• Childhood Kidney Diseases
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• v.8 no.1
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• pp.33-42
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• 2004

Purpose : Children with nephrotic syndrome(NS) are under high risk for metabolic bone disease(MBD) as a complication of long-term glucocorticoid therapy. We prospectively evaluated the effect of oral bisphosphonate(alendronate) therapy in children with NS, which has proven efficacy in adult patients with glucocorticoid induced MBD. Methods : Among 58 children with NS, aged 5 to 8 years and haying a disease duration of more than 2 years, 30(51.7%) were enrolled to meet the selection criteria, less than -1.0 Z-scores of lumbar spine bone mineral density(BMD) by dual energy X-ray absorptiometry (DEXA). These 30 children were divided into three groups and each were assigned to receive alendronate, calcitriol, and no-medication, respectively for one year. Lumbar spine BMD was followed up every 6 months and the biochemical indexes were measured before and 1 year after the treatment. There were no significant difference among groups with respect to the average age, the initial BMD, and the cumulative steroid doses. Analysis of the treatment efficacy was done by the % change of BMD and by the changes in Z-scores of lumbar spine BMD. Results : Mean age and disease duration of patients at the initial lumbar spine BMD evaluation was $7.4{\pm}1.7$ years and $2.2{\pm}1.2$ years, respectively. Twenty-three of 30 children(76%) had osteopenia, and seven(23%) had osteoporosis. There was no difference in the biochemical values among the groups, before and 1 year after the treatment(P<0.05). Twenty two children(73.3%) with frequent relapsing or steroid dependant NS had more frequent MBD, compared to the 8 children(26.6%) with infrequent relapsing NS. The one year % changes of BMD were 8.56 in alendronate group, 5.79 in calcitriol group, and 1.9 in no-medication group. The changes in Z-score of lumbar spine BMD increased in the alendronate group and the calcitriol group, but not in the no-medication group. One year % changes of BMD were different among groups(P=0.0002). Significant differences were found between the alendronate and the no-medication group, and between the calcitriol and the no-medication group(P<0.05). There was no difference between the alendronate and the calcitriol group. No serious adverse effect was observed in the alendronate group. Conclusion : Children with NS receiving high dose steroids are under the high risk of BMD and should undergo regular BMD evaluation. Z-score of lumbar spine BMD was a useful parameter in diagnosing low bone mass in children. Alendronate weekly oral therapy was effective and relatively safe in increasing the lumbar spine BMD in children with NS having steroid induced MBD.

• Childhood Kidney Diseases
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• v.7 no.1
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• pp.60-66
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• 2003

Purpose : Neonatal hydronephrosis has been detected with increasing frequency with the widespread use of prenatal ultrasonography, but the consensus about its postnatal management has not yet been reached, especially about surgical intervention. We attempted to determine the guideline of follow-up study and surgical intervention of hydronephrosis by analyzing clinical outcomes of neonates with hydronephrosis. Materials and Methods : Between 1994 and 2000, 128 hydronephrotic kidneys were postnatally confirmed. Cases associated with other urologic anomalies were excluded and 90 unilateral hydronephrotic kidneys with a minimum follow-up of 12 months were enrolled in this study. We classified the patients into 6 groups according to the anterior posterior pelvic diameter(APPD) at initial ultrasonography(USG) within 1 month after birth. Renal USG and $Tc^{99m}-mercaptoacetyl$ triglycerine(MAG3) scan were done according to a set protocol, and pyeloplasty was performed when indicated according to our protocol. Results : Most cases whose APPD were below 10 mm improved or resolved. Only few cases with APPD above 20 mm showed spontaneous improvement and most(88%) had undergone operation. Those with initial APPD within 10-19 mm showed variable outcomes. When the risk factors for irreversible renal functional deterioration were analyzed, the age at pyeloplasty and pre-operative functional deficit were significant. Conclusion : We concluded that in infants with initial APPD below 10 mm, consideration of surgery is not needed, and in those with initial APPD above 20 mm, early operation is recommended. Our set protocol based on initial USG is useful, but the cut-off value of relative renal function(RRF) for operation might be increased to 40% to improve post operative RRF.

• Childhood Kidney Diseases
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• v.16 no.2
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• pp.73-79
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• 2012

Purpose: The association of mitochondrial DNA (mtDNA) mutations, deletions and copy number with progressive changes in patients with some glomerular disease and end-stage renal disease have been reported. In this study, we performed mtDNA mutation analysis in children with IgA nephropathy to investigate its role in progressive clinical course. Methods: Seven children with IgA nephropathy were involved in this study. MtDNA isolated from platelet was amplified by PCR and sequenced entirely. Results: The mean age at renal biopsy was $11.5{\pm}2.2$ year and the mean age at latest evaluation was $17.9{\pm}3.2$ year. The mean follow-up period were $7.8{\pm}3.1$ years. Patients was divided into 2 groups according to the amount of proteinuria at presenting manifestation. Group 2 patients were nephrotic syndrome. Renal function reveals within normal range in all patients. In group 2 patients, the mean serum albumin level was significantly lower than those of group 1 ($3.7{\pm}0.6g/dL$ vs. $4.7{\pm}0.2g/dL$, P=0.0241) and the mean total cholesterol level was significantly higher than those of group 1 ($222.7{\pm}35.7mg/dL$ vs. $148.3{\pm}29.1mg/dL$, P=0.0283). In Group 2 patients, total amount of protein of 24 hour collected urine also significantly higher than those of group 1 ($1,466.0{\pm}742.5mg$ vs. $122.5{\pm}48.1mg$, P=0.0135). Pr/Cr ratio in random urine sample was also higher in group 2 than those of group 1 but the statistical significance was not noted ($1.8{\pm}1.6$ vs. $0.2{\pm}0.2$, P=0.0961). Deletion of mtDNA nt 8272-8281 were observed in two patients, one patient in each groups, respectively. This is noncoding lesion. No patients demonstrated the mtDNA mutations. Conclusions: We have identified a deletion of mtDNA nt 8272-8281 in two children with IgA nephropathy. Further studies are needed to clarify the role of mitochondrial function in the progressive change of IgA nephropathy.

• Childhood Kidney Diseases
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• v.16 no.2
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• pp.89-94
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• 2012

Purpose: The option of selecting isotonic rather than hypotonic fluids for maintenance fluid in children has been advocated by some authors. Pneumonia and CNS infections are frequent clinical settings for acute hyponatremia because of nonosmotic anti-diuretic hormone stimuli in children. We conducted the present study to identify the incidence of hyponatremia in pneumonia and CNS infection of children and to determine the importance of maintenance intravenous fluid therapy regimen and other related factors. Methods: The study included 1,992 patients admitted to the Department of Pediatrics at Pusan National University Children's Hospital between November 2008 and August 2011, who were diagnosed with pneumonia or CNS infections and checked for serum sodium concentration. Their clinical data including laboratory findings were reviewed retrospectively. Results: During the study period, 218 patients were identified to have acute hyponatremia among 1,992 patients. The overall incidence of hyponatremia was 10.9%. The incidence of hyponatremia in encephalitis (37.3%) was highest and the incidence in bacterial meningitis (27.4%), viral meningitis (20.0%), bacterial pneumonia (11.1%), mycoplasma pneumonia (9.2%), and viral pneumonia (6.8%) were in descending order. The mean age was higher in hyponatremic patients than in isonatremic patients. The incidence of hyponatremia was higher in who had 0.18% NaCl in 5% dextrose (D5 0.18% NS) than 0.45% NaCl in 5% dextrose infusion (D5 1/2NS) (9.0% vs. 2.2%). SIADH was identified in 20.5% among hospital acquired hyponatremic patients after adequate evaluation for SIADH. Conclusion: We recommend D5 1/2NS rather than D5 0.18% NS as the maintenance fluid given to children with pneumonia or infectious CNS diseases.

• Childhood Kidney Diseases
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• v.16 no.2
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• pp.80-88
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• 2012

Purpose: The aim of our study was to investigate the characteristics of the peritoneal dialysis (PD) - related peritonitis and to evaluate the effectiveness of the empirical antibiotics recommended by the International Society for Peritoneal Dialysis in Korean children. Methods: We retrospectively reviewed the medical records of 72 children on peritoneal dialysis at the Department of Pediatrics, Asan Medical Center over the period from March 2000 to February 2012. Results: Seventy-nine episodes of peritonitis occurred in 32 patients. The incidence of peritonitis was 0.43 episodes/patient year. There were no significant differences in the incidence of peritonitis in terms of dialysis modality (P=0.459). Twenty-one patients experienced 51 catheter exit-site infections (0.28 episode/patient year). There were no significant differences in the incidence of peritonitis between those with and without history of exit-site infections (P=0.721). Specific pathogens were isolated from 68.4% (54/79) of the patient with peritonitis episodes, including Gram-positive bacteria (n=34), Gram-negative bacteria (n=25) and fungus (n=1). Among Gram-positive bacteria, 85.3% of the isolates were susceptible to ${\beta}$-lactam antibiotics, among Gram-negative rods, 94.7% of the isolates were susceptible to ceftazidime. Among 25 cases with unknown etiologies, 92.0% of cases demonstrated satisfactory responses to cefazolin and ceftazidime. Conclusions: The incidence of peritonitis was 0.43 episodes/patient year. Initial empirical therapy consisting of cefazolin and ceftazidime was appropriate for 91.1% of the PD-related peritonitis treatment. Continuous monitoring for the emergence of the resistant organisms is an important part of the appropriate managements of PD-related peritonitis.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.143-153
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• 2010

Purpose: Recently, massive proteinuria has been observed in some transplant patients after switching cyclosporine A (CsA) to sirolimus. To evaluate the pathogenesis of sirolimus-associated proteinuria, we investigated the early changes in slit diaphragm molecules by various administrative conditions of sirolimus and CsA. Methods: In vitro-Mouse podocytes were incubated with buffer (C), sirolimus ($10\;{\mu}g/mL$) after CsA ($10\;{\mu}g/mL$) (C-S), sirolimus only (S) and CsA and sirolimus simultaneously (C+S) for 12, 24, and 48 hours. In vivo- twenty four SPF female Wistar rats were divided into 4 groups buffer (C), sirolimus after 2 weeks of CsA (C-S), sirolimus only (S) and CsA and sirolimus simultaneously (C+S). All groups were treated by intraperitoneal injection every other day for 4 weeks (CsA: 25 mg/kg, sirolimus: 0.5 mg/kg). The changes in mRNA of slit diaphragm molecules were examined by RT-PCR. Results: The mRNA of nephrin was significantly decreased in group C-S and C+S in vitro. In vivo, the mRNA of nephrin in all groups using sirolimus and the mRNA of podocin in group C-S and C+S were decreased. Microscopically, group C-S and C+S showed small vacuolization and calcification in proximal tubular epithelial cells. Immunohistochemistry using nephrin and podocin antibodies did not show remarkable decrease of staining along the glomerular capillaries. Electron-microscopically, focal fusion of foot processes was seen in group C-S and C+S. Conclusion: This study suggests the decrease of slit diaphragm molecules (nephrin and podocin) in podocyte may be one of the causes of sirolimus associated proteinuria, and podocyte injury by sirolimus may need a primary hit by CsA to develop the proteinuria.

• 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.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.143-149
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• 2008

Purpose : Urinary N-acetyl-beta-D-glucosaminidase(NAG) and beta 2-microglobulin(B2M) is considered to be a marker of tubulointerstitial injury. The aim of this study was to examine the urinary levels of NAG and B2M in children with various renal diseases. Methods : We studied 21 children(8.9$\pm$4.5 years, Male:Female=14:7) and they were divided into three groups: group I(steroid-sensitive nephrotic syndrome-4 patients), group II(various kinds of glomerulonephritis-4 patients), and group III(normal urinalysis or non-glomerular renal diseases-13 patients). Results : Urinary NAG levels in groups I and II were significantly higher than those in group III(19.4$\pm$11.5 and 30.0$\pm$30.1 vs. 4.7$\pm$3.9, P=0.01), while urinary B2M levels did not differ among the 3 groups, although urinary NAG levels were positively correlated with urinary B2M levels(r=0.49, P=0.03). Urinary NAG and B2M levels were all correlated with proteinuria(r=0.79, P<0.001 and r=0.68, respectively, P=0.001) serum albumin(r=-0.72, P<0.001 and r=-0.57, respectively, P=0.01) and cholesterol(r=0.58, P=0.006 and r=0.56, respectively, P=0.013) levels. Conclusions : Urinary excretions of NAG and B2M are increased in children with steroidsensitive nephrotic syndrome and various kinds of glomerulonephritis, suggesting tubular dysfunction might be present in these diseases.