Renal pathology and the 99mTc-DMSA image during the evolution of the early pyelonephritic scar: an experimental study

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

INTRODUCTION

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Development of visual scoring system with Tc-99m DMSA renal scintigraphy to predict the risk of recurrence of symptomatic urinary tract infections in pediatric patients

OBJECTIVE

Vesicoureteral reflux (VUR) is a major risk factor for recurrent symptomatic urinary tract infection (UTI) in pediatric patients. In addition, dimercaptosuccinic acid renal scintigraphy (DMSA) is an important diagnostic modality of VUR. However, the value of DMSA for predicting recurrent pediatric UTI has not been studied. Therefore, we aimed to develop visual scoring system (VSS) with DMSA to predict the risk of recurrence of symptomatic urinary tract infection in pediatric patient under the age of 24 months.

METHODS

Pediatric UTI patients who visited our tertiary hospital emergency department and underwent DMSA for initial work-up from January 2006 to December 2014 were reviewed retrospectively. We developed a VSS with Tc-99m DMSA renal scintigraphy. We compared sensitivity and specificity between VSS with DMSA and other variables in predicting recurrent symptomatic UTI. Laboratory indices for systemic inflammation, abnormal finding on ultrasonography, VUR on voiding cystourethrogram (VCUG), and the VSS with DMSA were considered as variables. In addition, we used Kaplan-Meier estimator analyses and Cox proportional regression analyses to evaluate the predictive value of each variable for the recurrence of symptomatic UTI.

RESULTS

A total of 338 patients were enrolled. During the follow-up period, 42 patients (12.4%) had UTI recurrence. Visual scoring with DMSA resulted in 69.1% sensitivity and 79.4% specificity with an optimal cut-off value of score 2 (AUC = 0.790, p < 0.001). Significant predictive factors associated with recurrent symptomatic UTI were CRP ≥ 67.0 mg/L, VUR on VCUG and VSS with DMSA ≥ score 2. On multivariate analysis, the visual score with DMSA was the only independent prognostic factor for recurrent symptomatic UTI (p < 0.001; adjusted hazard ratio = 7.522; 95% CI = 2.799-20.224).

CONCLUSION

High scores in VSS with DMSA were associated with frequent recurrence and short recurrence periods in pediatric UTI patients. VSS with DMSA can stratify risk of recurrence in pediatric UTI patients.

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.

Pyelonephritis in slaughter pigs and sows: morphological characterization and aspects of pathogenesis and aetiology

Background

Pyelonephritis is a serious disease in pig production that needs to be further studied. The purpose of this study was to describe the morphology, investigate the pathogenesis, and evaluate the aetiological role of Escherichia coli in pyelonephritis in slaughtered pigs by concurrent bacteriological, gross and histopathological examinations.

Methods

From Danish abattoirs, kidneys and corresponding lymph nodes from 22 slaughtered finishing pigs and 26 slaughtered sows with pyelonephritis were collected and evaluated by bacteriology and pathology. Based on gross lesions, each kidney (lesion) was grouped as acute, chronic, chronic active, or normal and their histological inflammatory stage was determined as normal (0), acute (1), sub-acute (2), chronic active (3), or chronic (4). Immunohistochemical identification of neutrophils, macrophages, T-lymphocytes, B-lymphocytes, plasma cells, E. coli and Tamm-Horsfall protein (THP) in renal sections was performed. The number of E. coli and the proportion of immunohistochemically visualized leukocytes out of the total number of infiltrating leukocytes were scored semi-quantitatively.

Results

Lesions in finishing pigs and sows were similar. Macroscopically, multiple unevenly distributed foci of inflammation mostly affecting the renal poles were observed. Histologically, tubulointerstitial infiltration with neutrophils and mononuclear cells and tubular destruction was the main findings. The significant highest scores of L1 antigen⁺ neutrophils were in inflammatory stage 1 while the significant highest scores of CD79αcy⁺ B-lymphocytes, IgG⁺ and IgA⁺ plasma cells were in stage 3 or 4. Neutrophils were the dominant leukocytes in stage 1 while CD3ε⁺ T-lymphocytes dominated in stage 2, 3 and 4. Interstitially THP was seen in 82% and 98% of kidneys with pyelonephritis from finishing pigs and sows, respectively. E. coli was demonstrated in monoculture and/or identified by immunohistochemistry in relation to inflammation in four kidneys from finishing pigs and in 34 kidneys from sows.

Conclusions

E. coli played a significant role in the aetiology of pyelonephritis. Neutrophils were involved in the first line of defence. CD3ε⁺ T-lymphocytes were involved in both the acute and chronic inflammatory response while a humoral immune response was most pronounced in later inflammatory stages. The observed renal lesions correspond with an ascending bacterial infection with presence of intra-renal reflux.

Evaluation of dynamic contrast-enhanced MRI in detecting renal scarring in a rat injury model

PURPOSE

To create a reliable rat model with small renal cortical scars and evaluate the accuracy and sensitivity of dynamic contrast-enhanced MRI in detecting the kinds of lesions that are associated with reflux nephropathy.

MATERIALS AND METHODS

In 16 rats, three unilateral renal cortical lesions were created using either electrocautery or pure alcohol with the contralateral kidney serving as control. MRI on a 1.5 Tesla GE Signa was performed 10-14 days after surgery. After bolus injection of 0.2 mM/Kg Gd-DTPA, sequential MRI acquisitions were performed using a 4-inch quadrature birdcage coil. Renal and scar volumes and pathology were compared after scanning and killing.

RESULTS

Of the 48 points of injury, 40 (83%) in the 16 rats were detected grossly. Under microscopy, 36 injuries (75%) were detected on mid-kidney cross-sections. The average lesion was 4.2 mm(3) corresponding to 0.5% of the kidney volume. Using pathological findings as the gold standard, the sensitivity and specificity of scar detection using MRI was 69% and 93%, respectively.

CONCLUSION

A rat model was created to demonstrate the sensitivity of dynamic contrast-enhanced MRI for detecting renal scars. Alcohol and electrocautery created reliable renal scars that were confirmed pathologically. MRI detected these lesions that averaged 4.2 mm(3) (0.5% total renal volume) with sensitivity and specificity of 69% and 93%, respectively.

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.

Early renal parenchymal histological changes in an experimental model of vesico-ureteral reflux and the role of apoptosis

OBJECTIVES

To observe early renal parenchymal cellular changes in an experimental model of vesico-ureteral reflux (VUR) and to show whether the apoptotic pathway plays a role in these cellular changes.

MATERIAL AND METHODS

Fourteen New Zealand breed rabbits were used and were divided into two equal groups (control and experimental groups). Urine samples were obtained in a sterile manner and cultured. In the study group, reflux was created in the right kidneys surgically. Renal scintigraphy and voiding cystourethrography (VCUG) were performed in both groups on Day 17. The kidneys were examined in terms of histology, apoptotic activity and caspase activity.

RESULTS

No growth was observed in urine cultures in either group. VUR was manifested in only two rabbits in the experimental group on VCUG. On renal scintigraphy, no renal scarring was observed in either of the groups and renal uptake values were in the normal range. There was a greater increase in collagen in the right kidneys in the experimental group than in the control group and apoptotic activity was significantly increased in the study group: 0% in the control group, 10.8%+/-0.7% in the experimental group (p<0.001). Caspase-6 activity was strongly positive and caspase-8 and -9 activities were moderately positive in the right kidneys of the experimental group. Caspase-6 activity was moderately positive, and caspase-8 and -9 activities were weakly positive in the contralateral kidneys of the experimental group. Caspase activities in the control group were negative (p<0.001).

CONCLUSIONS

In this experimental model of VUR, apoptotic activity was initiated via the caspase-8 and -9 pathway and collagen tissue increased in the renal parenchyma where reflux occurred. The balance of apoptotic activity may play a key role in the occurrence of reflux nephropathy.

Protective effects of cranberries on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux

OBJECTIVE

To evaluate the protective effects of cranberry fruit, which have known antioxidant effects, on infection-induced oxidative renal damage in a rabbit model of vesico-ureteric reflux (VUR).

MATERIALS AND METHODS

In all, 36 New Zealand male rabbits were divided into five groups, with a sham operation in four rabbits serving as the control (group 1). To create unilateral VUR the roof of the left intravesical ureter was incised, and VUR confirmed 2 weeks after surgery. In all, 32 rabbits with VUR were divided into four groups; 2, VUR alone (with sterile urine); 3, a group infected with Escherichia coli; 4, with intravesical E. coli instillation but fed cranberries; and 5, intravesical E. coli instillation plus an intraperitoneal injection with melatonin group. At 3 weeks after surgery the rabbits were killed, the kidneys obtained and examined histopathologically to evaluate inflammation, fibrosis and tubular changes. Oxidative renal damage was evaluated by measuring malondialdehyde in the renal tissue.

RESULTS

Grossly, the refluxing kidney was larger than the contralateral normal kidney, and the refluxing ureter was dilated and tortuous. Microscopy of tissues from the kidneys in group 3 showed apparent periglomerular mononuclear cell infiltration, tubular dilatation and atrophy, and interstitial fibrosis. The kidneys from groups 2, 4 and 5 showed mild mononuclear cell infiltration with no interstitial fibrosis. The level of malondialdehyde in the kidneys of group 3 was significantly higher than that in group 2, 4 and 5 (P < 0.05); the level in groups 4 and 5 did not differ significantly from that in group 2.

CONCLUSIONS

This study shows that cranberries have an anti-inflammatory effect through their antioxidant function and might prevent infection-induced oxidative renal damage. Thus, clinically cranberries might be used as a beneficial adjuvant treatment to prevent damage due to pyelonephritis in children with VUR.

Diagnostic significance of clinical and laboratory findings to localize site of urinary infection

The aim of this study was to define in children younger than 2 years of age the diagnostic significance of clinical and laboratory findings to localize site of febrile urinary tract infection. We reviewed the records of 185 children younger than 2 years of age admitted to hospital with febrile urinary tract infection. Patients were divided into having either acute pyelonephritis or acute cystitis according to the presence or absence of acute lesions on dimercaptosuccinic acid (DMSA) renal scintigraphy. Clinical and laboratory [white blood cell count (WBC), urinalysis, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)] findings were compared between the two groups using Student's t test, chi-square test, and multivariate analysis. Patients with pyelonephritis had statistically significant higher age, WBC, ESR, and CRP than those with cystitis. Although the sensitivity of the tests was 80-100%, their specificity was <28%. On multivariate analysis, 33% of patients with cystitis were diagnosed as having pyelonephritis, whereas 22% of those with pyelonephritis were considered to have cystitis. Given the low specificity of clinical findings and available laboratory tests to define the site of urine infection in this age group, we recommend DMSA renal scintigram as the test of choice to make the diagnosis of acute pyelonephritis in these patients.

Initial Experience With Laparoscopic Transvesical Ureteral Reimplantation at the Children’s Hospital of Philadelphia

PURPOSE

Laparoscopic transvesical ureteral reimplantation with or without robotic assisted surgical devices is being developed as an alternative to open surgery. We review our experience with laparoscopic transvesical ureteral reimplantation.

MATERIALS AND METHODS

A total of 32 patients underwent laparoscopic transvesical reimplantation by the same surgeon. Of the patients 5 had primary obstructing megaureters and 27 had vesicoureteral reflux. Transvesical laparoscopic cross-trigonal ureteral reimplantation was performed in patients with reflux, and a Glenn-Anderson reimplantation was used in patients with a primary obstructing megaureter. A pure laparoscopic approach using two 3 mm working ports and a 5 mm camera port was used.

RESULTS

The operative success rates were 92.6% and 80% for vesicoureteral reflux and primary obstructing megaureter cases, respectively. Complications included a postoperative urinary leak in 4 patients (12.5%) and ureteral stricture at the neoureterovesical anastomosis in 2 (6.3%). All but 1 complication occurred in patients 2 years or younger with bladder capacity less than 130 cc.

CONCLUSIONS

Laparoscopic intravesical reimplantation is in its infancy and appears to have higher complication rates in young patients with small bladder capacity.

[Evidence-based medicine and vesicoureteral reflux]

Vesicoureteral reflux (VUR) remains one of the most controversial subjects in paediatric urology. Much literature has been published on VUR, making the understanding of this anomaly and its treatments quite opaque. Evidence-Based Medicine (EBM) should be helpful to clarify the various VUR approaches contained in the 6224 titles found on Medline using the keywords "vesicoureteral reflux" and "vesicoureteric reflux". These articles were critically reviewed and graded according to EBM scorings, with regard to their methodological designs. This review of VUR literature suggests that most of our knowledge is based on publications with a low level of evidence, and that EBM lacks arguments to support recommendations for VUR diagnostic and treatment. It appears yet that antenatal dilatation of the urinary tract and symptomatic urinary tract infections (UTI) justify VUR screening. Surgery should be discussed in recurrent UTIs or deterioration of renal function. There is no consensus in case of persistent asymptomatic VUR regarding indication and duration of antibio-prophylaxis, and selection of radical treatment.

Experimental supratrigonal cystectomy: evaluation of long-term complications

OBJECTIVE

The present study aims at assessing the occurrence of pyelonephritis and long-term complications in rats submitted to surgical reduction of bladder capacity.

MATERIALS AND METHODS

Sprague-Dawley rats were submitted to supratrigonal cystectomy (animals) or sham operation ( animals) and sacrificed 2, 4 and 6 months after the surgical procedure. The arterial blood pressure and serum creatinine levels were assessed before the surgery and at the time of the sacrifice. After the sacrifice a careful inspection of the urinary apparatus was performed to the characterization of the hydronephrosis and for the detection of the presence of calculi. With sterile technique, the urine was aspirated from the bladder and the kidneys removed and sent to a microbiologic study.

RESULTS

Pyelonephritis was frequent in animals submitted to supratrigonal cystectomy. The most frequent and isolated microorganisms were Staphylococcus sp. and E. coli. The presence of urinary calculi was correlated significantly to the presence of urinary tract infection (p < 0.003). Arterial hypertension was frequent amongst animals submitted to supratrigonal cystectomy. Serum creatinine was high in 72.4% of the animals in the group submitted to supratrigonal cystectomy. The presence of calculi and pyelonephritis were frequent in rats presenting renal insufficiency and in hypertensive rats.

CONCLUSIONS

The long-term course of urinary infection in rats submitted to supratrigonal cystectomy was characterized by a high incidence of renal insufficiency and arterial hypertension that seem to be related to dysfunction and bladder obstruction induced by an extensive surgical procedure and the presence of urolithiasis and pyelonephritis.

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.

Recurrent urinary tract infection in the post-transplant reflux nephropathy patient: is reflux in the native ureter the culprit?

We assessed the prevalence of symptomatic, refluxing systems as a cause of recurrent urinary tract infection (UTI) in patients who underwent renal transplantation as result of renal failure from reflux nephropathy. Eleven patients from the age of 8 to 19 yr underwent renal transplantation for renal failure because of reflux nephropathy, between 1992 and 2003. Culture documented UTI were investigated and correlated with pre- and postoperative infection rates, voiding dysfunction (VD), concomitant nephrectomy, or nephroureterectomy with refluxing native remnants, and pretransplant ureteral reimplantation. Four patients with nephroureterectomies and no VD were infection free post-transplant. Two of three patients reimplanted pretransplant with a history of VD had one or more UTI per month. Patients with nephrectomies without partial ureterectomies with or without VD also had one or more UTI per month. Refluxing systems in the immunosuppressed transplant patient may play a role in UTI especially when associated with VD. Surgical intervention of native refluxing systems may be warranted.

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.

DMSA study performed during febrile urinary tract infection: a predictor of patient outcome?

Technetium-99m dimercaptosuccinic acid (DMSA) study has been advocated as a method for the assessment of renal sequelae after acute febrile urinary tract infection (UTI). However, it is not known whether DMSA scintigraphy performed during acute UTI has any prognostic value for outcome assessment. The objective of this study was to evaluate the usefulness of DMSA scintigraphy performed during UTI as a predictor of patient outcome, to identify children at risk of events [vesico-ureteral reflux (VUR) or recurrent UTI] that may lead to the development of progressive renal damage. One hundred and fifty-two children (including 78 girls) with a mean age of 20 months (range 1 month to 12 years) with first febrile UTI were evaluated by DMSA scintigraphy during acute UTI. After acute UTI, children were explored by voiding cysto-urethrography. Children who presented an abnormal DMSA study, or a normal DMSA study but VUR or recurrent UTI, underwent a DMSA control study 6 months after UTI. Children with VUR were followed up by direct radionuclide cystography. DMSA scintigraphy performed during acute UTI was normal in 112 children (74%). In 95 of these children, follow-up DMSA scintigraphy was not performed owing to a good clinical outcome. In the remaining 17 children, follow-up scintigraphy was normal. Forty children (26%) presented abnormal DMSA study during acute UTI. Twenty-five of them presented a normal follow-up DMSA, and 15 presented cortical lesions. Children with abnormal DMSA had a higher frequency of VUR than children with normal DMSA (48% vs 12%). It is concluded that children with normal DMSA during acute UTI have a low risk of renal damage. Children with normal follow-up DMSA and low-grade VUR have more frequent spontaneous resolution of VUR.

Using Tc-99m DMSA renal cortex scan to detect renal damage in women with type 2 diabetes

Women with diabetes mellitus (DM) have urinary tract infection (UTI) more often than women without DM. It is unknown, however, what the prevalence and type of renal damage due to UTI is in these women. Therefore, in this study, we compared type 2 DM women with or without UTI history for the prevalence and type of renal damage by technetium-99m dimercapto-succinic acid (Tc-99m DMSA) renal scan. A total of 128 type 2 DM women with or without UTI history received Tc-99m DMSA renal scan were included in this study. The patients were separated into three groups: (1) 43 patients without UTI history, (2) 42 patients with only lower UTI (cystitis) history and (3) 43 patients with upper UTI (pyelonephritis) history. The renal scan findings were separated into three types: (A) normal, (B) inflammation and (C) scar. The 31.9% (50/128) of type 2 DM patients had renal damages. Group 1 patients had a significantly lower prevalence of renal damages including inflammation and scar as compared to Groups 2 and 3 patients. In addition, the prevalence of renal damage was significantly higher in Group 3 than in Group 2 patients. Renal scars only were visualized in Group 3 patients. However, other clinical data were not statistically different among the three group patients. Type 2 DM women with UTI history, especially if they had upper UTI have a significantly higher prevalence of renal damage than in those without UTI.

Radiologic evaluation of patients with renal infections

Although renal imaging is not indicated routinely in cases of uncomplicated renal infection, CT is a highly sensitive modality to diagnose and guide the management of patients with acute renal infection. CT is particularly useful in identifying complications of renal infection. Intravenous urography and US are limited to screening for urinary obstruction, renal calculi, and underlying anomalies. CT is also of value in establishing the diagnosis in equivocal cases, in evaluating high-risk patients, and in determining the nature and extent of disease. CT urography is increasingly performed as a comprehensive urinary tract imaging study. MRI may be performed when patients have contraindications to iodinated contrast material. Cortical scintigraphy is the preferred imaging study for the evaluation of children with acute pyelonephritis, although power Doppler US can be considered as a possible alternative. Recent limited studies using gadolinium-enhanced MRI have been shown to be valuable in the depiction of changes of acute pyelonephritis.

The role of infection and free oxygen radical damage in reflux nephropathy: an experimental study

PURPOSE

We compared the effects of sterile and infected urine on reflux nephropathy in rabbits with experimental vesicoureteral reflux.

MATERIALS AND METHODS

We used 2-month-old male New Zealand rabbits in this study. Group 1 (5 rabbits) served as the control, group 2 (7) was the vesicoureteral reflux plus sterile urine group and group 3 (8) was the reflux plus infected urine group. Cystography and 99mTc-dimercapto-succinic acid renal scintigraphy were performed before the reflux procedure. To create unilateral vesicoureteral reflux the roof of the right intravesical ureter was incised. Escherichia coli suspension (2 ml.), 105 E. coli in 1 ml.) was introduced into the bladder in addition to the reflux procedure in group 3. Right vesicoureteral reflux was confirmed by cystography 2 weeks after reflux. Dimercapto-succinic acid scintigraphy was performed at 3 weeks and the animals were sacrificed and examined. Free oxygen radical damage was investigated by measuring malondialdehyde levels in renal tissue. ANOVA and Scheffe's test were used for statistical analysis.

RESULTS

Histopathological evaluation of the right kidney from group 2 rabbits showed mild interstitial fibrosis and mononuclear cell infiltration. The right kidney from group 3 rabbits showed apparent periglomerular fibrosis, tubular atrophy and dilatation, severe interstitial scarring and fibrosis with mononuclear cell infiltrate. There were marked histopathological changes in the right kidney of group 3 rabbits. The absolute percent dose uptake was unchanged in group 2 rabbits (p >0.05). There was significantly decreased uptake in refluxing kidneys and increased uptake in the contralateral nonrefluxing kidneys after vesicoureteral reflux in group 3 rabbits. The malondialdehyde level in the right renal tissue of group 3 was significantly higher than that in controls and in group 2 (p <0.05). The malondialdehyde level in the sterile reflux group did not differ significantly from that in the control group (p >0.05).

CONCLUSIONS

The results of this study show that free oxygen radical damage in the presence of infection has an important role in reflux nephropathy.

Using Tc-99m DMSA renal scan to detect renal damage in Taiwanese women with Type 2 diabetes--a preliminary report

In this preliminary study, we compared control women and Type 2 diabetes mellitus (DM) women for the prevalence and type of renal damage as revealed by technetium-99m dimercapto-succinic acid (Tc-99m DMSA) renal scan.

METHODS

A total of 20 control women and 60 women with Type 2 DM received Tc-99m DMSA renal scan were included in this study. The 60 women with Type 2 DM were separated into three groups: 20 women without UTI history, 20 patients with cystitis histories only, and 20 with pyelonephritis histories.

RESULTS

All of the control women had normal Tc-99m DMSA renal scan findings. However, 38.3% of Type 2 DM wonmen had abnormal Tc-99m DMSA renal scan findings. Type 2 DM women without UTI history had no abnormal scan findings. The prevalence of abnormal renal scan findings was significantly higher in Type 2 DM women with pyelonephritis (90.0%) than with cystitis alone (25.0%). Renal scar findings were found only in Type 2 DM women with pyelonephritis (40.0%).

CONCLUSIONS

Compared with control women, women with Type 2 DM, especially if they had UTI and pyelonephritis histories, have a significantly higher prevalence of abnormal Tc-99m DMSA renal scan findings.

Objective evidence of a high prevalence of renal damage in women with type 2 diabetes by technetium-99m DMSA renal cortex scan findings

OBJECTIVES

To compare control women with men and women with type 2 diabetes mellitus (DM) for the prevalence and type of renal damage due to urinary tract infections (UTIs) using technetium-99m dimercapto-succinic acid (99mTc DMSA) renal scanning. Women with DM have UTIs more often than do women without DM. It is unknown, however, what the prevalence and type of renal damage due to UTI are in these women.

METHODS

Three groups of patients: 28 control women without type 2 DM and a history of UTIs, 25 male patients with type 2 DM but without a history of UTIs, and 103 female patients with type 2 DM underwent 99mTc DMSA renal scan. The 103 women with type 2 DM were separated into three groups: 36 women without a history of UTIs, 34 patients with a history of cystitis only, and 33 with a history of pyelonephritis.

RESULTS

All the control women and male patients with type 2 DM without a history of UTIs had normal 99mTc DMSA renal scan findings. However, 39.8% of women with type 2 DM had abnormal 99mTc DMSA renal scan findings. Women with type 2 DM without a history of UTI had a significantly lower prevalence of abnormal renal scan findings than did those with a history of cystitis only or pyelonephritis. In addition, the prevalence of abnormal renal scan findings was significantly higher in women with type 2 DM with pyelonephritis than in those with a history of cystitis only. Renal scars on 99mTc DMSA renal scans were found in women with type 2 DM and a history of pyelonephritis.

CONCLUSIONS

Compared with control women and men with type 2 DM, women with type 2 DM, especially if they had a history of UTIs, had a significantly higher prevalence of abnormal 99mTc DMSA renal scan findings.

Follow-up of acute pyelonephritis in children by Tc-99m DMSA scintigraphy: quantitative and qualitative assessment

PURPOSE

The author's goal was to create a system to identify children at risk for development of progressive renal damage.

METHODS

Thirty-four children were examined with Tc-99m DMSA scintigraphy in the acute stage of an initial episode of pyelonephritis, after 6 months, and again after 1 year. The scintigraphic findings were correlated with clinical and laboratory data.

RESULTS

All children had parenchymal defects in the acute stage: 93% of the kidneys and 85% bilaterally. After 6 months, the defects had diminished or disappeared in 66% of the kidneys. New defects appeared in 22%. At 1 year, no further improvement was seen in the kidneys, with an improved or unchanged pattern at 6 months. New defects appeared in 34%. Mean kidney activity uptake expressed as the percentage of administered dose (KU/AD), was low in the acute stage, increased at 6 months, with no further significant increase at 1 year. Eighty-three percent of children with urine cultures growing > or = 104 bacteria/ml at follow-up had decreased KU/AD values, whereas all children with urine cultures growing < 104 bacteria/ml had increased KU/AD values.

CONCLUSIONS

Quantitative assessment increases the sensitivity of Tc-99m DMSA scintigraphy. Follow-up with this method makes it possible to identify the children with decreasing renal tubular function who may be at risk for progressive renal damage. Moderate bacteruria of 104 bacteria/ml urine is associated with deterioration of renal tubular function.

UTI: diagnosis and evaluation in symptomatic pediatric patients

We retrospectively reviewed data on 260 hospitalized pediatric patients with symptomatic urinary tract infection (UTI). To ascertain the colony-forming units (CFU)/mL compatible with the diagnosis of UTI, a culture from a catheterized urine specimen containing >1,000 CFU/mL was considered diagnostic of UTI and resulted in imaging by renal ultrasound, voiding cystourethrography, and renal nuclear scan with Tc99m dimercaptosuccinic acid (DMSA). A positive DMSA renal scan is indicative of pyelonephritis. We used logistic regression analysis to determine which patient characteristics were predictive of pyelonephritis. We determined that, in hospitalized pediatric patients, the colony count of the positive urine culture, the type of organism grown in culture, and the voiding cystourethrography (VCUG) result (positive or negative for vesicoureteral reflux) did not predict which patients had pyelonephritis. In females, advancing age of the patient and positive renal ultrasound results were predictive of which patients had pyelonephritis when we controlled for other factors. We feel this emphasizes the importance of a thorough evaluation of hospitalized symptomatic patients, including patients with colony counts of 1,000 to 50,000 CFU/mL, to locate the level of infection and plan appropriate therapy.

Does treatment of vesicoureteric reflux in childhood prevent end-stage renal disease attributable to reflux nephropathy?

OBJECTIVE

It is believed that end-stage renal disease (ESRD) attributable to reflux nephropathy is preventable by the active treatment of vesicoureteric reflux in childhood with long-term antibiotics and ureteric reimplantation surgery. We aimed to test this belief.

METHODOLOGY

The Australia and New Zealand Dialysis and Transplant Registry of new patients 5 to 44 years of age treated for ESRD between 1971 and 1998, categorized by age and primary renal disease, was used to analyze the age-specific incidences of ESRD attributable to reflux nephropathy using a before-after study design. The early 1960s were regarded as the introduction period for the active treatment of childhood vesicoureteric reflux. A time-delay in treatment effect was expected. Patients with ESRD attributable to other causes were used as a comparative group.

RESULTS

The incidence of ESRD attributable to reflux nephropathy and nonreflux nephropathy has increased. For reflux nephropathy, the rate of change was significantly associated with age, with a downward trend in incidence with decreasing age suggesting a minor treatment effect. This trend was no longer evident when adjustment was made for changing diagnostic practices. An opposite trend was observed for the nonreflux nephropathy group, who demonstrated an upward trend in incidence with decreasing age.

CONCLUSIONS

Treatment of children with vesicoureteric reflux has not been accompanied by the hoped-for reduction in the incidence of ESRD attributable to reflux nephropathy. A randomized trial with a control (no-treatment) arm is required to appropriately assess the medical belief that long-term antibiotics and surgery improve the natural history of vesicoureteric reflux.

[Initial imaging in pediatric urinary tract infection]

First step imaging investigations in urinary tract infections in children rely upon conventional sonography, and, when available. Power Doppler sonography. Enhanced computerised tomography (CT) and dimercaptosuccinic acid (DMSA) scintigraphy are complementary investigations in difficult cases. Contrast cystourethrogram has always to be performed. Intravenous pyelography is no longer used as a first step imaging technique.

Using technetium-99M dimercaptosuccinic acid renal cortex scintigraphy to differentiate acute pyelonephritis from other causes of fever in patients with spinal cord injury

OBJECTIVES

To differentiate acute pyelonephritis (APN) from fever due to other sources in patients with spinal cord injury by using technetium-99m dimercaptosuccinic acid (DMSA) renal cortex scintigraphy (DMSA scan).

METHODS

A total of 24 patients with spinal cord injury were admitted with fever. DMSA scans were performed on all patients. The final determination of the cause of the fever was based on the medical history, physical examination, laboratory evaluation, and imaging studies.

RESULTS

DMSA scan accurately diagnosed APN in 12 patients with inflammation on the DMSA scan. In 5 patients with scarred lesions on the DMSA scans and in 7 patients with negative DMSA scan, the fever was attributed to other causes. The sensitivity and specificity of the DMSA scan for detecting APN were both 100%.

CONCLUSIONS

The DMSA scan is a valuable adjunct in the evaluation of fever in patients with SCI.

Polymorphonuclear elastase as a diagnostic marker of acute pyelonephritis in children

OBJECTIVE

Experimental evidence suggests that neutrophils and their metabolites play an important role in the pathogenesis of pyelonephritis. The aim of this study was to investigate the diagnostic value of polymorphonuclear elastase-a(1)-antitrypsin complex (E-a(1)-Pi) for the detection of acute pyelonephritis in children.

METHODS

Eighty-three patients, 29 boys and 54 girls, 25 days to 14 years of age, with first-time symptomatic urinary tract infection were prospectively studied. Fifty-seven healthy children served as controls. Dimercaptosuccinic acid (DMSA) scan and voiding cystourethrography were performed in all patients. Plasma and urinary E-a(1)-Pi, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), neutrophil count, urinary N-acetyl-beta-glucosaminidase (NAG), N-acetyl-beta-glucosaminidase b (NAG b), and creatinine levels were measured in all patients on admission and 3 days after the introduction of antibiotics. The same markers were also measured in the control subjects.

RESULTS

Planar DMSA scintigraphy demonstrated changes of acute pyelonephritis in 30 of 83 children (group A). It was normal in the remaining 53 children (group B). The sex and age distributions were not significantly different between the 2 groups, as well as between the patients and the control subjects (group C). Nineteen of the 53 children with a normal DMSA had body temperature >/=38 degrees C, whereas all but 4 children with abnormal DMSA had temperature >/=38 degrees C. Therefore, the temperature was significantly different between these 2 groups. The sensitivity and specificity of fever (>/=38 degrees C) as an indicator of renal involvement based on isotopic findings were 86% and 64%, respectively. Given the significant number of the febrile children with normal DMSA scintiscans, group B was subdivided into B(1) with 19 febrile children (14 boys and 5 girls) and B(2) with 34 children whose body temperature was below 38 degrees C (8 boys and 26 girls). The sex and age distribution was significantly different between groups B(1) and B(2). The mean age of group B(1) was.78 years (range: 28 days to 9 years; median:.25 years; standard deviation: 2.1). All but 1 child in this group were younger than 1 year of age. In contrast, in group B(2), there were only 4 infants, the remaining 30 children were older than 2.5 years (mean age: 6 years; median: 7 years; standard deviation: 3.5; range: 34 days to 12 years). The mean duration of fever before hospital admission was 2.8 days for group A and 1.8 days for group B(1). This difference was not statistically significant. Similarly, body temperature was not significantly different between these 2 groups. The distribution of plasma E-a(1)-Pi values was normal in the control subjects. The sensitivity and specificity of plasma E-a(1)-Pi, as an indicator of renal involvement, were 96% and 50%, respectively, taking the 95th percentile of the reference range as a cutoff value. However, considering as a cutoff value the level of 72 microg/dL (95th percentile of group B(2)), its sensitivity and specificity were 74% and 86%, respectively. Plasma E-a(1)-Pi levels were significantly elevated in group A compared with group B and in both groups, the plasma E-a(1)-Pi values were significantly higher than in the control subjects. A significant difference also was noticed between group A and each of the subgroups B(1) and B(2) and also between the subgroups themselves. Plasma E-a(1)-Pi concentrations correlated significantly with neutrophil count in groups A (r =.3), B (r =.4), and B(2) (r =.46), but the correlation was not significant in group B(1.) ESR levels showed, among the different groups, similar differences with those of E-a(1)-Pi values. Unlike E-a(1)-Pi, CRP levels were comparable between groups A and B(1), which both consisted of febrile children. Neutrophil count was not significantly different between subgroups B(1) and B(2). (ABSTRACT TRUNCATED)

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.

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.

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.

Identification of new renal scarring in repeated episodes of acute pyelonephritis using Tc-99m DMSA renal SPECT

PURPOSE

This prospective study compared the value of Tc-99m DMSA renal planar scintigraphy with SPECT to detect new renal involvement in patients with repeated episodes of acute pyelonephritis (APN).

MATERIALS AND METHODS

Children with suspected APN were transferred to our department for DMSA renal scans. Seventy-two children (ages 1 week to 15 years) had DMSA planar and SPECT imaging performed twice because of clinical or laboratory suspicion of repeated APN. In addition, radiographic voiding cystourethrography was also performed in all cases. The presence of vesicoureteral reflux (VUR) was graded on a scale of 0 to 5.

RESULTS

New lesions were observed with SPECT in 56 kidneys and with planar scintigraphy in 38 kidneys. No patients had a negative result of Tc-99m DMSA renal SPECT who also had a positive Tc-99m DMSA planar result. The degree of VUR as related to APN was diagnosed better with SPECT than with planar scintigraphy (46 compared with 30 and 10 compared with 8, respectively). There is a significant difference (P < 0.05) between the diagnostic ability of these two methods to identify the increased tendency of repeated APN to occur with high-grade VUR compared with low-grade or no VUR.

CONCLUSIONS

High-grade VUR is more commonly associated with renal injury than is low-grade or no VUR. If only Tc-99m DMSA renal planar scintigraphy is performed, renal scarring may be underestimated. Our results suggest that Tc-99m DMSA renal SPECT, rather than planar scintigraphy, should be used routinely in children with a clinical suspicion of APN, especially for those with scarred kidneys and high-grade VUR.

Renal function up to 16 years after conduit (refluxing or anti-reflux anastomosis) or continent urinary diversion. 2. Renal scarring and location of bacteriuria

OBJECTIVE

To evaluate the importance of refluxing versus anti-reflux ureteric implantation for the development of renal scarring in patients with a conduit or continent urinary diversion and for the incidence of bacteriuria in the upper urinary tract of patients with a conduit.

PATIENTS AND METHODS

Renal scintigraphy using 99mTc-dimercaptosuccinic acid was performed on 32 of 37 evaluable patients from a prospective, randomized study at a mean of 150 months (range 102-198) after urinary diversion. In five patients with a conduit diversion and unilateral renal scarring, urine was samples for culture from the proximal end of the conduit and from both renal pelvices by direct percutaneous aspiration.

RESULTS

Of 35 renal units (18 patients), studied after conduit diversion, scarring was found in 11 (two grade I, six grade II and three grade III) of 17 with refluxing anastomosis and in six (one grade I, four grade II and one grade III) of 18 with anti-reflux anastomosis (P = 0.06). Of 25 renal units (14 patients) after continent diversion, 16 showed scarring (seven grade I and nine grade II). Bacteriuria was found in four of five upper urinary tracts with a refluxing anastomosis, but in only one of five with an anti-reflux anastomosis. In these five patients scarring was present in all kidneys with refluxing anastomosis.

CONCLUSION

Anti-reflux ureteric anastomosis seems to be important for preventing scarring and bacteriuria in the upper urinary tract of patients with a conduit urinary diversion. Despite the anti-reflux technique of ureteric implantation, most patients with a continent reservoir had renal scarring, though it was generally less severe than in patients with a conduit urinary diversion.

Pitfalls in the investigation of children with urinary tract infection

The histories and imaging results are presented in 10 children in whom errors had been made in the interpretation of early investigations. Ultrasonography may not detect either vesicoureteric reflux (VUR) or renal scars or inflammation. The reduced nephrogram or renal swelling following a first attack of acute pyelonephritis may not be recognised without renal measurement on an intravenous urogram. Renal scarring may be diagnosed incorrectly on the basis of functional defects of isotope uptake on a technetium 99m-dimercaptosuccinic acid study. In the absence of VUR, the micturating cystogram will not visualise the kidneys.

Renal pathology and the 99mTc-DMSA image before and after treatment of the evolving pyelonephritic scar: an experimental study

This study reports the effects of 3-weeks' antimicrobial treatment on the pathology and appearance of the 99mTc-DMSA renal image in piglets with pyelonephritis induced by a combination of vesicoureteral reflux (VUR) and urinary infection. Before treatment, either photon-deficient (B1, B2) or photon-absent (C) scintigraphic abnormalities were present in the refluxing kidney in all 22 animals examined. All (100%) of the initially B1 and the majority (71%) of B2 photon deficient defects resolved with treatment, leaving only insignificant residual pathologic lesions. Conversely almost all (93%) of the C photon-absent scintigraphic abnormalities persisted after treatment and were always associated with significant scarred or cratered pathologic lesions in the refluxing kidney at sacrifice.