Does early treatment of urinary tract infection prevent renal damage?

Visibility of the urethral meatus and risk of urinary tract infections in uncircumcised boys

BACKGROUND

Uncircumcised boys are at higher risk for urinary tract infections than circumcised boys. Whether this risk varies with the visibility of the urethral meatus is not known. Our aim was to determine whether there is a hierarchy of risk among uncircumcised boys whose urethral meatuses are visible to differing degrees.

METHODS

We conducted a prospective cross-sectional study in one pediatric emergency department. We screened 440 circumcised and uncircumcised boys. Of these, 393 boys who were not toilet trained and for whom the treating physician had requested a catheter urine culture were included in our analysis. At the time of catheter insertion, a nurse characterized the visibility of the urethral meatus (phimosis) using a 3-point scale (completely visible, partially visible or nonvisible). Our primary outcome was urinary tract infection, and our primary exposure variable was the degree of phimosis: completely visible versus partially or nonvisible urethral meatus.

RESULTS

Cultures grew from urine samples from 30.0% of uncircumcised boys with a completely visible meatus, and from 23.8% of those with a partially or nonvisible meatus (p = 0.4). The unadjusted odds ratio (OR) for culture growth was 0.73 (95% confidence interval [CI] 0.35-1.52), and the adjusted OR was 0.41 (95% CI 0.17-0.95). Of the boys who were circumcised, 4.8% had urinary tract infections, which was significantly lower than the rate among uncircumcised boys with a completely visible urethral meatus (unadjusted OR 0.12 [95% CI 0.04-0.39], adjusted OR 0.07 [95% CI 0.02-0.26]).

INTERPRETATION

We did not see variation in the risk of urinary tract infection with the visibility of the urethral meatus among uncircumcised boys. Compared with circumcised boys, we saw a higher risk of urinary tract infection in uncircumcised boys, irrespective of urethral visibility.

The impact of therapeutic delay time on acute scintigraphic lesion and ultimate scar formation in children with first febrile UTI

We assessed the role of therapeutic delay time (TDT) in acute renal cortical scintigraphic lesion (ASL) and ultimate scar formation (USF) in children with first febrile UTI and whether it is affected by the presence of vesico-ureteral reflux (VUR). 230 children, 90 girls and 140 boys with first febrile UTI were included. Radiologic (USG, DMSA, and VCUG), clinical (age, gender, peak fever, therapeutic delay time) and laboratory (CBC with differential count, ANC (absolute neutrophil count), BUN, Creatinine, urine analysis, gram stain, culture, CRP and ESR) variables were analysed. DMSA was performed within 5 days and after six months. VCUG was performed after acute phase of UTI. The differences in TDT according to the presence of ASL, USF and VUR were assessed. And the correlation between ASL or USF with the duration of TDT was assessed. Of 230 patients enrolled, 142 patients had refluxing UTI and 88 patients had non-refluxing UTI. TDT was the risk factor associated with ASL and USF along with presence of VUR. TDT was longer in ASL positive group compared with the ASL negative group. Also USF group showed longer TDT compared with those without USF in both refluxing UTI and non refluxing UTI. The TDT was significantly shorter in USF group with the presence of VUR. Positive linear association was noted between prevalence of ASL and USF and duration of TDT. In conclusion, the impact of UTI on formation of USF may be enhanced by the presence of VUR with shorter duration of TDT.

Development of a score based on urinalysis to improve the management of urinary tract infection in children

BACKGROUND

The need for reducing unnecessary antibiotic treatment is being emphasized in the management of urinary tract infections (UTI), a disease frequent in childhood. An ideal test should provide early diagnosis without the waiting times of urine culture, but even a simple test of exclusion could significantly improve patient management.

METHODS

We evaluated the sensitivity, specificity, negative and positive predictive value of automated microscopy IRIS iQ200 combined with the dipstick analyses in children with suspected UTI. Multivariable logistic regression analysis was used to identify the set of variables that best predict positive culture results and develop a numerical risk score.

RESULTS

Of 474 consecutive urine samples retrospectively analyzed, 69 were positive at urine culture with prevalence of infection of 14.6%. Parameters significantly associated with the presence of infection in multivariable analysis were age <1 year (p<0.001), leukocyte esterase ≥ 15×10^6/L (p<0.001), number of small particles (ASP) ≥ 5500 × 10^6/L (p<0.001) and bacteria ≥ 3 × 10^6/L (p=0.01). The derived score ranged from 0 to 10, with higher values indicating higher risk of UTI. The area under the score ROC curve was 79% (95% CI 0.72-0.85), and was better than those of the individual urinary chemical and microscopic analyses.

CONCLUSIONS

This routine method could improve the management of UTI in children by early identifying patients with low probability of infection, for whom antibiotic treatment can be withheld until the results of urine culture become available.

Managing urinary tract infections

Urinary tract infections (UTI) are common in childhood. Presence of pyuria and bacteriuria in an appropriately collected urine sample are diagnostic of UTI. The risk of UTI is increased with an underlying urological abnormality such as vesicoureteral reflux, constipation, and voiding dysfunction. Patients with acute pyelonephritis are at risk of renal scarring and subsequent complications such as hypertension, proteinuria with and without FSGS, pregnancy-related complications and even end-stage renal failure. The relevance and the sequence of the renal imaging following initial UTI, and the role of antimicrobial prophylaxis and surgical intervention are currently undergoing an intense debate. Prompt treatment of UTI and appropriate follow-up of those at increased risk of recurrence and/or renal scarring are important.

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.

Vesicoureteral reflux and reflux nephropathy

Primary vesicoureteral reflux (VUR) is the commonest congenital urological abnormality in children, which has been associated with an increased risk of urinary tract infection (UTI) and renal scarring, also called reflux nephropathy (RN). In children, RN is diagnosed mostly after UTI (acquired RN) or during follow-up for antenatally diagnosed hydronephrosis with no prior UTI (congenital RN). The acquired RN is more common in female children, whereas the congenital RN is more common in male children. This observation in children might help explain the differences in the clinical presentation of RN in adults, with males presenting mostly with hypertension, proteinuria, and progressive renal failure as compared with females who present mostly with recurrent UTI and have a better outcome. Known risk factors for RN include the severity of VUR, recurrent UTI, and bladder-bowel dysfunction; younger age and delay in treatment of UTI are believed to be other risk factors. Management of VUR is controversial and includes antimicrobial prophylaxis, surgical intervention, or surveillance only. No evidence-based guidelines exist for appropriate follow-up of patients with RN.

Technical report—Diagnosis and management of an initial UTI in febrile infants and young children

OBJECTIVES

The diagnosis and management of urinary tract infections (UTIs) in young children are clinically challenging. This report was developed to inform the revised, evidence-based, clinical guideline regarding the diagnosis and management of initial UTIs in febrile infants and young children, 2 to 24 months of age, from the American Academy of Pediatrics Subcommittee on Urinary Tract Infection.

METHODS

The conceptual model presented in the 1999 technical report was updated after a comprehensive review of published literature. Studies with potentially new information or with evidence that reinforced the 1999 technical report were retained. Meta-analyses on the effectiveness of antimicrobial prophylaxis to prevent recurrent UTI were performed.

RESULTS

Review of recent literature revealed new evidence in the following areas. Certain clinical findings and new urinalysis methods can help clinicians identify febrile children at very low risk of UTI. Oral antimicrobial therapy is as effective as parenteral therapy in treating UTI. Data from published, randomized controlled trials do not support antimicrobial prophylaxis to prevent febrile UTI when vesicoureteral reflux is found through voiding cystourethrography. Ultrasonography of the urinary tract after the first UTI has poor sensitivity. Early antimicrobial treatment may decrease the risk of renal damage from UTI.

CONCLUSIONS

Recent literature agrees with most of the evidence presented in the 1999 technical report, but meta-analyses of data from recent, randomized controlled trials do not support antimicrobial prophylaxis to prevent febrile UTI. This finding argues against voiding cystourethrography after the first UTI.

Trends in hospitalization for pediatric pyelonephritis: a population based study of California from 1985 to 2006

PURPOSE

We examined trends in pediatric hospitalization for pyelonephritis from 1985 to 2006 and identified factors associated with admission.

MATERIALS AND METHODS

We performed a population based analysis of hospital discharges using the Office of Statewide Health Planning and Development database to evaluate trends in California regarding pediatric hospitalizations for pyelonephritis from 1985 to 2006. Multivariable logistic regression was performed to identify factors associated with admission for pyelonephritis.

RESULTS

A total of 46,300 children were hospitalized for pyelonephritis in California from 1985 to 2006. The overall rate of hospitalization for pyelonephritis increased by greater than 80%, from 17 per 100,000 children in the California population in 1985 to 31 per 100,000 in 2005. This change was primarily due to the nearly ninefold increase in pyelonephritis hospitalizations observed in children younger than 1 year, from 28 per 100,000 in 1985 to 238 per 100,000 in 2005. Among children younger than 1 year males without private insurance and of nonwhite race had increased odds of hospitalization, while females with private insurance and of Asian race had increased odds of hospitalization, compared with nonprivate insurance and white race, respectively.

CONCLUSIONS

A significant increase in hospital admissions for pyelonephritis, primarily in children younger than 1 year, occurred in California between 1985 and 2006. Further studies are needed to establish the cause of this striking increase and to determine why certain pediatric populations are at increased risk for hospitalization.

Urinary tract infection in the newborn and the infant: state of the art

Urinary tract infection is one of the most common causes of infection in newborns. Obtaining a urinary tract infections (UTIs) diagnosis just on the basis of the clinical findings is frequently difficult, however, being the pediatrician's goal to reduce the risk of renal scarring, a prompt diagnosis and treatment is of extreme importance. The key instrument for the diagnosis of UTIs is represented today by urine culture. However, in reality, the caregivers and investigators are increasingly demanding fast and cheap methods for a rapid and effective diagnosis.

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.

Vesicoureteral reflux associated renal damage: congenital reflux nephropathy and acquired renal scarring

PURPOSE

The pathophysiology, evaluation, description and clinical implications of renal damage associated with vesicoureteral reflux remain controversial. We summarized the current understanding of this important aspect of clinical vesicoureteral reflux.

MATERIALS AND METHODS

We performed a detailed review of the literature on clinical, pathological and experimental data related to congenital vesicoureteral reflux and bladder dynamics. We also reviewed the clinical context and imaging evaluation with underlying experimental data related to post-infectious reflux nephropathy.

RESULTS

Congenital reflux nephropathy is a pattern of impaired renal function and development with renal dysplasia as the most severe but not the only form. Mechanisms of developmental disruption are potentially related to vesicoureteral reflux dynamics during gestation and associated bladder dynamics, which may continue into postnatal life. Acquired renal injury associated with infection is related to particular bacterial and host factors that determine infection virulence, host inflammatory response and tissue recovery. As best seen on dimercapto-succinic acid scan, acute changes may resolve but may also persist as permanent renal scarring. Specific risk factors for acute pyelonephritis and renal scarring in patients with vesicoureteral reflux include higher reflux grade, dysfunctional voiding/elimination, recurrent pyelonephritic episodes and delayed initiation of antibiotic therapy. Low pressure sterile reflux is not a cause of reflux nephropathy.

CONCLUSIONS

Renal damage associated with vesicoureteral reflux may be congenital or acquired and the respective pathophysiological mechanisms are likely different. Congenital damage is often dysplasia, which may be a result of disordered renal development secondary to significant alterations in bladder dynamics. These processes may continue into the newborn period while kidney maturation continues. Recognizing the clinical potential for ongoing effects on renal function and the role of bladder development are important for clinical care. Post-pyelonephritic acquired damage is the result of a complex interaction of host and bacterial factors that leads to acute alterations in renal function, and may lead to permanent renal scarring. Strategies for timely intervention as well as prevention are essential to limit the risk of permanent renal injury, which may predispose to hypertension and renal insufficiency in some patients.

Duration of fever affects the likelihood of a positive bag urinalysis or catheter culture in young children

OBJECTIVE

To test the hypothesis that there will be a clinically significant rise in the proportion of positive bag urinalyses and catheter cultures in young children with increasing duration of fever.

STUDY DESIGN

This was a prospective cohort study of 818 infants and children age 3-36 months presenting to a tertiary care emergency department with documented fever without source. Following the documentation of fever from < 1 to > or = 5 days, bag specimens were collected for urinalysis. The primary outcome was the yield of positive bag dipsticks by day, defined as positive for nitrates or more than trace leukocyte esterase. The secondary outcome was positive catheter cultures on each day of fever.

RESULTS

Positive bag urinalyses increased with duration of fever: 14.8% (35/237) on day 1 versus 26.4% (43/163) on day 3 (relative risk [RR] = 1.8; 95% confidence interval [CI] = 1.2-2.7; P = .004). Positive catheter cultures increased in the same fashion: 4.8% (11/229) on day 1 versus 12.6% (20/159) on day 3 (RR = 2.6; 95% CI = 1.3-5.3; P = .005).

CONCLUSIONS

The yield of positive bag urinalyses and catheter cultures increased significantly in children with fever of 3 days or longer duration.

Previous antimicrobial exposure is associated with drug-resistant urinary tract infections in children

OBJECTIVE

The aim of this study was to evaluate the impact of previous antimicrobial exposure on the development of antimicrobial resistance in children with their first urinary tract infection (UTI).

METHODS

We conducted a retrospective cohort study of children aged 6 months to 6 years and received their first diagnosis of UTI in a network of 27 outpatient pediatric practices between July 1, 2001, and May 31, 2006. We examined the relationship between antimicrobial resistance in UTI isolates and exposure to specific antimicrobial agents (amoxicillin, amoxicillin-clavulanate, cefdinir, trimethoprim-sulfamethoxazole, and azithromycin) in the previous 120 days. We developed multivariable logistic regression models for resistance to ampicillin, amoxicillin-clavulanate, trimethoprim-sulfamethoxazole, and first-generation and third-generation cephalosporins, adjusting for potential confounders such as age, number of siblings, recent hospitalizations, and child care exposure.

RESULTS

Of the 533 children who had a first UTI, 8%, 14%, and 21% were exposed to antimicrobial agents within 30, 60, and 120 days before the UTI, respectively. Amoxicillin exposure within 30 days (odds ratio [OR]: 3.6 [95% confidence interval (CI): 1.6-8.2]) and 31 to 60 days (OR: 2.8 [95% CI: 1.0-7.5]) before UTI both were associated with ampicillin resistance. Exposure to amoxicillin >60 days before the UTI was not associated with ampicillin resistance. Amoxicillin exposure within 30 days of UTI was also associated with amoxicillin-clavulanate resistance (OR: 3.9 [95% CI: 1.8-8.7]). No association between exposure to other antimicrobial agents and resistance to any of the antimicrobial agents was seen.

CONCLUSIONS

Recent antimicrobial exposure is associated with antimicrobial-resistant UTIs among pediatric outpatients, and the magnitude of this association decreases with time since exposure. Judicious antimicrobial prescribers should consider this association when selecting empiric antimicrobial agents for a new UTI and should use strategies to reduce unnecessary antimicrobial use to avoid development of resistant bacteria.

Update on childhood urinary tract infection and vesicoureteral reflux

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

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Vesicoureteral reflux, reflux nephropathy, and end-stage renal disease

Objective. To review the contribution of vesicoureteral reflux and reflux nephropathy to end-stage renal disease. Data Source. Published research articles and publicly available registries. Results. Vesicoureteral reflux (VUR) is commonly identified in pediatric patients and can be associated with reflux nephropathy (RN), chronic kidney disease (CKD), and rarely end-stage renal disease (ESRD). Patients with reduced GFR, bilateral disease, grade V VUR, proteinuria, and hypertension are more likely to progress to CKD and ESRD. Because progression to ESRD is rare in VUR and often requires many decades to develop, there are limited prospective, randomized, controlled trials available to direct therapy to prevent progression to ESRD. Conclusions. Identification of patients with increased risk of progression to CKD and ESRD should be the goal of clinical, biochemical, and radiological evaluation of patients with VUR. Treatment of patients with VUR should be directed at preventing new renal injury and preserving renal function.

Fever without apparent source on clinical examination

PURPOSE OF REVIEW

Routine immunization of children with the heptavalent pneumococcal conjugate (PCV7) vaccine and rapid tests for identification of viruses since the last review in 2002 make this review timely and relevant.

RECENT FINDINGS

Since the introduction of the PCV7 vaccine, the incidence of true bacteremia has decreased to 1% and has impacted the epidemiology of fever in the under-3-year-old population, making urinary tract infection the most common cause. Polymerase chain reaction testing for viruses helps in early diagnosis and serves to decrease the unnecessary use of antibiotics. Serious infections are dependent not only on the virulence of the agent, but also on host susceptibility, which has been getting more attention recently. Kawasaki disease in the very young infant is also discussed and awareness is increasing among physicians.

SUMMARY

The decrease in the rate of bacteremia since the PCV7 vaccine was introduced means that the management guidelines for fever in the under-3-year-old population need to be reviewed. In addition, better markers are required to predict serious bacterial infection in this population. Further research into the understanding of the host immune response is also needed.