New Developments in the Diagnosis and Management of Pediatric UTIs

Urinary tract infections in children: building a causal model-based decision support tool for diagnosis with domain knowledge and prospective data

BACKGROUND

Diagnosing urinary tract infections (UTIs) in children in the emergency department (ED) is challenging due to the variable clinical presentations and difficulties in obtaining a urine sample free from contamination. Clinicians need to weigh a range of observations to make timely diagnostic and management decisions, a difficult task to achieve without support due to the complex interactions among relevant factors. Directed acyclic graphs (DAG) and causal Bayesian networks (BN) offer a way to explicitly outline the underlying disease, contamination and diagnostic processes, and to further make quantitative inference on the event of interest thus serving as a tool for decision support.

METHODS

We prospectively collected data on children present to ED with suspected UTIs. Through knowledge elicitation workshops and one-on-one meetings, a DAG was co-developed with clinical domain experts (the Expert DAG) to describe the causal relationships among variables relevant to paediatric UTIs. The Expert DAG was combined with prospective data and further domain knowledge to inform the development of an application-oriented BN (the Applied BN), designed to support the diagnosis of UTI. We assessed the performance of the Applied BN using quantitative and qualitative methods.

RESULTS

We summarised patient background, clinical and laboratory characteristics of 431 episodes of suspected UTIs enrolled from May 2019 to November 2020. The Expert DAG was presented with a narrative description, elucidating how infection, specimen contamination and management pathways causally interact to form the complex picture of paediatric UTIs. Parameterised using prospective data and expert-elicited parameters, the Applied BN achieved an excellent and stable performance in predicting Escherichia coli culture results, with a mean area under the receiver operating characteristic curve of 0.86 and a mean log loss of 0.48 based on 10-fold cross-validation. The BN predictions were reviewed via a validation workshop, and we illustrate how they can be presented for decision support using three hypothetical clinical scenarios.

CONCLUSION

Causal BNs created from both expert knowledge and data can integrate case-specific information to provide individual decision support during the diagnosis of paediatric UTIs in ED. The model aids the interpretation of culture results and the diagnosis of UTIs, promising the prospect of improved patient care and judicious use of antibiotics.

Is There a Difference in the Contamination Rates of Urine Samples Obtained by Bladder Catheterization and Clean-Catch Collection in Preschool Children?

OBJECTIVE

The objective of this study was to compare contamination rates in urine samples obtained by transurethral catheterization and clean-catch methods in preschool children aged 2 to 5 years.

METHODS

A retrospective, chart review was performed on patients evaluated in our emergency department over a 6-month period who had a urine culture obtained by either transurethral catheterization or clean-catch methods. The charts were reviewed for urine bacterial colony counts and divided into positive, negative, or contaminated cohorts. Demographic data were collected as well.

RESULTS

Four hundred sixty patients met inclusion for this study. Of these patients, there were 120 samples collected by catheter (26.1%) and 340 samples collected by clean-catch method (73.9%).Female patients comprised 73% of the eligible samples (n = 336), and 27% were male (n = 124). Contamination rates significantly varied by collection method (P < 0.0001), with only 9 contaminated catheter samples (7.5%) and 125 contaminated clean-catch samples (36.76%). Contaminated samples were found in 122 of 336 female urine samples (36.3%), and 12 of 124 male urine samples (9.7%). There were no associations found between contamination rates and age within either sex.

CONCLUSIONS

Our study demonstrated a higher urine culture contamination rate in preschool age children in the clean-catch method group compared with the transurethral catheterization group. This finding was particularly strong within the female subset, which could partially be accounted for by the small male sample size.

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.

Infección del tracto urinario en niños, una de las enfermedades infecciosas más prevalentes

La infección del tracto urinario (ITU) es una patología frecuente en la infancia y una de las causas más comunes de consulta en el servicio de urgencias pediátricas. Las manifestaciones clínicas pueden ser inespecíficas en los lactantes y niños pequeños; sin embargo, en los niños mayores la sintomatología es más específica, con la aparición de fiebre, dolor en flanco, puño percusión renal positiva y signos de irritación vesical como disuria, polaquiuria, tenesmo e incontinencia. El diagnóstico definitivo confirmatorio se realiza mediante cultivo de orina. El conocimiento sobre los factores de riesgo, junto con ciertas consideraciones de valoración clínica y epidemiologia, son esenciales para encaminar las estrategias preventivas de las infecciones urinarias.

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.

Bacterial uropathogens isolates and antibiograms in children under 5 years of age

BACKGROUND

Childhood urinary infections are among the most common febrile illnesses occurring during this period with varying susceptibility to antibiotic.

AIM

The aim of this study was to identify uropathogens responsible to for urinarytract infection (UTIs) in children less than 5 years of age, and determine the antibiograms of the isolates to commonly used antibiotics.

PATIENTS AND METHODS

Hundred and four children (2 months - 5 years old) seen at the Gadarif Teaching Hospital from January 2012 and December 2013 were evaluated. A urine specimen was obtained by a plastic bag with an adhesive backing around an opening or by direct voiding into sterile container. Urine was examined microscopically and those with significant pyuria and bacteruria were further cultured and microorganisms were identified and tested for antimicrobial susceptibility.

RESULTS

Out of 304 children suffering from UTIs; 145(47.7%) had significant pyuria of them; 54(17.8 %) had positive bacterial growth. The frequency of sex and residency were almost the same. E. coli (42.6%) was the most common uropathogen, sensitive to ciprofloxacin (91.3%), followed by Pseudomonas aeruginosa (29.6%) sensitive to Ciprofloxacin (75%)and Norofloxacin (68.8%), Klebsiellapneumoniae (18.5%) sensitive to Ciprofloxacin and Norofloxacin and Nalidixic acid (90%) and Proteus mirabilis sensitive to Ciprofloxacin and Norofloxacin (90%), Amoxicillin / clavulanic acid (Augmentin(80%).

CONCLUSION

The most common uropathogens were E. coli, Pseudomonas aeruginosa,Klebsiellapneumoniae, and Proteus mirabilis. Ciprofloxacin is the recommended initial empirical therapy while awaiting the culture and sensitivity results.

Highlights for management of a child with a urinary tract infection

Urinary tract infections remain the most common bacterial infection in childhood. Escherichia coli is responsible for over 80% of Pediatric UTIs. Other common gram negative organisms include Kleibsiella, Proteus, Enterobacter and occasionally Pseudomonas. Signs and symptoms vary greatly by age of the patient becoming more specific as the child grows older. Even in the absence of specific signs a UTI should be included in the differential diagnosis of high grade fever. In younger children, presence of upper respiratory infections, otitis media or gastroenteritis does not eliminate the possibility of a UTI. Culture of the urine remains the gold standard for diagnosing UTIs. All males and females with well documented UTIs should be imaged for the presence of urological anomalies associated with UTI. Depending on patient's clinical symptoms and tolerance, therapy can be oral or parenteral as they have both been found equally efficacious. Healthcare professionals should ensure that when a child or young person has been identified as having a suspected UTI, they and their parents are given information about the need for treatment, the importance of completing any course of treatment and advice about prevention and possible long-term management.

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.

Pediatric urinary tract infections

Urinary tract infections (UTIs) in children are commonly seen in the emergency department and pose several challenges to establishing the proper diagnosis and determining management. This article reviews pediatric UTI and addresses epidemiology, diagnosis, treatment, and imaging, and their importance to the practicing emergency medicine provider. Accurate and timely diagnosis of pediatric UTI can prevent short-term complications, such as severe pyelonephritis or sepsis, and long-term sequelae including scarring of the kidneys, hypertension, and ultimately chronic renal insufficiency and need for transplant.

A guideline for the inpatient care of children with pyelonephritis

BACKGROUND AND OBJECTIVES

Febrile urinary tract infections and pyelonephritis are common in children and frequently lead to hospitalization for management, especially in the child who appears toxic. The American Academy of Pediatrics (AAP) practice parameter on the diagnosis, treatment and evaluation of the initial urinary tract infection in febrile infants and young children provides experience and evidence-based guidelines for the practitioner caring for children between the ages of 2 months to 2 years. No established guideline exists for older children and the AAP guideline does not specifically focus on inpatient care.

METHODS

We conducted a comprehensive review of recently published literature and practice guidelines to develop a consensus on the inpatient diagnosis and management of children with pyelonephritis.

RESULTS

Eight recommendations are proposed for the diagnosis and management, including revised guidelines for the imaging studies postpyelonephritis on the basis of current best evidence.

CONCLUSION

Proper diagnosis of pyelonephritis, timely initiation of appropriate therapy and identification of children at risk for renal injury will help to reduce immediate as well as long-term complications due to chronic kidney disease.

Urinalysis is not reliable to detect a urinary tract infection in febrile infants presenting to the ED

OBJECTIVE

Urinary tract infections are a common source of serious bacterial infections in febrile infants younger than 2 years. Our objective was to compare urinalysis with urine culture in the emergency department evaluation of febrile infants.

METHODS

A febrile infant registry was instituted at a tertiary care hospital treating an average of 55000 patients annually (27% children), from December 2002 to December 2003. Patients were eligible if they were younger than 3 months and had a temperature of at least 38 degrees C or if they were between 3 and 24 months of age and had a temperature of at least 39 degrees C. Data abstracted included age, sex, and temperature. Urinalysis (UA) and urine culture (UCx) results were obtained from electronic hospital archives.

RESULTS

Nine hundred eighty-five patients were entered into the febrile infant registry. Male patients comprised 55%. The mean age of patients was 12.6 months; median was 12 months. Four hundred thirty-five (78% of eligible patients) had both a UA and UCx from the same specimen, and there were 45 (10.3%) positive UCx result. Females accounted for 33 (73%) of 45 positive results. The sensitivity of UA for predicting a positive UCx result was 64% (95% confidence interval [CI], 49%-78%), whereas the specificity was 91% (95% CI, 88%-94%). The positive predictive value was 46% (95% CI, 31%-53%), with a negative predictive value of 96% (95% CI, 93%-97%).

CONCLUSION

Urinalysis is not reliable for the detection of urinary tract infections in febrile infants when compared with urine cultures.

Serious bacterial infections in febrile infants in the post-pneumococcal conjugate vaccine era

OBJECTIVES

The objective was to identify the epidemiology of serious bacterial infections (SBI) and the current utility of obtaining routine complete blood counts (CBC) and blood cultures to stratify infants at risk of SBI, in the study population of febrile infants in the post-heptavalent pneumococcal conjugate vaccine (PCV7) era.

METHODS

A cohort study with nested case-controls was undertaken at a tertiary care military hospital emergency department (ED) from December 2002 through December 2003. Irrespective of clinical findings at the initial encounter, patients were included if they were under 3 months of age and had a home or ED temperature of >or=100.4 degrees F or if they were between 3 and 24 months of age with a temperature of >or=102.3 degrees F. Data abstracted included age, temperature, peripheral white blood cell (WBC) count, and discharge diagnosis. Culture (blood, urine, and cerebrospinal fluid [CSF]) and chest radiograph (CXR) results were obtained through review of the electronic hospital archives. SBI was defined as pneumonia, urinary tract infection (UTI), meningitis, or bacteremia.

RESULTS

A total of 985 children aged 0 to 24 months were enrolled. Fifty-five percent were male, the median age was 12 months (interquartile range = 8-17 months), and 79% had received at least one PCV7. A total of 132 cases of SBI were identified in 129 infants (13.1%): 82 pneumonias, 45 UTI, five bacteremias, and no cases of bacterial meningitis. The frequency of bacteremia was 0.7%. No statistical difference was detected in the WBC count between the SBI and non-SBI groups (13.8 +/- 5.8 and 11.7 +/- 5.6, respectively; p = 0.055). No readily available WBC cutoff on the receiver operating characteristic (ROC) curve proved to be an accurate predictor of SBI. No statistical difference was detected in mean temperature between the SBI and non-SBI groups (103.3 +/- 1.2 and 103.2 +/- 1.2 degrees F, respectively; p = 0.26), nor was there a difference noted when groups were broken down by age or height of fever.

CONCLUSIONS

The WBC count and height of fever were not found to be accurate predictors of SBI in infants age 3 to 24 months. UTI and pneumonias made up the vast majority of SBI in this population of infants. The overall bacteremia frequency was well below 1%. This calls into question the continued utility of obtaining routine complete cell counts and blood cultures in the febrile infant in the post-PCV7 era.

Diagnosis of urinary tract infections in children

PURPOSE OF REVIEW

Urinary tract infections remain a significant cause of serious bacterial infections in children and can result in chronic kidney disease. Thus, prompt diagnosis and initiation of treatment of urinary tract infections are paramount objectives.

RECENT FINDINGS

A number of advances in technology have allowed expeditious examination of the urine. Recent meta-analyses evaluated the ability of these tests to determine the presence or absence of urinary tract infection in children. In addition, understanding the prevalence of urinary tract infection in various populations will help guide the clinician to the appropriate level of suspicion and the appropriate work-up for urinary tract infection.

SUMMARY

Although culture of the urine remains the gold standard for diagnosing and treating urinary tract infections, technical considerations including method of collection of the urine as well as the time necessary for culture results remain problematic. More rapid techniques include dipstick analyses for the presence of leukocyte esterase or nitrites, microscopic analysis for white blood cells or bacteria, and automated urine cell analyzer to determine bacterial and white blood cell counts in the urine. Recent results indicate it is possible to limit the number of urine cultures performed by eliminating those that have a low probability of being positive. In addition, recent studies reexamining the prevalence of urinary tract infections in various populations indicate that diagnostic testing can be aimed at those patients who are in the higher-risk groups.