• Childhood Kidney Diseases
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• v.13 no.1
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• pp.56-62
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• 2009

Purpose : The aim of this study was to evaluate the clinical usefulness of measurement of ${\beta}_2$ microglobulin (${\beta}_2$ MG), N-acetyl-$\beta$-D-glucosaminidase (NAG) of spot urine samples as indices of renal tubular damage and microalbumin of spot urine samples as a parameter of glomerular damage in children with vesicoureteral reflux (VUR) or renal defects. Methods : We studied 91 children with previous UTI. The children were classified as 62 children without VUR and renal defects (group I), 10 children with VUR, without renal defects (group II), and 19 children with VUR and renal defects (group III). Patients having VUR were separated according to the degree of VUR (mild VUR: VUR grade I-III, severe VUR: VUR grade IV-V). Urinary excretion of ${\beta}_$ microglobulin (${\beta}_2$ MG), microalbumin, N-acetyl-$\beta$-D-glucosaminidase (NAG), creatinine were measured in samples of morning urine specimens. Children with VUR or renal defects detected by voiding cystourethrography (VCUG) and DMSA renal scan were investigated. Results : Microalbumin/Cr ratio of spot urine was significantly increased in group III compared group I ($42.3{\pm}27.2\;mg/gCr$ vs $25.2{\pm}10.9\;mg/gCr$, P<0.05). NAG/Cr ratio of spot urine was significantly increased in group II compared group I ($3.70{\pm}23.4\;mg/gCr$ vs $18.7{\pm}12.7\;mg/gCr$, P<0.05). There was no statistically significant difference of ${\beta}_2$ MG/Cr ratio among three groups. Conclusion : Urinary microalbumin excretion of morning urine sample may be a simple and reliable clinical indicators for early identification of renal damage in children with VUR and renal defects. Urinary microalbumin excretion may be useful marker to predict the the severity of VUR.

• Childhood Kidney Diseases
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• v.13 no.1
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• pp.40-48
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• 2009

Purpose : This study was performed to identify factors related to the resolution of primary vesicoureteral reflux (VUR) in infants. Methods : We reviewed 183 infants (M : F=149 : 34) diagnosed as urinary tract infection (UTI) between February 2002 and July 2007 at Sanggye Paik Hospital. The diagnosis of UTI was made by culture from a urine specimen obtained by suprapubic puncture (n=97), catheterization (n=83), or collection bag method (n=3, twice positive culture of same organism). All of the infants were performed renal ultrasonography, DMSA scan and voiding cystourethrography (VCUG) study. Follow-up imaging consisted of contrast VCUG or direct isotope VCUG at interval of 1 year. We evaluated the relationship of clinical and laboratory finding, radiologic finding in infants with VUR. Results : Among 51 VUR patients, 18 infants had grade I-II, 12 infants had grade III and the other 21 patients had grade IV-V. Abnormal findings including hydronephrosis on renal ultrasonography were not correlated with severity of VUR. However, the incidence of renal defect in the first DMSA scan showed a tendency of direct correlation with severity of VUR in female patients only (P<0.001). There was significant difference of resolution rate in three VUR groups (grade I-II, III, IV-V) in male patients only (P=0.025). Resolution rate was higher for male patients with unilateral VUR than bilateral (P<0.001). But unilaterality had not any affect on VUR resolution in female VUR patients (P=0.786). Resolution rate was higher for VUR patients without renal scar than VUR patients with renal scar (P<0.001). Conclusion : According to our findings, grade of VUR, laterality and renal scar are the factors that contribute to resolution of primary VUR in male and female infants differently.

• Childhood Kidney Diseases
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• v.13 no.2
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• pp.229-234
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• 2009

Purpose : The aim of this study was evaluating the efficacy of endoscopic $Deflux^{(R)}$ submucosal injection in children with primary vesicoureteral reflux (VUR). Methods : Retrospective analysis of medical record was conducted on 38 children (59 ureters) who underwent endoscopic $Deflux^{(R)}$ injection due to primary VUR. Data were collected from March 2000 to February 2006. Mean infused amount of $Deflux^{(R)}$ was 0.77 cc. After $Deflux^{(R)}$ injection, patients were reassessed by voiding cystourethrogram (VCUG) 6 months later. Results : The success rate of endoscopic $Deflux^{(R)}$ submucosal injection 6 months later by VCUG was 100% for grade 1 VUR, 87.5% for grade 2, 60% for grade 3, 26.6% for grade 4, 16.6% for grade 5, respectively and there was negatively significant correlation between success rate and grade of VUR (P<.01). Degree of improvement of VUR by endoscopic $Deflux^{(R)}$ submucosal injection was not related to age at diagnosis, time to operation, existence of voiding dysfunction or constipation and infused amount of $Deflux^{(R)}$. However, group with anticholinergics medication had significantly lower success rate than non-medication group (P<0.047). Conclusion : Endoscopic $Deflux^{(R)}$ submucosal injection is effective therapy in patient with primary VUR, especially low grade VUR. It can be not only a useful substitute for prophylaxis with antibiotics, but also an effective management prior to ureteroneocystostomy in children with primary VUR.

• Childhood Kidney Diseases
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• v.13 no.2
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• pp.215-221
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• 2009

Purpose : Thymus is a lymphoproliferative organ that changes size in various physiological states in addition to some pathological conditions. Thymus is susceptible to involution, and shows a dramatic response to severe stress. Thymic measurements may be helpful in various diseases. UTI (urinary tract infection) is most common bacterial infection in infants and VUR (vesicoureteral reflux) is a common abnormality associated with UTI. In our study, the size of thymus was compared on the premise that a greater stress is exerted on the body when UTI is accompanied by VUR, than when occurs on its own. Methods : Thymic size was measured on standard chest anteroposterior radiographs and expressed as the ratio between the transverse diameter of the cardiothymic image at the level of the carina and that of the thorax (CT/T). The medical records of 99 febrile urinary tract infection infants without other genitourinary anomalies except VUR were reviewed retrospectively. Results : Among 99 patients with febrile UTIs, 25 were febrile UTI without VUR and 74 with VUR. For the UTI with VUR group, there was a significant decrease in the thymic size compared to the those without VUR group ($0.382{\pm}0.048$ vs $0.439{\pm}0.079$, P<0.05). However, there were no differences in the duration of fever and WBC, CRP between the UTI with VUR and UTI without VUR. In addition, there were no differences in the cardiothymic/thoracic ratios between renal defects and renal scars in febrile UTI patients. Conclusion : The results of this study show that the shirinkage of thymus was more frequently found in the UTI patients with VUR. Therefore, awareness of the risks associated with thymic size is important for the appropriate work up and management of UTI patients.

• Childhood Kidney Diseases
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• v.15 no.2
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• pp.163-171
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• 2011

Purpose : To evaluate the prevalence of vesicoureteral reflux (VUR) according to the timing of voiding cystourethrography (VCUG) in infantile urinary tract infection (UTI). Methods : The data of 134 infants (1-12 months) with renal cortical defect in $^{99m}Tc$-2, 3-dimercaptosuccinic acid ($^{99m}Tc$-DMSA) scan with a diagnosis of UTI in two hospitals from 2000 to 2010 were retrospectively analyzed. The VCUG was performed after 2 weeks from the diagnosis of UTI in Group I (n=68), and the VCUG was performed within 2 weeks from the diagnosis of UTI in Group II (n=66). Results : There were no significant differences between the two groups in the duration of fever, white blood cell count, C-reactive protein levels, and abnormalities in ultrasonography (P>0.05). There was no significant difference between the two groups in the prevelence of VUR, bilateral VUR, and severe VUR. VCUG-induced UTI was detected 16 (23.5%) of patients in whom the procedure was performed 2 weeks after the diagnosis, and none of VCUG-induced UTI occurred in those in whom the procedure was performed 2 weeks within the diagnosis. Conclusion : We conclude that the prevalence of VUR according to the timing of VCUG did not differ between the two groups in infantile UTI with renal cortical defect in DMSA scan. We also found that performing VCUG with antibiotics can decrease risk of VCUG-induced UTI.

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.62-69
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• 2008

Purpose: The most concerning issue in children with urinary tract infection(UTI) is the probability of underlying genitourinary anomalies and vesicoureteral reflux (VUR), which is frequently associated with renal scarring and eventually end-stage renal disease. Therefore, voiding cystourethrography(VCUG) is usually recommended at the earliest convenient time for children with UTI. However, VCUG is an invasive procedure that requires catheterization and exposure to X-ray. In this study, we aimed to determine the predictability of clinical, laboratory and imaging parameters for VUR in children with UTI. Methods: Data of children with bacteriologically proven UTI who underwent VCUG were evaluated retrospectively for clinical(age, gender, fever), laboratory(leukocytosis, ESR, CRP, pyuria, blood urea nitrogen, serum creatinine) and imaging(renal ultrasound and DMSA renal scan) findings. First, children with UTI were divided into two groups according to the presence of VUR as non-VUR group and with VUR group, and clinical, laboratory variables were compared between these groups. Second, patients who had VUR were reclassified as low-grade VUR(grade I-II) group and high-grade(grade III-V) VUR group according to grading of VUR, and clinical, laboratory and imaging variables were compared between these groups. Results: Among 410 children with UTI, 137 had VUR and 78 high-grade VUR. Fever, leukocytosis, ESR, CRP, pyuria were associated with VUR. In addition, abnormal findings of ultrasonography and DMSA renal scan were closely related to VUR. However, these clinical and laboratory variable in patients with high grade VUR were not different significantly, compared to those with low-grade VUR group. Conclusion: Fever, leukocytosis, ESR, CRP seems to be potentially useful predictors of VUR in pediatric patients with UTI. In addition, renal ultrasonography and DMSA renal scan findings supported the presence of VUR. Further study of these findings could limit unnecessary VCUG in patients with UTI.

• Childhood Kidney Diseases
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• v.7 no.1
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• pp.44-51
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• 2003

Purpose : Acute pyelonephritis in children may result in permanant renal damage which later in life may lead to hypertension and renal failure. The purpose of this study was to evaluate the factors that might be useful for predicting the development of renal scar in children with urinary tract infection(UTI). Methods : We retrospectively reviewed 442 patients with UTI who were admitted to the Department of Pediatrics of Chonbuk National University Hospital, during the period from April 1992 to March 2002. The patients were divided into two groups according to the presence of renal scar on the follow-up DMSA renal scan, and we compared the factors associated with renal scarring between the two groups. Results : There were no significant differences in sex, causative organism and acute phase reactants between the groups with and without renal scar. The age at diagnosis was significantly higher in the renal scar group compared to that without scar. Of the 60 patients with renal scar, 78% had vesicoureteral reflux(VUR), but 13% of patients without scar had VUR. Furthermore, the severity of VUR was significantly correlated with renal scar formation. 53% showed multiple cortical defects on the initial DMSA renal scan, compared to 32% in the non-scar group. In addition, 76% of patients showing multiple cortical defects on the initial DMSA renal scan with VUR had renal scar. Conclusion : The presence and grade of VUR, and findings on the initial DMSA renal scan would contribute to predict risk of renal scar formation in children with UTI.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.178-185
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• 2008

Purpose : Our aim was to investigate the predictive factors for detecting grade III-V vesicoureteral reflux(VUR) in young infants less than 3 months with urinary tract infections (UTI). Methods : Data of infants who underwent ultrasonography and VCUG between January 2004 and September 2007 were reviewed. Age, gender, incidence of bacteremia, C-reactive protein(CRP) and imaging studies were compared between group I(grade III-V VUR) and group II (normal or grade I and II VUR) retrospectively. Sensitivity, specificity, positive and negative predictive values, odds ratio, and likelihood ratio of ultrasonography for high grade VUR were evaluated. Results : Among 54 enrolled infants(41 males, 13 females), 14 infants were group I and 40 infants were group II. In the group I, CRP level was significantly higher(6.11$\pm$5.18 vs. 3.27$\pm$3.45, P=0.025), and there were more ultrasonographic abnormal findings(71.4%, vs. 22.5%, P=0.002) compared with group II. However, ultrasonography was the only significant factor after adjusting with logistic regression(P=0.002). Incidence of bacteremia and abnormal DMSA findings were not significantly different in two groups. Sensitivity, specificity, and odds ratio of ultrasonography was 71.4%, 77.5%, 6.9 respectively. Negative predictive value was 88.6% and negative likelihood ratio was 0.37. Ultrasonography had significant negative likelihood ratio for grade III-V VUR, but missed 4 infants with grade III VUR. Conclusion : We could not find any alternative predictive factors to reduce VCUG in detecting high grade VUR. Therefore, VCUG must be considered in young infants less than 3 months with UTI.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.46-55
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• 2005

Purpose : Recurrent urinary tract Infection(UTI) in primary vesicoureteral reflux(VUR) may lead to serious renal scarring, a major cause of childhood hypertension and end-stage renal disease. To prevent recurrent UTI, low-dose long--term antibiotic prophylaxis has been recommended. However, recurrent UTI still develops during antibiotic prophylaxis, the efficacy of which is now being disputed. The emergence of resistant bacteria has also raised concerns. To evaluate the effect of antibiotic prophylaxis, we investigated recurrent UTI during prophylactic antibiotic use in children with primary VUR Materials : The incidence and risk factors of recurrent UTI were retrospectively evaluated in ninety-one children with primary VUR on trimethoprim- sulfamethoxazole(TMP/SMX) prophylafis during the year following their index febri]e UTI. Results : Recurrent UTI occurred in 31.9%(29/91) children and comprised 0.32 episodes/patient year. Febrile UTI was 0.26 episode/patient year and afebrile UTI was 0.07 episodes/patient year. The recurrent rate of UTI in male patients with phimosis was 37.2%(19/51), which was significantly higher than in males without phimosis 0%(0/5)(P=0.025). In the logistic regression analysis for recurrent UTI, renal scar was the significant risk factor for recurrent UTI [RR 3.8(95% CI 1.0-14.1) P=0.04]. For other well-known risk factors such as sex, age, degree of VUR, APN, and voiding dysfunction, the differences were not significant. Conclusion : TMP/SMX prophylaxis did not prevent recurrent UTI in children with primary VUR. Phimosis and renal scars were the risk factors for recurrent UTI but the grade of primary VUR was not. In VUR without phlmosis and renal scar, a randomized controlled study without antibiotic prophylaxis is required. (J Korean Soc Pediatr Nephrol 2005;9:46-55)

• Childhood Kidney Diseases
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• v.5 no.1
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• pp.15-21
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• 2001

Purpose : Urinary tract infections (UTIs) of children require prompt and correct diagnosis and treatment to reduce the risk of renal damage. As a first step to improve the outcome of UTI in Korea, we investigated the practical variations in the methods of diagnosis, treatment, and evaluation of children with UTI and UTI prevention. Method :A questionnaire related to the individual policy on UTI diagnosis. treatment, imaging test, and prevention was submitted to 26 experts. Result Majority of the experts used bag-collected urine specimen for infants and mid-stream urine specimen for children for urinary culture. With a negative result of culture study, they diagnosed UTI when there was pyuria, positive results of the nitrite test, or bacteriuria. 80 $\%$ of experts prescribed prophylactic antibiotics after upper tract UTI. Operative treatment of vesicoureteral reflux (VUR) was indicated for children older than one or two years old with high-grade VUR, refractory breakthrough infections, or recurrent UTIs. Most of them performed kidney ultrasonography on the diagnosis of UTI and more than half of them evaluated children treated of UTI with vesicocystourethrogram and/or DMSA scintigraphy. Majority did not recommend circumcision. Half of the experts were screening siblings of VUR patients. Conclusion : Considering the variations exposed through this study systematic guidelines for management of children with UTI in Korean would be necessary. (J. Korean Soc Pediatr Nephrol 5 : 15-21, 2001)