Urography versus DMSA scan in children with vesicoureteric reflux

Current Management of Urinary Tract Infection and Vesicoureteral Reflux

Urinary tract infection (UTI) is defined as the growth of a significant number of microorganisms of a single species in the urine, in the presence of symptoms. Symptoms in young children are non-specific such as fever without focus; young infants may manifest with irritability, failure to thrive, jaundice, vomiting and diarrhea. Older children usually have symptoms of cystitis or pyelonephritis. Symptoms of cystitis are dysuria, frequency, new onset incontinence and malodorous urine while symptoms of pyelonephritis are high grade fever, flank pain and vomiting. Rapid urine testing by microscopy for pus cells, dipstick testing for leukocyte esterase and nitrite, and enhanced urinalysis are supportive tests. Urine culture samples should be collected with proper technique and results interpreted for significant growth accordingly. Antibiotic therapy for 7-14 d for complicated UTI and 3-4 d for uncomplicated UTI is adequate. Further evaluation is recommended clinically for bladder-bowel dysfunction and obvious anatomical defects and by imaging for vesicoureteral reflux (VUR), usually by micturating cystourethrography (MCU). Since MCU involves exposure to radiation and urethral catheterization, it is now reserved for children with parenchymal involvement or recurrent UTI. VUR is the backward flow of urine into one or both ureters. Clinical manifestations other than UTI include incidental diagnosis on antenatal ultrasonography. Reflux nephropathy, the renal scarring associated with VUR may manifest clinically as hypertension, proteinuria and renal failure. The management of VUR is primarily with antibiotic prophylaxis. Anatomical correction is indicated in case of breakthrough febrile UTI. No intervention has been shown to reduce renal scarring.

Antibiotic prophylaxis in the management of vesicoureteric reflux: a randomized double-blind placebo-controlled trial

BACKGROUND

The benefits of long-term low-dose antibiotics in preventing urinary tract infection (UTI) and renal damage in children with primary vesicoureteric reflux (VUR) are unclear.

METHODS

Children aged between 1 and 12 years with VUR grade I-IV and a microbiologically proven UTI were randomized into two groups to receive either antibiotic prophylaxis [2 mg/kg trimethoprim + sulfamethoxazole (TMP-SMX)] daily or placebo, respectively, for 12 months. Primary outcome was microbiologically confirmed symptomatic UTI. Intention-to-treat analysis using time-to-event data was performed.

RESULTS

A total of 93 children (66.7 % boys) with a median age of 4.6 years were enrolled in this study; VUR grade III-IV was present in 73.1 % of these children. At least one symptomatic UTI occurred in ten (21.3 %) patients receiving antibiotic prophylaxis and in three (6.5 %) patients receiving placebo [hazard ratio in antibiotic group 3.9; 95 % confidence interval (CI) 1- 14; log rank test P = 0.02). Compared to the group receiving placebo, the antibiotic group had a 14.8 % increased risk for developing UTI (95 % CI 1-28; P = 0.03). Of the total number of episodes of UTI, 58.3 % of those in the antibiotic group were caused by TMP-SMX-resistant bacteria compared to 20 % in the placebo group (P = 0.15). A renal scan at 12 months revealed that six of 37 (16.2 %) patients in the antibiotic group and seven of 43 (16.3 %) patients in the placebo group had new or worsening of pre-existing scar.

CONCLUSIONS

Long-term antibiotic prophylaxis with TMP-SMX is associated with increased risk of symptomatic UTI compared to placebo in children with grade I-IV VUR.

DNAzyme tunable lead(ii) gating based on ion-track etched conical nanochannels

A simple biomimetic ionic gate has been developed by modifying lead(ii) ion responsive DNAzymes onto the inner surface of ion-etched polymer nanochannels.

Is Imaging Time Between two Tc 99m DMSA Scans Sufficient for Reporting as Renal Parenchymal Scarring? Healed Parenchymal Renal Defect After 6 Years

We aimed to report a healed renal parenchymal defect after 6 years in a 9-year-old girl who was being followed for recurrent urinary tract infection (UTI). The first UTI was at the age of two. She was being followed with ultrasonography, urine analysis and urine culture since the first UTI. Technetium-99m dimercaptosuccinic acid (DMSA) scintigraphy was repeated four times up to the present day. She had a renal parenchymal defect reported as parenchymal scarring, which healed 6 years after the first DMSA scintigraphy.

Conflict of interest:None declared.

Parental consent to participation in a randomised trial in children: associated child, family, and physician factors

BACKGROUND

Low participation rates in randomised controlled trials involving children are almost a universal problem, leading to high cost and low statistical power. Trial, parent/family, child, and physician factors have been reported to influence parental willingness to consent for paediatric trials.

PURPOSE

To identify modifiable and unmodifiable factors associated with parental consent.

METHODS

Demographic and clinical characteristics of children and their families and physician characteristics associated with parental consent were evaluated in a recent randomised placebo-controlled trial of prophylactic antibiotics to prevent recurrent urinary tract infection.

RESULTS

Of 1109 eligible children identified (mean age, 2.0 years), 412 parents (37.2%) consented. On a multivariate analysis, the only modifiable factor associated with consent was request for consent by a member of the research study team rather than by a member of the clinical team (risk ratio (RR) = 1.9, 95% confidence interval (CI): 1.2-2.9). The unmodifiable factors significantly associated with consent were age of the child (≥4 years) (RR = 1.2, 95% CI: 1.1-1.4), presence of vesicoureteric reflux (RR = 1.5, 95% CI: 1.3-1.8), inpatient management of the index infection (RR = 0.8, 95% CI: 0.7-0.9), and multiple (≥4) symptoms at presentation (RR = 1.3, 95% CI: 1.1-1.5).

LIMITATIONS

We have reported data from only one of the four participating centres in this trial. Data on non-consenters in other participating centres were not completely collected. Data on characteristics of the recruiting physician were limited. These findings are applicable for those considering a single randomised controlled trial.

CONCLUSIONS

Parent, child, and physician factors are associated with consent for trial participation, with most not being modifiable. Having a member of the research study team approach the parent for consent appears to be the only feasible strategy for increasing recruitment to randomised trials in this setting.

Persistent renin-angiotensin system activation after anti-reflux surgery and its management

PURPOSE

To study renin-angiotensin system activation and the role of angiotensin-converting enzyme inhibition (ACE-I) after anti-reflux surgery.

MATERIAL AND METHODS

Thirty nine children underwent anti-reflux surgery for high grades of primary VUR. Plasma renin activity (PRA), urinary microalbumin, renal scars, split renal function (SRF), glomerular filtration rate (GFR), serum creatinine, blood pressure and episodes of breakthrough urinary tract infection were monitored in the early (5.9 ± 3.9; range 3-9 months) and late (27.1 ± 6.5; range 15-36 months) postoperative phase, before and after therapy with ACE-I (mean period 13.6 ± 2.5; range 10-24 months).

RESULTS

The early postoperative improvement in renal parameters (rise in SRF and GFR by 11.2% and 7.3%, respectively, and fall in PRA by 68.8%), was not sustained subsequently (minimal improvement in SRF, 7.4%, and GFR, 0.14%, was accompanied by a rise in PRA by 92.3%). After ACE-I therapy, improvement was noted in SRF and GFR by 0.5% and 7.5%, respectively, and there was a fall in urinary microalbumin by 52.3%.

CONCLUSIONS

Significant down regulation of rennin-angiotensin system activation and the accompanying improvement in renal function seen early after surgery is not sustained during follow up. ACE-I aids renal recovery.

Renal scarring and osteopontin gene C/T polymorphism in children with primary vesicoureteral reflux

We examined for osteopontin (OPN) gene C/T polymorphism in 78 patients (53 girls) with vesicoureteric reflux, with or without renal scarring. The T allele frequency was associated with a significantly increased risk (26.4 fold) of renal scarring.

Vesicoureteral reflux associated renal damage: congenital reflux nephropathy and acquired renal scarring

PURPOSE

The pathophysiology, evaluation, description and clinical implications of renal damage associated with vesicoureteral reflux remain controversial. We summarized the current understanding of this important aspect of clinical vesicoureteral reflux.

MATERIALS AND METHODS

We performed a detailed review of the literature on clinical, pathological and experimental data related to congenital vesicoureteral reflux and bladder dynamics. We also reviewed the clinical context and imaging evaluation with underlying experimental data related to post-infectious reflux nephropathy.

RESULTS

Congenital reflux nephropathy is a pattern of impaired renal function and development with renal dysplasia as the most severe but not the only form. Mechanisms of developmental disruption are potentially related to vesicoureteral reflux dynamics during gestation and associated bladder dynamics, which may continue into postnatal life. Acquired renal injury associated with infection is related to particular bacterial and host factors that determine infection virulence, host inflammatory response and tissue recovery. As best seen on dimercapto-succinic acid scan, acute changes may resolve but may also persist as permanent renal scarring. Specific risk factors for acute pyelonephritis and renal scarring in patients with vesicoureteral reflux include higher reflux grade, dysfunctional voiding/elimination, recurrent pyelonephritic episodes and delayed initiation of antibiotic therapy. Low pressure sterile reflux is not a cause of reflux nephropathy.

CONCLUSIONS

Renal damage associated with vesicoureteral reflux may be congenital or acquired and the respective pathophysiological mechanisms are likely different. Congenital damage is often dysplasia, which may be a result of disordered renal development secondary to significant alterations in bladder dynamics. These processes may continue into the newborn period while kidney maturation continues. Recognizing the clinical potential for ongoing effects on renal function and the role of bladder development are important for clinical care. Post-pyelonephritic acquired damage is the result of a complex interaction of host and bacterial factors that leads to acute alterations in renal function, and may lead to permanent renal scarring. Strategies for timely intervention as well as prevention are essential to limit the risk of permanent renal injury, which may predispose to hypertension and renal insufficiency in some patients.

Risk factors for recurrent urinary tract infections in a cohort of patients with primary vesicoureteral reflux

BACKGROUND

Knowledge of risk of urinary tract infection (UTI) recurrence in vesicoureteral reflux (VUR) can help clinicians make therapeutic decisions. The aim of this retrospective cohort study was to identify risk factors associated with recurrent urinary tract infection in children with VUR. In addition, a risk score that might predict the chance of UTI recurrence was also proposed.

METHODS

Between 1970 and 2007, 740 patients were diagnosed with VUR and were systematically followed up at a single tertiary Renal Unit. Recurrent UTI was defined as more than 1 episode during follow-up. A binary logistic regression model was applied to identify variables independently associated with recurrent UTIs.

RESULTS

During follow-up, information was obtained on 58,856 person-months. Recurrent UTIs occurred in 120 (16.2%) patients. The overall incidence rate of UTI was 8.4 episodes per 1000 person-months (95% CI, 7.7, 9.2). After adjustment by multivariable analysis, 5 variables were independent predictors of recurrent UTI: UTI as clinical presentation, age < 6 months, female gender, dysfunctional elimination syndrome, and severe grade of reflux. The risk for recurrent UTI was classified as low in 24% of children, medium in 42%, and high in 34%. UTI incidence rates per 1000 person-months were 4.3 (95% CI, 3.2, 5.6), 7.9 (95% CI, 6.7, 9.1), and 11.3 (95% CI, 9.9, 12.8) for low-, medium-, and high-risk groups, respectively.

CONCLUSION

The prediction model of recurrent UTI allows an early recognition of patients at risk for long-term morbidity and might contribute to the formulation of therapeutic strategies.

Antibiotic prophylaxis and recurrent urinary tract infection in children

BACKGROUND

Antibiotics are widely administered to children with the intention of preventing urinary tract infection, but adequately powered, placebo-controlled trials regarding efficacy are lacking. This study from four Australian centers examined whether low-dose, continuous oral antibiotic therapy prevents urinary tract infection in predisposed children.

METHODS

We randomly assigned children under the age of 18 years who had had one or more microbiologically proven urinary tract infections to receive either daily trimethoprim-sulfamethoxazole suspension (as 2 mg of trimethoprim plus 10 mg of sulfamethoxazole per kilogram of body weight) or placebo for 12 months. The primary outcome was microbiologically confirmed symptomatic urinary tract infection. Intention-to-treat analyses were performed with the use of time-to-event data.

RESULTS

From December 1998 to March 2007, a total of 576 children (of 780 planned) underwent randomization. The median age at entry was 14 months; 64% of the patients were girls, 42% had known vesicoureteral reflux (at least grade III in 53% of these patients), and 71% were enrolled after the first diagnosis of urinary tract infection. During the study, urinary tract infection developed in 36 of 288 patients (13%) in the group receiving trimethoprim-sulfamethoxazole (antibiotic group) and in 55 of 288 patients (19%) in the placebo group (hazard ratio in the antibiotic group, 0.61; 95% confidence interval, 0.40 to 0.93; P = 0.02 by the log-rank test). In the antibiotic group, the reduction in the absolute risk of urinary tract infection (6 percentage points) appeared to be consistent across all subgroups of patients (P > or = 0.20 for all interactions).

CONCLUSIONS

Long-term, low-dose trimethoprim-sulfamethoxazole was associated with a decreased number of urinary tract infections in predisposed children. The treatment effect appeared to be consistent but modest across subgroups. (Australian New Zealand Clinical Trials Registry number, ACTRN12608000470392.)

Reflux nephropathy

Vesicoureteral reflux may be associated with abnormalities of the renal parenchyma. The purpose of this review is to define what the parenchymal abnormalities are histologically, what their etiologies may be, how they are identified and what their long-term clinical impact may be. Two categories are recognized, renal dysplasia and post-infection, chronic pyelonephritis. The diagnostic gold standard is microscopic evaluation of biopsy specimens but renal scintigraphy can be used in the diagnosis of renal dysplasia versus chronic pyelonephritis. Potential long-term sequelae of reflux nephropathy include hypertension and renal insufficiency although these may occur infrequently. A review of the current literature is provided.

Randomized Intervention for Children With Vesicoureteral Reflux (RIVUR): background commentary of RIVUR investigators

Because of the frequency of urinary tract infections in children, off-label use of antimicrobial prophylaxis is often the usual treatment of children with vesicoureteral reflux, and such use is increasingly being called into question; hence, a definitive study to determine the value of antimicrobial prophylaxis with regard to the recurrence of urinary tract infection and the incidence of renal scarring is essential. The currently recommended follow-up procedures (repeated urine cultures, renal and genitourinary imaging, antimicrobial therapy and prophylaxis, as well as other factors including cleanliness, adequate bladder and bowel emptying, and compliance with protocols) are expensive (in terms of time, attention to detail, and cost) and cumbersome. Such recommendations should be evidence-based.

Randomised trial of oral versus sequential intravenous/oral cephalosporins in children with pyelonephritis

The hypothesis was tested that oral antibiotic treatment in children with acute pyelonephritis and scintigraphy-documented lesions is equally as efficacious as sequential intravenous/oral therapy with respect to the incidence of renal scarring. A randomised multi-centre trial was conducted in 365 children aged 6 months to 16 years with bacterial growth in cultures from urine collected by catheter. The children were assigned to receive either oral ceftibuten (9 mg/kg once daily) for 14 days or intravenous ceftriaxone (50 mg/kg once daily) for 3 days followed by oral ceftibuten for 11 days. Only patients with lesions detected on acute-phase dimercaptosuccinic acid (DMSA) scintigraphy underwent follow-up scintigraphy. Efficacy was evaluated by the rate of renal scarring after 6 months on follow-up scintigraphy. Of 219 children with lesions on acute-phase scintigraphy, 152 completed the study; 80 (72 females, median age 2.2 years) were given ceftibuten and 72 (62 females, median age 1.6 years) were given ceftriaxone/ceftibuten. Patients in the intravenous/oral group had significantly higher C-reactive protein (CRP) concentrations at baseline and larger lesion(s) on acute-phase scintigraphy. Follow-up scintigraphy showed renal scarring in 21/80 children treated with ceftibuten and 33/72 with ceftriaxone/ceftibuten (p = 0.01). However, after adjustment for the confounding variables (CRP and size of acute-phase lesion), no significant difference was observed for renal scarring between the two groups (p = 0.2). Renal scarring correlated with the extent of the acute-phase lesion (r = 0.60, p < 0.0001) and the grade of vesico-ureteric reflux (r = 0.31, p = 0.03), and was more frequent in refluxing renal units (p = 0.04). The majority of patients, i.e. 44 in the oral group and 47 in the intravenous/oral group, were managed as out-patients. Side effects were not observed. From this study, we can conclude that once-daily oral ceftibuten for 14 days yielded comparable results to sequential ceftriaxone/ceftibuten treatment in children aged 6 months to 16 years with DMSA-documented acute pyelonephritis and it allowed out-patient management in the majority of these children.

Spontaneous resolution rates of vesicoureteral reflux in Brazilian children: a 30-year experience

OBJECTIVE

We evaluated clinical characteristics of primary vesicoureteral reflux (VUR) in infants in a 30-year period in Brazil with special reference to the relation of renal parenchymal damage to urinary tract infection and gender.

MATERIALS AND METHODS

From 1975 through 2005, 417 girls (81.6%) and 94 boys (18.4%) with all grades of reflux were retrospectively reviewed. Patients were categorized by the worst grade of reflux, maintained on antibiotic prophylaxis and underwent yearly voiding cystourethrography until the reflux was resolved. VUR was considered resolved when a follow-up cystogram demonstrated no reflux. Surgical correction was recommended for those who fail medical therapy, severe renal scarring or persistent VUR.

RESULTS

Grades I to V VUR resolved in 87.5%, 77.6%, 52.8%, 12.2% and 4.3%, respectively. Renal scars were present at presentation in 98 patients (19.2%). Neither gender nor bilaterality versus unilaterality was a helpful predictor of resolution. The significant difference was found among the curves using the log rank (p<0.001) or Wilcoxon (p<0.001) test.

CONCLUSION

Despite the current use of screening prenatal ultrasound, many infants are still diagnosed as having vesicoureteral reflux only after the occurrence of urinary tract infection in our country. Scarring may be associated to any reflux grade and it may be initially diagnosed at any age but half of the scars are noted with higher grades of reflux (IV and V). The incidence of reflux related morbidity in children has significantly diminished over the last three decades.

Risk of hypertension in primary vesicoureteral reflux

The aim of this report was to estimate the risk of hypertension in children with primary vesicoureteral reflux (VUR). Between 1970 and 2004, 735 patients were diagnosed with VUR at a single tertiary renal unit. Of 735 patients, 664 (90%) were systematically followed and had multiple measurements of blood pressure. Hypertension was defined as values persistently above 95th for age, sex, and height in three consecutive visits. Risk of hypertension was analyzed by the Kaplan-Meier method. Of 664 patients followed, 20 (3%) developed hypertension. The estimated probability of hypertension was 2% (95%CI, 0.5%-3%), 6% (95%CI, 2%-10%), 15% (95%CI, 11%-20%) at 10, 15, and 21 years of age, respectively. The prevalence of hypertension has increased with age: it was 1.7% for patients with 1 yr-9.9 yr, 1.8% for adolescents with 10 yr-14.9 yr, 4.7% for patients with 15-19.9 yr, and 35% for patients>20 years at the end of the follow-up (P<0.001). It was estimated by survival analysis that 50% of patients with unilateral and bilateral renal damage would have sustained hypertension at about 30 and 22 years of age, respectively. Hypertension increased with age and was strongly associated with renal damage at entry in an unselected population of primary VUR.

Factors affecting renal scarring in posterior urethral valves

AIM

To retrospectively review the occurrence of renal scarring in patients with posterior urethral valves (PUV), and correlate it with various causative factors.

METHODS

The records of 52 patients treated for PUV by the authors were reviewed. Patients with vesico-ureteric reflex (VUR) dysplasia syndrome were excluded from the study. The patients were divided into group I (no renal scarring, n=18) and group II (renal scars present, n=34) based on dimercapto-succinic acid scans. The mode of treatment, presence/absence of breakthrough urinary tract infections (UTI), presence/absence of history of nocturnal/diurnal incontinence, presence/absence of VUR, stable postoperative serum creatinine, rate of drainage of ureters on diethylene triamine penta acetic acid (DTPA) scans and management of bladder dysfunction, if any, were noted. The presence or absence of renal scarring was statistically correlated with occurrence of any of the above factors.

RESULTS

Primary valve fulguration was performed in 41 patients and 11 patients had an initial vesicostomy. The median follow up was 3.5 years (range 1.5-15 years). Renal scarring was present in either kidney in 34 patients (bilateral 14, unilateral 20). The mode of initial treatment did not affect the incidence or rate of scarring. The preoperative and postoperative serum creatinine at the end of 1 year did not differ between the two groups. Presence/severity of VUR did not affect the pattern of renal scarring. A highly significant correlation between the occurrence of renal scarring and presence of diurnal incontinence (P< or =0.007, odds ratio=4.5) and breakthrough UTI (P< or =0.002, odds ratio=7.0) was observed. There was also correlation with slow drainage in the ureters on a DTPA scan (P< or =0.0005). Detrusor instability and low compliance on urodynamic assessment did not affect occurrence in the limited number of patients studied. The rate of somatic growth in both groups was retarded as compared to normal healthy counterparts.

CONCLUSION

Breakthrough UTI, diurnal incontinence and poor drainage of ureters on DTPA are associated with a higher incidence of renal scarring. Mode of initial treatment, presence or absence of VUR, and bladder abnormalities do not affect renal scarring in the short term.

[Evaluation of renal lesions using 99mTc-DMSA in children with urinary tract infection and the relation with vesicoureteral reflux]

OBJECTIVE

Paediatric patients with urinary tract infection (UTI) have risk of developing renal scarrings. Although it is known that vesicoureteral reflux (VUR) predisposes to UTIs and it seems to have an important role in the development of renal lesions, some recent published studies question that relation. The aim of the study was to evaluate renal scarring by using renal scintigraphy 99mTc-DMSA and see the relation with or without the presence of VUR.

MATERIAL AND METHODS

We evaluated retrospectively a total of 230 patients (460 renal units), mean age: 11 months (range: 12d-5y), with UTI probed by urinoculture. All were studied with voiding cistourethrography (MCU) to evaluate the presence or absence of VUR. Patients were evaluated with 99mTc-DMSA scan 6 months after UTI to determine if UTI caused renal scarring.

RESULTS

Renal scans with 99mTc-DMSA 6 months post-infection were abnormal in 62 renal units, affecting 54 patients (23 %). From all patients studied, 110 were diagnosis of VUR being affected 161 renal units, 43 of them (27 %) presented renal scarrings. From the remaining 120 patients without VUR that is 240 renal units, 19 of them (8 %) presented parenchymatous damage.

CONCLUSION

Renal scarring resulting from UTI are in some cases related to VUR, but sometimes are caused by the infection itself. Not all patients with VUR develop renal lesions, and neither the presence of VUR always predispose children to renal lesions. MCU and direct isotopic cystography are useful for diagnosis of VUR but we shouldn't avoid 99mTc-DMSA scan in the management of children with UTI.

Predictive factors of chronic kidney disease in severe vesicoureteral reflux

The aim of this retrospective cohort study was to evaluate independent predictive factors of chronic kidney disease (CKD) in children with severe bilateral primary vesicoureteral reflux (VUR). Between 1970 and 2004, 184 patients were diagnosed with VUR (grades III-V) and were systematically followed up at a single tertiary renal unit. CKD was defined as estimated glomerular filtration rate <75 ml/min per 1.73 m2 body surface area in two consecutive examinations. Risk of CKD was analyzed by the Kaplan-Meier method and Cox's regression model. The probability of CKD for patients with bilateral severe reflux was estimated at 15% by 10 years after VUR diagnosis. After adjustment, four variables remained independently associated with CKD during follow-up: age at diagnosis >24 months [relative risk (RR)=4.8, 95% confidence interval (95%CI), 1.8-12.7, P<0.001], VUR grade V (RR=3.5, 95%CI, 1.5-7.9, P=0.002), bilateral renal damage (RR=2.86, 95%CI, 1.3-6.1, P=0.007), and decade of admission after 1990 as a protective factor (RR=0.16, 95%CI 0.06-0.43, P<0.001). A delay in the diagnosis of VUR more than 12 months after urinary tract infection (UTI) was also a predictive factor in an alternative model (RR=2.2, 95%CI, 1.1-6.6, P=0.03). Prognosis regarding renal function was relatively poor after a long-term follow-up of patients with bilateral severe reflux.

Controversies in the diagnosis and management of urinary tract infections in children

Urinary tract infection (UTI) is one of the most common childhood bacterial infections, after upper respiratory tract and middle ear infections. The current goal of management is to prevent detrimental effects of UTI by early detection and treatment. Recommendations for the imaging of children depend upon age at presentation and sex. All children aged <5 years who have had a febrile UTI require a radiologic evaluation to identify any underlying genitourinary pathology. Older children can undergo a more tailored work-up depending on whether there is a febrile UTI or cystitis-type symptoms. Dysfunctional voiding and urge syndrome significantly increase the risk of developing UTIs in children. Vesicoureteral reflux can increase the risk of pyelonephritis and renal scarring in children with UTIs. For the most part, pyelonephritis can be diagnosed on clinical grounds in the majority of patients and a subsequent (99m)Tc-dimercaptosuccinic acid scan can be reserved to identify post-nephritic renal scarring. When renal scarring is identified, the child and parents need to be educated regarding the possibility of hypertension, proteinuria, progressive nephropathy, and the risk of complications in future pregnancies. Treatment of UTI is started in the unwell child before the culture results are available and subsequently changed to culture-specific antimicrobial therapy. A short course of treatment is required for acute uncomplicated UTIs. A child with acute pyelonephritis requires 10-14 days of antibacterial treatment. The oral route in young children often causes vomiting, which implies therapeutic delay, a well known risk factor for scarring.

Permanent renal parenchymal defects after febrile UTI are closely associated with vesicoureteric reflux

The finding of scintigraphic renal defects in children with febrile urinary tract infection (UTI) even in the absence of vesicoureteric reflux (VUR) has led to the conclusion that VUR is a weak predictor of renal defects in these patients. We used isotopic cystography (IC) for diagnosis of VUR in children with febrile UTI. Dimercaptosuccinic acid renal scintigraphy was performed 6 months after cure of the last UTI. Renal defects were defined by the finding of focal defects of radionuclide uptake and/or by a split renal function <43%. The study included 206 children with primary VUR and 77 without VUR. Among the subjects with and without VUR, respectively, renal defects were found in 40 and 6% (p=0.0001), focal uptake defects in 33 and 5% (p=0.0001) and split renal function <43% in 26 and 5% (p=0.0001). Permanent renal defects in children with febrile UTI are closely associated with VUR. The possibility that a child will have permanent renal defects can reasonably be ruled out on the basis of the absence of VUR by IC.

Role of Technetium-99m N,N-Ethylenedicysteine Renal Scintigraphy in the Evaluation of Differential Renal Function and Cortical Defects

PURPOSE

This study was performed to evaluate the effectiveness of technetium-99m N,N-ethylenedicysteine (Tc-99m EC) in comparison to technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) scintigraphy. Differential renal function (DRF) was calculated by both methods and the cortical-phase images of dynamic Tc-99m EC scintigraphy were evaluated for parenchymal defects.

MATERIALS AND METHODS

A total of 62 patients with various kidney disorders ranging in age from 1 to 44 years underwent both Tc-99m DMSA and Tc-99m EC scintigraphy. Tc-99m EC summed images of the cortical phase and Tc-99m DMSA images were evaluated visually and quantitatively. Visual analysis was used to define renal parenchymal abnormalities. Quantitative analysis was used in the calculation of DRF. The Tc-99m DMSA scan was taken as the gold standard, and the summed Tc-99m EC scan findings were compared against it.

RESULTS

The images obtained with Tc-99m DMSA and Tc-99m EC scintigraphy revealed 99 and 97 focal defects, respectively. The 2 renal parenchyma defects located in the ventral middle sections remained undetected with Tc-99m EC scintigraphy. DRF of the kidneys in each patient was compared using both radiopharmaceuticals. Highly positive correlation between the differential function of these 2 investigations was found (R = 0.91, P = 0.001). The values of mean DRF of the left kidney on Tc-99m EC and Tc-99m DMSA images were 45.8 +/- 19.1 and 45.0 +/- 20.4, respectively. There were no significant differences (P > 0.05).

CONCLUSION

This study suggests that although Tc-99m DMSA scintigraphy remains the gold standard method for evaluating parenchymal abnormalities, Tc-99m EC scintigraphy can be a reliable single-modality study to evaluate renal cortical defects, DRF, perfusion, drainage of the urinary system, and indirect evidence of vesicoureteric reflux with the added advantage of low radiation exposure to the patient.

Evaluation of acute pyelonephritis with DMSA scans in children presenting after the age of 5 years

It is generally believed that infants are more susceptible to development of renal scarring after pyelonephritis than children over 5 years old. This view has led to differences in investigations and treatment according to age. The aim of this prospective study was to assess the occurrence of renal parenchymal lesion in children over 5 years admitted with a first-time symptomatic urinary tract infection (UTI). Between October 2000 and April 2002, 52 children aged over 5 years who were admitted to our department with probable acute pyelonephritis (APN) and a positive urine culture were included in this study. All children received antibiotics for 14 days. During the acute phase of infection, scintigraphy with technetium-99m-labeled dimercaptosuccinic acid (DMSA) and ultrasonography (US) were done. Voiding cystourethrography (VCUG) was performed in all children early in the course of the illness, generally within 5-7 days of hospitalization. When scintigraphy showed renal parenchymal changes, repeat scintigraphy was done after at least 3 months to assess the progression of renal abnormalities. Of the 52 children with a first-time documented pyelonephritis, cortical scintigraphy showed renal lesion in 41 children (78.8%). US was normal in all children with normal renal scintigraphy, while it detected renal abnormalities in 16 of the 41 (39 %) with abnormal scintigraphy (p <0.0001). Topographic analysis of the 165 focal lesions showed that 42.4% were localized to the upper poles, 17.5% to the middle third, and 40% to the lower poles of the kidneys. Repeat scintigraphy showed persistent lesions corresponding to those on the initial scan in nine (28.2%) of the 32 children. Renal lesions had partly regressed in 23 (71.8%) of the patients who underwent repeat scintigraphy. Vesicoureteral reflux was observed in 13.4% of kidneys and renal parenchymal abnormalities were identified in 71.4% and 72.2% of renal units, respectively, with and without reflux ( p >0.05). In conclusion, our data did not confirm the conventional opinion that the risk of renal scarring after pyelonephritis is low in children over the age of 5 years. Our findings suggest that renal scintigraphy may be a more appropriate method of investigation than VCUG for evaluation of the children over 5 years with acute pyelonephritis. Additionally, the frequency of scintigraphic changes is high, and a strategy based exclusively on ultrasound findings would miss about 61% of the abnormal renal units. We recommend that all children, irrespective of age, will benefit from further investigations that might prevent or limit the development of scarring process and renal complications.

Magnetic resonance voiding cystography in the diagnosis of vesicoureteral reflux: comparative study with voiding cystourethrography

PURPOSE

To evaluate the feasibility of magnetic resonance voiding cystography (MRVC) compared with voiding cystourethrography (VCUG) for detecting and grading vesicoureteral reflux (VUR).

MATERIALS AND METHODS

MRVC was performed upon 20 children referred for investigation of reflux. Either coronal T1-weighted spin-echo (SE) or gradient-echo (GE) (fast multiplanar spoiled gradient-echo (FMPSPGR) or turbo fast low-angle-shot (FLASH)) images were obtained before and after transurethral administration of gadolinium solution, and immediately after voiding. The findings of MRVC were compared with those of VCUG and technetium-99m ((99m)Tc) dimercaptosuccinic acid (DMSA) single-photon emission computed tomography (SPECT) performed within 6 months of MRVC.

RESULTS

VUR was detected in 23 ureterorenal units (16 VURs by both methods, 5 VURs by VCUG, and 2 VURs by MRVC). With VCUG as the standard of reference, the sensitivity of MRVC was 76.2%; the specificity, 90.0%; the positive predictive value, 88.9%; and the negative predictive value, 78.3%. There was concordance between two methods regarding the grade of reflux in all 16 ureterorenal units with VUR detected by both methods. Of 40 kidneys, MRVC detected findings of renal damage or reflux nephropathy in 13 kidneys, and (99m)Tc DMSA renal SPECT detected findings of reflux nephropathy in 17 kidneys.

CONCLUSION

Although MRVC is shown to have less sensitivity for VUR than VCUG, MRVC may represent a method of choice offering a safer nonradiation test that can additionally evaluate the kidneys for changes related to reflux nephropathy.

Casual and ambulatory blood pressure monitoring in children with renal scarring

INTRODUCTION Renal scarring is the most common cause of arterial hypertension in children. High blood pressure (BP) and microalbuminuria contribute to the progression of chronic renal disease. OBJECTIVE The aims of the study were: to assess BP in children with renal scarring by continuous ambulatory blood pressure measurement (ABPM) in comparison to the casual method (CBP), and to determine the correlation between ambulatory blood pressure (ABP) and/or casual blood pressure (CBP) values and proteinuria in children with renal scarring. METHOD This forward-looking study comprised thirty-five children (26 girls and 9 boys), aged between 3-13 years, 10.4?3.9, X+SD. Blood pressure was measured using the casual method (CBP) with a mercury manometer; BP was measured three times and the average was taken as a referent value. ABPM was performed using the oscillometric method with the Space Labs device, model 90207. RESULTS 45.71% of patients were classified as hypertensive by ABPM, while only 22.6% of CBP measurements were above the 95th percentile (p<0.01). "White coat hypertension" was present in 40% of the patients. Non-dipping BP alteration was detected in 37.14% of the patients. CONCLUSION Nocturnal systolic hypertension (systolic non-dipping alteration) is very frequent in children with renal scarring. Nocturnal diastolic blood pressure, detectable only via ABPM, is positively correlated with proteinuria and may be an initial sign of the progression of renal scarring. ABPM is more sensitive than CBP in the evaluation of BP in children with renal scarring.

Renal outcome in adults with renal insufficiency and irregular asymmetric kidneys

BACKGROUND

The commonest cause of end-stage renal failure (ESRF) in children and young adults is congenital malformation of the kidney and urinary tract. In this retrospective review, we examine whether progression to ESRF can be predicted and whether treatment with angiotensin converting enzyme inhibitors (ACEI) can delay or prevent this.

METHODS

We reviewed 78 patients with asymmetric irregular kidneys as a consequence of either primary vesico-ureteric reflux or renal dysplasia (Group 1, n = 44), or abnormal bladder function (Group 2, n = 34). Patients (median age 24 years) had an estimated GFR (eGFR) < 60 ml/min/1.73 m2 with at least 5 years of follow up (median 143 months). 48 patients received ACEI. We explored potential prognostic factors that affect the time to ESRF using Cox-regression analyses.

RESULTS

At start, mean (SE) creatinine was 189 (8) mumol/l, mean eGFR 41 (1) ml/min 1.73 m2, mean proteinuria 144 (14) mg/mmol creatinine (1.7 g/24 hrs). Of 78 patients, 36 (46%) developed ESRF, but none of 19 with proteinuria less than 50 mg/mmol and only two of 18 patients with eGFR above 50 ml/min did so. Renal outcome between Groups 1 and 2 appeared similar with no evidence for a difference. A benefit in favour of treatment with ACEI was observed above an eGFR of 40 ml/min (p = 0.024).

CONCLUSION

The similar outcome of the two groups supports the nephrological nature of progressive renal failure in young men born with abnormal bladders. There is a watershed GFR of 40-50 ml/min at which ACEI treatment can be successful at improving renal outcome.

ABNORMAL DIMERCAPTO-SUCCINIC ACID SCANS PREDICT AN INCREASED RISK OF BREAKTHROUGH INFECTION IN CHILDREN WITH VESICOURETERAL REFLUX

PURPOSE

The management of high grade vesicoureteral reflux remains controversial, with breakthrough infections being an indication for surgical repair. We sought to determine if technetium dimercapto-succinic acid (DMSA) scan could help predict which children are at risk for breakthrough urinary tract infection.

MATERIALS AND METHODS

A retrospective review was performed on children presenting with a febrile urinary tract infection and prenatal hydronephrosis who were found to have vesicoureteral reflux and underwent a DMSA scan. Reflux was tabulated according to the highest grade. DMSA results were graded as 0-normal, no parenchymal or size defects, grade 1-focal parenchymal defects or less than a quarter of a renal unit involved, or grade 2-severe defects to include at least half of a renal unit, bilateral defects or unilateral atrophy.

RESULTS

A total of 120 consecutive patients were evaluated. An abnormal DMSA scan was documented in 57 (33 females and 24 males), and 35 with grade 1 and 22 with grade 2 defects. Of the patients 53 females and 10 males had a normal scan. Of the 57 children with an abnormal DMSA scan 6% presented with grades 1 and 2 vesicoureteral reflux, 24% with grade 3, 38% with grade 4 and 26% with grade 5. Of the children with grades 3 to 5 reflux 60% had a subsequent breakthrough infection. Of the 63 children with a normal DMSA scan 11% presented with grade 1 reflux, 28% with grade 2, 48% with grade 3, 11% with grade 4 and 2% with grade 5. Of these children 5 had a subsequent breakthrough infection.

CONCLUSIONS

An abnormality on DMSA scan in the presence of grade 3 to 5 reflux correlates with a greater chance of having a breakthrough infection (60%). We conclude that children with grade 3 to 5 vesicoureteral reflux and an abnormal DMSA scan are at increased risk for breakthrough urinary tract infection.

Renal damage in vesico-ureteric reflux

OBJECTIVE

To detect the different extent of renal parenchymal involvement in primary vesico-ureteric reflux (VUR), and to evaluate the relationship between VUR grade, patient age and different patterns of parenchymal damage.

PATIENTS AND METHODS

This blinded retrospective study included 197 consecutive children (mean age 4.26 years, range 1 month to 13 years) with primary VUR detected by voiding cysto-urethrography (VCUG), 99mTc-dimercaptosuccinic acid (DMSA; 120 MBq/1.73 m2) renal scintigraphy, with scanning for 3 h after intravenous injection. An abnormal DMSA scan was classified into three subtypes: cortical defects as a single scar (SS), multiple cortical scarring (MS) and diffuse reduced uptake with small renal size. Renal absolute uptake (AU), and split-kidney relative uptake were evaluated in refluxing and nonrefluxing renal units, and correlated with parenchymal damage and patient age. Student's t-test and the chi-square test were used for the statistical analysis.

RESULTS

In all, 282 refluxing and 112 nonrefluxing units were assessed. Renal damage was detected in 188 of 282 units with VUR (67%) and in 18 of 112 (16%) contralateral nonrefluxing kidneys. The mean AU was 18.7% in kidneys with VUR and 29% in nonrefluxing units (P < 0.001). The mean (SD) AU decreased from lower to higher grades of VUR, i.e. grade 0 VUR (group A), 28.97 (9.71); grade 1-3 (group B), 21.28 (8.33); grade 4-5 (group C), 14.78 (8.02). The differences were statistically significant (A vs B, B vs C, both P < 0.001). Renal damage was differently distributed in the three groups: 69 of 109 kidneys (63%) in group C (MS prevalent), 39 of 173 (22.5%) in group B (SS prevalent) and 17 of 112 (15.2%) in group A. There was no significant difference in the distribution of renal damage subtypes in patients aged < or > 2 years (SS 19.6% vs 17.9%, MS 29.6% vs 30.1%, small size 48.2% vs 46.3%). The VUR was severe (group C) in 65% of patients aged < 2 years and in 46% aged > 2 years (chi-square, P = 0.016).

CONCLUSIONS

VUR is commonly associated with renal damage. Age (< or > 2 years) did not significantly influence the kidney lesion subtype. Reduced parenchymal function (AU) progressively decreased with the severity of VUR. Focal MS, reduced size and relative uptake were significantly more common in severe VUR, leading to multifocal lesions and hypo-dysplasia. Renal scarring was present in up to 15% of contralateral nonrefluxing kidneys. Severe VUR behaved differently from lesser VUR in the renal scan parenchymal uptake.

Split renal function does not change after successful treatment in children with primary vesico-ureteric reflux

OBJECTIVE

To evaluate the renal growth pattern in patients with primary vesico-ureteric reflux (VUR) using long-term measurements of split renal function with 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy.

PATIENTS AND METHODS

In all, 712 children aged < 16 years (466 boys and 246 girls) with primary VUR were referred to our hospital from July 1991 to December 2000. VUR was diagnosed by voiding cysto-urethrography. The patients were treated either surgically (group 1) or conservatively (group 2) and followed with serial 99mTc-DMSA scintigraphy for up to 10 years. There were 942 examinations in 367 of 712 patients who had repeat scintigraphy. Patients with secondary VUR, VUR to a solitary or fused kidney, or upper urinary tract obstruction, were excluded. Five of 298 patients (1.7%) who had ureteric reimplantation had a febrile urinary tract infection (UTI) soon after surgery but none recurred (recurrence is an indication for surgery in children with VUR); there was no febrile UTI in the 69 patients in group 2. Planar scintigraphy with 99mTc-DMSA was used to assess the absolute uptake (AU) of each kidney, measured as a percentage of the injected dose, and the relative uptake (RU = AU of each kidney/AU of both kidneys) calculated. The initial examination was at least 4 weeks after any febrile UTI in most patients. Serial studies were conducted 1 year after surgery and then biannually in group 1. In group 2 the DMSA scan was repeated every 2-3 years. The change in split renal function was compared with the RU of the right kidney.

RESULTS

The RU of the right kidney at the initial scan correlated closely with those on repeated scans in both groups. The correlation coefficients were 0.99 in group 1 and 0.94-0.97 in group 2 at every study. The change of RU remained within 0.05 in all patients after treatment.

CONCLUSIONS

Under strict control of UTI, split renal function in children with primary VUR does not change. There may be no possibility of accelerated or compensatory growth of the kidney with reflux nephropathy, but no concern about deterioration and atrophy either.

Long-term follow-up of women hospitalized for acute pyelonephritis

Long-term outcome of acute pyelonephritis (AP) in adults is unknown. We evaluated the frequency of renal damage 10-20 years after hospitalization for AP in adult women and the utility of technetium Tc 99m-labeled dimercaptosuccinic acid (Tc 99m-DMSA) scanning for detection of renal scars; 63 of 203 women hospitalized with AP during 1982-1992 were included in the study. Tc 99m-DMSA scanning detected renal scarring in 29 women (46%). Multivariate analysis showed that pregnancy and hypoalbuminemia (albumin level, <3.2 g/dL) at hospitalization were independent risk factors for subsequent development of renal scars. At follow-up, hypertension was observed in approximately one-fifth of patients, regardless of renal scarring status. Four women with scars had a glomerular filtration rate of < or =75 mL/min; none of them developed severe renal impairment. In conclusion, the risk of developing renal scarring after AP in adult women is high. However, clinically relevant renal damage is rare 10-20 years after AP. Tc 99m-DMSA scanning is useful for detecting renal scars in adults but is not routinely needed in practice.

Technetium-99m-N,N-ethylenedicysteine and Tc-99m DMSA scintigraphy in the evaluation of renal parenchymal abnormalities in children

Technetium-99m dimercaptosuccinic acid (Tc-99m DMSA) as a static renal agent is currently the most frequently used agent in the detection of renal scarring, and allows accurate calculation of differential renal function (DRF). But this agent has some disadvantages such as relatively higher radiation dose and time consumption.

METHODS

The purpose of this study was to evaluate the potential of summed image that obtained from parenchymal phase of the dynamic technetium-99m-N,N-ethylenedicysteine (Tc-99m EC) scintigraphy in the detection of renal parenchymal defects and in the estimation of DRF, and to compare the results of this method with those of Tc-99m DMSA scintigraphy. The uptake ratios of the kidney to body background were also calculated for these two methods. Twenty-nine children with various renal disorders underwent both static Tc-99m DMSA and dynamic Tc-99m EC scintigraphy. The cortical analysis of Tc-99m EC scintigraphy was performed on the summed image obtained from dynamic images using the time interval between the first 45-120 sec.

RESULTS

There was a very close correlation between these two methods with respect to DRF (r = 0.99). In the detection of renal parenchymal lesions, scintigraphy with Tc-99m DMSA detected more lesions, and the sensitivity and specificity of the summed Tc-99m EC images were calculated as 92.6% and 100%, respectively. In addition, the ratios of mean uptake values for Tc-99m DMSA and Tc-99m EC images were 7.59 +/- 2.17 and 2.95 +/- 0.91, respectively. This ratio of Tc-99m EC seems to be acceptable and allows good delineation of the kidneys. But, the main disadvantages of the summed Tc-99m EC images in comparison with static Tc-99m DMSA images are the use of only posterior projection that may be an important drawback in patients with abnormal kidney positions, lower image counts and higher pixel size because of dynamic acquisition.

CONCLUSION

These results show that summed Tc-99m EC images with an acceptable high image contrast provide an accurate DRF calculation in patients without abnormal kidney positions and allow the detection of most renal parenchymal abnormalities. However, Tc-99m DMSA scintigraphy remains the gold standard method because of its well known advantages.

Acute pyelonephritis and sequelae of renal scar in pediatric first febrile urinary tract infection

To investigate the incidence of acute pyelonephritis (APN) and renal scarring in children with febrile urinary tract infection (UTI), 191 of 216 (88%) children with their first episode of UTI received (99m)Tc-dimercaptosuccinic acid renal single-photon emission computed tomography. They were investigated within 7 days of admission and were followed for 6 months. One hundred and six patients (49.1%) underwent a voiding cystourethrogram. The incidence of vesicoureteric reflux (VUR) in group I (</=1 year old) was 22%, group II (1-5 years old) 69%, and group III (5-17 years old) 44%. The overall incidence of APN in febrile UTI was 70% (male 66%, female 76%, P=0.110). Children had a higher incidence of APN than infants ( P<0.05 in group I vs. II and group I vs. III). Of patients with APN, 57% (35/61) showed renal scar formation. VUR was found in 31%(24/78) of children with APN and 58% (14/24) of children with renal scar. In addition, children with high-grade VUR were more susceptible to APN and scar formation than those with low-grade VUR ( P<0.05). Older children with a first febrile UTI had a higher incidence of APN than infants (</=1 year), and half of the children with APN developed a renal scar.

Primary vesicoureteric reflux as a predictor of renal damage in children hospitalized with urinary tract infection: a systematic review and meta-analysis

Renal parenchymal disease after urinary tract infection (UTI) has been associated with the development of hypertension and renal functional impairment. A systematic literature review and meta-analysis was performed to determine how effectively the finding of primary vesicoureteric reflux (VUR) on micturating cystography (MCU) in children hospitalized with UTI predicted renal parenchymal disease on (99m)Technetium-dimercaptosuccinic acid ((99m)Tc-DMSA) scintigraphy. Medline, Embase, and PubMed were use to find reports with original data for children hospitalized with bacteriologically-proven UTI who had undergone both MCU and (99m)Tc-DMSA scintigraphy, and which also reported both positive and negative results of these tests. A meta-analysis of likelihood ratios positive and negative for MCU was then performed, including tests for heterogeneity. Twelve valid studies were found, seven with data for 537 children, with a positive (99m)Tc-DMSA scan prevalence of 59% overall, and seven studies with data for 1062 kidneys, with a positive (99m)Tc-DMSA scan prevalence of 36%. The likelihood ratio positive for MCU was 1.96 (95% CI, 1.51 to 2.54) for children, and 2.34 (1.53 to 3.57) for kidneys. The likelihood ratio negative was 0.71 (0.58 to 0.85) for children and 0.72 (0.61 to 0.86) for kidneys. There was evidence of heterogeneity. The meta-analysis showed that a positive MCU increases the risk of renal damage in hospitalized UTI patients by about 20%, whereas a negative MCU increases the chance of no renal involvement by just 8%. VUR is hence a weak predictor of renal damage in pediatric patients hospitalized with UTI. Physicians should be aware of the limitations of using MCU-detected primary VUR as an effective screening test for renal damage in this population. Furthermore, the pathogenesis of renal damage in such patients is probably complex because it is often detected without demonstrable VUR.

Imaging studies after a first febrile urinary tract infection in young children

BACKGROUND

Guidelines from the American Academy of Pediatrics recommend obtaining a voiding cystourethrogram and a renal ultrasonogram for young children after a first urinary tract infection; renal scanning with technetium-99m-labeled dimercaptosuccinic acid has also been endorsed by other authorities. We investigated whether imaging studies altered management or improved outcomes in young children with a first febrile urinary tract infection.

METHODS

In a prospective trial involving 309 children (1 to 24 months old), an ultrasonogram and an initial renal scan were obtained within 72 hours after diagnosis, contrast voiding cystourethrography was performed one month later, and renal scanning was repeated six months later.

RESULTS

The ultrasonographic results were normal in 88 percent of the children (272 of 309); the identified abnormalities did not modify management. Acute pyelonephritis was diagnosed in 61 percent of the children (190 of 309). Thirty-nine percent of the children who underwent cystourethrography (117 of 302) had vesicoureteral reflux; 96 percent of these children (112 of 117) had grade I, II, or III vesicoureteral reflux. Repeated scans were obtained for 89 percent of the children (275 of 309); renal scarring was noted in 9.5 percent of these children (26 of 275).

CONCLUSIONS

An ultrasonogram performed at the time of acute illness is of limited value. A voiding cystourethrogram for the identification of reflux is useful only if antimicrobial prophylaxis is effective in reducing reinfections and renal scarring. Renal scans obtained at presentation identify children with acute pyelonephritis, and scans obtained six months later identify those with renal scarring. The routine performance of urinalysis, urine culture, or both during subsequent febrile illnesses in all children with a previous febrile urinary tract infection will probably obviate the need to obtain either early or late scans.

Nuclear medicine studies in the dialysis patient

Nuclear medicine (scintigraphy) studies that are performed in patients being prepared for regular dialysis treatment include the measurement of renal clearance and dynamic studies of renal perfusion and function. Static scintigraphy with 99mTc-DMSA may be used in the evaluation of children at risk of renal damage and further functional deterioration. In patients on peritoneal dialysis, nuclear medicine procedures enable the diagnosis of structural complications such as intra-abdominal herniations and leaks. Diagnosis of infections of the vascular access sites in patients on hemodialysis and of the catheter tunnel in patients on peritoneal dialysis can be made with high diagnostic accuracy using radiolabeled, autologous leukocytes. Scintigraphy is valuable in delineating the extent of deposits of amyloid and parenchymal microcalcifications, and may be helpful in the functional evaluation of organs and tissues involved in the pathophysiology of renal impairment and dialysis. If radioiodine therapy with 131I is performed in patients on hemodialysis with benign or malignant thyroid disease, then pretherapeutic dosimetry is necessary to avoid over- and undertreatment. Radioiodine therapy in the dialysis patient leads to only insignificant contamination of dialysis equipment and marginal exposure to the medical staff.

Role of TGF-beta1 in renal parenchymal scarring following childhood urinary tract infection

BACKGROUND

Significant variability exists in the outcome of renal parenchymal inflammation following urinary tract infection (UTI) in childhood as some children experience renal parenchymal scarring (RPS) while others do not scar. Since TGF-beta1 is pro-fibrotic, we examined the role of this cytokine in RPS following UTI.

METHODS

Five polymorphisms of the TGF-beta1 gene were investigated as well as the relationship between these polymorphisms and TGF-beta1 production by peripheral blood mononuclear cells (PBMC) in vitro. DNA was isolated from 91 children shown to have developed RPS, 43 children with no evidence of scarring (NS) following UTI, and 171 healthy controls. Genotyping was performed by restriction fragment length polymorphism (RFLP). PBMC were isolated from a subgroup of 24 patients from the total population. Cells were stimulated with LPS + PMA + PHA and then TGF-beta1 production was determined by ELISA.

RESULTS

Comparing the NS with the RPS group, there was an increase in the -800 GA genotypes (18.6 vs. 7.4%, P=0.05; chi2) and the Leu10-->Pro CT (62.8 vs. 41.5%, P=0.021), and a decrease in the -509 TT genotype (0.0 vs. 8.5%, P=0.049). PBMC TGF-beta1 production was higher in those patients with the -800 GG compared to those with a GA genotype stimulation index [stimulated/unstimulated TGF-beta1 levels were 1.54 interquartile range (IQR) 1.42 to 1.75 vs. 1.19, IQR 0.94 to 1.51, P=0.031].

CONCLUSIONS

There is an association between the TGF-beta1 -800 GA, -509 TT and Leu10-->Pro CT genotypes and the presence or absence of RPS. The low TGF-beta1 producer status of the -800 GA genotype may protect against the development of a pro-fibrotic pathology.

Randomised controlled trial of three day versus 10 day intravenous antibiotics in acute pyelonephritis: effect on renal scarring

BACKGROUND

Acute pyelonephritis often leaves children with permanent renal scarring.

AIMS

To compare the prevalence of scarring following initial treatment with antibiotics administered intravenously for 10 or three days.

METHODS

In a prospective two centre trial, 220 patients aged 3 months to 16 years with positive urine culture and acute renal lesions on initial DMSA scintigraphy, were randomly assigned to receive intravenous ceftriaxone (50 mg/kg once daily) for 10 or three days, followed by oral cefixime (4 mg/kg twice daily) to complete a 15 day course. After three months, scintigraphy was repeated in order to diagnose renal scars.

RESULTS

Renal scarring developed in 33% of the 110 children in the 10 day intravenous group and 36% of the 110 children in the three day group. Children older than 1 year had more renal scarring than infants (42% (54/129) and 24% (22/91), respectively). After adjustment for age, sex, duration of fever before treatment, degree of inflammation, presence of vesicoureteric reflux, and the patients' recruitment centres, there was no significant difference between the two treatments on renal scarring. During follow up, 15 children had recurrence of urinary infection with no significant difference between the two treatment groups.

CONCLUSION

In children with acute pyelonephritis, initial intravenous treatment for 10 days, compared with three days, does not significantly reduce the development of renal scarring.

Paediatric anatrophic nephrolithotomy; stone clearance - at what price?

OBJECTIVE

To evaluate the functional outcome of anatrophic nephrolithotomy in children.

PATIENTS AND METHODS

All children undergoing anatrophic nephrolithotomy for complex branching and multiple renal calculi over an 11-year period were studied prospectively. Demographic data, treatment details and outcome, as assessed by X-ray, ultrasonography and isotope studies, were recorded. Anatrophic nephrolithotomy was carried out with surface cooling of the kidney followed by nephrostomy drainage for 5-7 days.

RESULTS

Nine children (median age 4 years, range 7 months to 9 years) underwent anatrophic nephrolithotomy. Predisposing factors included urinary tract infection (by Proteus mirabilis) in all and hyper-calciuria in two children. The median (range) total ischaemic time at operation was 25 (15-40) min and the operative duration 150 (120-200) min. Three children required a blood transfusion. Stone clearance was incomplete in one child. There was no recurrent stone formation after a long-term follow-up (median 32 months, range 14-107) in the other patients. Isotope studies showed impaired split renal function (<40%) in six children before surgery; there was a significant decline (>5%) in divided function in five children (range 6-16%) after surgery.

CONCLUSION

Anatrophic nephrolithotomy is an effective means of rendering children with branching calculi stone-free, but this study suggests that it leads to some further parenchymal damage.

Imaging of renal scarring

Children with urinary tract infection should be investigated and followed up, as those with pyelonephritis may develop renal scarring. In this review, after discussing the advantages and disadvantages of various imaging modalities for diagnosis of renal scarring, it is concluded that DMSA scintigraphy and urography can both be used to detect significant renal scarring. With DMSA scintigraphy, small renal lesions (functional uptake defects) not seen at urography will also be detected. The long-term clinical significance of these lesions is, as yet, unknown. A normal DMSA scintigraphy after infection indicates low risk for clinically significant damage. In order to allow acute, reversible lesions to first disappear, a follow-up DMSA examination should not be performed until at least 6 mo after the acute infection. Ultrasonography in isolation cannot be recommended for the diagnosis of renal scarring.

Evaluation and management of pediatric urinary tract infections

Urinary tract infections (UTIs) are relatively common in children. We describe the evaluation and management of children with UTIs, as well as the risks and consequences related to the UTI. This article describes a rational approach to the evaluation and management of childhood UTIs with the relation to the natural history and risk factors.

Vesico-ureteric reflux and other risk factors for renal damage: identification of high- and low-risk children

This article reviews the literature with respect to various risk factors for permanent renal damage in children with urinary tract infection. Vesico-ureteric reflux is an important risk factor, but renal damage can occur in the absence of reflux. Renal damage does not always occur in the presence of gross reflux. Renal scars always develop at the same site as a previous infection in the kidney. Recurrent pyelonephritis and delay in therapy increase the likelihood of renal damage, although it is not known how long a delay is dangerous to the human kidney. Recent studies using 99mtechnetium-dimercaptosuccinic acid (DMSA) scintigraphy have not confirmed the findings of previous studies showing that children below 1 y of age are more vulnerable to renal damage. It is more likely that all children run the risk of renal scarring in cases of acute pyelonephritis. The role of bladder pressure is still not entirely understood. Therefore more studies are needed in order to determine the relationship between high voiding pressures in some, otherwise healthy, children with urinary tract infection and renal scarring. The importance of bacterial virulence in the development of renal scarring is unclear. DMSA scintigraphy and voiding cystourethrography are the most reliable tools for identifying children at risk of renal scarring. As a single method DMSA scintigraphy appears to be better than voiding cystourethrography.

No further development of renal scarring after antireflux surgery in children with primary vesicoureteral reflux: review of the results of 99mtechnetium dimercapto-succinic acid renal scan

PURPOSE

Reports of previous studies using excretory urography indicate that significant numbers of new scars developed in 5 to 31% of cases and scarring progressed in 11 to 16% after antireflux surgery. We evaluated renal scarring after surgery using a more accurate method, that is dimercapto-succinic acid renal scintigraphy.

MATERIALS AND METHODS

Between 1985 and 1997 antireflux surgery was performed for primary vesicoureteral reflux in 223 children at our hospital. Of these patients 45 boys and 29 girls with a median age of 74 months at surgery in whom preoperative and postoperative renal scans were available form the basis of our retrospective study. Renal scan was performed 0.3 to 58 months (median 2) preoperatively and 5.3 to 44 months (median 18.7) postoperatively. A total of 24 children (39 renal units) were followed further by additional scanning for as long as 25 to 120 months (median 43.2) postoperatively. Each scan was blindly reviewed for the size, number and zone location of cortical defects based on morphology. Interval changes were grouped into categories as improved, no change, progressed and new scar formation.

RESULTS

Postoperatively there was no ureteral obstruction. Pyelonephritis developed in 2 patients (2.7%) and asymptomatic bacteriuria was noted in 35 (47.3%) postoperatively. Of the renal units 110 (86.6%) showed no change, while 15 (11.8%) were improved and 2 (1.6%) had progression. In no case was new renal scar formation observed.

CONCLUSIONS

Contrary to most previous reports involving excretory urography, our results indicate no significant progression of renal scarring after antireflux surgery. In most cases postoperative followup renal scans demonstrated no significant morphological change. When there was change, it mostly involved the disappearance or decrease of renal scars.

No further development of renal scarring after antireflux surgery in children with primary vesicoureteral reflux: review of the results of 99mtechnetium dimercapto-succinic acid renal scan

PURPOSE

Reports of previous studies using excretory urography indicate that significant numbers of new scars developed in 5 to 31% of cases and scarring progressed in 11 to 16% after antireflux surgery. We evaluated renal scarring after surgery using a more accurate method, that is dimercapto-succinic acid renal scintigraphy.

MATERIALS AND METHODS

Between 1985 and 1997 antireflux surgery was performed for primary vesicoureteral reflux in 223 children at our hospital. Of these patients 45 boys and 29 girls with a median age of 74 months at surgery in whom preoperative and postoperative renal scans were available form the basis of our retrospective study. Renal scan was performed 0.3 to 58 months (median 2) preoperatively and 5.3 to 44 months (median 18.7) postoperatively. A total of 24 children (39 renal units) were followed further by additional scanning for as long as 25 to 120 months (median 43.2) postoperatively. Each scan was blindly reviewed for the size, number and zone location of cortical defects based on morphology. Interval changes were grouped into categories as improved, no change, progressed and new scar formation.

RESULTS

Postoperatively there was no ureteral obstruction. Pyelonephritis developed in 2 patients (2.7%) and asymptomatic bacteriuria was noted in 35 (47.3%) postoperatively. Of the renal units 110 (86.6%) showed no change, while 15 (11.8%) were improved and 2 (1.6%) had progression. In no case was new renal scar formation observed.

CONCLUSIONS

Contrary to most previous reports involving excretory urography, our results indicate no significant progression of renal scarring after antireflux surgery. In most cases postoperative followup renal scans demonstrated no significant morphological change. When there was change, it mostly involved the disappearance or decrease of renal scars.

Consensus on renal cortical scintigraphy in children with urinary tract infection. Scientific Committee of Radionuclides in Nephrourology

A questionnaire related to cortical scintigraphy in children with urinary tract infection was submitted to 30 experts. A wide consensus was reached on several issues related to planar images: 99mTc dimercapto succinic acid (DMSA) appears as the most appropriate tracer for renal imaging; dynamic tracers are considered to be inferior, in particular 99mTc diethylenetriaminepentaacetate, which is not recommended. The general opinion is that DMSA scintigraphy is not feasible with a minimal dose below 15 MBq, whereas the maximum dose should not be higher than 110 MBq. The dose schedule generally is based on body surface area, and sedation is only exceptionally given to children. Images are obtained 2 to 3 hours after injection, preferably with high resolution collimators; pinhole images are used by only half of the experts. Posterior and posterior oblique views are used by most of the experts, and the posterior view is acquired in supine positions. At least 200.000 kcounts or 5 minute acquisition is required for nonzoomed images. As a quality control, experts check the presence of blurred or double outlines on the DMSA images. Color images are not used and experts report on film or directly on the computer screen. As far as normal DMSA images are concerned, most experts agree on several normal variants. Hydronephrosis is not a contraindication for DMSA scintigraphy but constitutes a pitfall. Differential renal function generally is measured, but no consensus is reached whether or not background should be subtracted. Most of the experts consider 45% as the lowest normal value. A consensus is reached on some scintigraphic aspects that are likely to improve and on some others that probably represent persistent sequelae. There is a wide consensus for the systematic use of DMSA scintigraphy for detection of renal sequelae, whereas only 58% of the experts are systematically performing this examination during the acute phase of infection.