to the presence of scars, with few exceptions. This finding, in our opinion, could lead to a decrease in the number of invasive procedures, in particular DMSA scan, in patients with APN.

Quantitative unspun-urine microscopy as a quick, reliable examination for bacteriuria

The diagnosis and treatment of urinary infection are often delayed, causing renal damage, largely because of the unavailability of quick, accurate, diagnostic examinations. Three hundred and twenty-five urine samples from 130 patients were examined for significant bacteriuria using the standard culture method. The urine samples were also examined using the Gram-stain method and quantitative unspun-urine microscopy. When particles could not be distinguished definitely as bacilli by quantitative microscopy, the unspun urine was examined on a slide glass using oil-immersion microscopy at x 1000 magnification. Significant bacteriuria in 37 urine samples was detected by bacterial culture. Using quantitative microscopy, rods were found in 30, cocci in a chain in 3, and indefinite particles in 44 samples. In the 44 indefinite samples, oil-immersion microscopy was able to distinguish rods in one, cocci in a chain in one, cocci in a cluster in two, and negative in 40, which were confirmed by culture as rods, streptococci, staphylococci, and negative, respectively. The quantitative microscopy method was similarly reliable (94.6% sensitivity, 99.3% specificity) for diagnosis of significant bacteriuria when compared with the Gram-stain method (89.2% sensitivity, 98.6% specificity). Quantitative unspun-urine microscopy, confirmed by oil-immersion, is a quick, reliable method for diagnosis of significant bacteriuria, and is considered to be useful for early diagnosis of urinary infection.

A method comparison study to assess the reliability of urine collection pads as a means of obtaining urine specimens from non-toilet-trained children for microbiological examination

BACKGROUND

In young, non-toilet-trained children, the collection of a urine sample for microbiology can be challenging, with the application of a urine bag being the main method of collection. However, recent research has shown that absorbent pads can be used yielding similar results to bag specimens. However, weaknesses in study design erode confidence in research findings. Therefore, improvements in research design are required to fully evaluate the reliability of pad collection.

AIMS OF THE STUDY

This pilot study sought to test the feasibility of a technique for the collection of concurrent bag/pad urine samples from non-toilet-trained children, and to assess the reliability of urine pads over bags as a collection method for urine specimens for microbiological evaluation.

DESIGN

A pilot, method comparison study.

METHODS

Twenty concurrent bag and pad specimens were collected from non-toilet-trained children, following parental consent. Urine specimens were analysed for presence or absence of white cell count (WBC), and bacterial growth, using standard laboratory methods.

DATA ANALYSIS

The Kappa (kappa) statistics and confidence interval (CI) estimation were used to assess agreement between the two collection methods.

RESULTS

Despite concurrent samples there was a lack of agreement between bag and pad specimens on both main outcome measures. Agreement between bag and pad specimens for the presence of WBC yielded a kappa=0.10 (95% CI: 0.19, 0.39), indicating poor agreement, while a kappa of 0.5 (95% CI: 0.12, 0.88) was calculated for the degree of agreement in bacterial growth reflecting moderate agreement. Differences in proportions of the presence of WBC between bag and pad did not quite reach significance at the 5% level 0.2 (95% CI: 0.00, 0.42, P=0.062). For cultures the difference was calculated as 0.15 (95% CI: 0.05, 0.35, P=0.125).

CONCLUSION

The pilot study demonstrates that concurrent urine samples can be obtained without difficulty. Despite poor to moderate agreement on outcome measures the level of agreement is greater than reported in those other studies, that use non-current methods of urine collection, suggesting an advantage of the concurrent technique. It is recommended that larger scale studies be undertaken using the concurrent collection technique to assess reliability of these findings.

C-reactive protein in febrile children 1 to 36 months of age with clinically undetectable serious bacterial infection

OBJECTIVE

To determine the diagnostic properties of quantitative C-reactive protein (CRP) associated with clinically undetectable serious bacterial infection (SBI) in febrile children 1 to 36 months of age.

METHODS

Febrile children presenting to a pediatric emergency department (ED) with ages ranging from 1 to 36 months, temperatures > or =39 degrees C, and clinically undetectable source of fever were enrolled in this prospective cohort study. Demographic information, ED temperature, duration of fever, and clinical evaluation using the Yale observation scale were recorded at the time of the initial evaluation. The white blood cell count (WBC), band count, absolute neutrophil count (ANC), and CRP concentration were measured at the same time. All patients received blood cultures and either a screening urinalysis or urine culture. A chest radiograph was obtained at the discretion of the ED physician. Patients with history of using antibiotics within 1 week of their presentation to the ED were excluded. The main outcome result was the presence of laboratory or radiographically proven SBI (bacteremia, meningitis, urinary tract infection, pneumonia, septic arthritis, and osteomyelitis).

RESULTS

Seventy-seven patients were enrolled in the study. Fourteen (18%) had a SBI (6 urinary tract infection; 4 pneumonia, including 1 patient with Streptococcus pneumoniae bacteremia; and 4 occult S pneumoniae bacteremia), and 63 had no SBI. The 2 groups were indistinguishable in age, sex, ED temperature, duration of fever, and Yale observation scale. CRP concentration, WBC, and ANC were significantly different between the 2 groups. In a multivariate logistic regression analysis, only CRP remained as a predictor of SBI (Beta = 0.76, 95% confidence interval [CI]: 0.64, 0.89). Receiver-operating characteristic analysis demonstrated CRP (area under curve [AUC] 0.905, standard error [SE] 0.05, 95% CI: 0.808, 1.002) to be superior to ANC (AUC 0.805, SE 0.051, 95% CI: 0.705, 0.905) and to WBC (AUC 0.761, SE 0.068, 95% CI: 0.628, 0.895). A CRP cutoff point of 7 was determined to maximize both sensitivity and specificity (sensitivity 79%, specificity 91%, likelihood ratio 8.3, 95% CI: 3.8, 27.3). Multilevel likelihood ratios and posttest probabilities were calculated for a variety of CRP levels. A CRP concentration of <5 mg/dL effectively ruled out SBI (likelihood ratio 0.087, 95% CI: 0.02, 0.38, posttest probability of SBI 1.9%).

CONCLUSIONS

Quantitative CRP concentration is a valuable laboratory test in the evaluation of febrile young children who are at risk for occult bacteremia and SBI, with a better predictive value than the WBC or ANC.

Abolishing the bag: a quality assurance project on urine collection

To audit practice in diagnosis of urinary tract infection (UTI) and implement a protocol to reduce the number of falsely diagnosed or misse

UTI: diagnosis and evaluation in symptomatic pediatric patients

We retrospectively reviewed data on 260 hospitalized pediatric patients with symptomatic urinary tract infection (UTI). To ascertain the colony-forming units (CFU)/mL compatible with the diagnosis of UTI, a culture from a catheterized urine specimen containing >1,000 CFU/mL was considered diagnostic of UTI and resulted in imaging by renal ultrasound, voiding cystourethrography, and renal nuclear scan with Tc99m dimercaptosuccinic acid (DMSA). A positive DMSA renal scan is indicative of pyelonephritis. We used logistic regression analysis to determine which patient characteristics were predictive of pyelonephritis. We determined that, in hospitalized pediatric patients, the colony count of the positive urine culture, the type of organism grown in culture, and the voiding cystourethrography (VCUG) result (positive or negative for vesicoureteral reflux) did not predict which patients had pyelonephritis. In females, advancing age of the patient and positive renal ultrasound results were predictive of which patients had pyelonephritis when we controlled for other factors. We feel this emphasizes the importance of a thorough evaluation of hospitalized symptomatic patients, including patients with colony counts of 1,000 to 50,000 CFU/mL, to locate the level of infection and plan appropriate therapy.

Evaluation and management of pediatric urinary tract infections

Urinary tract infections (UTIs) are relatively common in children. We describe the evaluation and management of children with UTIs, as well as the risks and consequences related to the UTI. This article describes a rational approach to the evaluation and management of childhood UTIs with the relation to the natural history and risk factors.

Practice parameter: the diagnosis, treatment, and evaluation of the initial urinary tract infection in febrile infants and young children. American Academy of Pediatrics. Committee on Quality Improvement. Subcommittee on Urinary Tract Infection

OBJECTIVE

To formulate recommendations for health care professionals about the diagnosis, treatment, and evaluation of an initial urinary tract infection (UTI) in febrile infants and young children (ages 2 months to 2 years).

DESIGN

Comprehensive search and analysis of the medical literature, supplemented with consensus opinion of Subcommittee members.

PARTICIPANTS

The American Academy of Pediatrics (AAP) Committee on Quality Improvement selected a Subcommittee composed of pediatricians with expertise in the fields of epidemiology and informatics, infectious diseases, nephrology, pediatric practice, radiology, and urology to draft the parameter. The Subcommittee, the AAP Committee on Quality Improvement, a review panel of office-based practitioners, and other groups within and outside the AAP reviewed and revised the parameter.

METHODS

The Subcommittee identified the population at highest risk of incurring renal damage from UTI-infants and young children with UTI and fever. A comprehensive bibliography on UTI in infants and young children was compiled. Literature was abstracted in a formal manner, and evidence tables were constructed. Decision analysis and cost-effectiveness analyses were performed to assess various strategies for diagnosis, treatment, and evaluation.

TECHNICAL REPORT

The overall problem of managing UTI in children between 2 months and 2 years of age was conceptualized as an evidence model. The model depicts the relationship between the steps in diagnosis and management of UTI. The steps are divided into the following four phases: 1) recognizing the child at risk for UTI, 2) making the diagnosis of UTI, 3) short-term treatment of UTI, and 4) evaluation of the child with UTI for possible urinary tract abnormality. Phase 1 represents the recognition of the child at risk for UTI. Age and other clinical features define a prevalence or a prior probability of UTI, determining whether the diagnosis should be pursued. Phase 2 depicts the diagnosis of UTI. Alternative diagnostic strategies may be characterized by their cost, sensitivity, and specificity. The result of testing is the division of patients into groups according to a relatively higher or lower probability of having a UTI. The probability of UTI in each of these groups depends not only on the sensitivity and specificity of the test, but also on the prior probability of the UTI among the children being tested. In this way, the usefulness of a diagnostic test depends on the prior probability of UTI established in Phase 1. Phase 3 represents the short-term treatment of UTI. Alternatives for treatment of UTI may be compared, based on their likelihood of clearing the initial UTI. Phase 4 depicts the imaging evaluation of infants with the diagnosis of UTI to identify those with urinary tract abnormalities such as vesicoureteral reflux (VUR). Children with VUR are believed to be at risk for ongoing renal damage with subsequent infections, resulting in hypertension and renal failure. Prophylactic antibiotic therapy or surgical procedures such as ureteral reimplantation may prevent progressive renal damage. Therefore, identifying urinary abnormalities may offer the benefit of preventing hypertension and renal failure. Because the consequences of detection and early management of UTI are affected by subsequent evaluation and long-term management and, likewise, long-term management of patients with UTI depends on how they are detected at the outset, the Subcommittee elected to analyze the entire process from detection of UTI to the evaluation for, and consequences of, urinary tract abnormalities. The full analysis of these data can be found in the technical report. History of the literature review along with evidence-tables and a comprehensive bibliography also are available in the report. (ABSTRACT TRUNCATED)

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

OVERVIEW

The Urinary Tract Subcommittee of the American Academy of Pediatrics Committee on Quality Improvement has analyzed alternative strategies for the diagnosis and management of urinary tract infection (UTI) in children. The target population is limited to children between 2 months and 2 years of age who are examined because of fever without an obvious cause. Diagnosis and management of UTI in this group are especially challenging for these three reasons: 1) the manifestation of UTI tends to be nonspecific, and cases may be missed easily; 2) clean voided midstream urine specimens rarely can be obtained, leaving only urine collection methods that are invasive (transurethral catheterization or bladder tap) or result in nonspecific test results (bag urine); and 3) a substantial number of infants with UTI also may have structural or functional abnormalities of the urinary tract that put them at risk for ongoing renal damage, hypertension, and end-stage renal disease (ESRD).

METHODS

To examine alternative management strategies for UTI in infants, a conceptual model of the steps in diagnosis and management of UTI was developed. The model was expanded into a decision tree. Probabilities for branch points in the decision tree were obtained by review of the literature on childhood UTI. Data were extracted on standardized forms. Cost data were obtained by literature review and from hospital billing data. The data were collated into evidence tables. Analysis of the decision tree was used to produce risk tables and incremental cost-effectiveness ratios for alternative strategies.

RESULTS

Based on the results of this analysis and, when necessary, consensus opinion, the Committee developed recommendations for the management of UTI in this population. This document provides the evidence the Subcommittee used in the development of its recommendations.

CONCLUSIONS

The Subcommittee agreed that the objective of the practice parameter would be to minimize the risk of chronic renal damage within reasonable economic constraints. Steps involved in achieving these objectives are: 1) identifying UTI; 2) short-term treatment of UTI; and 3) evaluation for urinary tract abnormalities.

Urinary tract infections in young febrile children

UTI is a common and important clinical problem in infants and young children, with a prevalence of 5.3% among febrile infants seen in our Emergency Department. White females with rectal temperature > or = 39 degrees C are at particularly high risk (prevalence, 17%). Several studies have highlighted the limitations of the standard urinalysis for identifying UTI in infants and young children and have recommended performance of both urinalysis and urine culture. Alternative methods such as dipstick urinalysis, although attractive because of ease of performance, are inadequate as a screen for UTI. Hemocytometer WBC counts of an uncentrifuged urine specimen can be performed in an office or hospital-based laboratory with minimal training. Performance of Gram-stained smears, however, is most appropriate for the hospital-based laboratory. In the hospital setting where both tests can readily be performed, the positive predictive value of the combination of pyuria and bacteriuria (85%) allows prompt institution of antimicrobial therapy before culture results are available, whereas the lower positive predictive value of the single finding of either pyuria or bacteriuria (40%) justifies delaying treatment decisions until culture results are available. In the office setting where hemocytometer counts can easily be performed, culturing only specimens with pyuria and those of children presumptively treated with antimicrobials will result in the identification of almost all patients with true UTI, sparing large health care expenditures. Although the urine culture is traditionally regarded as the gold standard of UTI, positive urine cultures may occur secondary to contamination or in cases of ABU, leading to a false diagnosis of UTI. In contrast we found pyuria to be a reliable marker to discriminate infection from colonization of the urinary tract. The sustained absence of an inflammatory response, on repeat UA within 24 h, constitutes strong evidence that infection is absent. Management of ABU is controversial; many experts recommend withholding antibiotics because eradication of low virulence organisms may be followed by colonization with more virulent species that cause pyelonephritis. Preliminary results of our ongoing treatment trial suggest that management of young febrile children with UTI as outpatients receiving oral cefixime is as efficacious as inpatient management with intravenous cefotaxime. Results of renal ultrasound and DMSA scan at the time of infection have not modified management in any patient. Accordingly selective rather than routine performance of ultrasound is recommended. A voiding cystourethrogram at 1 month and a DMSA scan 6 months later have been valuable in identifying patients with vesicoureteral reflux and renal scarring, respectively. Among patients initially identified as having acute pyelonephritis, the incidence of renal scarring at 6 months has been substantially more frequent (approximately 40%) than we had expected. However, the long term implications of small scars identified with renal scintigraphy remain to be determined.

The management of brainstem gliomas in patients with neurofibromatosis 1

The appropriate management of brainstem tumors in patients with neurofibromatosis 1 (NF1) has been problematic because the natural history of these lesions remains poorly defined. To formulate rational guidelines for the evaluation and treatment of these tumors, we reviewed the outcome of 21 patients with brainstem mass lesions followed in our NF clinic during the last 9 years. We subdivided the imaging features of these lesions into four groups: (1) diffuse enlargement of the brainstem with hypointensity on T1-weighted MR images and hyperintensity on T2-weighted images (n = 9); (2) focal enhancing masses (n = 7); (3) intrinsic tectal tumors (n = 5); and (4) focal nonenhancing areas of hypointensity on T1-weighted MR images (n = 2). Two cases exhibited two types of lesions. Twelve patients presented with, or developed, symptoms that were referable to the mass; in nine, the lesion was asymptomatic. A distinguishing feature of these tumors was their generally indolent biological behavior. With a median follow-up of 3.75 years, only 10 patients have had radiographic (n = 9) or clinical (n = 3) evidence of disease progression. In seven of these patients, the tumor subsequently stabilized in size or regressed without intervention. Only four patients, each with a focal enhancing tumor, received specific therapy for the tumor; this consisted of biopsy (n = 1), excision (n = 3), and adjuvant radiotherapy (n = 2). Each of these lesions was a low-grade glioma histologically and each remained stable in size after treatment (median follow-up = 4.25 years). Four patients with tectal tumors underwent insertion of a CSF shunt for hydrocephalus, but required no specific treatment for the tumor. None of the patients with diffuse brainstem lesions or focal areas of hypointensity required any intervention for the tumor. All 21 patients are presently alive and well. We conclude that the biological behavior of brainstem lesions in patients with NF1 differs significantly from that of lesions with a similar appearance in patients without this disorder. Although these lesions may at some time in their course exhibit clinical and radiographic progression, most do not require specific intervention. The lesions that are most likely to progress and require therapy are focal enhancing tumors; however, even lesions in this subgroup may stabilize in size or regress spontaneously without intervention. Based on these results, we recommend that intervention be limited to those lesions that exhibit rapid or unrelenting growth on serial images or that produce significant clinical deterioration.

Is urine culture necessary to rule out urinary tract infection in young febrile children?

OBJECTIVE

To determine whether the absence of pyuria on the enhanced urinalysis can be used to eliminate the diagnosis of urinary tract infection, avoiding the need for urine culture and sparing large health care expenditures.

DESIGN

Results of an enhanced urinalysis (hemocytometer counts and interpretation of Gram-stained smears) performed on uncentrifuged urine specimens obtained by catheter were correlated with urine cultures in young febrile children at the Children's Hospital of Pittsburgh Emergency Department. In a group of 4253 children (95% febrile) less than 2 years of age, pyuria was defined as > or = 10 white blood cells/mm3, bacteriuria as any bacteria on any of 10 oil immersion fields in a Gram-stained smear and a positive culture as > or = 50,000 colony-forming units/ml. A subgroup of 153 children with their first diagnosed urinary tract infection were enrolled in a separate treatment trial, acute phase reactants (peripheral white blood cell count, erythrocyte sedimentation rate and C-reactive protein) were obtained and 99Tc-dimercaptosuccinic acid renal scans were performed.

RESULTS

The presence of either pyuria or bacteriuria and the presence of both pyuria and bacteriuria have the highest sensitivity (95%) and positive predictive value (85%), respectively, for identifying positive urine cultures. Because a white blood cell count in a hemocytometer is the technically simpler component of the enhanced urinalysis, we chose to analyze the false negative results and achievable cost savings of using pyuria alone as the sole criterion for omitting urine cultures. If in this study urine cultures had been performed only on specimens from children who had pyuria or were managed presumptively with antibiotics, cultures of 2600 (61%) specimens would have been avoided. Twenty-two of 212 patients with positive urine cultures would not have been identified initially. However, based on interpretation of acute phase reactants, initial 99Tc-dimercaptosuccinic acid scan results, response to management and incidence of renal scarring 6 months later, 14 of the 22 patients most likely had asymptomatic bacteriuria and fever from another cause. The remaining 8 patients probably had early urinary tract infection.

CONCLUSIONS

The analysis of urine samples obtained by catheter for the presence of significant pyuria (> or = 10 white blood cells/mm3) can be used to guide decisions regarding the need for urine culture in young febrile children.