Purpose : HUS usually occurs in children after infection with shiga toxin-producing microorganism(D＋HUS). In contrast, non-postdiarrheal(D-) HUS occurs at any age and has a high rate of relapse and a poor prognosis. The clinical presentation of D-HUS is similar to that of thrombotic thrombocytopenic purpura(TTP). Recently severe deficiencies of ADAMTS13 were reported not only in TTP and D- HUS but also in D+ HUS during their acute phase. The purpose of the study is to evaluate the plasma ADAMTS13 activity in D＋ and D-HUS. Methods : Nineteen children with HUS(D＋ HUS 12 and D- HUS 7) were enrolled. The assays of plasma ADAMTS13 activity were performed during the acute stage in the D＋ HUS and at various stages of relapsing courses in the D- HUS patients by multimer assay, based on electrophoresis. Results : The median plasma activity of ADAMTS13 in D＋ HUS and D- HUS were 80.9%(37.8-132.4%) and 53.9%(1.0-94.1%), respectively, which were not statistically significantly different from control(86.4%, 34.2-112.3%)(P>0.05). One boy with D- HUS had severe deficiency of ADAMTS13(1.0%). His platelet count was normalized temporarily by fresh frozen plasma infusion. Conclusion : We have demonstrated that there is no significant difference of the plasma ADAMTS13 activity between D＋ HUS, D- HUS and control. We detected severe deficiency of ADAMTS13 in one boy who presented with relapsing episodes of D- HUS. ADAMTS13 deficiency should be considered in the subgroup of D- HUS especially with early onset and recurrent courses. Plasma therapy can be beneficial in this subgroup.

Purpose : The prognosis of acute poststreptococcal glomerulonephritis(APSGN) has been reported to be favorable. However, several studies have reported that patients with nephrotic range proteinuria in the acute phase or persistent proteinuria may progress to chronic renal failure. To elucidate this further, we analyzed the features of proteinuria and its prognosis in pediatric patients with APSGN. Methods : A total of 48 children with APSGN admitted to our hospital between Jan. 2000 and Dec. 2004 were included. After discharge from the hospital, patients were regularly followed up every month by clinical evaluations and laboratory tests including routine urinalysis and quantification of proteinuria. Results : Age of the patients ranged from 3 to 15 years(median 5.8 years) at the time of disease onset. Proteinuria was present in 34(70.8%) patients and 5 of them showed heavy proteinuria. Proteinuria normalized within one month in most patients(82.3%) and there was no one with proteinuria after 6 months. Cyclosporine A(5 mg/kg/day in two divided doses) was given to 3 patients with massive proteinuria that lasted longer than 2 months and the result was complete remission within 4 months. Conclusions : Our data indicated that the prognosis of APSGN during childhood is excellent. Children with severe proteinuria or subnormal renal function in poststreptococcal glomerulonephritis had favorable prognosis without chronic renal failure, and children with crescentic formation also had favorable prognosis. Three patients who continued to have heavy proteinuria for more than 2 months received cyclosporine A and remission of proteinuria was achieved within a couple of months.

Purpose : High interleukin-1 beta(IL-$1{\beta}$) expression in the skin biopsy specimens of patients with Henoch-$Sch\ddot{o}nlein$ Purpura(HSP) has been observed. We examined IL-$1{\beta}$ gene polymorphism in patients with HSP. The purpose of this study is to examine the relationship between IL-$1{\beta}$ gene polymorphism and renal involvement in HSP. Methods : Patients from mideast Korea with HSP were studied. All patients had at least 6 months of follow up. Patients and ethnically matched controls were genotyped for IL-$1{\beta}$ gene polymorphism by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP). Results : Thirty-four patients(all younger than 15 years old) who had been diagnosed with HSP and 27 controls were examined. No allele or genotype differences between the HSP and control groups were observed. No significant association between the carriage of IL-$1{\beta}$(-511) T allele and renal involvement(P=0.525, OR:1.417, CI:0.545-3.686) was found. Conclusion : In unselected patients with HSP, carriage of IL-$1{\beta}$(-511) T allele does not appear to influence renal involvement.

Purpose : This study was aimed to determine the predictive risk factors for the treatment response and relapse rate in children diagnosed with idiopathic nephrotic syndrome. Methods : We analyzed the medical records of children who were diagnosed and treated for childhood idiopathic nephrotic syndrome from November 1991 to May 2005. Variables selected in this study were age at onset, sex, laboratory data, concomitant bacterial infections, days to remission, and interval to first relapse. Results : There were 46 males and 11 females, giving a male:female ratio of 4.2:1. The age($mean{\pm}SD$) of patients was $5.8{\pm}4.1$ years old. Of all patients who were initially given corticosteroids, complete remission(CR) was observed in 54(94.7%). Of the 54 patients who showed CR with initial treatment, 40(70.2%) showed CR within 2 weeks and 14(24.6%) showed CR after 2 weeks. The levels of serum IgG were lower in the latter group who showed CR after 2 weeks(P=0.036). Of the 54 patients who showed CR with initial treatment, 47(82.5%) relapsed. Of these patients, 35.1% were frequent relapsers and 43.9% were infrequent relapsers. There was no significant correlation between the frequency of relapse and the following variables : sex, days to remission, and laboratory data. However, age at onset and interval to first relapse had a negative correlation with the frequency of relapse(Pearson's coefficient=-0.337, -0.433, P<0.012, P<0.01). Conclusion : The age at onset and the interval to first relapse were found to be predictive clinical parameters for the relapse rate, while the levels of serum IgG at initial presentation were a predictive laboratory factor for treatment response in childhood idiopathic nephrotic syndrome.

Purpose : Growth retardation is one of the serious problems in children with nephropathy requiring long-term steroid therapy. We observed the efficacy and safety of recombinant human growth hormone(rhGH) on the growth in children with long-term steroid therapy. Methods : We studied 60 children(male 47, female 13) with nephropathy who received rhGH(1 U/kg/week) for more than 0.5 years($1.39{\pm}1.12$). Their mean age was 11.0 years($11.17{\pm}2.62$). They received steroid therapy from January 1987 through July 2005, and the mean duration of steroid therapy was $4.32{\pm}2.97$ years. Among the patients, there were 32 nephrotic syndrome, 9 IgA nephropathy, 4 mesangial proliferative glomerulonephritis, 4 focal segmental glomerulosclerosis, 2 Henoch $Sch\ddot{o}nlein$ nephritis, 2 Alport syndrome and 7 other cases. Data were gathered on the growth parameters, such as growth velocity, height standard deviation score(SDS), IGF-1, IGFBP-3, bone mass density(BMD) and general chemistry changes. Results : Height velocity increased significantly with rhGH therapy from $3.29{\pm}1.95$ to $8.66{\pm}3.75$(cm/yr) and height SDS decreased from $-0.72{\pm}0.93$ to $-1.04{\pm}0.86$ at one year after steroid therapy but increased to $-0.55{\pm}0.96$ at one year after rhGH administration(P<0.05). BMD improved from $0.71{\pm}0.14$ to $0.79{\pm}0.15g/cm^2$(P<0.05). IGF-1 increased from $445.09{\pm}138.01$ to $506.62{\pm}181.31ng/mL$(P<0.05). IGFBP-3 decreased from $4073.75{\pm}700.78$ to $3933.61{\pm}789.25ug/L$ numerically, but there was no statistically significant difference(P=0.533). Conclusion : The administration of rhGH in the short stature patients who received long-term steroid therapy showed improvement in growth parameters such as SDS, growth velocity, and BMD without significant side-effects or changes in the biochemical parameters.

Purpose : In Korea, the school urine screening program is a useful tool for screening urine abnormalities. It is particularly useful in early detection of membranoproliferative glomerulonephritis(MPGN) I, which frequently progresses to chronic renal failure. In this study, we studied the medical history, laboratory findings, and histologic findings of MPGN to gain helpful information on early detection and treatment. Methods : The subjects were 19 children, who were diagnosed with MPGN from kidney biopsies that were performed in ten nationwide university hospitals because of abnormal urine findings from school urine screening programs conducted from July 1999 to April 2004. We divided the patients into 2 groups, a nephrotic range proteinuria group(n=8) and a non-nephrotic proteinuria group(n=11), and retrospectively analyzed the clinical features, laboratory findings, histologic findings, treatment, and clinical course. Results : The mean age at the first abnormal urinalysis was $10.6{\pm}2.2$ years in the nephrotic proteinuria group and $9.6{\pm}3.2$ years in the non-nephrotic proteinuria group. The mean age at the time of kidney biopsy was $11.3{\pm}2.3$ years in the nephrotic range proteinuria group and $10.4{\pm}3.2$ years in the non-nephrotic proteinuria group respectively. There was no significant difference in the mean age and sex between the two groups. In the nephrotic proteinuria group, 6 children had a low plasma C3 level and in the non-nephrotic proteinuria group, 8 children had a low plasma C3 level, but there was no significant difference between the 2 groups. There was no significant difference in the laboratory test results(including WBC count, RBC count, platelet count and other serologic tests) between the 2 groups except for 24 hour urine protein secretion. There was no difference between the 2 groups with regard to the acute and chronic changes in the glomerulus on light microscopic findings, IgG, IgA, Ig M, C1q, C3, C4, fibrogen deposition on immunofluoroscence findings, and mesangial deposits, subendothelial deposits, and subepithelial deposits on electron microscopic findings. The children were treated with corticosteroids, ACE(angiotensin-converting enzyme) inhibitors, dipyridamole and other immunosuppressive agents. During the course of treatment, there were no children whose clinical condition worsened. Among 19 children, 3 children went into remission(2 in the nephrotic proteinuria group, 1 in the non-nephrotic proteinuria group) and 9 children went into a partial remission(4 in the nephrotic proteinuria group, 5 in the non-nephrotic proteinuria group) on urinalysis. There was no significant difference in the treatment results between the two groups. Conclusion : The 73.7% of children who were incidentally diagnosed with MPGN by the school urine screening program had reduced C3. 42.1% of the children had nephrotic range proteinuria. There were no significant differences in clinical features, laboratory test results, light microscopic, immunofluorescence microscopic, and electron microscopic findings between the nephrotic proteinuria group and the non-nephrotic proteinuria group except for the 24 hour urine protein secretion. Therefore, for early detection of MPGN during the school urine screening program, we strongly recommend a kidney biopsy if children have abnormal urine findings such as persistent proteinuria and persistent hematuria, or if the serum C3 is reduced.

Purpose : To report the decreasing indicence of HBV(Hepatitis B virus)-associated membranous nephropathy in children after HBV vaccination and to elucidate the clinical course and treatment strategies of IMN(Idiopathic membranous nephropathy). Methods : We retrospectively reviewed the clinico-pathological findings of HBV-MN and IMN patients who underwent a renal biopsy from 1986 to 2005. We compared the HBV-MN and the IMN groups and the remission and the non-remission groups of patients with IMN. Results : Among 24 cases of MN patients, HBV-MN comprised 6 cases(25%) and IMN 18 cases(75%). Clinical masnifestations were nephrotic syndrome(3 cases, 50%), nephritic syndrome(1 case, 16.7%), asymptomatic(2 cases, 33.4%) in the HBV-MN group, asymptomatic(10 cases, 55.5%), nephrotic syndrome(5 cases, 27.8%), and gross hematuria(3 cases, 16.7%) in the IMN groups. From 1996 to 2000, there were 2 cases(28%) of HBV-MN and 5 cases(72%) of IMN. After 2001 all 10 cases were IMN. In the HBV-MN group, 4 cases(66.7%) received interferon and 1 cases received methylprednisolone pulse therapy. In the IMN group, 16 cases(88.9%) received methylprednisolone, 8 cases(44.4%) were in complete remission, 2 cases(11.1%) were in partial remission, 2 cases(11.1%) were in chronic renal failure, and 5 cases(27.8%) were lost to follow-up with sustained proteinuria, 1 case(5.6%) continued to have frequent relapse of nephrotic syndrome without renal insufficiency. In the comparison between remission and non-remission groups, nephrotic range proteinuria and hypertension were more significantly common in the non-remission group(P<0.05). Conclusion : With HBV vaccination, HBV-MN has decreased markedly. IMN is a rare glomerular disease in children. Because the prognosis for patients with nephrotic range proteinuria is poor this group needs more aggressive treatment.

Purpose : To analyse the results of the renal biopsies and the clinical diagnoses of patients who had undergone percutaneous kidney biopsies in the department of pediatrics at Kyunghee University Hospital for 22 years from 1984 to 2005. Methods : We retrospectively reviewed the medical records of 1559 patients and analyzed the chief complaints that led to a renal biopsy, age, sex, histopathologic findings and diagnosis. Routine kidney biopsies were performed by automated gun biopsy guided by real time ultrasonography. The diagnoses were made based on the specimen's light microscopy, immunofluorescence microscopy and electron microscopy findings and clinical symptoms and signs. Results : The mean age of the patients was 10 years with the male to female ratio being 1.3:1. The chief complaints that led to a renal biopsy included hematuria only(753 cases, 48.3%), proteinuria only(125 cases, 8.0%) and hematuria combined with proteinuria(537 cases, 34.4%). The most frequent histopathological finding was primary glomerular disease(75.4%) which included IgA nephropathy(30.1%) and mesangial proliferative glomerulonephritis(27.6 %). Systemic disease comprised 11.4% which included Henoch-$Sch\ddot{o}nlein$ nephritis(10.5%) and lupus nephritis(0.8%). Alport syndrome was found in 1.1% of cases which was attributed to hereditary causes. 628 children(40.3%) visited the clinic due to abnormal school urine screening abnormalities and among these, 237 children had mesangial proliferative glomerulonephritis and 234 children who had IgA nephropathy were managed thereafter. Conclusion : IgA nephropathy and mesangial proliferative glomerulonephritis were the two major forms of primary glomerulonephritis found in Korean children who had kidney biopsies from 1984 to 2005.

Purpose : We studied the degree of changes in antibiotic sensitivity toward causative organisms, prevalence and clinical manifestations of extended-spectrum $\beta$-lactamase(ESBL)-producers of urinary tract infection(UTI) for a period of three years. This serves to provide useful information in selecting adequate drugs for the treatment of UTI. Methods : We recruited 137 patients who grew more than $10^5$ CFU/mL in their urine culture among 250 patients who visited and were admitted to Handong University's Sunlin Hospital for UTI treatment from January 2003 to December 2005. We retrospectively analyzed the data from the medical records. Results : The common pathogenic organisms were Escherichia coli(65.0%), Klepsiella pneumoniae(14.0%), Enterococcus faecalis(5.8%) and Proteus vulgaris(2.9%) in consecutive order. The prevalence of ESBL-producers among isolated E. coli and K. pneumoniae was 4.5%(4 cases) and 14.3%(2 cases), respectively. The antibiotic sensitivity rates of E. coli were relatively high to amikacin(100%), imipenem(100%), ceftriaxone(95.5%) and tobramycin(91.4%) while relatively low to TMP/SMZ(55.4%), ampicillin/sulbactam(29.4%) and ampicillin(24.2%). Conclusion : The use of ampicillin, ampicillin/sulbactam and TMP/SMZ, which have been the first choices in the treatment of UTI, should be reconsidered due to the low sensitivity rates towards these antibiotics. Due to the high incidence and antibiotic tolerance of ESBL that might have risen from the development of new antibiotics and increased antibiotic use, it is necessary to consider changing the standard antibiotics that have been used in the treatment of UTI.

Purpose : This study was performed to identify longitudinal changes in the prevalence of organisms isolated from urinary tract infection(UTI) and in the pattern of Escherichia coli susceptibility to antibiotics during the past 10 years in children with UTI. Methods : We performed a retrospective study of a total of 192 urine cultures from children with UTI in the Department of Pediatrics, Seoul Adventist Hospital over two periods(1st: 1995-2000, 2nd:2001-2005). Antimicrobial susceptibility of the isolates was compared between the two groups. Results : The pathogens of UTI in the two groups were similar. In the first period, E. coli was the leading uropathogen(66.2%) followed by Klebsiella pneumoniae(7.8%), Enterobacter cloacae(6.5%), and others(19.5%). In the second period, E. coli was the leading uropathogen(67%) followed by K. pneumoniae(12.2%), E. cloacae(3.5%), Enterobacter aerogenes(3.5%), and others(13.8%). The susceptibility pattern of E. coli to amoxicillin/clavulanate(87.5%, 81.0%) did not present any statistically significant difference between the two periods(P>0.05). The susceptibility of E. coli to TMP/SMX(52.4%, 50.0%) was still low with no significant difference between the two periods(P>0.05). Conclusion : Our results suggest that the use of amoxicillin/clavulanate is still an excellent therapeutic option in children with UTI. The low rate of susceptibility to TMP/SMX against uropathogens suggest that TMP/SMX may be reevaluated as the first-line therapeutic drug for UTI.

Purpose : Vesicoureteral reflux(VUR) is the major risk factor of urinary tract infection(UTI) in children and may result in serious complications such as renal scarring and chronic renal failure. The purpose of this study was to evaluate the relationship between VUR and renal scar formation, the usefulness and correlation of various imaging studies in reflux nephropathy, and the spontaneous resolution of VUR. Methods : We retrospectively reviewed 106 patients with VUR with no accompanying urogenital anomalies in the Department of Pediatrics, Bundang CHA Hospital during the period from Jan. 1996 to Mar. 2005. Ultrasonography and $^{99m}Tc$-dimercaptosuccinic acid(DMSA) scan were performed in the acute period of UTI. Voiding cystourethrography(VCUG) was performed 1 to 3 weeks after treatment with UTI. Follow-up DMSA scan was performed 4 to 6 months after treatment and a follow-up VCUG was performed every 12 months. Results : The mean age at detection of VUR was $13.8{\pm}22.2$ months and the male to female ratio was 2:1. The incidence of renal scarring showed a tendency of direct correlation between severity of VUR(P<0.001) and abnormal findings of renal ultrasonography(P<0.01). 63.2%(24 of 38 renal units) of renal parenchymal defects present in the first DMSA scan disappeared on follow-up DMSA scans. Follow-up DMSA scans detected renal scars in 7(14%) of 50 renal units with ultrasonographically normal kidneys. Meanwhile, ultrasonography did not show parenchymal defects in 7(36.8%) of 19 renal units where renal scarring was demonstrated on a follow-up DMSA scan. The spontaneous resolution rate of VUR was higher(75%) in cases with low grade(I to III) VUR(P<0.01). Conclusions : The presence and severity of VUR and abnormal findings of renal ultrasonography significantly correlated with renal scar formation. DMSA scan was useful in the diagnosis of renal defects. Meanwhile renal ultrasonography was an inadequate method for evaluating renal parenchymal damage. Therefore, follow-up DMSA scans should be performed to detect renal scars even in children with low-grade VUR and normal renal ultrasonography.

Purpose : Nutcracker syndrome refers to compression of the left renal vein(LRV) between the aorta and superior mesenteric artery(SMA) that results in elevation of pressure in the LRV and development of collateral veins. It must be considered as a possible factor when hematuria or proteinuria occurs in a healthy child. The purpose of this study is to determine the time to spontaneous resolution in childhood nutcracker syndrome, and to observe whether this is affected by sex, age, proteinuria or initial ratio of peak velocity of LRV. Methods : We investigated 26 patients who were found to have spontaneous resolution by follow-up Doppler ultrasonography among 117 patients diagnosed with nutcracker syndrome by renal Doppler ultrasonography from May 2001 to December 2005. We determined the time to spontaneous resolution in childhood nutcracker syndrome, and observed whether the duration was affected by sex, age, proteinuria or initial ratio of peak velocity. Results : 26 patients(59%) achieved spontaneous resolution by 1.2 years(mean). The time to spontaneous resolution of childhood nutcracker syndrome in 26 patients was $16.71{\pm}9.99$ months(range 6.0-49.2). The time to spontaneous resolution was not affected by sex, age, proteinuria nor initial ratio of peak velocity of LRV. Conclusion : More than half of the patients who were diagnosed by renal Doppler ultrasonography achieved spontaneous resolution. The time to spontaneous resolution was not affected by sex, age, proteinuria nor initial ratio of peak velocity of LRV.

Purpose : We aim to identify the clinical and demographic characteristics in children who underwent renal transplantation(RTx) and to evaluate the influence on growth of RTx in children. Methods : We reviewed 17 medical records of chronic renal failure patients who underwent RTx from April 1992 and June 2004 at Busan Paik Hospital. Age and sex distribution, cause of disease, donor analysis, patient and graft survival rate, and the status of growth after RTx were analysed by retrospective study. Results : Eighteen RTx were performed in 17 patients(8 boys, 9 girls). The mean age at the time of RTx was $15.8{\pm}3.5$ years and the mean duration of dialysis therapy before RTx was $22.4{\pm}18.0$ months. The 1 year and 5 year patient survival rate were each 100%, and the 1 year and 5 year graft survival rate were 88%, 36% respectively. The most common cause of graft failure was chronic rejection. The mean final height of male patients was $162.8{\pm}10.0$ cm(143.0-172.5 cm) and of female patients was $154.5{\pm}12.1$ cm(135.8-160.0 cm). The mean height standard deviation score(Ht SDS) increased after RTx from -1.95 to -1.53 but the increment rate was not statistically significant. Similar changes were noted in individual patient analysis. Also there was no significant difference between the living-related donors and cadaveric donors. Conclusion : Our data shows that even successful RTx rarely results in full growth rehabilitation. To overcome retarded growth in children with chronic renal failure, appropriate combined management of metabolic and nutritional problems, correction of anemia, proper use of recombinant growth hormone therapy, early renal transplantation and shortening of the duration of dialysis would be necessary.

Acute interstital nephritis can occur by acetaminophen, but it is rarely presented as acute renal failure with azotemia. We report a case of acute interstitial nephritis induced by acetaminophen in a 14-year-old girl who developed non-oliguric acute renal failure. She has taken acetaminophen to control the persistent throat pain for the last two months. Renal biopsy revealed diffuse infiltration of mononuclear inflammatory cells admixed with eosinophils in the edematous interstitia. After the discontinuation of acetaminophen and the administration of corticosteroid, the serum creatinine level returned to normal.

MRKH 증후군은 비뇨생식기계 및 골격계에 기형을 동반하지만 쇄항에 대한 동반 기형유무 검사상에서 MRKH 증후군으로 진단된 경우는 거의 보고되고 있지 않다. 이에 저자들은 쇄항을 주소로 내원한 34주 미숙아에서 MRKH 증후군으로 진단된 본 증례를 경험하였기에 문헌고찰과 함께 보고하는 바이다.

Nephrotic syndrome in childhood is known to be associated with a hypercoagulable state and thromboembolic complications, among which cerebral venous thrombosis is a very rare and serious one, with only a few isolated reports in the literature. A 9-year-old boy with known nephrotic syndrome was admitted due to a relapse with massive proteinuria and generalized edema. He complained of a prolonged frontal headache. The enhanced brain magnetic resonance imaging(MRI) showed a high signal in the region of the superior sagittal sinus and right transverse sinus consistent with a thrombus. He was managed with steroids, cyclosporine and warfarin. His headache subsided 2 weeks later and proteinuria resolved 1 month later. An MRI 2 months later was normal. We describe this case and review the literature to emphasize the importance of recognizing this potentially life threatening complication and initiating anticoagulation therapy.

Shigella infection usually produces gastrointestinal symptoms but rarely causes urinary tract infection. A 7-year-old girl was admitted for fever, chills, right flank pain, and dysuria. She had no vomiting or diarrhea. There was mild tenderness in her right lower abdomen, and right CVA tenderness was also noted. Acute pyelonephritis was diagnosed by abdominal CT. She showed improvement with intravenous administration of antibiotics. The first urine culture grew $1{\times}10^5$ CFU/mL Shigella dysenteri. Although urinary tract infections due to Shigella species are extremely rare, Shigella species should be considered as a possible cause of pediatric urinary tract infection. We report the first case of urinary tract infection caused by S. dysenteri, which presented as acute pyelonephritis without gastrointestinal symptoms in a child.

Diarrhea-associated hemolytic uremic syndrome(D+ HUS) is induced by enterohemorrhagic Escherichia coli(EHEC) and is characterized by the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The disease is usually transmitted by meat and water contaminated by excreta of domestic animals. We report a son and his mother with diarrhea-associated hemolytic uremic syndrome that spread within the family.