• Childhood Kidney Diseases
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• v.11 no.1
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• pp.24-31
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• 2007

Purpose : Nitric oxide(NO) is a very potent vasodilator synthesized from L-arginine by endothelial cells. We investigated whether urinary NO excretion was altered in various renal diseases in children and whether urinary NO excretion could be used in predicting pathologic causes and fibrosis in renal diseases in children. Methods : We recruited 48 patients(32 minimal change nephrotic syndrome[MCNS] and 16 vesicoureteral reflux[VUR] patients from the pediatric renal clinic in Korea University Guro Hospital. We measured the concentration of nitrite$(NO_2)$ and nitrate$(NO_3)$ by Griess reaction and that of creatinine(Cr) by Jaffe method in randomized spot urines. We then analyzed the urinary$(NO_2+NO_3)/Cr$ ratios and compared the values between each patient group. Urinary $(NO_2+NO_3)/Cr$ ratios were also evaluated according to the recurrence and the degree of proteinuria at sampling in the MCNS group and compared according to the presence of renal scarring and the grade of reflux in the VUR group. Results : The ratios of urinary$(NO_2+NO_3)/Cr$ were significantly increased in the VUR and MCNS groups, as compared to the control group. In the MCNS group, a higher level of urine $(NO_2+NO_3)/Cr$ was observed In frequent relapse patients(relapse over four times within one year after first diagnosis) and the patients with severe proteinuria at sampling, respectively. The VUR group with renal scars also showed a higher level of urinary$(NO_2+NO_3)/Cr$ compared to that without scars. Conclusions : In summary, VUR may play a role in the pathogenesis of VUR and MCNS. NO also seems to affect proteinuria and renal scar formation. (J Korean Soc Pediatr Nephrol 2007;11:24-31)

• Childhood Kidney Diseases
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• v.5 no.1
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• pp.30-35
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• 2001

Purpose : To evaluate tile frequency of urinary tract anomalies in male neonates less than 3 months old who presented with urinary tract infection(UTI) and to evaluate a appropriate imaging approach after first UTI. Materials and methods : During a period of 5 years from March 1994 to February 1999, 65 male infants less than 3months old(range: 4-92 days, mean: 43 days) with UTI were evaluated. Ultrasound(US) and Voiding cystourethrogram(VCUG) were done in 60 patients. Due to refusal and technological problem, 5 patients were missed. 99mTc-dimercaptosuccinic acid renal scan (99mTc-DMSA renal scan) was recommended to most patients but performed in 40 patients. Renal scan was performed at least 3 months later after urinary tract infection. Results : Urinary tract anomalies were found in 26 of 65 infants. Twenty-six had vesicoureteral reflux(VUR), two had both VUR and double ureter, two had both U and posterior urethral valve. In patients with VUR, eight had renal scar or renal atrophies. In case of renal scar or atrophy, grades of VUR were III or above. Conclusion : We suggest that US and VCUG should be routinely performed in infants(<3months)with first UTI. 99mTc-DMSA renal scan should be performed only when renal parenchymal damage was observed in US and VUR grade III or above in VCUG. (J. Korean Soc Pediatr Nephrol 5 : 30- 5, 2001)

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.194-200
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• 2015

Purpose: Urinary tract infection (UTI) is a common bacterial infection in children and Escherichia coli is a predominant pathogen. The purpose of this study is to evaluate phylogenetic groups and virulence factors of E. coli causing UTI in children in Korea. Methods: From October 2010 to April 2013, urinary E. coli strains were isolated from the 33 pediatric patients of UTI. Multiplex polymerase chain reactions were performed to evaluate the phylogenetic groups and 5 virulence factor genes (fimH, sfa, papA, hylA, and cnf1) of E. coli. Distribution of molecular characteristics of E. coli was analyzed by clinical diagnosis and accompanying vesicoureteral reflux (VUR). Results: Most (84.8%) uropathogenic E. coli were belonged to phylogenetics group B2 and the others (15.2%) were belonged to group D. The virulence factors were distributed as: fimH (100%), sfa (100%), hylA (63.6%), cnfI (63.6%), and papA (36.4%). According to clinical diagnosis, phylogenetic distribution of E. coli strain was 92.3% of B2 and 7.7% of D in acute pyelonephritis and 57.1% of B2 and 42.9% of D in cystitis. Distribution of virulence factors was similar in both groups. In patients with acute pyelonephritis, phylogenetic distribution was similar in VUR and non-VUR group, but proportion of papA genes were lower in VUR group than that of non-VUR group (43.8% vs. 20.0%, P=0.399). Conclusions: This study provides current epidemiologic molecular data of E. coli causing pediatric UTI in Korea and will be a fundamental for understanding the pathogenesis of pediatric UTI.

• Childhood Kidney Diseases
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• v.19 no.2
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• pp.56-64
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• 2015

To revise the clinical guideline for childhood urinary tract infections (UTIs) of the Korean Society of Pediatric Nephrology (2007), the recently updated guidelines and new data were reviewed. The major revisions are as follows. In diagnosis, the criterion for a positive culture of the catheterized or suprapubic aspirated urine is reduced to 50,000 colony forming uits (CFUs)/mL from 100,000 CFU/mL. Diagnosis is more confirmatory if the urinalysis is abnormal. In treating febrile UTI and pyelonephritis, oral antibiotics is considered to be as effective as parenteral antibiotics. In urologic imaging studies, the traditional aggressive approach to find primary vesicoureteral reflux (VUR) and renal scar is shifted to the targeted restrictive approach. A voiding cystourethrography is not routinely recommended and is indicated only in atypical or complex clinical conditions, abnormal ultrasonography and recurrent UTIs. $^{99m}Tc$-DMSA renal scan is valuable in diagnosing pyelonephritis in children with negative culture or normal RBUS. Although it is not routinely recommended, normal scan can safely avoid VCUG. In prevention, a more natural approach is preferred. Antimicrobial prophylaxis is not supported any more even in children with VUR. Topical steroid (2-4 weeks) to non-retractile physiologic phimosis or labial adhesion is a reasonable first-line treatment. Urogenital hygiene is important and must be adequately performed. Breast milk, probiotics and cranberries are dietary factors to prevent UTIs. Voiding dysfunction and constipation should be properly treated and prevented by initiating toilet training at an appropriate age (18-24 months). The follow-up urine test on subsequent unexplained febrile illness is strongly recommended. Changes of this revision is not exclusive and appropriate variation still may be accepted.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.2
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• pp.89-94
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• 2013

Purpose: The aim of this study was to evaluate the prevalence of increased aminotransferase levels and to identify associated factors in children admitted to hospital with urinary tract infections (UTIs). Methods: The study included children with a diagnosis of UTI who were admitted to the Konyang University Hospital from January 2007 to May 2011. The total number of patients was 249 and the mean age was $15.88{\pm}28.21$ months. UTI was defined as a positive urine culture (> $10^5$/colony forming unit [CFU]) with pyrexia. Patients were treated by intravenous antibiotics, such as ampicillin/sulbactam, aminoglycoside, cephalosporins or vancomycin. Patients with neonatal jaundice or other liver disease were excluded. We investigated the relationship of aminotransferase levels with the type of antibiotic, degree of vesicoureteral reflux (VUR), and causative organisms. Results: Children with increased aminotransferase levels were younger than those with normal levels (p=0.001), but white blood cell count, platelet count, causative organisms, type of antibiotics and presence of VUR were not associated with aminotransferase levels. Aminotransferase levels became normal within 1 month after discharge without special measures, except in 1 case. Conclusion: We found that many children with UTI have abnormal aminotransferase levels. In most cases, this change is mild and self-limiting. We conclude that increased aminotransferase level increase during UTI do not require unnecessary tests and excessive treatment.

• Clinical and Experimental Pediatrics
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• v.64 no.6
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• pp.293-300
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• 2021

Background: Understanding the epidemiology and prevalence of febrile urinary tract infection (fUTI) in children is important for risk stratification and selecting appropriate urine sample collection candidates to aid in its diagnosis and treatment. Purpose: This study aimed to analyze the epidemiology, etiology, and changes in antibiotic susceptibility patterns of the first fUTI in children. Methods: This retrospective observational cohort study included children younger than 19 years of age who were diagnosed and treated for their first fUTI in 2006-2016. Electronic medical records were analyzed and radiologic images were evaluated. Results: A total of 359 patients (median age, 5.1 months; interquartile range, 3.0-10.5 months) fit the inclusion criteria; of them, 78.0% (n=280) were younger than 12 months old. The male to female ratio was 5.3:1 for patients aged 0-2 months, 2.1:1 for those 3-5 months, and 1.6:1 for those 6-11 months. Beyond 12 months of age, there was a female predominance. Escherichia coli was the leading cause (83.8%), followed by Enterococcus species (6.7%), and Klebsiella pneumoniae (3.6%). Significant yearly increases in the proportions of multidrug-resistant strains (P<0.001) and extended-spectrum beta-lactamase (ESBL) producers (P<0.001) were observed. In patients with vesicoureteral reflux (VUR), the overall recurrence rate was 53.6% (n=15). A significantly higher recurrence rate was observed when the fUTI was caused by an ESBL versus non-ESBL producer (75.0% vs. 30.0%, P=0.03). Conclusion: fUTI was most prevalent in children younger than 12 months of age and showed a female predominance in patients older than 12 months of age. The proportion of ESBL producers causing fUTI is increasing. Carbapenems, rather than noncarbapenems, should be considered for treating fUTI caused by ESBL-producing enteric gram-negative rods to reduce short-term recurrence rates in children with VUR.

• Childhood Kidney Diseases
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• v.11 no.1
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• pp.83-91
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• 2007

Purpose : Childhood primary VUR is generally diagnosed after urinary tract infection, is more prevalent among girls and has a low spontaneous resolution rate in cases of severe VUR. The aim of the present study is to examine the age and gender-related characteristics and the spontaneous resolution rate of infantile primary VUR. Methods : The medical records of 96 infants with primary VUR, diagnosed after their first UTI, were retrospectively reviewed(1995-2004). The clinical characteristics including gender, the degree of VUR and presence of renal scars were evaluated. The spontaneous resolution rate and contributing factors were also analyzed Results : Infantile primary VUR was more prevalent in males than females. The percentage of atrophic scarred kidney was significantly higher in males than females(17.2% vs 3.4%) (P<0.05). The cumulative spontaneous resolution rate in 3 years was very high(89.1%), and was not significantly different between gender and among VUR grades. But in the first year, the spontaneous resolution rate of severe refluxing ureters was significantly higher in males than in females(46.2% vs 7.1%)(P<0.05) and the spontaneous resolution rate of refluxing ureters with no scarred kidneys was significantly higher than those associated with atrophic scarred kidneys(76.6% vs 20%)(P<0.05). Conclusion : Infantile Primary VUR was more prevalent among males and tends to be associated with atrophic scarred kidneys In male infants. The cumulative spontaneous resolution rate in 3 years was very high, even in high-grade VUR and associated atrophic scarred kidneys. In infantile primary VUR, surgery should be withheld even in infants with high-grade VUR with atrophic scarred kidneys.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.194-201
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• 2008

Purpose : Voiding cystourethrography(VCUG) is required to detect vesicoureteral reflux(VUR), which may manifest as urinary tract infection(UTI) in children. It is well known that VCUG can cause UTI(post-VCUG UTI). In this study, risk factors for post-VCUG UTI and the preventive effect of antibiotics against this complication of VCUG were explored. Methods : Medical records of 284 patients who underwent VCUG at our hospital in 2007 were reviewed retrospectively. The incidence of post-VCUG UTI and risk factors for post-VCUG UTI, and the impact of antibiotic use on prevention of post-VCUG UTI were evaluated. According to antibiotics usage, we divided the enrolled patients into 4 groups of noantibiotics group, prophylactic antibiotics group(prophylactic antibiotics having been used before), antibiotics-for-VCUG group(antibiotics added for VCUG) and antibiotics-for-treatment group(treatment dose of antibiotics). Results : Seven of 284 children(2.5%) developed UTI after they underwent VCUG. Highgrade(grade$\geq$III) VUR was the only statistically significant risk factor(odds ratio[OR] 6.266, P=0.026) for post-VCUG UTI, while sex, age, and other anomalies of urinary system were not significant. Five post-VCUG UTI cases belonged to prophylactic antibiotics group. Antibiotics use (three groups using antibiotics vs. no-antibiotics group) or addition of antibiotics for VCUG (antibiotics-for-VCUG vs. other groups) did not have any effect on prevention of post-VCUG UTI. Conclusion : The risk factor for post-VCUG UTI was high-grade VUR. Antibiotics use did not prevent post-VCUG UTI in this study.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.184-194
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• 2010

Purpose : The aim of this study was to evaluate the incidence of febrile urinary tract infection (UTI) according to clinical characteristics in patients with congenital hydronephrosis (CH) and hydronephrotic patients first diagnosed with hydronephrosis during treatment of febrile UTII. Methods : In this study, 200 patients with congenital hydronephrosis were enrolled in group 1 and 252 patients first diagnosed with hydronephrosis during treatment of febrile UTI were enrolled in group 2. We counted the episodes of UTI in the two groups according to clinical characteristics, the presence of VUR, type of feeding, and clinical outcomes since 2000. And we compared those results between the two groups. and compared two groups as well. Results : The incidence of recurrent UTI was 10%, 0.028 per person-year in group 1 and 16.7%, 0.051 per person-year in group 2, respectively (P <0.05). Group 2 had more VUR (3% vs. 27%, P <0.05) and higher incidence of UTI than group 1. The incidence of UTI in patients with CH of Society of Fetal Urology (SFU) grade 4 or grade 4-5 VUR was 80% and 44.4%, respectively. No significant differences were found in incidence of UTI between BMF (breast milk feeding) and artificial milk feeding group in both groups (P 1=0.274, P 2=0.4). The time of resolution of CH had no correlation with either number of UTI episodes or the presence of VUR. Conclusion : The overall incidence of UTI is low in patients with CH as well as patients patients first diagnosed with hydronephrosis during treatment of febrile UTI except patients with SFU grade 4 or grade 4-5 VUR. BMF has no protective effect against UTI.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.176-181
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• 2001

Purpose : Urinary tract infection is a common problem in children. To evaluate for reflux most authorities recommend a voiding cystourethrogram 3 to 6 weeks after the first urinary tract infection. But during the 3 to 6 weeks interval, patients may fail to show up for the scheduled VCUG and thus risk for loss of follow up. We analyzed patient's records to evaluate whether the timing of VCUG after UTI influenced the prevalence or severity of VUR. Methods : We retrospectively reviewed 213 children diagnosed with UTI from March 1997 to December 2000. These children were divided into 2 groups according to whether they had VCUG scheduled to be performed either within 1 weeks after the diagnosis of UTI (Group A) or later than 1 week after the diagnosis(Group B). We compared tile presence and severity of reflux in the 2 groups. Results : Reflux was present in $19\%$ of the patients studied within 1 week after UTI and in $18\%$ of those studied after 1 week. This difference was not statistically significant. Whereas $100\%$ of the scheduled VCUGs in the Group A were performed, only $48\%$ of those scheduled in the Group B were performed. This difference is statistically significant. Conclusion : Because there was no significant difference between the presence or severity of reflux and timing of VCUG after UTI, we suggest that a hospitalized patient with UTI should have VCUG performed before discharge. (J. Korean Sor Pediatr Nephrol 2001 ;5 : 176-81)