• 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.14 no.2
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• pp.174-183
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• 2010

Purpose : The organisms causing peritonitis and their antibiotic sensitivities vary in different regions and centers, and these data are necessary to establish regional treatment guidelines. The aim of this study was to investigate the changes in incidence and characteristics of the organisms that cause peritonitis in children undergoing peritoneal dialysis (PD) during recent 10 years. Methods : We retrospectively collected and analyzed the data from medical records of 110 children on PD during the period from 2000 to 2010. Results : One hundred and forty episodes of peritonitis have occurred in 57 patients. The overall incidence of peritonitis was 0.43 episodes/patient year, and similar incidence have been maintained since 2003. Sixty percent of the patients experienced peritonitis within 1 year of PD, and all patients commencing PD in infancy experienced peritonitis. Gram positive (G (+)), gram negative (G (-)) organisms and fungi were cultured in 58%, 38%, and 4.1% respectively and cultures were negative in 13.6%. Staphylococcus was the most common G (+) organism, and Pseudomonas and Acinetobacter were 2 most frequent G (-) organisms isolated. Fifty-six percent of the G (+) organisms were sensitive to first generation cephalosporin and 91% of G (-) pathogens were sensitive to ceftazidime. Methicillin-resistance rate was not higher in children less than 2 years of age than in those more than 2 years. Conclusion : An additional breakthrough has to be made to further reduce the incidence of peritonitis. Treatment guideline customized for peritonitis in Korean children on PD need to be established through a nationwide co-work.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.166-173
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• 2010

Purpose : Genetic and clinical factors can influence the permeability of the peritoneal membrane. The peritoneal equilibration test (PET) is helpful in measuring peritoneal permeability in peritoneal dialysis (PD). We investigated the influence of genetic polymorphism of vascular endothelial growth factor (VEGF) on the PET parameters. Methods : Pediatric patients who underwent PET within 12 months of initiating PD at Seoul National University Children's Hospital and Samsung Medical Center were selected. The patients with positive history of peritonitis before PET were excluded. The VEGF -2578C/A, -14978T/C, -1154G/A, -634G/C, and +936C/T single-nucleotide polymorphisms were genotyped. Results : The mean 4-hour dialysate-to-plasma ratio for creatinine (D/P creatinine) and the mean 4-hour dialysate glucose to baseline dialysate glucose ratio (D/$D_0$ glucose) were $0.56{\pm}0.13$ and $0.43{\pm}0.11$, respectively. The patients with haplotype CTGGC showed higher 4-hour D/P creatinine ($0.67{\pm}0.12$ vs $0.50{\pm}0.09$, P=0.007) and lower 4-hour D/$D_0$ glucose ($0.35{\pm}0.12$ vs $0.47{\pm}0.08$, P=0.037) than those without haplotype CTGGC. Conclusion : The VEGF genetic polymorphism may influence the peritoneal solute transport.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.154-165
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• 2010

Purpose : We know little about the natural course of IgA nephropathy (IgAN) in association with histologic changes especially in children. We investigated clinicopathologic features with long-term follow-up biopsy to clarify the outcomes and prognostic indicators for childhood IgAN. Methods : From our patients' medical records, we retrieved 20 patients with IgAN, to whom renal biopsies had been performed for the initial diagnosis and follow-up to find out any histologic changes. Initial and follow-up biopsies were classified by Haas classification. The changes of these parameters were compared with the evolution of clinical features. Results : Patients were treated with angiotensin-converting enzyme inhibitors in combination with angiotensin receptor blockers (in subclass II or above) and short-term cyclosporine A(in patients showing nephrotic syndrome). Histologic improvement in 7 cases and deterioration in 3 cases were observed. At the time of last biopsy, 10 cases (50%) showed clinical remission and the others showed improved clinical features. These clinical outcomes did not correlate with initial Haas classifications. Hypertension at onset observed in 5 cases (25%) revealed significant correlation with clinical outcome (P =0.01) and last Haas classification (P =0.007). None of the cases showed progression to CRF or ESRD. Conclusion : During a mean follow-up of $10.8{\pm}3.4$ years, childhood IgAN showed good clinicopathologic outcome. Hypertension at onset was only a strong predictor of clinicopathologic outcomes, but initial Haas classification cannot predict outcomes in children. Histologic change of IgAN in long term follow-up period cannot be completely predicted by clinical data and vice versa. Therefore, a renal biopsy should be considered as a part of follow-up plan.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.170-177
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• 2008

Purpose : The aim of this study was to evaluate whether the incidence of relapse or nephritis might be influenced by the duration of corticosteroid therapy in children with Henoch-Schonlein purpura(HSP). Methods : We retrospectively analyzed 186 children with a diagnosis of HSP in two major hospitals in Ilsan, Korea from the years 2000 to 2003. To evaluate whether renal involvement or relapse might be influenced by the duration of corticosteroid therapy in children with HSP, one pediatric nephrologist from hospital A, maintained corticosteroid therapy for at least 2 weeks(Group A, n=94). The other from hospital B used only during the symptomatic period(Group B, n=92). Results : There were no significant differences in age, sex, body weight, white blood cell count, hemoglobin, hematocrit, platelet count, serum protein and albumin levels between the two groups. The incidence of abdominal pain or arthralgia also did not differ between two groups. However, the duration of steroid therapy was significantly longer in Group A than in Group B and the cumulative dose of prednisolone was also higher in Group A than in Group B. The development of nephritis was more frequent in Group A. Conclusion : The longer duration of steroid use was not associated with the decreased rate of nephritis. Therefore, corticosteroids should be used carefully in a selected group of HSP children, and be tapered rapidly after control of the acute symptoms.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.213-220
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• 2008

Purpose : This study aims to verify the effectiveness of initial empirical antibiotic choice recommended by the International Society for Peritoneal Dialysis(ISPD) guide among Korean children. Methods : We have collected data on peritonitis from January 2001 to December 2007 in Samsung Medical Center. Results : Of the 42 patients, 48 episodes of peritonitis had occurred in 21 patients. The rate of peritonitis was one episode over 35.3 patient-months. Mean dialysis duration before peritonitis was 18.06$\pm$15.81 months. Gram-positive organisms accounted for 58.3% of all episodes. Of the gram-positive organisms, the most common pathogen was Staphylococcus aureus(29.2%), the next common pathogens were Coagulase negative staphylococcus(14.6%) and Streptococcus species(6.3%). 35.7% of gram-positive pathogens were resistant to 1st cephalosporin. However, in patients younger than 4 years old, 50% of gram-positive pathogens were resistant to 1st generation cephalosporin. 10 episodes of peritonitis were methicillin-resistant and were treated by vancomycin. Of the gram-negative organisms, E. coli was the most common (8.3%). 64.8% of all pathogens were sensitive to cephalothin or ceftazidime. Conclusion : The empirical therapy with 1st generation cephalosporin and ceftazidime can be also effective to peritoneal dialysis associated peritonitis in Korean children. However, in patients younger than 4 years old, glycopeptide should be considered as the first empirical therapy in Korean children.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.157-163
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• 2008

Purpose : Several studies have reported the recent increase in the incidence of acute poststreptococcal glomerulonephritis(APSGN). The objective of this study is to see changes of clinical findings/manifwstation in children with APSGN. Methods : Medical records of 63 children who were diagnosed with APSGN in the deparment of Pediatrics, Kyungpook National University Hospital, between January 1992 and December 2006 were reviewed retrospectively. We analyzed various clinical characteristics such as age, sex, degrees of proteinuria, degrees of hematuria, and presence or absence of histories of systemic antibiotic use in children with APSGN, and compared the children with APSGN who were diagnosed between 1992 and 2000 to those who were diagnosed between 2001 and 2006. Results : Age of the patients ranged from 2-14 years(median 7.11 years) at the time of disease onset. Study patients consisted of 41 boys and 22 girls. APSGN followed infection of the throat in 87% of cases. Patient developed an acute nephritic syndrome 12 days after an antecedent streptococcal pharyngitis. Forty patients presented with gross hematuria. Fortyone patients had hypertension at the time of diagnosis. Hypertension disappeared within 7.8$\pm$8.2 days, gross hematuria within 11.3$\pm$17.2 days and microscopic hematuria within 3.5$\pm$3.9 months from the disease onset. Patients in 2001-2006 had significantly higher increase of antistreptolysin O(ASO) titer. However, no significant differences in clinical characteristics were observed. Age, sex, severity of proteinuria, gross or microscopic hematuria, antibiotic therapy did not affect the clinical manifestations of glomerulonephritis. In other words, hypertension, duration of hematuria, recovery of serum C3 level are not different between the two time periods. Conclusion : Our data indicates that patients in 2001-2006 had significantly higher level of ASO titer. However, they did not show significant clinical differences. To evaluate the causes of the resurgence of APSGN, a national epidemic is needed.

• 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.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.

• Clinical and Experimental Pediatrics
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• v.45 no.10
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• pp.1213-1218
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• 2002

Purpose : Hydronephrosis constitutes a great portion of fetal anomalies screened by prenatal sonogram. The present authors made an attempt to access its natural courses through follow up neonatal hydronephrosis diagnosed by prenatal sonogram. Methods : The study was composed of 23 neonates(36 renal units) who were diagnosed with hydronephrosis through prenatal sonogram screening and confirmed 3-7 days after birth with sonographic evaluation at Kyung Hee University Hospital. The neonates were closely monitored for 12-24 months with renal sonogram, diuretic renogram, intravenous pyelography(IVP) and voiding cystoureterography(VCUG). Results : The underlying diseases were composed of 16 cases(44%) of functional abnormalities, 14 cases(39%) of ureteropelvic junction(UPJ) obstruction, three cases(8%) of vesicoureteral reflux (VUR) and on case each of multicystic dysplastic kidney, UPJ obstruction with ureteral stenosis and ureterovesical junction(UVJ) obstruction with VUR. The degree of hydronephrosis was divided into three classes according to its severity. In 30 renal units with UPJ obstruction and functional abnormalities, 26(87%) showed mild hydronephrosis, while four(13%) were moderate. During the follow up period, six cases(20%) showed natural resolution of hydronephrosis, 15 cases(50%) showed improvement while two cases(7%) were aggravated with improvement only after surgery of the underlying disease. The cases which showed natural resolution were all mild hydronephrosis at diagnosis and the cases which underwent surgery due to continuous aggravation were mild one case and moderate one case. Conclusion : Those with cases of mild hydronephrosis show rapid natural improvement. On the other hand, in some cases, follow up monitoring reveal aggravation of the situation, emphasizing the necessity for thorough follow up for a long period of time.