Predictors of renal scar in children with urinary infection and vesicoureteral reflux

Impact of Urinary Tract Infection on Progression of Renal Scars and Formation of New Scars in Patients with Primary Vesicoureteric Reflux

INTRODUCTION

Primary vesicoureteric reflux (VUR) is a prevalent cause of end-stage renal failure in children. Scars on radionuclide imaging indicate irreparable damage to the growing kidneys. This study aims to determine whether a urinary tract infection (UTI) associated with primary VUR promotes the development of new renal scars or progression in the pre-existing ones.

MATERIALS AND METHODS

Children with primary VUR on continuous antibiotic prophylaxis at a tertiary teaching hospital's paediatric nephrourology clinic were observed prospectively. At recruitment, a renal cortical (dimercaptosuccinic acid [DMSA]) scan was done, and the children were followed up every 3 months. Breakthrough UTIs were documented, and follow-up DMSA scans were performed to document new scarring/grade advancement of existing scars in the renoureteric units (RUUs).

RESULTS

Seventy-two RUUs in 36 patients were monitored. Fifty-four (75%) RUUs were exposed to VUR of different grades, and 46 (85.1%) had a UTI. On the DMSA scan, these showed new scar development in 10/18 (55%) RUUs and scar progression in 13/28 (46.4%) RUUs. Of the 8 RUUs with VUR and without UTI, new scars manifest in 4/5 (80%) and progressed in 1/3 (33%). On univariate analysis, there was no significant difference in the formation of new scars or scar advancement on the DMSA scan between RUU with VUR and UTI and those without UTI. There was a significant positive correlation between the scarring on DMSA scan and the grade of reflux (P < 0.001).

CONCLUSION

Primary VUR patients had fresh or progressed scarring regardless of urinary infection. A higher VUR grade at presentation was a significant risk factor for scarring.

Correlation of Renal Scarring to Urinary Tract Infections and Vesicoureteral Reflux in Children

Objective

To study the association of the grade of vesicoureteral reflux (VUR) and urinary tract infections (UTI) with renal scarring at the first clinical presentation of patients who underwent antireflux surgery. Materials and methods. Between 2015 and 2020, 150 patients (194 units) who underwent antireflux surgery had dimercaptosuccinic acid (DMSA) renal scans preoperatively. Patients were classified into the nonscar and scar groups according to DMSA scan results. Moreover, cases were classified into afebrile UTI, febrile UTI, and antenatal hydronephrosis (ANH) according to the mode of presentation. We correlated the mode of presentation and the grade of VUR to the presence/absence of renal scars in both groups.

Results

The mean follow-up was 45 months preoperatively. The mode of presentation was afebrile, febrile UTIs, and antenatal hydronephrosis in (50, 14), (20, 46), and (10, 10) patients in the nonscar and scar groups, respectively. Of the 20 patients who presented ANH, 10 (50%) had scars. Clinical presentation was correlated to the presence of renal scarring and its degree. The scar group had significantly higher grades of VUR than the nonscar group (grades I–II (50 units versus 10 units), grade III (28 units versus 40 units), and grade IV–V (22 units versus 44 units) for the nonscar versus scar groups, respectively (pvalue <0.001).

Conclusion

Renal scarring is associated with higher grades of reflux and urinary tract infections. We advocate further research investigating infants who had UTIs with or without fever for early detection of reflux.

Coagulase-negative Staphylococci: a rare cause of urinary tract infections in children with consequences on clinical practice

Isolation of coagulase-negative Staphylococci (CoNS) in urine cultures of children is usually considered a contamination of the sample, except for Staphylococcus saprophyticus in older children. The aim of this study was to describe the characteristics of children in whom CoNS was considered a true urinary pathogen. The medical records of all children aged 0 to 18 years at Shaare Zedek Medical Center between 2013 and 2020 who were diagnosed with CoNS urinary tract infection (UTI) were reviewed for demographic, clinical, and laboratory data. CoNS were identified as the causative organism of UTIs in 30 children, none of whom was bacteremic. Male sex, younger age, and infection with non-S. saprophyticus CoNS were associated with higher risk of pyelonephritis in comparison to cystitis. Eleven (37%) children had previously known or newly diagnosed underlying urinary tract abnormalities. All patients recovered. CoNS were found to be an uncommon urinary pathogen among children but can cause pyelonephritis, especially in young children and in males.Conclusion: The finding of CoNS pyelonephritis requires thorough search for urinary abnormalities.

Acute pyelonephritis in children and the risk of end-stage kidney disease

BACKGROUND

Pyelonephritis is the most common serious bacterial infection during childhood. The long-term importance of kidney scarring is unclear.

OBJECTIVE

To assess the risk of end-stage kidney disease (ESKD) in adolescents and young adults with history of pyelonephritis.

STUDY DESIGN

A nationwide, population-based, historical cohort study, including 1,509,902 persons (62% male) examined for military service between 1967 and 1997. Participants with a history of pyelonephritis were sub-grouped according to presence of kidney scarring and baseline kidney function. Data were linked to the Israeli ESKD registry to identify incident ESKD cases. Cox proportional hazards models were used to estimate the hazard ratio (HR) of treated ESKD (dialysis or kidney transplant).

RESULTS

Pyelonephritis was diagnosed in 6979 participants (0.46%). 6479 had normal kidney function and no evidence of kidney scarring, 400 had normal kidney function with evidence of scarring, and 100 demonstrated reduced baseline kidney function. Treated ESKD developed in 2352 individuals (0.2%) without history of pyelonephritis, 58 individuals (0.9%) with normal kidney function, history of pyelonephritis and no kidney scarring, 14 individuals (3.5%) with normal kidney function, history of pyelonephritis and kidney scarring, and 23 individuals (23.0%) with history of pyelonephritis and reduced baseline kidney function, yielding HR of 3.3, 34.8 and 43.2, respectively, controlling for age, gender, paternal origin, enrollment year, body mass index, and blood pressure, and accounting for death as a competing risk.

CONCLUSION

History of pyelonephritis was associated with significantly increased risk of treated ESKD, particularly when associated with kidney scarring or reduced baseline kidney function.

Renal scar formation and kidney function following antibiotic-treated murine pyelonephritis

We present a new preclinical model to study treatment, resolution and sequelae of severe ascending pyelonephritis. Urinary tract infection (UTI), primarily caused by uropathogenic Escherichia coli (UPEC), is a common disease in children. Severe pyelonephritis is the primary cause of acquired renal scarring in childhood, which may eventually lead to hypertension and chronic kidney disease in a small but important fraction of patients. Preclinical modeling of UTI utilizes almost exclusively females, which (in most mouse strains) exhibit inherent resistance to severe ascending kidney infection; consequently, no existing preclinical model has assessed the consequences of recovery from pyelonephritis following antibiotic treatment. We recently published a novel mini-surgical bladder inoculation technique, with which male C3H/HeN mice develop robust ascending pyelonephritis, highly prevalent renal abscesses and evidence of fibrosis. Here, we devised and optimized an antibiotic treatment strategy within this male model to more closely reflect the clinical course of pyelonephritis. A 5-day ceftriaxone regimen initiated at the onset of abscess development achieved resolution of bladder and kidney infection. A minority of treated mice displayed persistent histological abscess at the end of treatment, despite microbiological cure of pyelonephritis; a matching fraction of mice 1 month later exhibited renal scars featuring fibrosis and ongoing inflammatory infiltrates. Successful antibiotic treatment preserved renal function in almost all infected mice, as assessed by biochemical markers 1 and 5 months post-treatment; hydronephrosis was observed as a late effect of treated pyelonephritis. An occasional mouse developed chronic kidney disease, generally reflecting the incidence of this late sequela in humans. In total, this model offers a platform to study the molecular pathogenesis of pyelonephritis, response to antibiotic therapy and emergence of sequelae, including fibrosis and renal scarring. Future studies in this system may inform adjunctive therapies that may reduce the long-term complications of this very common bacterial infection.

Summary: A new model of antibiotic-treated severe pyelonephritis offers a novel platform to study the molecular pathogenesis of pyelonephritis, response to antibiotic therapy, and sequelae, including fibrosis and renal scarring.

Antireflux surgery does not change ongoing renal functional deterioration

AIM

Treatment modalities of vesicoureteral reflux (VUR) consist of antimicrobial prophylaxis and antireflux surgery. In this study, we aimed to determine if antireflux surgery changes the course of renal functional deterioration in children with VUR and urinary tract infections (UTI).

METHODS

Medical files of patients with VUR diagnosed during evaluation for UTI were evaluated retrospectively for gender, age, follow-up period, and renal ultrasonography (US) and serial 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy findings. Estimated glomerular filtration rate and urinary protein levels were determined at the initial and last visits, and before the operation in children who had antireflux surgery. The patients were divided into two groups as solely medically treated (Group 1) and both medically and surgically treated (Group 2). Group 2 was further divided as those with stable renal function (Group 2a) and with progressive renal injury (Group 2b).

RESULTS

There were 140 patients (77 female; mean age 51.6 ± 51.9 months). Group 1 and Group 2 included 82 and 58 patients, respectively. In Group 2, the number of patients with the abnormal US, DMSA scintigraphy, and renal function was higher than in Group 1. Recurrent UTI rate was similar, but progressive scarring was more prominent in the antireflux surgery group. In Group 2, 31 patients had a stable renal function (Group 2a) while 27 had progressive deterioration of renal functions (Group 2b). These subgroups were not different with respect to the rate of high-grade VUR, the presence of a renal scar in DMSA, and UTI recurrence. However, the bilateral renal scar was more common in Group 2b.

CONCLUSION

Antireflux surgery does not change the course of ongoing renal injury and renal functional deterioration.

Acoustic radiation force impulse (ARFI) elastography for detection of renal damage in children

BACKGROUND

Acoustic radiation force impulse (ARFI) imaging is a promising method for noninvasive evaluation of the renal parenchyma.

OBJECTIVE

To investigate the contribution of ARFI quantitative US elastography for the detection of renal damage in kidneys with and without vesicoureteral reflux (VUR).

MATERIALS AND METHODS

One hundred seventy-six kidneys of 88 children (46 male, 42 female) who had been referred for voiding cystourethrography and 20 healthy controls were prospectively investigated. Patients were assessed according to severity of renal damage on dimercaptosuccinic acid (DMSA) scintigraphy. Ninety-eight age- and gender-matched healthy children constituted the control group. Quantitative shear wave velocity (SWV) measurements were performed in the upper and lower poles and in the interpolar region of each kidney. DMSA scintigraphy was performed in 62 children (124 kidneys). Comparisons of SWV values of kidneys with and without renal damage and/or VUR were done.

RESULTS

Significantly higher SWV values were found in non-damaged kidneys. Severely damaged kidneys had the lowest SWV values (P < 0.001). High-grade (grade V-IV) refluxing kidneys had the lowest SWV values, while non-refluxing kidneys had the highest values (P < 0.05). Significant negative correlations were found between the mean quantitative US elastography values and DMSA scarring score (r = -0.788, P < 0.001) and VUR grade (r = -0.634, P < 0.001). SWV values of the control kidneys were significantly higher than those of damaged kidneys (P < 0.05).

CONCLUSION

Our findings suggest decreasing SWV of renal units with increasing grades of vesicoureteric reflux, increasing DMSA-assessed renal damage and decreasing DMSA-assessed differential function.

The relative function of damaged kidneys in children does not deteriorate further at 3-year follow-up

PURPOSE

It is thought that the function of a damaged kidney will deteriorate further with time because of impaired maturation and compensatory hyperfiltration. The aim of this study was to determine changes in relative renal function (RRF) over time in children with vesicoureteric reflux (VUR) and/or urinary tract infection (UTI) where the unilaterally scarred kidney was found to contribute 30% or less to overall function.

PATIENTS AND METHODS

Children who met the inclusion criteria and had multiple radionuclide studies during a 12-year period were identified, and RRF was compared.

RESULTS

Twenty-seven boys and 3 girls with a median age of 0.8 years (0.08-13.05 years) were included. Eight patients had unilateral VUR, 21 patients had bilateral VUR, and 1 patient had UTIs without VUR. Twenty-one patients underwent reimplantation surgery, and 9 were managed conservatively.At a mean follow-up of 2.64 years (0.26-6.77 years), there was a nonsignificant mean decrease in RRF from 19% (11%-28%) to 18% (9%-29%). The mean change in renal function was not affected by the severity of the initial RRF.

CONCLUSIONS

In the medium term, there is no deterioration of RRF of unilaterally severely damaged kidneys associated with either VUR or UTI managed either surgically or conservatively. Boys are at a much greater risk of severe reflux nephropathy.

Predictive risk factors in childhood urinary tract infection, vesicoureteral reflux, and renal scarring management

Approaches to the management of children with urinary tract infection (UTI), vesicoureteral reflux (VUR), and renal scars have been challenged and have become controversial over the past decade. It is difficult to determine when, how, and which patients will benefit from the diagnosis and management of this condition. Therefore, the issues of diagnostic imaging, observation, follow-up, and intervention tend to be decided more on a case-by-case basis, rather than by using an algorithm. Over the past few years, there have been advances in the identification of risk factors that predispose patients with UTI to present with VUR, to develop recurrent UTIs and renal scars, to have deteriorating renal function, to show VUR improvement and/or spontaneous resolution, and to be candidates for and benefit from early surgical intervention.

Differences in urodynamic variables for vesicoureteral reflux depending on the neurogenic bladder type

Objective

To compare the urodynamic study variables at the onset of vesicoureteral reflux (VUR) between the overactive and underactive bladders in patients with spinal cord injury who presented with VUR.

Methods

A total of 28 (13 cases of detrusor overactivity and 15 detrusor underactivity) men were enrolled. We compared the urodynamic variables between the two groups; detrusor pressure and bladder compliance, the infused volume at the onset of VUR measured on a voiding cystourethrography and cystometric capacity, maximum detrusor pressure, and bladder compliance during filling cystometry were recorded.

Results

At the onset of VUR, the bladder volume and compliance, except for the detrusor pressure, showed a significant difference between the two groups. The detrusor pressure, bladder volume, and bladder compliance relative to the cystometric capacity showed a significant difference between the two groups. The detrusor pressure, bladder volume, and bladder compliance at the onset of VUR relative to the cystometric bladder capacity did not show any significant difference between the two groups.

Conclusion

There were differences in some variables at the onset of VUR depending on the type of neurogenic bladder. The VUR occurred at a lower capacity in neurogenic bladder with detrusor overactivity than in neurogenic bladder with detrusor underactivity at the same pressure. VUR occurred at a lower intravesical pressure compared to that known as the critical detrusor pressure (≥40 cm H₂O) required for the development of VUR. The results of our study demonstrate that the detrusor pressure should be maintained lower than the well known effective critical detrusor pressure for the prevention and treatment of VUR.

Prevalence and risk factors for renal scars in children with febrile UTI and/or VUR: a cross-sectional observational study of 565 consecutive patients

PURPOSE

To determine prevalence and risk factors for renal scar in children referred for urologic assessment of febrile UTI and/or VUR.

METHODS

Pre-determined risk factors for renal scar were prospectively recorded in consecutive patients referred for UTI/VUR. Age, gender, VUR grade, and reported number of febrile and non-febrile UTIs were analyzed with logistic regression to determine risk for focal cortical defects on non-acute DMSA.

RESULTS

Of 565 consecutive children, 24 (4%) had congenital renal dysplasia and 84 (15.5%) had focal defect(s). VUR, especially grades IV-V, recurrent febrile UTI, and older age increased risk. For any age child with the same number of UTIs, VUR increased odds of renal defect 5.4-fold (OR = 5.4, 95% CI = 2.7-10.6, AUC = 0.759).

CONCLUSIONS

Focal DMSA defects were present in 15.5% of 565 consecutive children referred for febrile UTI and/or VUR; 4% had presumed congenital reflux nephropathy without cortical defect. All VUR grades increased risk for these defects, as did recurrent febrile UTIs and older age. However, 43% with grades IV-V VUR and 76% with recurrent UTI had normal DMSA.

Risk factors for renal scarring and deterioration of renal function in primary vesico-ureteral reflux children: a long-term follow-up retrospective cohort study

BACKGROUND AND PURPOSE

The aim was to identify the risk factors for renal scarring and deteriorating renal function in children with primary vesico-ureteral reflux (VUR).

MATERIALS AND METHODS

Patients with primary VUR admitted to the National Cheng Kung University Hospital were retrospectively analyzed. The outcomes were renal scarring, assessed by technetium-99 m dimercaptosuccinic acid scanning, and renal function, assessed by estimated glomerular filtration rate. Univariate and multivariate models were applied to identify the corresponding independent predictors.

RESULTS

A total of 173 patients with primary VUR were recruited. The median age of VUR diagnosis was 10.0 months (IQR: 4.0-43.0 months). After adjusting for confounding factors, it was found that older age of VUR diagnosis (≥5 years vs. <1 year, adjusted OR = 2.78, 95% CI = 1.00-7.70, p = 0.049), higher grade of VUR (high grade [IV-V] vs. none, adjusted OR = 15.17, 95% CI = 5.33-43.19, p<0.0001; low grade [I-III] vs. none, adjusted OR = 5.72, 95% CI = 2.43-13.45, p<0.0001), and higher number of UTI (≥2 vs. 0, adjusted OR = 3.21, 95% CI = 1.06-9.76, p = 0.039) were risk factors for renal scarring, whereas a younger age of VUR diagnosis (≥5 years vs. <1 year, adjusted HR = 0.16, 95% CI: 0.05-0.51, p = 0.002), renal scarring (yes vs. no, adjusted HR = 3.66, 95% CI: 1.32-10.16, p = 0.013), and APN (yes vs. no, adjusted HR = 3.10, 95% CI: 1.05-9.14, p = 0.041) were risk factors for developing chronic kidney disease stage 2 or higher.

CONCLUSIONS

Our findings expand on the current knowledge of risk factors for renal scarring and deteriorating renal function, and this information can be used to modify the management and treatment of VUR.

The role of DMSA renal scintigraphy in the first episode of urinary tract infection in childhood

OBJECTIVE

The role of dimercaptosuccinic acid (DMSA) renal scintigraphy in the first episode of urinary tract infection (UTI) has been the subject of debate for many years. The aim of this study was to evaluate the relationship of voiding cystourethrography (VCUG), renal ultrasonography and DMSA renal scintigraphy and to detect renal parenchymal changes by performing DMSA renal scintigraphy at 6 months after the first episode of UTI.

METHODS

A prospective study was conducted in 67 hospitalized children (46 boys, 21 girls). Mean age of the patients was 0.97 ± 1.57 years (0.02-7.26 years). All children received VCUG, renal ultrasonography and DMSA renal scintigraphy. DMSA renal scintigraphy was performed at 1 and 6 months after UTI.

RESULTS

Of 67 children, 17 (25.4%), 23 (34.3%) and 20 (29.9%) had vesicoureteral reflux (VUR), abnormal renal ultrasonography and abnormal DMSA renal scintigraphy, respectively. Unilateral hydronephrosis had a significant correlation with VUR at p value 0.024. In renal units, abnormal renal ultrasonography and hydronephrosis had significant correlations with VUR at p values 0.039 and 0.021, respectively. In patients and renal units, hydronephrosis had no significant correlation with abnormal DMSA renal scintigraphy at 1 month after UTI. However, abnormal renal ultrasonography and VUR had significant correlations with abnormal DMSA renal scintigraphy at p values 0.022 and < 0.001 in patients and at p values 0.024 and < 0.001 in renal units, respectively. Both in patients and renal units, VUR (Grade I-III) had no significant correlation with abnormal DMSA renal scintigraphy. However, severe VUR (Grade IV-V) had significant correlations with abnormal DMSA renal scintigraphy at p values < 0.001 and < 0.001, respectively. Seventeen patients underwent DMSA renal scintigraphy at 6 months after UTI. In addition, 15 (88.2%) developed persistent renal scarring.

CONCLUSION

Abnormal renal ultrasonography and severe VUR identify renal parenchymal changes. DMSA renal scintigraphy in the first episode of UTI should be carried out in those patients. Abnormal DMSA renal scintigraphy at 1 month after UTI has a tendency to persist.

Does hydronephrosis predict the presence of severe vesicoureteral reflux?

We hypothesized that, in patients with vesicoureteral reflux (VUR) grade IV or V, hydronephrosis will likely be found, if the patient has a full bladder during the renal ultrasound examination. Eight hundred thirty-seven patients were included in the study. Patients ranged in age from <1 month to 18.7 years, with a median age of 1.3 years. Five hundred sixty-nine were female and 268 were male. In this retrospective study, each patient underwent a voiding cystourethrogram (VCUG) and a renal ultrasound examination. The presence of hydronephrosis and bladder filling status in 131 renal units with VUR grade IV or V was evaluated. Sensitivity and specificity for hydronephrosis to detect the presence of VUR grades IV and V were 60 and 92 %, respectively. Positive predictive value and negative predictive value were 74 and 87 %, respectively. Odds ratios for the relationship between hydronephrosis and severe VUR was significant (p = 0.046).

CONCLUSION

In patients with grade IV or V VUR, hydronephrosis will be observed in the presence of a full bladder. Therefore, a renal ultrasound could be considered a screening test to decide on performing a VCUG.

Renal scar formation after urinary tract infection in children

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.

Predicting factors of breakthrough infection in children with primary vesicoureteral reflux

PURPOSE

Many pediatric urologists still favor using prophylactic antibiotics to treat children with vesicoureteral reflux (VUR). However, breakthrough infection sometimes occurs, leading to significant increases in morbidity as a result of renal scarring. Therefore, we tested whether abnormal renal scan and other factors are predictive of breakthrough infection using univariate analyses.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 163 consecutive children who were diagnosed with vesicoureteral reflux between November 1997 and June 2010. Clinical parameters for the statistical analysis included form of presentation, gender, age, VUR grade, laterality, presence of intrarenal reflux, class of antibiotic drug, and presence of abnormal renal scan by Dimercapto-succinic acid. Clinical parameters used for prognostic factors were established by univariate analyses. Fisher's exact test and unpaired t-test were done using SPSS software [SPSS ver. 12.0 (SPSS Inc., Chicago, IL, USA)].

RESULTS

Breakthrough infection developed in 61 children (48.0%). A total of 58 children (45.7%) had abnormal renal scans. Time to development of breakthrough infection was significantly longer in girls (9.0±8.2 months) than in boys (5.8±4.8 months, p<0.05). On univariate analysis, though statistically not significant, the most predictive factor of breakthrough infection was abnormal renal scan (p=0.062). In patients with abnormal renal scans, breakthrough infection was not associated with mode of presentation, gender, grade or prophylactic antibiotics. However, there was a significant difference between patients younger than 1 year and those 1 year old or older. Mean±SD age at diagnosis of VUR in patients with breakthrough infection (1.14±3.14) was significantly younger than in those without breakthrough infection (5.05±3.31, p=0.009). There was also a significant difference between patients with bilateral or unilateral reflux (p=0.028).

CONCLUSION

Our data showed that abnormal renal scan was the most predictive factor of breakthrough infection and demonstrated statistical significance in patients under the age of 1 year. Parents and physicians should remain aware that these patients are at high risk of breakthrough urinary tract infection, which may potentially lead to renal damage.

Risk factors for renal scar formation in infants with first episode of acute pyelonephritis: a prospective clinical study

PURPOSE

We prospectively determined the risk factors for renal scar formation after the first episode of acute pyelonephritis as confirmed on dimercapto-succinic acid scintigraphy in children younger than 1 year.

MATERIALS AND METHODS

A total of 213 infants with acute pyelonephritis were enrolled in the study. Infants with urological abnormalities other than vesicoureteral reflux were excluded from analysis. Followup scanning was performed 6 months after acute pyelonephritis and voiding cystourethrography was performed after the acute phase of infection. Possible risk factors were evaluated including gender, peak fever, duration of fever before and after treatment with antibiotics, white blood cell count, C-reactive protein concentration, presence of vesicoureteral reflux and reflux grade.

RESULTS

Six months after acute pyelonephritis 37 of 213 (17.4%) infants and 41 of 248 (16.5%) renal units with acute photon defects on initial dimercapto-succinic acid scintigraphy had renal scars. The rates of scar formation were significantly higher in infants with vesicoureteral reflux than in those without (39.4% vs 7.5%, p <0.001, OR 9.433) and in renal units with vesicoureteral reflux than in those without (39.4% vs 8.2%, p <0.001, OR 7.237). Renal scar formation was related to reflux grade (none-8.2%, grade I-20%, grade II-22.7%, grade III-40%, grade IV-70%, grade V-55.6%, p <0.001) but not to any other clinical or laboratory variables.

CONCLUSIONS

The presence of vesicoureteral reflux was the only independent risk factor for renal scar formation after acute pyelonephritis in infants. The prevalence of renal scarring was significantly correlated with reflux grade. Voiding cystourethrography is necessary in infants after the first acute pyelonephritis episode is confirmed on dimercapto-succinic acid renal scintigraphy.

Predictors of abnormal renal cortical scintigraphy in children with first urinary tract infection: the importance of time factor

INTRODUCTION

We evaluated different factors predicting the development of acute pyelonephritis in Iranian children, with special attention to time factor.

METHODS

One hundred nineteen patients (93 females and 26 males; age = 32.6 ± 30.8 months) with first urinary tract infection (UTI) were evaluated. None had previous urological problems. Prior to antibiotic therapy blood samples were gathered for laboratory evaluation. Vital signs on admission were measured. Clinical and laboratory indices, including therapeutic delay time (TDT) and therapeutic response time (TRT), were measured. Most patients were evaluated with renal ultrasound in the first three days following admission. All patients underwent dimercaptosuccinic acid (DMSA) renal scintigraphy and 71 were assessed for vesicoureteral reflux (VUR).

RESULTS

DMSA scans were abnormal in 77 cases, of which 11 cases had bilateral renal involvement. Mean values for TDT, TRT, leukocyte count (LC), absolute neutrophil count (ANC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were 74.1 h, 39.6 h, 15725 ± 6682 mm(-3), 10772 ± 6458 mm(-3), 51.9 ± 32.5 mm, and 27.3 ± 25.1 mg l(-1), respectively. VUR was present in 29 of 142 evaluated renal units.

CONCLUSION

TDT ≥ 48 h, TRT ≥ 24 h, axillary temperature ≥ 39°C, LC ≥ 13500 mm(-3), and age ≥ 18 months predicted abnormal DMSA scan in patients with first episode of UTI. Considerably higher TDT and TRT values of the current study compared to previous ones suggests the more important role of time factor in predicting abnormal DMSA findings in a developing country than in developed ones.

Controversies in the management of vesicoureteral reflux: the rationale for the RIVUR study

The current management of vesicoureteral reflux (VUR) focuses on the prevention of urinary tract infections (UTI), with curative surgery being limited to those children that fail conservative measures. This is based on the assumption that UTIs are preventable with the use of prophylatic antibiotics, leading to reduction of renal scarring, and the possibility that VUR in children can resolve spontaneously.

METHODS

Review of the recent literature has demonstrated a growing concern that antibiotic prophylaxis may not lead to prevention of UTIs. Additionally, data indicate that renal scarring may not be preventable with antibiotic prophylaxis or even surgical correction of VUR. An overview of all of the current controversies is presented in this paper.

RESULTS

Does antibiotic prophylaxis lead to reduction in UTIs in children with VUR? To address this question, the National Institutes of Health have developed a randomized placebo-controlled study of children with VUR (the RIVUR Study), identified following the development of a UTI.

CONCLUSIONS

There are far reaching consequences of the results of the RIVUR Study. If antibiotic prophylaxis does not prevent UTI in children with VUR, or lead to reduction in renal scarring, does identification of VUR provide any benefits? Perhaps appropriate treatment of UTI may be all that is necessary for preserving renal function. Final answers will have to wait until the completion of this study.

The significance of 99mtechnetium dimercapto-succinic acid renal scan in children with spina bifida during long-term followup

PURPOSE

(99m)Technetium dimercapto-succinic acid renal scans are ideal for demonstrating renal scarring in children with spina bifida. However, doubt persists about the need for routine application. We assessed the associations among abnormal (99m)technetium dimercapto-succinic acid renal scans, vesicoureteral reflux and urodynamic findings in patients with spina bifida during long-term followup.

MATERIALS AND METHODS

We retrospectively reviewed the records of 64 patients with spina bifida followed at our center. All patients were older than 10 years (mean 15.8, range 10 to 23). Dimercapto-succinic acid renal scans were considered abnormal with differential function of less than 40% or focal defects. Patient age, gender, previous febrile urinary tract infections, positive vesicoureteral reflux history, timing of clean intermittent catheterization initiation and the latest urodynamic findings were noted. Patients were grouped based on normal/abnormal scan results. Statistical analysis included univariate and multivariate regression analyses and chi-square tests.

RESULTS

A total of 16 patients (25%) had abnormal scans. Mean patient age, male-to-female ratio, leak point pressure, bladder compliance and timing of clean intermittent catheterization initiation did not differ between groups. Rates of previous febrile urinary tract infections differed significantly (11 of 16 in the abnormal group vs 9 of 48 in the normal group, p <0.01), as did positive reflux history (100% vs 31%, p <0.01). No patient with a negative reflux history had an abnormal dimercapto-succinic acid renal scan. Multivariate analysis identified previous febrile urinary tract infections as a significant risk factor for an abnormal scan.

CONCLUSIONS

A positive vesicoureteral reflux history and febrile urinary tract infections were associated with abnormal dimercapto-succinic acid renal scan in followup of patients older than 10 years with spina bifida. Thus, these factors are indicators of proactive evaluation of renal function using dimercapto-succinic acid renal scanning.