• Childhood Kidney Diseases
• /
• v.20 no.2
• /
• pp.74-78
• /
• 2016

Purpose: Early diagnosis and treatment of urinary tract infection have been emphasized to prevent renal scarring. If untreated, acute pyelonephritis could cause renal injury, which leads to renal scarring, hypertension, proteinuria, and chronic renal failure. The purpose of this study was to assess risk factors of renal scarring after treatment of acute pyelonephritis (APN). Methods: The medical records of 59 patients admitted at Daegu Fatima Hospital because of APN between March 2008 and April 2015 whose renal cortical defects were confirmed by using initial technetium-99m dimercaptosuccinic acid (DMSA) scans were reviewed retrospectively. We divided 59 patients into 2 groups according to the presence of renal scar and assessed risk factors of renal scar, including sex, age at diagnosis, feeding method, hydronephrosis, bacterial species, vesicoureteral reflux, and vesicoureteral reflux grade. Results: Of 59 patients (41%), 24 showed renal scar on follow-up DMSA scan. No significant differences in sex, hydronephrosis, bacterial species, and fever duration were found between the renal-scarred and non-scarred groups. As for age at diagnosis, age of >12 months had 5.8 times higher incidence rate of renal scarring. Vesicoureteral reflux (VUR) affected renal scar formation. VUR grade III or IV had 14.7 times greater influence on renal scar formation than VUR grade I or II. Conclusion: Our data suggest that the presence of VUR and its grade and age at diagnosis are risk factors of renal scar on follow-up DMSA scan after APN.

• Clinical and Experimental Pediatrics
• /
• v.55 no.10
• /
• pp.367-370
• /
• 2012

Urinary tract infection (UTI) is a common bacterial illness in children. Acute pyelonephritis in children may lead to renal scarring with the risk of later hypertension, preeclampsia during pregnancy, proteinuria, and renal insufficiency. Until now, vesicoureteral reflux (VUR) has been considered the most important risk factor for post-UTI renal scar formation in children. VUR predisposes children with UTI to pyelonephritis, and both are associated with renal scarring. However, reflux nephropathy is not always acquired; rather, it reflects reflux-associated congenital dysplastic kidneys. The viewpoint that chronic kidney disease results from renal maldevelopment-associated VUR has led to questioning the utility of any regimen directed at identifying or treating VUR. Despite the recognition that underlying renal anomalies may be the cause of renal scarring that was previously attributed to infection, the prevention of renal scarring remains the goal of all therapies for childhood UTI. Therefore, children at high risk of renal scar formation after UTI should be treated and investigated until a large clinical study and basic research give us more information.

• Childhood Kidney Diseases
• /
• v.15 no.2
• /
• pp.179-183
• /
• 2011

Abrupt progression of renal scarring associated with vesicoureteral reflux (VUR) is rare in males over 2 years old of age. We report a 5 year old boy with sustained unilateral high grade VUR who experienced abrupt progression of renal scarring; he had a relative renal radionuclide uptake of 38% at 2 years of age that dropped to 8% after three years. Per his parent's wishes, he took prophylactic antibiotics for 25 months after his first febrile urinary tract infection (UTI) at 4 months old without surgical management. One episode of recurrent breakthrough infection occurred at the age of 2 years. This observation reminds us that a recommending surgical management for sustained high grade VUR associated with renal scarring might be needed. Close follow up of DMSA for renal scanning, and long term follow up of patients after the first febrile UTI are important.

• Childhood Kidney Diseases
• /
• v.19 no.2
• /
• pp.125-130
• /
• 2015

Introduction: This study investigated whether renal and bladder ultrasonography (RBUS) findings performed in children with the first incidence of febrile urinary tract infection (UTI) can predict UTI recurrence, high-grade vesicoureteral reflux (high-grade VUR), or acquired renal scarring (aRS). Methods: In all, 917 children who were admitted to our hospital from January 2001 to October 2010, owing to the first incidence of febrile UTI were enrolled in this study. All children underwent RBUS during admission. The mean follow-up was 7.9 months (standard deviation $[SD]{\pm}13.3$). UTI recurrence rates were calculated according to various clinical parameters. By using bivariate and multiple logistic regression analyses, we determined whether age, sex, abnormal RBUS findings, abnormal dimercaptosuccinic acid renal scan findings, or RBUS findings parameters were predictive of UTI recurrence, high-grade VUR, or aRS. Results: On RBUS, hydronephrosis and congenital anomaly of the kidney and urinary tract significantly predicted UTI recurrence. A small kidney, hydroureter, hydronephrosis, cortical thinning, and increased parenchymal echogenicity significantly predicted high-grade VUR. However, their odds ratios (OR) are low compared to normal RBUS findings (recurrent UTI: OR 0.432 and 0.354 vs. 0.934, respectively, high-grade VUR: .019, 0.329, 0.126, 0.058, and 0.188 vs. 2.082, respectively). No RBUS findings significantly predicted aRS. Recurrent UTI, high-grade VUR, and abnormal RBUS findings significantly predicted aRS (OR of 4.80, 4.61, and 2.58, respectively). Conclusion: RBUS is necessary to exclude severe congenital renal scarring, obstructive uropathy, and renal abscess at the first incidence of febrile UTI and is helpful in determining the need for subsequent clinical imaging.

• Childhood Kidney Diseases
• /
• v.10 no.2
• /
• pp.201-212
• /
• 2006

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.

• Clinical and Experimental Pediatrics
• /
• v.52 no.9
• /
• pp.976-983
• /
• 2009

Urinary tract infection (UTI), the most common bacterial disease in childhood, is frequently associated with urinary tract anomalies (15-50%) and can induce renal scarring, which is a cause of hypertension and chronic kidney disease. Despite the high risk of renal scarring in infancy, the diagnosis may be delayed due to its nonspecific presenting symptoms; moreover, over-diagnosis is frequent due to the contamination of urine samples. The delay in diagnosis and treatment may induce sepsis or renal scar, while over-diagnosis is responsible for unnecessary antibiotic treatment and costly urinary imaging studies. UTI guidelines have been ever-changing for the past three decades, but some controversial issues remain. This article is a revision of the previous KSPN (Korean Society of Pediatric Nephrology) guideline and addresses the recent controversies concerning childhood UTI.

• Childhood Kidney Diseases
• /
• v.24 no.2
• /
• pp.98-106
• /
• 2020

Purpose: The aim of this study is to evaluate the clinical utility of late 6-month dimercapto-succinic acid (DMSA) renal scan in predicting vesicoureteral reflux (VUR) and long-lasting renal scars in children with first acute pyelonephritis (APN). Methods: A retrospective case study of children admitted with APN from January 2010 to July 2017 was performed. The study included patients with voiding cystourethrography (VCUG) and acute and late 6-month DMSA scan. We analyzed the clinical, laboratory and imaging findings of patients with and without late cortical defects at 6 months and those with or without VUR. Results: Among 145 children with APN, 50 (34.5%) had cortical defects on the late DMSA renal scan and 60 (41.4%) showed VUR. Thirteen of 38 (34.2%) children undergoing 18-month DMSA renal scan showed a long-lasting renal scars. Compared with children without late cortical defects, patients with late 6-month cortical defects had a higher incidence of VUR and long-lasting renal scars, and relapse of UTI (all P<0.05). In a multivariable analysis, both high-grade VUR and relapse of UTI were independently correlated with the presence of late 6-month cortical defects (P<0.05). Late cortical defects and relapse of UTI were also associated with the presence of VUR (P<0.05). Only the late 6-mo cortical defects was an independent predictor of long-lasting renal scars in children with APN (P<0.05). Conclusion: An abnormal late 6-month DMSA renal scan may be useful in identifying VUR and long-lasting renal scars in children diagnosed with APN.

• Childhood Kidney Diseases
• /
• v.5 no.1
• /
• pp.43-50
• /
• 2001

Purpose : The urinary tract infection associated with vesicoureteral reflux(VUR) in children may result in serious complications such as renal scarring, hypertension, proteinuria and end stage renal disease. The purpose of this study was to evaluate the factors affecting renal scar such as age, gender, grade of VUR, and ACE gene polymorphism, and body growth in the patients with and those without renal scar associated with VUR Methods : During the period from January 1994 to July 2000, We had 93 children with urinary tract infection associated with VUR who were admitted to the Department of pediatrics of Chonbuk National University Hospital. The patients were divided into two groups according to follow up 99mTc-DMSA renal scan; patients with renal scar group and those with non-scar group. We analyzed and compared the factors associated with renal scarring between the two groups. Results : There were no significant difference in gender, causative organism, ACE gene polymorphism, height and weight at diagnosis between renal scar group and non-scar group. Fifty four patients were in renal scar group and forty seven of them had VUR. The age at diagnosis was significantly higher in renal scar group (2.48${\pm}$2.64yr) than in non renal scar group (1.26${\pm}$1.83yr). Especially, the infants who were less than 1 year of age with VUR developed relatively more renal scar compared with infants older than 1 tear of age. The incidence of renal scarring showed a direct correlation with the severity of VUR. Conclusion : The factors affecting renal scar formation were age at diagnosis, presence and grade of VUR, but the other factors such as gender, causative organism, ACE gene polymorphism were not associated with renal scarring. Therefore, further evaluation about uropathogenic E coli and foflow up study about body growth associated with severity of renal scar would be necessary. (J. Korean Soc Pediatr Nephrol 5 : 43- 50, 2001)

• Childhood Kidney Diseases
• /
• v.9 no.1
• /
• pp.56-63
• /
• 2005

Purpose : Development of renal scarring is associated with delayed diagnosis and treatment of urinary tract infection(UTI). This study was performed to clarify how soon treatment should be started to Inhibit renal scarring after onset of UTI and the factors associated with renal scarring in children with a first episode of febrile UTI. Methods : We retrospectively reviewed 163 patients with a first episode of febrile UTI under the age of 2 years from April 2000 to Ap,il 2004. All patients had a DMSA renal scan and voiding cystourethrogram done in the diagnostic period, 6 months after which a follow-up renal scan was done. After patients wet-e divided into 2 groups according to the duration of fever prior to start of treatment, the duration of fever after start of treatment, and total duration of fever, initial and follow-up DMSA scan findings were analyzed among the different groups. We compared the factors associated with renal scars between the groups with and without renal scars. Results : The initial DMSA renal scan identified abnormal finding in 23% of the patients who were treated $\leq$24 hr from the onset of disease and in 43% of those with fever more than 24 hr. Renal scars developed in 33% of patients who were treated $\leq$24 hr and 38% of those with fever >24 hr prior to treatment. Renal scars developed in 34% of patients with remission of fever $\leq$48 hr after treatment and ill 50% of those with fever >48 hr after treatment. The risk for renal scars was significantly higher in children who had total duration of feyer >72 hr(67%) than in those with shorter duration(19%). In children with renal scars, VUR was most highly associated with an increased risk of renal scar formation. Conclusion : Although children with a first episode of febrile UTI are treated within 24 hr after onset of the fever, renal damage cannot be prevented completely and it is mainly associated with VUR. (J Korean Soc Pediatr Nephrol 2005;9:56-63)

• Clinical and Experimental Pediatrics
• /
• v.62 no.12
• /
• pp.433-437
• /
• 2019

Acute pyelonephritis (APN) should be detected and treated as soon as possible to reduce the risk of the development of acquired renal scarring. However, in the medical field, urine culture results are not available or considered when the prompt discrimination of APN is necessary and empirical treatment is started. Furthermore, urine culture cannot discriminate APN among children with febrile urinary tract infection (UTI) (pyelitis, lower UTI with other fever focus). Therefore, the usefulness of urine culture for diagnostic purposes is small and the sampling procedure is invasive. Congenital hypoplastic kidney is the most common cause of chronic kidney injury in children. Thus, it is desirable that a main target be detected as early as possible when imaging studies are performed in children with APN. However, if APN does not recur, no medical or surgical treatment or imaging studies would be needed because the acquired renal scar would not progress further. Therefore, the long-term prognosis of APN in young children, particularly infants, depends on the number of recurrent APN, not other febrile UTI. New methods that enable prompt, practical, and comfortable APN diagnosis in children are needed as alternatives to urinary catheterization for urine culture sampling.