• Childhood Kidney Diseases
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• v.12 no.1
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• pp.70-77
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• 2008

Purpose: Urinary tract infections(UTIs) are not uncommon findings in febrile pediatric patients and approximately one third of patients with UTI may have renal scars. This research was intended to establish the relationship between duration of fever and renal scars. Methods: The medical records of 143 patients were reviewed retrospectively. Inclusion criteria were as follows: 1) fever as defined by an axillary temperature $\geq37.5^{\circ}C$, 2) accurate history of fever duration and the use of antibiotics 3) no previous history of UTI and 4) positive urine culture. We observed whether the longer fever duration could be associated with the development of initial renal defects and subsequent renal scars, increased C-reactive protein(CRP), leukocytosis and the presence of vesicoureteral reflux(VUR). Results: 1) Patients with longer fever duration after antibiotics showed more frequent initial renal defects(P=0.014). However, fever duration before antibiotic use was not associated with the development of initial renal defects(P=0.244). 2) Incidence of renal scar increased with fever duration before antibiotic use(P=0.006) and fever duration after antibiotic use(P=0.015). 3) CRP correlated with the fever duration after antibiotic use(r=0.287, P=0.003). 4) There was no relationships between fever duration and VUR(P>0.05). Conclusion: Our data suggest that fever duration before/after antibiotic use is significantly associated with the increased development of renal scars in pediatric UTI.

• Childhood Kidney Diseases
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• v.17 no.2
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• pp.65-72
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• 2013

Purpose: Urinary tract infection (UTI) caused by gram-positive uropathogens is usually hospital-acquired and associated with predisposing conditions. However, the incidence of gram-positive bacteria in community-acquired UTIs has recently increased worldwide. We aimed to investigate the clinical significance of UTI and associated genitourinary malformations in young children with febrile UTIs caused by gram-positive bacteria. Methods: We retrospectively reviewed the medical records of 566 patients (age, <1 year) who visited the Korea University Medical Center for febrile UTIs between January 2008 and May 2013. We classified the patients into the following two groups: gram-positive (P group) and gram-negative (N group), according to the results of urine culture. The fever duration; white blood cell (WBC) counts and C-reactive protein (CRP) levels in peripheral blood; and the presence of hydronephrosis, cortical defects, vesicoureteral reflux (VUR), and renal scarring were compared between the two groups. Results: The number of patients with gram-positive bacteria was 23 (4.1%) and with gram-negative bacteria was 543 (95.9%). The most common pathogen was Escherichia coli, and Enterococcus faecalis showed the highest incidence among gram-positive uropathogens. Patients with gram-positive bacteria showed longer fever duration compared to that in patients with gram-negative bacteria (P vs. N, $3.4{\pm}1.2$ vs. $2.9{\pm}1.6$ days, P <0.05). The incidence of VUR was increased in the gram-positive group compared to that in the gram-negative group (P vs. N, 55.6 vs. 17.8%, P<0.05). However, there were no significant differences in other laboratory and radiologic findings. Conclusion: The findings of our study show that community-acquired UTIs in patients younger than 1 year of age, caused by gram-positive uropathogens, can be associated with prolonged fever duration and the presence of VUR.

• Childhood Kidney Diseases
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• v.19 no.2
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• pp.136-142
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• 2015

Purpose: Although the American Academy of Pediatrics provides clinical guidelines for urinary tract infection (UTI) infants, guidelines are not appropriate for neonates and infants less than 2 months of age due to insufficient data. The aim of this study was to evaluate the characteristics of neonates and young infants less than 2 months old (group 1) with UTI compared to older infants from 2 to 12 months old (group 2). Methods: We reviewed UTI patients aged 0 to 12 months admitted to the pediatric department in the last 5 years. Clinical characteristics such as age, sex, fever duration, recurrence, progression to acute pyelonephritis (APN), malformations like hydronephrosis and vesicoureteral reflux (VUR), and laboratory results were compared between group 1 and group 2. Results: 615 patients were included in this study. Group 1 had 94 cases and group 2 had 521 cases. Escherichia coli was the most commonly isolated pathogen in urine cultures. Fever duration was shorter in group 1 (vs.) 2 ($1.91{\pm}1.43$ days vs. $3.42{\pm}2.40$ days, P<0.05). As compared to group 2, group 1 had a higher proportion of patients with antenatal hydronephrosis and hydronephrosis found after admission (10.6% vs. 3.6% and 75.5% vs. 55.9%, P<0.05). There were differences between two groups in white blood cell (WBC) count (Group 1: $13,694{\pm}5,315/{\mu}L$, Group 2: $15,271{\pm}6,130/{\mu}L$, P<0.05) and C-reactive protein (Group 1: $32.02{\pm}35.17mg/L$, Group 2: $46.51{\pm}46.63mg/L$, P<0.05). Conclusion: Compared to older infants, UTI in neonates and young infants shows milder clinical manifestations except higher rates of hydronephrosis but outcome is alike.

• Pediatric Infection and Vaccine
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• v.17 no.1
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• pp.23-29
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• 2010

Purpose : Urinary tract infection (UTI) in children is the most common disease during the infantile period, therefore early diagnosis and treatment are important. Pyuria is a useful clinical parameter for the initial diagnosis of a UTI. In this study we aimed to compare the clinical, laboratory, and imaging findings in relation to the duration of pyuria in infants with UTIs. Methods : Three hundred seventy-four infants <12 months of age who were admitted between January 1995 and December 2005 for the first episode of a febrile UTI were retrospectively reviewed. Patients were divided into two groups according to the duration of pyuria as follows: group 1, pyuria resolved <3 days after initial treatment; and group 2, pyuria lasted at least 3 days after initial treatment. Results : There were no significant differences between the two groups in relation to gender, age, total duration of fever, and organisms in the urine. Group 2 had a significantly higher peripheral blood leukocyte count ($14,360.86{\pm}5,526.16cells/mm^3$ vs. $11,822.55{\pm}5,687.26cells/mm^3$, P <0.001), erythrocyte sedimentation rate ($32.81{\pm}19.34mm/hr$ vs. $23.74{\pm}20.43mm/hr$, P <0.001), and C-reactive protein ($6.84{\pm}5.68mg/dL$ vs. $3.78{\pm}3.99mg/dL$, P <0.001) than group 1. There was a significantly higher incidence of hydronephrosis and a higher grade of vesicoureteral reflux (VUR) in group 2 compared to group 1. Conclusion : In infants with UTI, pyuria of longer duration is related to severe UTI and higher grade VUR, therefore aggressive radiologic studies may be necessary.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.203-211
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• 2007

Purpose : We attempted to compare the independent factors such as age, sex, C-reactive protein(CRP), and white blood cell count(WBC) in children with radiologic studies and assess the necessity of performing voiding cystourethrography(VCUG). Method : 98 children who have been diagnosed their first time febrile urinary tract infection from Janurary 2002 to Januray 2005 were enrolled. In all patient, the duration of fever which occurred before and after treatment was recorded, and CRP, WBC, $^{99m}Tc$-2,3-dimercaptosuccinic acid($^{99m}Tc$-DMSA) renal scans, renal ultrasound and VCUG were analyzed. Results : Of the 98 children diagnosed with urinary tract infection(UTI), 52 were male and 46 were female. 18 had abnormalities in VCUG, 17 had abnormalities in kidney ultrasound, and 20 had partial defects or diffuse uptake decrease in $^{99m}Tc$-DMSA renal scans. There were no significant relationship between incidence of radiologic abnormalities and age. The risk of renal scar was significantly higher in children who had a longer febrile period before treatment than in those with shorter period. Both CRP and WBC were significantly elevated in children with the radiological abnormalities. A positive of $^{99m}Tc$-DMSA renal scans and renal ultrasound were highly associated with vesicoureteral reflux(VUR). Conclusion : If there are abnormalities in the kidney ultrasound and $^{99m}Tc$-DMSA renal scan of a child with initial UTI, a VCUG is recommended. Even in cases without abnormal findings in $^{99m}Tc$-DMSA renal scan and renal ultrasound, clinical data such as CRP and WBC should be assessed, and VCUG should be Performed for the undetected VUR.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.203-209
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• 2010

Purpose : It has been a common medical practice to use prophylactic antibiotics to prevent recurrent urinary tract infections (UTI) in high risk situations such as urinary tract obstruction, vesicoureteral reflux, neurogenic bladder, or urinary stones. But sometimes, we meet difficult situation of breakthrough infections (BI) which might cause new or progressive renal scarring. The clinical characteristics of children contracting breakthrough UTI experienced in a single center were studied. Methods : The study was done retrospectively through medical records of 150 pediatric patients who had been cared in pediatric and urologic clinics of Pusan National University Hospital from Jan. 2001 till June 2006 and had prophylactic antibiotics to prevent recurrent UTI. Results : The starting age of prophylactic antibiotics of 150 patient was 1-76 months, and median age was 5 months. The BI developed 61 times in 43 patients (28.7%), 1.5 times per 100 patient-months. The BI occurred more frequently in patients with higher grade of VUR, and in the cases with abnormal DMSA scan. Co-trimoxazole was more effective than 2nd and 3rd generation cephalosporins to prevent UTI. The distribution of causative organisms was more diverse than usual UTI. The causative organisms were sensitive to the antibiotics used for prophylaxis in 29.5%, and resistant in 59.1%. After experience of BI, 40 percents of patients went to the surgical treatment including endoscopic injection of Deflux, 35% to new antibiotics for prophylaxis, 26% remain on the same antibiotics as the previous one. Conclusion : Based on our study results, preexisting renal scar might be one of the factors which should be considered in favor of early surgical interventions of VUR. Poor compliance and wrong selection of antibiotics such as cephalosporins are important underlying causes of breakthrough UTIs.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.223-228
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• 2004

Purpose and Methods: Urinary tract infection(UTI) is one of the most important diseases of childhood, especially for young infants. To characterize the patients diagnosed with febrile UTI in their first 6 months of life and to explore the risk factors of recurrent UTI, a retrospective study was performed. Results: Among the 90 patients studied, 77 were boys(86%). First episodes of UTI were diagnosed at the age of $2.5{\pm}1.4$ months. These patients underwent ultrasonographic evaluation of urinary tract(n=90) and voiding cystourethrography(n=81) where 53 and 35 studies showed abnormal findings respectively, and a total of 45 cases of urinary tract anomaly including vesicoureteral reflux(VUR, n=35) were diagnosed. Normal findings on ultrasonography indicated decreased risk of VUR in boys of 1-3 months of age(n=30). 53 patients were followed up more than 6 months and 45 episodes of subsequent UTI developed in 29 patients during the first 6-month period. Patients with relapse were older than patients without relapse at the diagnosis of first UTI, but other clinical parameters including abnormal findings on the imaging studies and prophylactic antibiotics prescription were not different between the two groups. Conclusion: UTI in early infancy occurred mainly in male infants and half of the patients had structural anomalies. USG was of clinical value in detecting anomalies requiring surgical intervention, and to rule out high grade VUR in 1-3 months old boys. Results of the imaging study or prophylactic antibiotics could not modify the risk of recurrent UTI. (J Korean Soc Pediatr Nephrol 2004;8:223-228)

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.203-208
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• 1999

Purpose: The information on the change of the relative renal function after operation is essential to set the initial treatment plan in unilateral hydronephrosis. So we analyzed the preoperative and postoperative relative renal function, and observed the functional changes by operation and reliability of the various factors in those changes. Materials and Methods: A retrospective trial was done of 81 patients, 35 ureteropelvic junction(UPJ) obstruction and 46 vesicoureteral reflux(VUR), among 393 patients undergoing operations at our institution from March. 1992 to February. 1997. The patients who had infravesical abnormalities, abnormal contralateral kidney and insufficient research data were excluded. We determined the relative renal functions using DTPA and MAG3 scan in UPJ obstruction and DMSA scan in VUR. The mean observation period after operation was 2.01(0.25-4) years. Results: A. UPJ Obstruction 1. The relative renal function was improved significantly after operation(P=0.0007). 2. The kidneys which have preoperative functions between 20% and 40% improved significantly in relative renal function comparing to the kidneys of the other functions(P=0.0046). B. VUR 1. The renal functions didn't improve significantly after operation(P>0.05). 2. There was no significant factor affecting the prognosis in renal functions. Conclusions: 1. The kidneys with UPJ Obstruction show the difference in functional improvement after operation according to the degree of the preoperative renal function, but more investigations about the exact value are needed. 2. In VUR there was no difference between preoperative and postoperative functions, the theoretical basis on objectives of the operation could be the symptoms or factors except the operation.

• Childhood Kidney Diseases
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• v.16 no.2
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• pp.102-108
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• 2012

Purpose: We investigated the clinical presentation of febrile pediatric patients with acute pyelonephritis (APN) with a mixed urine culture from an aseptic urine sample, and compared with that of those with a single culture. Methods: We retrospectively reviewed the medical charts of 95 patients diagnosed as APN with fever between January 2008 and October 2010 at Korea University Medical Center. We classified the patients with APN into two groups with a positive single culture (S group) and a positive mixed culture (M group) from an aseptic urine sample of suprapubic bladder aspiration or urethral catheterization and compared the fever duration, laboratory markers such as serum white blood cell (WBC) counts and C-reactive protein (CRP) values in peripheral blood, and the presence of hydronephrosis, renal scar and vesicoureteral reflux (VUR) between the two groups (If presence of hydronephrosis, scar and VUR=1 and no=0). Results: Total pediatric patients with febrile APN were 95 patients, a positive S group was 89 patients and a positive M group was 6 patients. Fever duration (S vs. M, $4.7{\pm}3.1$ vs. $6{\pm}5.7$ days), serum WBC (S vs. M, $18,630{\pm}6,483$ vs. $20,153{\pm}7,660/{\mu}L$) and CRP (S vs. M, $100.6{\pm}2.46$ vs. $81.1{\pm}0.09\;mg/L$) values, and the presence of hydronephrosis, renal scar and VUR were not different between the two groups. Conclusion: Our data shows that there were no specific differences of clinical manifestation between a positive single urine culture and a positive mixed urine culture in pediatric APN. A mixed urine culture from an aseptic urine sample should be interpreted cautiously.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.245-253
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• 2003

Puorpose: The purpose of this study was to evaluate the usefulness of $^{99m}Tc$ DMSA scintigraphy on the dignosis of a renal scar in children with urinary tract infections. Materials and Methods: Eighty three patients were included in this study, who were diagnosed as the urinary tract infection on the basis of symptom, urinalysis and urine culture. $^{99m}Tc$ DMSA scintigraphy and voiding cystoureterography were peformed within 7days before the treatment in all patients. We classified the scintigraphic findings as follow s : 1 ; a large hypoactive upper or lower pole. 2 ; a small hypoactive area. 3 ; single defect resulting in localized deformity of the outlines. 4 ; deformed outlines in a small or normal sized kidney. 5 ; multiple defects. 6 ; diffuse hypoactive kidney without regional impairment. Follow-up scintigraphy was done at least 6 months after the initial study. When the abnormality on the initial scintigraphy was not completely resolved on the follow-up scan, the lesion was defined as containing a scar. Results: One hundred and fifteen renal units of 166 units(69.3%) showed abnormal findings on the DMSA scintigraphy. 65 units(56.5%) was diagnosed as containing renal scars on follow-up scintigraphies. Incidences of renal scar among renal units showing pattern 3, 4 and 5 on the initial scan was 75%, 78% and 78%, respectively. Whereas many of renal units showing 1, 2 and 6 pattern were recovered(65%, 76%, 50%). Sensitivity, specificity and accuracy of pattern-based DMSA scintigraphic findings on the diagnosis of renal scar was 76.9%, 85.1% and 81.9%, respectively. VUR was significantly associated with the renal scar when the initial DMSA shows unrecoverable findings(pattern 3, 4, 5). Odds ratio of the renal scar in a kidney showing unrecoverable initial scintigraphic findings was 19.1. Odds ratio in a kidney with mild or moderate-to-severe VUR was 3.5 and 14.4 respectively. Conclusion: In the urinary tract infection, renal scar was significantly developed in a kidney showing unrecoverable findings on the initial DMSA scan and VUR on voiding cystoureterography.