Update on dimercaptosuccinic acid renal scanning in children with urinary tract infection

MR-Proadrenomedullin as biomarker of renal damage in urinary tract infection in children

Background

Midregional-proadrenomedullin (MR-proADM) is a useful prognostic peptide in severe infectious pathologies in the adult population. However, there are no studies that analyze its utility in febrile urinary tract infection (fUTI) in children. An accurate biomarker would provide an early detection of patients with kidney damage, avoiding other invasive tests like renal scintigraphy scans. Our objective is to study the usefulness of MR-proADM as a biomarker of acute and chronic renal parenchymal damage in fUTI within the pediatric population.

Methods

A prospective cohort study was conducted in pediatric patients with fUTI between January 2015 and December 2018. Plasma and urine MR-proADM levels were measured at admission in addition to other laboratory parameters. After confirmation of fUTI, renal scintigraphy scans were performed during the acute and follow-up stages. A descriptive study has been carried out and sensitivity, specificity and ROC curves for MR-proADM, C-reactive protein, and procalcitonin were calculated.

Results

62 pediatric patients (34 female) were enrolled. Scintigraphy showed acute pyelonephritis in 35 patients (56.5%). Of those patients, the median of plasmatic MR-proADM (P-MR-proADM) showed no differences compared to patients without pyelonephritis. 7 patients (11.3%) developed renal scars (RS). Their median P-MR-proADM levels were 1.07 nmol/L (IQR 0.66–1.59), while in patients without RS were 0.48 nmol/L (0.43–0.63) (p < 0.01). The AUC in this case was 0.92 (95% CI 0.77–0.99). We established an optimal cut-off point at 0.66 nmol/L with sensitivity 83.3% and specificity 81.8%.

Conclusion

MR-ProADM has demonstrated a poor ability to diagnose pyelonephritis in pediatric patients with fUTI. However, P-MR-proADM proved to be a very reliable biomarker for RS prediction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02765-2.

Diagnostic performance of contrast-enhanced ultrasound for acute pyelonephritis in children

The objective of our study was to evaluate the performance of renal contrast-enhanced ultrasound (CEUS) against the 99m-labeled dimercaptosuccinic acid (DMSA) scan and computed tomography (CT) in children for the diagnosis of acute pyelonephritis. We included children who underwent both renal CEUS and the DMSA scan or CT. A total of 33 children (21 males and 12 females, mean age 26 ± 36 months) were included. Using the DMSA scan as the reference standard, the sensitivity, specificity, positive predictive value, and negative predictive value of CEUS was 86.8%, 71.4%, 80.5%, and 80.0%, respectively. When CT was used as the reference standard, the sensitivity, specificity, positive predictive value, and negative predictive value of CEUS was 87.5%, 80.0%, 87.5%, and 80.0%, respectively. The diagnostic accuracy of CEUS for the diagnosis of acute pyelonephritis was 80.3% and 84.6% compared to the DMSA scan and CT, respectively. Inter-observer (kappa = 0.54) and intra-observer agreement (kappa = 0.59) for renal CEUS was moderate. In conclusion, CEUS had good diagnostic accuracy for diagnosing acute pyelonephritis with moderate inter- and intra-observer agreement. As CEUS does not require radiation or sedation, it could play an important role in the future when diagnosing acute pyelonephritis in children.

Effectiveness of the smoothing filter in pediatric 99mTc-dimercaptosuccinic acid renal scintigraphy

The present study aimed to evaluate whether the use of a smoothing filter would improve the image quality in pediatric ^99mTc-dimercaptosuccinic acid (^99mTc-DMSA) scintigraphy. We retrospectively reviewed 31 kidneys in 16 consecutive pediatric patients aged 10 months to 14 years. The administered dose was calculated using a weight-based method. Two reviewers randomly evaluated the original planar posterior images and smoothing filter image; they assessed image quality and performed defect evaluations. The evaluation of visual image quality yielded significantly better results for the smoothing filter images than for the original images. Although the smoothing filter images were slightly inferior to the original images in terms of edge sharpness, no significant difference was observed in the defect evaluation. We confirmed that ^99mTc-DMSA scintigraphy with a smoothing filter yielded reduced image noise, while maintaining defect evaluation performance and improving image quality.

Serum soluble ST2 as a marker of renal scar in pediatric upper urinary tract infection

BACKGROUND AND OBJECTIVES

Upper urinary tract infection is the most common serious bacterial infection in childhood. Patients with upper urinary tract infection have a risk for renal scarring with subsequent complications including hypertension, proteinuria, and progressive renal failure. However, the predictive biomarkers of renal scarring in children with upper urinary tract infection are still unknown. In this study, we evaluated whether soluble ST2 levels can be biomarkers of subsequent renal scarring in patients with upper urinary tract infection.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We retrospectively studied pediatric patients with upper urinary tract infection at a tertiary center. Twenty-eight children had an upper urinary tract infection with (n = 14) and without (n = 14) renal scarring and underwent 99mtechnetium dimercaptosuccinic acid imaging. In addition, 13 control subjects were enrolled. The clinical data and serum cytokine levels, including soluble ST2 levels, were compared between those with and without renal scars.

RESULTS

Serum soluble ST2 levels were significantly higher in the scar group than in the non-scar group, whereas there was no difference in the levels of serum interferon-γ, interleukin-6, interleukin-10, soluble tumor necrosis factor receptor 1, and transforming growth factor-β between the scar and non-scar groups. The area under the curve for differentiating between the non-scar and scar groups on the basis of measurements of serum soluble ST2 was 0.79, with a sensitivity and specificity of 92.9% and 64.3%, respectively.

CONCLUSION

These results suggest that serum soluble ST2 levels on admission could be a useful biomarker of subsequent renal scarring in pediatric patients with upper urinary tract infection.

Plasma Neutrophil Gelatinase-Associated Lipocalin as a Predictor of Renal Parenchymal Involvement in Infants With Febrile Urinary Tract Infection: A Preliminary Study

BACKGROUND

Urinary tract infection (UTI) is the most common bacterial infection in infants. Renal parenchymal involvement is an important prognostic factor; however, early detection of parenchymal involvement in UTI may be difficult during infancy. This study aimed to assess whether a recently established biomarker of UTI, neutrophil gelatinase-associated lipocalin (NGAL), can serve as a useful marker for the detection of cortical defects (CD) and to determine the appropriate diagnostic cut-off value of NGAL in infants with febrile UTI.

METHODS

Infants hospitalized for febrile UTI were divided into two groups according to the presence of cortical defects on dimercaptosuccinic acid (DMSA) scintigraphy. Among 64 enrolled infants, 43 (67%) had CD (UTI-CD) and 21 (33%) had no CD (UTI-ND). The white blood cell count, C-reactive protein, and plasma NGAL (pNGAL) levels were determined before antibiotic therapy and compared between the two groups.

RESULTS

pNGAL level was significantly higher in the UTI-CD group than in the UTI-ND group (340 μg/L vs 214 μg/L, P=0.002). Multivariate analysis showed that pNGAL level was the only independent predictor of CD (odds ratio 2.759, P=0.039). In the ROC curve analysis, pNGAL showed the highest area under the curve (0.745; 95% confidence interval, 0.561-0.821; P=0.014). The appropriate cut-off value of pNGAL was 267 μg/L (sensitivity, 72.1%; specificity, 71.4%).

CONCLUSIONS

pNGAL was found to be a useful marker for early prediction of renal parenchymal involvement in infants with febrile UTI.

Vascular endothelial growth factor-A gene polymorphism is associated with congenital renal lesions in children with urinary tract infections

AIM

This study investigated the relationship between vascular endothelial growth factor-A (VEGF-A)-460C/T functional gene polymorphism and renal parenchymal lesions, vesicoureteral reflux and other urinary tract abnormalities in children with a urinary tract infection (UTI).

METHODS

VEGF-A-460C/T gene polymorphism was investigated with restriction length polymorphism analysis in 76 children with their first UTI and in 63 controls without infections. Genotype and allele frequencies were compared between children with UTIs and controls and between different groups with UTIs.

RESULTS

The VEGF-A-460C/T genotype frequencies differed significantly between those with and without renal parenchymal lesions in the UTI cohort. Allele C homozygosity was significantly more common in those with renal parenchymal lesions (36.6% versus 8.7%, p = 0.007). A separate analysis showed that allele C was associated with lesions compatible with hypodysplasia, rather than with focal ones associated with infections, with an odds ratio of 11.55 and 95% confidence interval of 3.03-43.9 (p = 0.0001). No significant differences in genotypes or allele frequencies were found between children with and without reflux or other urinary tract anomalies.

CONCLUSION

In children with UTIs, C allele polymorphism of the VEGF-A gene was associated with hypodysplastic renal parenchymal lesions, which were possibly congenital and existed before the infection.

Urinary tract infection in small children: the evolution of renal damage over time

BACKGROUND

Our objective was to analyze the evolution of kidney damage over time in small children with urinary tract infection (UTI) and factors associated with progression of renal damage.

METHODS

From a cohort of 1003 children <2 years of age with first-time UTI, a retrospective analysis of 103 children was done. Children were selected because of renal damage at index ^99mTc-dimercaptosuccinic acid (DMSA) scintigraphy at least 3 months after UTI, and a late DMSA scan was performed after at least 2 years. Damage was classified as progression when there was a decline in differential renal function (DRF) by ≥4%, as regression when there was complete or partial resolution of uptake defects.

RESULTS

Of 103 children, 20 showed progression, 20 regression, and 63 remained unchanged. There were no differences between groups regarding gender or age. In the progression group, 16/20 (80%) children had vesicoureteral reflux (VUR) grade III-V and 13 (65%) had recurrent UTI. In multivariable regression analysis, both VUR grade III-V and recurrent UTI were associated with progression. In the regression group, 16/20 (80%) had no VUR or grade I-II, and two (10%) had recurrent UTI.

CONCLUSIONS

Most small children with febrile UTI do not develop renal damage and if they do the majority remain unchanged or regress over time. However, up to one-fifth of children with renal damage diagnosed after UTI are at risk of renal deterioration. These children are characterized by the presence of VUR grades III-V and recurrent febrile UTI and may benefit from follow-up.

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.

Mean platelet volume in young children with urinary tract infection

Mean platelet volume (MPV) has not yet been well-established in urinary tract infection (UTI). The purpose of this study was to evaluate the role of MPV as an acute phase reactant in children with UTI. Data from 118 young children (<2 years) with UTI between 2012 and 2013 were grouped as acute pyelonephritis (APN) and lower UTI according to the dimercaptosuccinic acid (DMSA) scan abnormalities. MPV, platelet distribution width (PDW) platelet count, and other infection markers (white blood cell [WBC] count, erythrocyte sedimentation rate [ESR], and C-reactive protein [CRP]) were measured. WBC (P = 0.001), ESR (P = 0.005), CRP (P < 0.001) and MPV levels (P = 0.011) were significantly higher in the APN group than those in the lower UTI group. MPV positively correlated with PDW, CRP and negatively with platelet count. Multiple logistic regression analyses showed that CRP and MPV were independent predictive factors for APN patients. However, the area under the Receiver Operating Characteristic (ROC) curve analysis for MPV was lower than CRP. Our results suggest that MPV can be an inflammatory marker in UTI, but the predictive value of MPV was not superior to CRP in the diagnosis of APN.

Interleukin-6 and interleukin-8 levels in the urine of children with renal scarring

BACKGROUND

Acute pyelonephritis (APN) is one of the most significant bacterial infections in infancy and early childhood, and can lead to permanent kidney damage and chronic renal failure.

OBJECTIVE

To evaluate interleukin-6 (IL-6) and interleukin-8 (IL-8) levels in the urine of children with renal scarring (RS), searching for clinical information about the immuno-inflammatory process that contributes to RS.

METHODS

Urine concentrations of IL-6 and IL-8 were evaluated in 50 children, 33 with RS detected after an episode of acute pyelonephritis (group A) and 17 children with a history of acute pyelonephritis, but without RS (group B). These children were divided into four groups: group A(1), 23 children with RS and vesicoureteral reflux (VUR); group A(2), 10 children with RS without VUR; group B(1), 13 children without RS and without VUR; group B(2), 4 children without RS, but with VUR. None of them had had urinary tract infection for a minimum of 6 months. To avoid dilution effects, urinary levels of IL-6 and IL-8 were expressed as the ratio of cytokine to urinary creatinine (pg/mg).

RESULTS

Urinary IL-8 levels were below the lower detection limit in all samples. IL-6 was detectable in the majority of children with RS and below the detection limits in the urine samples of children without RS. There were no statistically significant differences between urinary interleukin-6 levels in children with and those without VUR. There was a significant relationship between the grade of renal scars, the time passed since the last episode of acute pyelonephritis and the urinary levels of IL-6 (p < 0.0001 and p < 0.04 respectively).

CONCLUSION

Further experimental studies are required to demonstrate the correlation between histopathology and urinary cytokine levels.

Abdominopelvic ultrasound: a cost-effective way to diagnose solitary kidney

PURPOSE

Solitary kidneys are detected on approximately 1 of 1,500 prenatal ultrasounds and during evaluation for other urological complaints. Although renal scintigraphy is currently the gold standard for confirming the diagnosis and ruling out renal ectopia, scintigraphy is associated with radiation exposure, placement of an intravenous line and sedation. We hypothesize that ultrasonography alone is sufficient to detect solitary kidneys and that confirmatory renal scintigraphy is unnecessary.

MATERIALS AND METHODS

We reviewed the records of children with a solitary kidney who underwent ultrasound and nuclear scintigraphy at our institution from 2001 to 2010. Radiological findings were compared to assess the accuracy of ultrasound in diagnosing solitary kidneys. Costs were calculated based on 2011 Medicare global reimbursement.

RESULTS

A total of 25 children met the inclusion criteria of undergoing ultrasound and renal scintigraphy (dimercapto-succinic acid or mercaptoacetyltriglycine scan). The majority of cases were male (16, 64%) and left sided (17, 68%). Median age was 9 days (range 1 day to 11.6 years) at first ultrasound and 4.4 months (3 weeks to 12 years) at first renal scintigraphy. In 24 patients ultrasound correctly diagnosed a solitary kidney as confirmed by nuclear scan. In 1 patient ultrasound suggested a pelvic kidney but repeat ultrasound was negative, as was dimercapto-succinic acid scan. The diagnostic accuracy of ultrasound was 96%. Medicare reimbursement for dimercapto-succinic acid scan (CPT 78700) is $460 to $720 ($222 plus $240 for radiotracer plus $260 for anesthesia, if used).

CONCLUSIONS

Our findings suggest that ultrasonography alone is sufficient to make the diagnosis of solitary kidney. Omitting routine renal scintigraphy saves approximately $460 to $720 per case, and avoids radiation and discomfort without sacrificing diagnostic accuracy.

Is a routine voiding cystourethrogram necessary in children after the first febrile urinary tract infection?

AIM

The aim of this study was to estimate the value of identifying vesicoureteral reflux (VUR) on a voiding cystourethrogram (VCUG) and the benefit of VUR management according to imaging strategies at the first febrile urinary tract infection (UTI).

METHODS

Children aged 1-144 months (n = 618) with the first febrile UTI admitted at our hospital from 2000 to 2009 were enrolled. In all patients, renal sonogram (US), (99m) Tc-dimercaptosuccinic acid (DMSA) renal scanning and VCUG were performed. Retrospective analyses per patient and per renal unit were performed.

RESULTS

Abnormal US or DMSA scans had a sensitivity of 100% and a negative predictive value (NPV) of 100% to detect high-grade reflux. In hydronephrotic kidneys, DMSA scanning had a sensitivity of 88.2% and a NPV of 97.1% to detect high-grade reflux.

CONCLUSION

Routine VCUG is not required after the first febrile UTI in patients with normal US or normal DMSA scan. Even if the US reveals hydronephrosis, routine VCUG is not necessary if the DMSA findings are normal. It is recommended that children who did not receive both a DMSA scan and VCUG after the first febrile UTI should be followed up over the long term.

Update on childhood urinary tract infection and vesicoureteral reflux

Urinary tract infection (UTI) is a leading cause of serious bacterial infection in young children. Vesicoureteral reflux (VUR), a common pediatric urologic disorder, is believed to predispose to UTI, and both are associated with renal scarring. The complex interaction of bacterial virulence factors and host defense mechanisms influence renal damage. However, some renal parenchymal abnormalities associated with VUR are noninfectious in origin. Long-term, renal parenchymal injury may be associated with hypertension, pregnancy complications, proteinuria, and renal insufficiency. Optimal management of VUR and UTI is controversial because of the paucity of appropriate randomized controlled trials; there is a need for well-designed studies. The recently launched Randomized Intervention for children with VesicoUreteral Reflux (RIVUR) study hopefully will provide insight into the role of antimicrobial prophylaxis of UTI in children with VUR.

Procalcitonin as a predictor of renal scarring in infants and young children

The aim of this study was to evaluate the usefulness of procalcitonin (PCT) as a marker of renal scars in infants and young children with a first episode of acute pyelonephritis. Children aged 7 days to 36 months admitted for first febrile urinary tract infection (UTI) to a pediatric emergency department were prospectively enrolled. The PCT concentration was determined at admission. Acute (99m)Tc-dimercaptosuccinic acid (DMSA) scintigraphy was performed within 7 days of admission and repeated 12 months later when abnormal findings were obtained on the first scan. Of the 72 children enrolled in the study, 52 showed signs of acute pyelonephritis (APN) on the first DMSA scan. A follow-up scintigraphy at the 12-month follow-up performed on 41 patients revealed that 14 (34%) patients had developed renal scars; these patients also presented significantly higher PCT values than those without permanent renal lesions [2.3 (interquartile range 1-11.6) vs. 0.5 (0.2-1.4) ng/mL; p = 0.007]. A comparison of the PCT concentration in patients with febrile UTI without renal involvement, with APN without scar development and with APN with subsequent renal scarring revealed a significant increasing trend (p = 0.006, Kruskal-Wallis test). The area under the ROC curve for scar prediction was 0.74 (95% confidence interval 0.61-0.85), with an optimum statistical cut-off value of 1 ng/mL (sensitivity 78.6%; specificity 63.8%). Based on these results, we suggest that serum PCT concentration at admission is a useful predictive tool of renal scarring in infants and young children with acute pyelonephritis.

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.

Renal length discrepancy by ultrasound is a reliable predictor of an abnormal DMSA scan in children

A renal length discrepancy (RLD) of more than 10 mm by ultrasound (US) is accepted as a potential indicator of an underlying renal pathology; however, there are few supporting data for this in children. Our objective was to determine a cutoff at which RLD on US is a reliable predictor of dimercaptosuccinate acid (DMSA) scan abnormality. We present data from 90 patients who had both renal US and a DMSA scan, as well as DMSA scan results compared with bipolar RLD by US. Positive (PPV) and negative (NPV) predictive values were calculated for renal RLD from 6 to >10 mm. The left kidney was longer in 56%, whereas the right kidney was longer in 37%; their lengths were equal in 8%. For children at all ages, a left kidney longer than the right by >or=10 mm or a right kidney longer than the left by >or=7 mm gave a PPV for DMSA abnormality of 79% and 100%, respectively. In children older than 4 years, if the right kidney was longer by >or=7 mm or if the left kidney was longer by >or=10 mm, the PPVs for DMSA abnormality were 100% and 63%, respectively. In children younger than 4 years, when the right kidney was longer by >or=6 mm or the left was kidney longer by >or=10 mm, the PPV were 86% and 100%, respectively. Thus, children with a right kidney longer than the left by even <10 mm is a reliable predictor of an abnormal DMSA scan.

Risk factors for renal scarring in children and adolescents with lower urinary tract dysfunction

Risk factors for renal scarring in children with lower urinary tract dysfunction (LUTD) were evaluated. The medical records of 120 patients were assessed concerning gender, presence of vesicoureteric reflux (VUR), bladder capacity, detrusor overactivity, residual urine, febrile urinary tract infection (UTI), bacteriuria, constipation, detrusor sphincter incoordination (DSI), high detrusor pressure at maximal cystometric capacity (PMCC), low compliance, and thickness and trabeculation of the bladder wall. Renal scarring was diagnosed by (99m)technetium-dimercaptosuccinic acid renal scan (DMSA). Renal scarring was detected in 38 patients (31%). VUR, UTI, decreased bladder capacity, urinary residue, and trabeculated and thick bladder wall were associated with scarring at univariate analysis. Multivariate analysis showed VUR (P < 0.0001) as the independent risk factor for renal scarring. Thickness of the bladder wall was a marginal risk factor (P = 0.07). Although UTI was not a risk factor, it was associated with VUR (P = 0.03). In our analysis, VUR was the main risk factor; however, renal scarring was probably due to multifactorial causes, as VUR was associated with UTI.

Renal infection and vesico-ureteric reflux

Urinary tract infection (UTI) is a common disease of childhood. The investigation of UTI in children has been the subject of debate and controversy for many years. Most workers agree that the first imaging modality to be used should be an ultrasound examination to exclude obstruction, structural abnormalities, and renal calculi. The role of (99m)Tc dimercaptosuccinic acid scintigraphy (DMSA) in the diagnosis of acute pyelonephritis is becoming increasingly important. Many argue that if the DMSA study is normal at the time of acute UTI, no further investigation is required because the kidneys have not been involved and thus there will be no late sequelae. Others use the acute DMSA study to determine the intensity of antibiotic therapy. The importance of the role of vesico-ureteric reflux (VUR) is being debated. Some workers will only proceed to cystography to detect VUR if the DMSA study is abnormal, whereas others advocate a more aggressive approach. VUR can be identified by a variety of radiological and scintigraphic techniques. Although the radiological cystogram is the gold standard and is essential in the first UTI in a male patient, to exclude the presence of posterior urethral valves, radionuclide cystograms are advantageous in other situations. Suprapubic cystography techniques have been described to overcome the trauma of urethral catheterization but have not been widely accepted.

[Acute lobar nephronia: Diagnosis, treatment and prognosis]

Acute lobar nephronia is a focal form of acute bacterial renal infection. The prevalence of this disease is low. We report four cases of acute lobar nephronia. Three patients were diagnosed among 77 patients admitted to hospital for acute pyelonephritis. The fourth case was atypical and associated with epidermolysis bullosa. All cases were diagnosed by renal ultrasonography and the diagnosis was confirmed by computed tomographic examination in two patients with poor clinical course. A small abscess was detected in one patient. Urine cultures were positive in three of the four patients. Acute lobar nephronia is a radiological diagnosis and requires aggressive treatment and strict follow-up due to the risk of renal abscesses. Because the clinical manifestations are insidious and laboratory findings can be contradictory, this entity should be suspected in patients with poor clinical course or alterations on renal ultrasonography. Medical treatment is usually sufficient and prognosis is generally good.

Ten-year results of randomized treatment of children with severe vesicoureteral reflux. Final report of the International Reflux Study in Children

For the comparison of long-term outcome of the management of medical or surgical treatment of children with severe vesicoureteral reflux (VUR), children aged <11 years with non-obstructive grade III/IV reflux, previous urinary tract infection (UTI) and glomerular filtration rate (GFR) >or=70 ml/min per 1.73 m2 body surface area were recruited, and 306 were randomly allocated to receive antimicrobial prophylaxis or ureteral reimplantation. Primary endpoints were new renal scars and renal growth. Follow up, originally planned for 5 years, was extended to 10 years for 252 children, 223 of whom had follow-up imaging. Up to 5 years, 40 new urographic scars (medical 19, surgical 21) were seen. Between 5 years and 10 years, only two further scars were observed. Renal growth and UTI recurrence rate were similar, except that medically treated patients had more febrile infections. There was no difference in somatic growth, radionuclide imaging or renal function. A GFR <70 ml/min per 1.73 m2 was found in only one patient. Three patients developed hypertension requiring treatment. We conclude that, with close supervision and prompt treatment of recurrences, children entering the study with GFR >or=70 ml/min per 1.73 m2 progressed remarkably well under either medical or surgical management, emphasizing the importance of continued supervision and the entry level of renal function.

Proinflammatory cytokines and procalcitonin in children with acute pyelonephritis

This prospective study, performed in 76 children with a urinary tract infection (UTI), evaluates the diagnostic value of procalcitonin (PCT) and proinflammatory cytokines (IL-1beta, IL-6 and TNF-alpha) in children with acute pyelonephritis documented by dimercaptosuccinic acid scintigraphy (DMSA). Renal parenchymal involvement was assessed by (99m )Tc-DMSA scintigraphy within 7 days of admission. The diagnosis of acute pyelonephritis was confirmed only in patients with reversible lesions on scintigraphy. According to DMSA scan results, patients were divided into two groups, lower UTI or acute pyelonephritis. In acute pyelonephritis, serum PCT level was found to be significantly higher than it is in the lower UTI (p <0.001). Also, significantly higher serum proinflammatory cytokines (IL-1beta, IL-6 and TNF-alpha) levels were detected in those with acute pyelonephritis than those with lower UTI (p <0.001). We conclude that both serum PCT and proinflammatory cytokine levels may be used as accurate markers for diagnosis of acute pyelonephritis.

Megaureter visualization on Tc-99m DMSA scintigraphy

We present a patient with left-sided obstructed megaureter secondary to neuropathic bladder. He was referred for technetium-99m dimercaptosuccinic acid ((99m)Tc-DMSA) renal cortical scintigraphy to evaluate renal cortical function. Images obtained 4 hr after injection showed significant activity in the dilated left ureter. When the ureter is visualized on DMSA scan, obstructive megaureter should be considered in the differential diagnosis.

Imaging strategies in pediatric urinary tract infection

This article is focused on the controversial topic of imaging strategies in pediatric urinary tract infection. A review of the recent literature illustrates the complementary roles of ultrasound, diagnostic radiology and nuclear medicine. The authors stress the key role of ultrasound which has recently been debated. The commonly associated vesicoureteric reflux has to be classified as congenital or secondary due to voiding dysfunction. A series of frequently asked questions are addressed in a second section. The proposed answers are not the product of a consensus but should rather be considered as proposals to enrich the ongoing debate concerning the evaluation of urinary tract infection in children.

IMPACT OF VESICOURETERAL REFLUX ON THE SIZE OF RENAL LESIONS AFTER AN EPISODE OF ACUTE PYELONEPHRITIS

PURPOSE

We determined the impact of vesicoureteral reflux (VUR) on the size of renal lesions in children after an episode of acute pyelonephritis.

MATERIALS AND METHODS

A total of 161 children (mean age 2.44 years) with acute pyelonephritis were studied. All had renal lesions on dimercapto-succinic acid scintigraphy done at admission to the hospital. A second dimercapto-succinic acid scan was performed at 3 months. Voiding cystourethrography was done at 6 weeks and VUR was graded I to V. For each renal unit layouts of renal lesions were drawn, and the damage surface was calculated and reported for the total surface of the kidney.

RESULTS

Mean size of acute lesions and scars increased with severity of reflux (p <0.0001), with an important overlap of individual values. Mean size of renal scars in the group of renal units with acute lesions was 5.8% +/- 8.5% in patients without VUR, 9.9% +/- 7.3% in those with grade I reflux, 7.7% +/- 11.0% in those with grade II reflux, 17.7% +/- 14.7% in those with grade III reflux and 17.4% +/- 27.7% in those with grade IV reflux (p <0.001). The size of renal lesions decreased significantly with time. The rate of regression of lesions decreased with increasing reflux. When analyzed according to 3 age groups sizes of scars increased significantly with age.

CONCLUSIONS

VUR has an impact on the size of renal lesions after an episode of pyelonephritis. Children with a grade III or IV reflux are more likely to have larger renal scars. On the other hand, acute lesions of important size may develop even in the absence of VUR.

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.

Comparative study between intravenous urography and renal scintigraphy with DMSA for the diagnosis of renal scars in children with vesicoureteral reflux

PURPOSE

To assess the value of intravenous urography (IVU) in detecting and grading the renal scar, comparing its results with those of scintigraphy with dimercaptosuccinic acid (DMSA).

MATERIALS AND METHODS

The study included 43 children investigated by DMSA and IVU, who had vesicoureteral reflux diagnosed and classified through voiding cystourethrography.

RESULTS

Among the kidneys with reflux, there was agreement between the results of DMSA and IVU concerning the presence and the absence of scars in 82.4% of the cases. Based on the results obtained, IVU would have a sensitivity of 66.6%, specificity of 94.4%; accuracy of 82.5%; positive predictive value (PPV) of 90% and negative predictive value (NPV) of 79%, when compared with DMSA results. Our data also confirm the close relation between the reflux grade and the presence of renal scar, since 75% of the kidneys with grade IV and V reflux presented scars. In relation to the grading of nephropathy, in 78% of patients the classification of the scar by both methods was identical. The highest disagreement was verified in the group with segmental scar on DMSA, where 41.6% of the kidneys were classified as normal on IVU.

CONCLUSION

The data obtained confirm that the scintigraphy with DMSA is essential in the investigation of patients with renal scar, and cannot be replaced by IVU, due to its low sensitivity and lower ability of satisfactory grading.

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.

Vesicoureteric reflux and reflux nephropathy

Reflux nephropathy i.e. renal scarring associated with vesico-ureteric reflux (VUR) and urinary tract infection (UTI) was originally considered an acquired disease. The renal scarring seems to get worse with recurrent urine infections especially in the young. Therefore, in the past much effort was undertaken to correct the VUR surgically and minimize the number of recurrent urinary tract infections by antibiotic prophylaxis with the hope of reducing if not arresting the onset of complications that follow i.e. hypertension and renal failure. However, it is now becoming clear that reflux nephropathy encompass at least two major categories of disease; "acquired" renal scarring secondary to UTI and VUR predominantly affecting females and "congenital" scarring with dysplastic features associated with prenatal VUR but with no infection and predominantly affecting boys. The latter is much less common but is disproportionately represented in the group of patients with reflux nephropathy that go on to develop renal failure. Unfortunately, the susceptibility to renal scarring, the onset of hypertension and progression to renal failure seems to be significantly influenced by genetic factors and hence measures undertaken to prevent recurrence of UTI may not change the ultimate outcome although it will certainly improve the comfort of the individual. Therefore, the extensive investigation and management routines adopted today in these children may not be cost-effective in preventing end stage renal disease in VUR. The progression to renal failure, however, can be delayed but not halted with adequate control of high blood pressure and hence the need for life long follow-up.

Meatus tightly covered by the prepuce is associated with urinary infection

BACKGROUND

Almost all newborns have phimosis, which is known as one of the risk factors for urinary infection. The present study analyzed which specific prepuce conditions correlated with the development of febrile urinary infection in Japanese male infants.

METHODS

The subjects consisted of 100 children, 64 boys and 36 girls, with febrile urinary infection. Prepuces were classified by their retractability in the male patients and in 714 healthy boys.

RESULTS

Ninety-four percent of first febrile urinary infections occurred before 7 months of age in boys, whereas only 37% of the girls had first infections by that age. The prepuce covered the external urethral meatus in 96% of the healthy boys aged 3 years or less. A gentle retraction maneuver could not uncover the urethral meatus in approximately 40% of the boys aged 0-6 months. The frequency started to decline spontaneously after that age. Male patients aged 0-6 months significantly more often had tightly covered meatus than did healthy neonates (85%vs 42%, P < 0.0001).

CONCLUSIONS

These findings indicate that it is specifically those boys whose external urethral meatus are tightly covered with foreskin who constitute the high-risk group for urinary infection. Awareness of this observation should help with diagnosing and managing urinary infection in young boys.

[Diagnosis of renovascular hypertension by pre- and post-captopril renal scintigraphy with 99mTc-DMSA]

AIM

Value the utility of studies with 99mTc-DMSA with captopril (scintigraphy imaging and unilateral renal function) in identifying renovascular disease or renal disease in hypertension patients with high probability of renovascular hypertension.

METHODS

We studied 27 hypertension patients (12 males, 15 females) mean age 49 years, SD: 9.46, with high probability of renovascular disease. General analysis and radiology was made to all of them including renal arteriography as gold standard. Two renal scintigraphies with 99mTc-DMSA were made to all of them, baseline study and one hour after administration of 50 mg of captopril, a week between both studies. Renal scintigraphy (anterior and posterior images) was obtained 4 hours after the administration of 111 MBq (3 mCi) of 99mTc-DMSA and results were evaluated quantitatively and qualitatively calculating unilateral renal function. We considered positive for renovascular hypertension studies with decrease of more than five percentual points in unilateral renal function or a new defect absent in baseline study. Scintigraphic results were compared with arteriography to determine sensitivity, specificity and predictive values.

RESULTS

Arteriography demonstrated significant renal artery stenosis in 18.5% of patients. Renal scintigraphy with captopril using 99mTc-DMSA demonstrated sensitivity of 60%, specificity of 91%, positive predictive value of 60% and negative predictive value of 91%. We identified 3 patients with segmental defects of uptake consistent with chronic pyelonephritis scarring.

CONCLUSIONS

Studies with 99mTc-DMSA using captopril present high specificity and are useful in patients with high probability for renovascular hypertension, identifying high number of patients with significant renal artery stenosis. The utility of DMSA in identify renal abnormalities, as specially pyelonephritis scarring, add value to renal studies with captopril using others tracers. DMSA could identify renal etiologies of renovascular hypertension different to renal artery stenosis.

Reflux nephropathy in infancy: a comparison of infants presenting with and without urinary tract infection

PURPOSE

We compared the incidence of renal scarring in infants with high grade vesicoureteral reflux in those presenting with and without urinary tract infection.

METHODS AND METHODS

We reviewed the medical records of 81 male and 46 female infants (194 renal refluxing units) with a mean age of 4 months who had grade IV or V primary vesicoureteral reflux and underwent an anti-reflux procedure between 1984 and 1997. Dimercapto-succinic acid (DMSA) scans and voiding cystourethrography were performed in all cases. Patients were followed for 2 to 16 years, including 90% for greater than 3 years. Renal ultrasound and DMSA scan were done at followup.

RESULTS

A total of 97 patients (76%) (148 refluxing renal units) presented clinically with urinary tract infection. The initial DMSA scan demonstrated renal scarring in 40 of the 106 grade IV (38%) and 28 of the 42 grade V (67%) refluxing renal units. There was no scarring on followup in previously normal refluxing renal units. Of the patients 30 (24%) (46 refluxing renal units) were diagnosed before a urinary tract infection developed, 16 underwent screening due to vesicoureteral reflux in a sibling and in 10 reflux was initially suspected due to hydronephrosis on prenatal ultrasound. In the remaining 4 patients vesicoureteral reflux was suspected during abdominal ultrasound to investigate abdominal pain, jaundice, associated hypospadias and fetal alcohol syndrome, respectively. DMSA scan showed evidence of scarring in 6 of 21 grade IV (29%) and 9 of 25 grade V (36%) refluxing renal units in this group. Followup revealed scarring in only 1 previously normal refluxing renal unit.

CONCLUSIONS

The incidence of reflux nephropathy in primary grade V vesicoureteral reflux is lower in cases detected by screening and with treatment it remained lower than in cases of urinary tract infection that presented clinically. Early treatment of grade V vesicoureteral reflux made possible by screening may prevent renal damage.

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.

Primary and acquired renal scarring in boys and girls with urinary tract infection

OBJECTIVES

To determine when pyelonephritic renal scarring was detected in children with urinary tract infection (UTI) and characterize those with primary and acquired scarring, respectively.

STUDY DESIGN

A population-based cohort of 1221 children (989 girls and 232 boys) with first recognized symptomatic UTI, aged 0 to 15 years, were diagnosed and followed up prospectively at a single children's hospital; 652 had febrile UTI. Seven hundred fifty-three were evaluated by urography. Renal scarring was classified as primary or acquired, the latter without signs of scarring at the first investigation. To evaluate the frequency of recurrent UTI in those with acquired scarring, a comparison with group-matched children without scarring was performed.

RESULTS

A total of 74 children without obstruction had renal scarring (acquired in 40). Primary scarring was found in 18 of 21 (86%) of the boys and 16 of 53 (30%) of the girls (P <.001). The majority of boys with scarring had dilated reflux (67%) in contrast to girls (23%). Recurrent UTI was rare in boys, whereas girls with acquired scarring had significantly more febrile recurrences than girls without scarring.

CONCLUSIONS

Most boys had primary, probably congenital, reflux-associated renal damage, whereas most girls had acquired scarring related to recurrences of febrile UTI.

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.

Utility of SPECT DMSA renal scanning in the evaluation of children with primary vesicoureteral reflux

OBJECTIVES

DMSA renal scanning is more sensitive than ultrasound in detecting renal parenchymal scars. We proposed to determine the utility of single-photon emission computed tomography (SPECT) dimercaptosuccinic acid (DMSA) renal scanning in children with primary vesicoureteral reflux (VUR).

METHODS

During a 24-month period, we evaluated the charts of 368 patients who had undergone SPECT DMSA renal scanning for primary VUR. Patients were divided into three age groups: (a) less than 1 year, (b) between 1 and 5 years, and (c) older than 6 years. Renal scars were deemed severe or focal. The data were analyzed to evaluate the utility of SPECT DMSA scanning in children with primary VUR and to determine the indications for performing SPECT DMSA. We also evaluated the sensitivity of recent renal ultrasound technology in detecting focal and diffuse scars.

RESULTS

One hundred twenty-eight patients were younger than 1 year at presentation. These included 24 cases that were detected prenatally. One hundred eighty-five were between the ages of 1 and 5 years, and 55 were 6 years or older. Reflux nephropathy at presentation was found in 99 (26.9%) of 368 patients. DMSA scanning changed the treatment in only 13 patients (3.5%). When scarring was diffuse, ultrasound examination correlated 100% with DMSA scanning; when focal scarring was present, the correlation was poor.

CONCLUSIONS

Our results suggest that DMSA scans should be tailored to children who have ultrasound abnormalities, high-grade reflux, or recurrent breakthrough urinary tract infections. These guidelines will result in a substantial cost savings and a significant decrease in radiation exposure.

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.

The usefulness of Tc-99m DMSA SPECT and three-dimensional surface rendering in an asymptomatic patient with a single kidney in the pelvis

The diagnostic problems in a clinically asymptomatic patient with a previously unknown ectopic single kidney in the pelvis and the diagnostic utility of three-dimensional surface rendering of Tc-99m DMSA SPECT for delineating ectopic functional renal parenchyma are reported. Inconclusive dynamic planar Tc-99m MAG3 renal scintigraphy was performed with the field of view centered at the upper abdomen. Twenty-four hours later, static planar Tc-99m DMSA scintigraphy 3 hours after injection delineated functional renal parenchyma only in the pelvis but did not reveal the shape of the organ. Three-dimensional surface rendering exposed a single ectopic kidney in the pelvis. This case is the first description of the advantages of three-dimensional surface rendering of Tc-99m SPECT in the diagnosis of an ectopic kidney.

Trends in the health burden due to urinary tract infection in children in Australia

OBJECTIVE

To estimate the health burden of urinary tract infection in children less than 15 years of age in Australia and to ascertain whether any significant change has occurred during the past decade.

METHODOLOGY

The number of children less than 15 years of age who were admitted in New South Wales for urinary tract infection between 1981 and 1994 was ascertained from the Department of Health, and age and sex specific incidence rates were calculated using Australian Bureau of Statistics population data. Costs for inpatient care were calculated using the cost weights from Australia National Disease Related Groups Version 3 for urinary tract infection (DRG 577). The frequency of the four most commonly requested renal tract imaging procedures in children following urinary tract infection and which qualified for Medicare reimbursement were obtained from the Health Insurance Commission for 1984-1994: micturating cystourethrography, intravenous urography, renal ultrasonography, and nuclear medicine renal studies.

RESULTS

There were 1203 children who were admitted with urinary tract infection in New South Wales in 1994, at an estimated cost of $A1.6 million. Since 1981, the age standardized annual incidence of urinary tract infection requiring hospitalization has increased from 0.5 to 0.9 per 1000 children, largely because of an increase in the number of young children admitted (from 0.6 to 2.0 per 1000 children less than 5 years of age). In 1994, 46,230 non-inpatient renal imaging procedures were undertaken in children under 15 years of age at a cost of $A5.3 million.

CONCLUSIONS

Urinary tract infection is an important and increasing health problem for Australian children, particularly for preschool children. Whether this represents a true increase in the incidence of urinary tract infection or improved diagnosis and more intensive management is not possible to establish with this study design. Prospective population based studies are required to assess more completely the frequency with which urinary tract infection occurs in children and any changes that may be occurring.

The natural history of bacteriuria in childhood

Urinary tract infections are common during infancy and childhood but are easily overlooked because of the unspecific symptoms. Prevention of renal scarring and its potential long-term consequences is possible but requires an increased awareness of the diagnosis, the imaging revealing anomalies within the urinary tract, and the long-term supervision. This should include any possibility of the child having pyelonephritic recurrences, which should be treated without delay; however, asymptomatic bacteriuria in infants and children is an innocent condition and screening is not recommended.

Transient pyelonephritic changes on 99mTechnetium-dimercaptosuccinic acid scan for at least five months after infection

A prospective study was performed on 185 children with symptomatic urinary tract infection (UTI), 130F and 55M, having a median age of 0.9 y (range 0.1-9.8) at the time of UTI. The aim of the study was to find out how the 99mTechnetium-dimercaptosuccinic acid (DMSA) scan should be used to investigate UTI, and to follow the development of renal changes during pyelonephritis into subsequent permanent renal damage. All children were investigated with a DMSA scan within 5 days after admission and after 3.9-53.3 (median 9.2) weeks, and 159 were studied again after approximately 2 y (range 1.5-3.9 y). They all underwent micturition cystourethrography at the time of the second study. At the time of infection, the DMSA scan was abnormal in 85% of the children, in 58% at the first follow-up and in 36% at the second follow-up. An abnormal DMSA scan performed within 20 weeks from infection became normal in 38% of cases on the third study, while only 1/10 abnormal DMSA scans performed more than 20 weeks after infection became normal after 1.5-3.9 y. Persistent renal changes were more common in children > 4 y of age than in children < or = 1 y of age. Two months after the presenting infection, it was unusual to see a normal DMSA scan in a child with a VUR gr. > or = 3. The study suggests that DMSA changes after an index UTI may be transient for a longer period of time than has been previously considered. Therefore, in order to detect persistent changes, a DMSA scan should be performed more than 5 months after UTI.

Kidney swelling. Findings on DMSA scintigraphy

OBJECTIVE

To develop criteria identifying swollen kidneys on dimercaptosuccinic acid (DMSA) renal scintigraphy in acute pyelonephritis with regard to the DMSA distribution pattern, kidney functional size, and radioactive uptake.

SUBJECTS AND METHODS

Thirty-eight children aged 15 days to 7 years with known pyelonephritis were examined with DMSA renal scintigraphy. All children were observed 2 or 3 times. In total, 94 scintigrams were evaluated. Qualitative and quantitative criteria for swelling were defined.

RESULTS

Thirty-one observed kidneys satisfied the criteria of swelling. Quantitatively, kidney length and width/length were greater in swollen kidneys. Kidney uptake in percent of injected dose and kidney uptake/background were lower in swollen kidneys. Qualitatively, focal radioactive uptake defects known from a previous examination were sometimes obscured by swelling, and reappeared at follow-up. In 5 children with signs of swelling on repeat imaging, scintigraphy reinfection at the time of swelling was verified.

CONCLUSIONS

Swollen kidneys may be the only sign of acute pyelonephritis on DMSA scintigraphy and swelling may obscure focal radioactive uptake defects. Measurement of kidney size and radioactive uptake can help identify swollen kidneys at DMSA scintigraphy and disclose acute pyelonephritis in the absence of overt clinical symptoms.

The true clinical significance of renography in nephro-urology

Isotopic renography is a non-invasive technique used routinely by the clinician to provide information about kidney structure and function. Whilst there is no doubt of its value in the accurate measurement of glomerular filtration rate and in the detection of parenchymal abnormalities, its role in the diagnosis of renovascular disease (especially in patients with renal insufficiency), the exclusion of obstruction and the evaluation of the patient with either acute renal failure or renal transplant dysfunction remains unproven. In part, this reflects a failure to standardise protocols and rigorously evaluate diagnostic techniques. Recent developments in ultrasound, computerised X-ray tomography and nuclear magnetic resonance now present the clinician with rival techniques and emphasise the need for the clinical development of isotopic renography.