Vesicoureteral reflux

Value of contrast-enhanced sonography in the diagnosis of vesicoureteral reflux

BACKGROUND

 Contrast-enhanced ultrasound of the urinary tract and bladder (ceVUS) is an alternative examination method to micturition cysturethrography (MCU/VCUG) for suspected vesicoureteral reflux (VUR) that is increasing in practice. The purpose of this review is to present the current value of ceVUS in the diagnosis.

METHOD

 A systematic literature search was performed using the keywords "vesicoureteral reflux", "ceVUS", "VCUG" of the databases MEDLINE and Cochrane Library as well as a review of current German, European, and American guidelines on this topic. In addition, recommendations for action in clinical practice were developed.

CONCLUSION

 ceVUS is a quick-to-learn examination method that is equivalent to VCUG for the diagnosis of vesicoureteral reflux and should be used as the diagnostic method of first choice when available given the absence of radiation exposure.

KEY POINTS

  · Like VCUG, ceVUS is the diagnostic method of first choice in suspected vesicoureteral reflux and should be used preferentially given the absence of radiation exposure.. · Especially in comparison to the alternative VCUG, ceVUS is a quick-to-learn examination method.. · ceVUS can also be used to diagnose other pathologies of the lower urinary tract..

CITATION FORMAT

· Conen P, Thiemann J, Stredele R et al. Value of contrast-enhanced sonography in the diagnosis of vesicoureteral reflux. Fortschr Röntgenstr 2024; 196: 1022 - 1028.

The Utility of Noninvasive Urinary Biomarkers for the Evaluation of Vesicoureteral Reflux in Children

Vesicoureteral reflux (VUR) is one of the most important disorders encountered in pediatric nephrology due to its frequency and potential evolution to chronic kidney disease (CKD). The aim of our study was to identify noninvasive and easy-to-determine urinary markers to facilitate the diagnosis and staging of VUR. We performed a cross-section study including 39 patients with VUR followed over three years (August 2021-September 2023) and 39 children without urinary disorder (the control group). We measured the urinary concentration of interleukin-6 (IL-6), cathelicidin (LL-37), and neutrophil gelatinase-associated lipocalin (NGAL) in VUR and healthy controls. Moreover, we analyzed the correlation between these biomarkers and the presence of renal scars (RS), reflux nephropathy (RN), and CKD. The NGAL concentrations were significantly higher in patients with VUR than in the controls (p = 0.02). Regarding the severity of the reflux, NGAL/creatinine and LL-37/creatinine were positively correlated with severe reflux (p = 0.04, respectively, p = 0.02). In patients with VUR and RS, LL-37/creatinine was significantly lower (p = 0.01). LL-37/creatinine with an AUC of 0.71 and NGAL/creatinine with an AUC of 0.72 could be acceptable diagnostic tests for severe VUR. In conclusion, urinary IL-6, NGAL, and LL-37 could serve as valuable markers for diagnosing and predicting outcomes in patients with VUR and RN.

Efficacy and safety of Hyadex for treatment of vesicoureteral reflux: a multicenter experience

OBJECTIVE

This study was performed to evaluate the efficacy and safety of dextranomer/cross-linked hyaluronic acid (Hyadex) in patients with a clinical diagnosis of vesicoureteral reflux (VUR).

METHODS

In this cross-sectional multicenter observational study, Hyadex was used in four different centers for the endoscopic treatment of VUR from 2020 to 2022. The study involved 74 patients (93 renal units) who were diagnosed with VUR according to voiding cystourethrography (VCUG) findings and were considered suitable for subureteric endoscopic treatment. The follow-up time (control VCUG time) was 3 months.

RESULTS

In the VCUG evaluation, grade I VUR was found in 13 renal units, grade II in 23 renal units, grade III in 42 renal units, and grade IV in 12 renal units. The success rates of Hyadex treatment according to the degree of VUR were as follows: 84.6% for grade I, 82.6% for grade II, 71.4% for grade III, and 66.0% for grade IV. No major complications were observed.

CONCLUSION

Endoscopic subureteric Hyadex injection had high success rates in appropriately selected patients with VUR and may be used as the first-line treatment for children with VUR.

Spontaneous vesicoureteral reflux resolution curves based on ureteral diameter ratio

INTRODUCTION

Various factors influence the clinical course of vesicoureteral reflux (VUR) in the pediatric population. Distal ureteral diameter ratio (UDR) is an objective measure reflective of ureterovesical junction anatomy that has been shown to independently predict both spontaneous resolution and breakthrough febrile urinary tract infection (UTI) in children with primary reflux. UDR resolution curves were created, hypothesizing that a UDR value existed at which spontaneous resolution was unlikely to occur.

MATERIALS AND METHODS

UDR was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between L1-L3 vertebral bodies. Recursive partitioning with 10-fold cross validation methodology for time to event data, utilizing martingale residuals was used to create high and low risk groups based on UDR, and stratified by age at diagnosis and laterality.

RESULTS

Three hundred and four patients (226 female, 78 male) were analyzed with a mean age at diagnosis of 1.55 ± 1.98 years. Unilateral reflux (p = 0.02), VUR grades 1-3 (p < 0.001), and lower UDR (p < 0.001) were associated with spontaneous resolution on univariate analysis. UDR values were categorized into risk groups based on recursive partitioning. Low risk patients (those with UDR <0.30) achieved VUR resolution faster and with a continuing rate compared to the high-risk group (≥0.30), which had persistent reflux after 3 years [Summary Figure]. When the 0.30 cutoff was applied randomly to patients in test group, the cutoff significantly discriminated between low and high-risk patients (log rank test p = 0.02).

DISCUSSION

Primary VUR is often a self-limiting diagnosis, with conservative management favored in low-risk children, UDR may be used to help distinguish those children who may benefit from intervention. Unlike traditional VUR grading where children with any grade of reflux may spontaneously resolve, there appears to be a consistent UDR cutoff whereby patients are very unlikely to spontaneously resolve, regardless of length of follow-up. Therefore, parents of children with a UDR above the 0.3 cutoff, regardless of VUR grade, may be counselled that VUR is very unlikely to resolve over time - thereby reducing the number of VCUGs and length of time these patients are on prophylactic antibiotic prior to surgical intervention.

CONCLUSIONS

Children with primary VUR and a UDR of greater than 0.30 are significantly less likely to spontaneously resolve regardless of length of follow-up, and resolution after 3 years was rare. UDR provides objective prognostic information facilitating individualized patient management.

Laparoscopic Ureteral Reimplantation after Failed Open Surgery: Incorporating the Psoas Hitch Maneuver for Sufficient Tunnel Length

BACKGROUND

 Failure after open ureteral reimplantation has been reported to occur in 2 to 7% of cases. While a second open reconstructive surgery is appropriate in most cases, there are data suggesting similar outcomes utilizing the laparoscopic approach. The objective of this study is to describe a modification and report our experience with laparoscopic ureteral reimplantation after failed open reimplantation reinforced with a psoas hitch.

MATERIALS AND METHODS

 A retrospective review of pediatric patients who underwent laparoscopic ureteral reimplantation after failed open surgery between September 2012 and April 2018 at three different academic centers was performed. Patient demographics, surgical indications, complications, and outcomes were reviewed. Either ipsilateral ureteral reimplantation with a combined intravesical and extravesical approaches or a cross-trigonal extravesical approach was utilized, depending on the length of the ureter. In all cases, a psoas hitch was performed to gain a longer submucosal tunnel and relieve tension, thus facilitating an efficient antireflux mechanism.

RESULTS

 Seventeen patients underwent a laparoscopic ureteral reimplantation after failed open surgery. Median age at second surgery was 106 months (interquartile range [IQR]: 53-122.5). Ipsilateral ureteral reimplantation with a combined intravesical and extravesical approaches was performed in 11 cases and cross-trigonal extravesical approach in 6 cases. Median ureteral diameter before the redo surgery was 16 mm (IQR: 14.5-18.5) and after surgery was 6 mm (IQR: 3.5-8.5) (p < 0.001). Postoperative mercaptoacetyltriglycine renal scan showed a nonobstructive pattern and stable renal function in all cases.

CONCLUSION

 Laparoscopic ureteral reimplantation with incorporation of a psoas hitch after failed open reimplantation is safe and effective.

Voiding cystourethrogram: Who gets a cyclic study and does it matter?

BACKGROUND

Voiding cystourethrogram (VCUG) images the urethra and bladder during both bladder filling and emptying, as well as the ureters and kidneys when vesicoureteral reflux (VUR) is present. Given the variation in VCUG technique and reporting, the American Academy of Pediatrics Sections on Urology and Radiology published a joint standardized VCUG protocol in 2016, which included the recommendation of at least 2 voiding cycles to identify intermittent VUR and/or ureteral ectopia.

STUDY DESIGN

VCUG were assessed for adherence to performance of cyclic study. Children who underwent cyclic evaluation were compared to those who underwent a single cycle VCUG. Radiation dosage was also analyzed. Studies performed on patients >18 years of age and those obtained as part of a trauma evaluation were excluded from study.

RESULTS

Two hundred and eighty-four VCUGs were analyzed, 97 (34.2%) were positive for VUR on the initial cycle. Of the remaining 187 studies, 116 (62%) had multiple filling-voiding cycles while in 71 (38%) only a single cycle was performed. One hundred and sixty-one (86.1%) were negative for vesicoureteral reflux. Twenty-six (13.9%) children were diagnosed with VUR after the initial filling-voiding cycle: 6 were diagnosed with grade I, 2 grade II, 11 grade III, 2 grade IV and 5 grade V. Of the 123 total children found to have VUR, 26 (21.2%) were diagnosed after an initial negative cycle. Younger children were significantly more likely to have a cyclic study performed; mean age of patients undergoing a cyclic study was 1.09 ± 2.16 years versus 3.86 ± 4.5 years (p ≤ 0.0001). Categorically, 74.1% of children less than 1 year of age underwent a cyclic study compared to 6.9% of children older than 5 years of age (p ≤ 0.0001). There was no difference based on sex with 49.1% of males and 50.9% of females (p = 0.667) undergoing cyclic evaluation. Children undergoing a cyclic study had lower median radiation dose 2.15 microGy m2 (range 0.09-111) compared to 4.41 (range 1.3-104) [p = 0.01].

DISCUSSION

Vesicoureteral reflux may occur intermittently and cyclic VCUG is thought to enhance the ability to detect reflux. In our cohort, 26 children (9.2%) were only diagnosed after an additional cycle - ie 21.1% of reflux would have been missed had a cyclic study not been performed. The majority of these patients (69.2%, 18 of 26) were found to have dilating, and thus perhaps more clinically significant, reflux. Our study highlights the importance of obtaining as much information as possible and adhering to the standardized VCUG protocol.

CONCLUSION

Younger children are more likely to undergo cyclic VCUG. While most reflux is detected with the initial filling-voiding cycle, 26 (21.2%) patients were diagnosed after an initial negative cycle with the majority being dilating VUR.

Surgical management of vesicoureteral reflux with recurrent urinary tract infection after renal transplantation in a dog

CASE DESCRIPTION A 3-year-old male Cocker Spaniel renal transplant recipient was readmitted 39 weeks after transplantation because of acute clinical signs of pollakiuria, intermittent vomiting, decreased appetite, lethargy, and mild fever. CLINICAL FINDINGS Hydronephrosis and hydroureter were observed with ultrasonography and contrast cystography, and a diagnosis of vesicoureteral reflux (VUR) was made. Urinary tract infection (UTI) caused by Escherichia coli was also diagnosed on the basis of results of urine culture. TREATMENT AND OUTCOME Despite treatment of the UTI with an appropriate antimicrobial for 6 weeks, the VUR persisted and the UTI recurred 9 weeks after cessation of antimicrobial treatment. Therefore, surgical correction by means of revision extravesicular ureteroneocytostomy was performed. Both VUR and hydronephrosis resolved after surgery. No recurrences of clinical signs of urinary tract complications were observed during the subsequent 22-month follow-up period. CLINICAL RELEVANCE Results suggested that ureteral reimplantation with an extravesicular technique incorporating a long submucosal tunnel may be an effective treatment for VUR when medical management fails in canine renal transplant recipients with recurrent UTIs.

The association of hypercalciuria and hyperuricosuria with vesicoureteral reflux in children

OBJECTIVES

One of the important complications of vesicoureteral reflux (VUR) is the development of urolithiasis. Identifying factors involved in development of urolithiasis in children with VUR is immensely important. This study was conducted to determine the association between hypercalciuria and hyperuricosuria with VUR in children.

METHODS

One-hundred children with VUR (case group) were compared to 100 healthy children (control group) in terms of hypercalciuria and hyperuricosuria. To measure these markers, random morning fasting urine samples were used. Data were analyzed using statistical tests.

RESULTS

Hypercalciuria and hyperuricosuria frequencies, and also urine calcium/creatinine (Ca/Cr) and urine uric acid/creatinine (UA/Cr) ratios were significantly higher in the case group compared to the control group (P < 0.05). A significant difference was found between hypercalciuria and hyperuricosuria in severity of VUR (P < 0.05). A positive correlation was observed between hypercalciuria and hyperuricosuria and severity of VUR (P < 0.05).

CONCLUSIONS

The present study showed that there is association between hypercalciuria, hyperuricosuria and VUR in children. It is recommended to adopt measures to prevent the development of urolithiasis in VUR patients.

Bioelectric Impedance Analysis in the Diagnosis of Vesicoureteral Reflux

Background:

Vesicoureteral reflux (VUR) is a common abnormality of the urinary tract in childhood.

Objectives:

As urine enters the ureters and renal pelvis during voiding in vesicoureteral reflux (VUR), we hypothesized that change in body water composition before and after voiding may be less different in children with VUR.

Patients and Methods:

Patients were grouped as those with VUR (Group 1) and without VUR (Group 2). Bioelectric impedance analysis was performed before and after voiding, and third space fluid (TSF) (L), percent of total body fluid (TBF%), extracellular fluid (ECF%), and intracellular fluid (ICF%) were recorded. After change of TSF, TBF, ECF, ICF (ΔTSF, ΔTBF%, ΔECF%, ΔICF%), urine volume (mL), and urine volume/body weight (mL/kg) were calculated. Groups 1 and 2 were compared for these parameters. In addition, pre- and post-voiding body fluid values were compared in each group.

Results:

TBF%, ECF%, ICF%, and TSF in both pre- and post-voiding states and ΔTBF%, ΔECF%, ΔICF%, and ΔTSF after voiding were not different between groups. However, while post-voiding TBF%, ECF% was significantly decreased in Group 1 (64.5 ± 8.1 vs 63.7 ± 7.2, P = 0.013 for TBF%), there was not post-voiding change in TSF in the same group. On the other hand, there was also a significant TSF decrease in Group 2.

Conclusions:

Bladder and ureter can be considered as the third space. Thus, we think that BIA has been useful in discriminating children with VUR as there was no decreased in patients with VUR, although there was decreased TSF in patients without VUR. However, further studies are needed to increase the accuracy of this hypothesis.

Intravoxel incoherent motion magnetic resonance imaging to predict vesicoureteral reflux in children with urinary tract infection

OBJECTIVES

To compare the diffusion parameters of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) between the "reflux" and the "non-reflux" kidneys, and to evaluate the feasibility of using IVIM DWI to predict vesicoureteral reflux (VUR) in children with a urinary tract infection (UTI).

METHODS

Eighty-three kidneys from 57 pediatric patients with a UTI were classified into "reflux" and "non-reflux" groups according to voiding cystourethrography (VCUG) results. The apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (PF) were measured and compared in the renal pelvis of both groups. Four indices (D*/ADC, PF/ADC, D*/D, and PF/D) were calculated and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

VURs were detected on VCUG in 21 kidneys. PF and D* were significantly higher in the "reflux" group than in the "non-reflux" group. The indices were all significantly higher. The PF/D index showed the best diagnostic performance in predicting VUR in children with UTI (Az = 0.864).

CONCLUSION

PF and D* were significantly higher in the "reflux" kidney than in the "non-reflux" kidney. Our new index (PF/D) could prove useful for predicting VUR.

KEY POINTS

• IVIM DWI is both radiation-free and contrast media-free. • IVIM DWI index is easily calculated by combining diffusion parameters. • IVIM DWI may help predict VUR in children with UTI. • PF is significantly higher in the "reflux" than the "non-reflux" kidneys. • A new VUR index, PF/D could prove useful for predicting VUR.

The value of direct radionuclide cystography in the detection of vesicoureteral reflux in children with normal voiding cystourethrography

BACKGROUND

Vesicoureteral reflux (VUR) is one of the most important risk factors for urinary tract infection (UTI). Diagnosis and treatment of VUR is important to prevent irreversible complications, such as renal scarring and chronic renal failure. This study was conducted to assess the value of direct radionuclide cystography (DRNC) in the detection of VUR in children with UTI and a normal voiding cystourethrography (VCUG).

METHODS

DRNC was performed in 35 children with a normal VCUG after an episode of febrile UTI who had hydronephrosis or hydroureter, abnormal acute dimercaptosuccinic acid (DMSA) scan results and/or febrile UTI recurrence. This study was conducted in the nephrology department of Mofid Children's Hospital, Tehran (Iran).

RESULTS

The results were statistically analyzed. Among the 70 ureters studied, 33 (49.1 %) were observed to have VUR. Of these, 17 (51.5 %) had mild, 14 (42.4 %) moderate, and 2 (6.1 %) severe reflux. A significant relationship was observed between DRNC results and DMSA renal scan findings (P < 0.05).

CONCLUSIONS

Based on our results, we suggest that DRNC may reveal VUR despite a normal VCUG in children with hydronephrosis, abnormal acute DMSA, and/or recurrent febrile UTI.

Gender-based differences in pediatric nuclear medicine

Gender-based differences commonly encountered in pediatric nuclear medicine reflect both basic embryologic differences of the sexes, which are evident from infancy, and evolving physiological changes due to gender, which occur as the pediatric patient grows, undergoes puberty, and matures to adulthood. It is important for a nuclear medicine physician or radiologist to know both the gender and the age of a patient when interpreting her or his studies. It is also important that the reading physician be familiar with the normally evolving physiological changes that are specific for that patient's stage of development. It is particularly important that the reading physician consider such changes when comparing serial studies of the patient that are acquired during the patient's transitions through her or his different significant stages of development. Many pediatric nuclear medicine imaging protocols are modifications or adaptations of the protocols for adult imaging. Physicians reading pediatric studies must routinely incorporate knowledge on age and gender that is relevant to the patient for any given study. The age-defined gender-based subtleties of potential findings in pediatric nuclear medicine studies are often underrecognized. However, they are often of interest and at times important in the workup of both benign entities and pathologic processes of the pediatric patient.

Are clinical, laboratory, and imaging markers suitable predictors of vesicoureteral reflux in children with their first febrile urinary tract infection?

Purpose

This study was conducted to determine the predictive value of clinical, laboratory, and imaging variables for the diagnosis of vesicoureteral reflux in children with their first febrile urinary tract infection.

Materials and Methods

One hundred fifty-three children with their first febrile urinary tract infection were divided into two groups according to the results of voiding cystourethrography: 60 children with vesicoureteral reflux and 93 children without. The sensitivity, specificity, positive and negative predictive value, likelihood ratio (positive and negative), and accuracy of the clinical, laboratory, and imaging variables for the diagnosis of vesicoureteral reflux were determined.

Results

Of the 153 children with febrile urinary tract infection, 60 patients (39.2%) had vesicoureteral reflux. There were significant differences between the two groups regarding fever>38℃, suprapubic pain, C-reactive protein quantitative level, number of red blood cells in the urine, and results of renal ultrasound and dimercaptosuccinic acid renal scanning (p<0.05). There were significant positive correlations between fever>38.2℃ and dimercaptosuccinic acid renal scanning and vesicoureteral reflux. Also, there were significant positive correlations between the erythrocyte sedimentation rate, positive urinary nitrite test, hyaline cast, and renal ultrasound and high-grade vesicoureteral reflux.

Conclusions

This study revealed fever>38.2℃ and dimercaptosuccinic acid renal scanning as the best predictive markers for vesicoureteral reflux in children with their first febrile urinary tract infection. In addition, erythrocyte sedimentation rate, positive urinary nitrite test, hyaline cast, and renal ultrasound are the best predictive markers for high-grade vesicoureteral reflux.

Voiding urosonography with second-generation ultrasound contrast versus micturating cystourethrography in the diagnosis of vesicoureteric reflux

Vesicoureteric reflux has been associated with paediatric urinary tract infection. Fluoroscopic micturating cystourethrography (MCU) has been the gold standard of diagnostic test for decades; however, it has been criticized owing to its lower detection rate and radiation dose to children. Therefore, new radiation-free reflux imaging modalities have been developed, in which ultrasound-based contrast-enhanced voiding urosonography (ceVUS) is a good example. However, ultrasonography has been considered as an operator-dependent examination. Therefore, our study aimed to examine the inter-observer agreement of this sonographic technique, which has not been evaluated before. Moreover, the second-generation ultrasound contrast SonoVue has been recently marketed, and the data on its efficacy on intravesical use in ceVUS is relatively scarce. Thus, we also aimed to investigate the diagnostic performance and safety profile of SonoVue-enhanced VUS in the diagnosis of vesicoureteric reflux. Our prospective comparative study compared the diagnostic performance of ceVUS with MCU in young children presenting with first episode of urinary tract infection. We performed sequential ceVUS and MCU examinations in 31 patients (62 pelvi-ureter units). Perfect inter-observer agreement (Cohen’s kappa statistics = 1.0, p < 0.001) was achieved in ceVUS, suggesting its good reliability in reflux detection and grading. Using MCU as reference, ceVUS had 100 % sensitivity and 84 % specificity and carried higher reflux detection rate than MCU (p < 0.001). There was no complication encountered. Conclusion: Voiding urosonography is a reliable, sensitive, safe and radiation-free modality in the investigation of vesicoureteric reflux in children. It should be incorporated in the diagnostic algorithm in paediatric urinary tract infection.

Current trends in dextranomer hyaluronic acid copolymer (Deflux) injection technique for endoscopic treatment of vesicoureteral reflux

OBJECTIVE

To determine the current preferred injection technique(s) for endoscopic management of pediatric vesicoureteral reflux (VUR). Since the approval of dextranomer hyaluronic acid copolymer (Dx/HA) in 2001, injection methods have evolved and now include the hydrodistention implantation technique (HIT) and double HIT as well as subureteral transurethral injection (STING) method.

METHODS

In July 2012, 278 pediatric urologists in the United States were contacted to complete a 15-question survey regarding Dx/HA injection technique(s) currently used in their practice.

RESULTS

Fifty board-certified pediatric urologists completed the survey for a response rate of 18%. Most respondents (60%) were in a single-specialty group practice, and 12% were affiliated with an academic- or university-based practice. Respondents reported seeing a mean of 159 pediatric patients (range, 40-400 patients) with VUR annually, and 94% used Dx/HA ≥4 times in the past year. Forty-seven respondents (94%) reported using double HIT over the course of their career compared with 36 (72%) for STING and 30 (60%) for HIT (P <.05). Double HIT gained widespread acceptance between 2007 and 2008, paralleled by a decline in use of other injection techniques. A significantly higher percentage currently perform double HIT (92%) compared with either STING (24%) or HIT (34%; P <.001). Respondents reported the use of double HIT 15 times more often than STING technique and 5 times more often than HIT during the past 12 months (P <.001).

CONCLUSION

The double HIT method is currently the most commonly performed technique for endoscopic correction of VUR by pediatric urologists in the United States.

Evaluation of new Deflux administration techniques: intraureteric HIT and Double HIT for the endoscopic correction of vesicoureteral reflux

Vesicoureteral reflux (VUR) is one of the most common urologic diagnoses affecting children, and optimal treatment requires an individualized approach that considers potential risks. Management options include observation with or without continuous antibiotic prophylaxis and surgical correction via endoscopic, open or laparoscopic/robotic approaches. Endoscopic correction of VUR is an outpatient procedure associated with decreased morbidity compared with ureteral reimplantation. The concept of ureteral hydrodistention and intraluminal submucosal injection (Hydrodistention Implantation Technique [HIT]) has led to improved success rates in eliminating VUR compared with the subureteral transurethral injection technique. Further modifications now include use of proximal and distal intraluminal injections (Double HIT) that result in coaptation of both the ureteral tunnel and orifice. Endoscopic injection of dextranomer/hyaluronic acid copolymer, via the HIT and Double HIT, has emerged as a highly successful, minimally invasive alternative to open surgical correction, with minimal associated morbidity.

Vesicoureteric reflux and reflux nephropathy: from mouse models to childhood disease

Vesicoureteric reflux (VUR) is a common congenital urinary tract defect that predisposes children to recurrent kidney infections. Kidney infections can result in renal scarring or reflux nephropathy defined by the presence of chronic tubulo-interstitial inflammation and fibrosis that is a frequent cause of end-stage renal failure. The discovery of mouse models with VUR and with reflux nephropathy has provided new opportunities to understand the pathogenesis of these conditions and may provide insight on the genes and the associated phenotypes that need to be examined in human studies.

Urinary infections in children

Urinary tract infection (UTI) is a common infection in infants and children. During infancy, boys are more commonly affected than girls and thereafter, female preponderance is found. Presentation varies among different age groups. Clinical features in neonates and young infants are non-specific, manifest as septicemia where a high index of suspicion is needed. Older children typically present as simple or complicated UTI. Rapid diagnosis, institution of early treatment and further evaluation by imaging modalities are of utmost importance. The prevention of recurrent UTI and detection of congenital anomalies of kidney and urinary tract are major objectives in the management. Use of ultrasound is required to detect underlying congenital abnormalities, whereas voiding cystourethrogram and dimercaptosuccinic acid (DMSA) scan are useful in the diagnosis of obstructive uropathy and vesicoureteric reflux and renal scar, respectively. The children requiring surgical interventions are to be recognised early to prevent recurrent UTI. The treatment of vesicoureteric reflux by chemoprophylaxis in lower grades and surgical treatment in higher grades are important consideration in prevention of recurrent UTI. This is required to prevent renal parenchymal damage and scarring that can cause hypertension and progressive renal insufficiency in later life.

A unique presentation, and management, of acute urinary retention in a young boy with underlying vesicoureteral reflux

Vesicoureteral reflux (VUR) affects ∼1% of children. We present an unusual case of urinary retention secondary to an obstructing urethral stone, underlying reflux, and its management. A 7-year-old boy presenting with acute urinary retention had a palpable penile shaft swelling and patent urethral meatus on examination. Cysto-urethroscopy with a 6.6Fr ureteroscope, due to unavailability of paediatric instruments, revealed an obstructing calculus impacted in the navicular fossa. This was laser fragmented and extracted. Cystoscopy revealed multiple bladder calculi with a patulous right ureteric orifice. Post-operative investigations revealed a small, scarred right kidney (ultrasound), bilateral ureteric reflux (micturating-cystourethrogram), 4 cm by 0.8 cm right ureteric calculus (CT-KUB) and 4% right split renal function (DMSA). Right laparoscopic nephroureterectomy was subsequently performed. Our case highlights the variety with which VUR can present and the effectiveness of a ureteroscope in an emergency setting as an alternative to a paediatric cystoscope to visualize the urethra and the bladder.

Detecting reflux: does ureteric jet Doppler waveform have a role?

BACKGROUND

Vesicoureteral reflux (VUR) has a prevalence of 30-40 % post-febrile urinary tract infection (UTI). If not detected early and treated, renal scarring, hypertension, and renal failure may occur. Micturating cystourethrography (MCU) is an invasive procedure associated with radiation exposure. Hence, this study aimed at evaluating the utility of ureteric jet Doppler waveform (UJDW) as a screening tool in detecting VUR, and at assessing the feasibility of performing it in children aged 2-4 years.

METHODS

Any child 2-18 years old who needed an MCU was included. Exclusion criteria were active UTI, indwelling catheter, and inability to drink the required amount of fluid. The UJDW was performed prior to the MCU.

RESULTS

One hundred eighty-two ureteric units were analyzed. Sensitivity and specificity of UJDW in detecting VUR was 80.3 and 87.9 %. Twenty-three children (45 ureteric units), aged 2-4 years were compared with 73 children (137 ureteric units), aged 5-18 years. Sensitivity and specificity of UJDW in detecting VUR in 2-4 years was 77.3 and 91.3 %, respectively; while in children ≥5 years, it was 81.8 and 87.1 %, respectively.

CONCLUSIONS

UJDW has a uniformly high specificity regardless of age or etiological groups, making it a good tool for follow-up. UJDW is a feasible technique, even in children aged 2-4 years.

Does routine ultrasound change management in the follow-up of patients with vesicoureteral reflux?

INTRODUCTION

Children with vesicoureteral reflux (VUR) usually need a renal ultrasound (RUS). There is little data on the role of follow-up RUS in VUR. We evaluated the impact of follow-up RUS on the change in clinical management in patients with VUR.

METHODS

We prospectively analyzed children with a previous diagnosis of VUR seen in the outpatient clinic with a routine follow-up RUS within 4 months. Variables collected included: demographic data, VUR history, dysfunctional voiding symptoms and concurrent ultrasound findings. Change in management was defined as addition of new medication, nurse counselling, surgery or further investigations.

RESULTS

The study included 114 consecutive patients. The mean patient age was 4.5 years old, mean age of VUR diagnosis was 1.7 years, with average follow-up of 2.8 years. A change in management with stable RUS occurred in 14 patients, in which the change included ordering a DMSA in 9, nurse counselling for dysfunctional voiding in 3, and booking surgery in 2 patients. Change on RUS was seen in 4 patients. Multivariable analysis showed that history of urinary tract infection (UTI) since the last follow-up visit was more significant than RUS findings.

CONCLUSIONS

The RUS findings in most patients followed for VUR remain stable or with minimal changes. The variable showing a significant effect on change in management in our study was history of UTI since the last follow-up visit rather than RUS findings. The value of follow-up RUS for children with VUR may need to be revisited.

Acoustic radiation force impulse (ARFI) in the evaluation of the renal parenchymal stiffness in paediatric patients with vesicoureteral reflux: preliminary results

OBJECTIVES

To prospectively evaluate acoustic radiation force impulse (ARFI) imaging of the kidneys in children with and without chronic renal disease.

METHODS

Twenty-eight children (age range 9-16 years) with primary or secondary vesicoureteral reflux (≥ grade III) underwent scintigraphy and ultrasound with ARFI. Kidneys were divided-according to scintigraphy-into "affected" and "contralateral"; the results were compared with 16 age-matched healthy subjects. An ARFI value, expressed as speed (m/s) of wave propagation through the tissue, was calculated for each kidney through the mean of the values obtained at the upper, middle and lower third. The Wilcoxon test was used; P values <0.05 were considered statistically significant.

RESULTS

The mean ARFI values obtained in the "affected" kidneys (5.70 ± 1.71 m/s) were significantly higher than those measured in both "contralateral" (4.09 ± 0.97, P < 0.0001) and "healthy" kidneys (3.13 ± 0.09, P < 0.0001). The difference between values in the "contralateral" kidneys and "healthy" ones was significant (P < 0.0001). The "affected" kidneys with secondary reflux had mean ARFI values (6.59 ± 1.45) significantly higher than those with primary reflux (5.35 ± 1.72).

CONCLUSIONS

ARFI values decrease from kidneys with secondary vesicoureteral reflux to kidneys with primary reflux to unaffected kidneys contralateral to reflux to normal kidneys.

Gil-Vernet antireflux surgery in children's primary vesicoureteral reflux

PURPOSE

The assessment of the results of Gil-Vernet antireflux surgery in children with primary vesicoureteral reflux.

MATERIALS AND METHODS

In a descriptive retrospective study, 72 patients with vesicoureteral reflux (VUR) and 104 refluxing units underwent Gil-Vernet antireflux surgery in Mofid children's hospital from Dec 2000 to Nov 2005. The study group was selected from among the patients with VUR who had been operated in our center. Data were collected from the medical records of the patients in the archive of the hospital and analyzed for gender, age, method of diagnosis, side of involvement, grading types, usage of catheter and stent, operating time, hospital stay, reflux down grading, operative success rate, recurrence and operative complication.

RESULTS

Among 72 patients, 47 (65%) were females and 25 (35%) were males with a mean age of 4.35 ± 2.96 years (range 1-13 years). 32 patients had bilateral and 40 had unilateral reflux, and 76% were in grades III and IV. Mean operative time was 55 ± 13 min, median hospital stay was 2 ± 0.9 days and mean follow-up period was 48 ± 9 months. Reflux was improved completely in 100 (96.15%) refluxing units, and down-graded in 4 (3.84%) units. Treatment was performed medically in 2 and surgically in 2 refluxing units, and all were improved successfully. There were no complications post-operatively.

CONCLUSION

Gil-Vernet antireflux technique is a useful method, and it has many advantages such as simplicity, shorter operative time, lower complication rate and high success rate.

Has the data efflux regarding the promising outcome following injection of deflux changed the management of adult vesicoureteral reflux?

Primary vesicoureteral reflux (VUR), traditionally considered a problem of childhood, can also be detected during adulthood. However, while the concept regarding the therapeutic management of VUR in children has undergone revolutionary changes, moving from surgical to conservative approach, the optimal therapeutic approach in adult reflux is poorly addressed and is still unknown. Herein, we review clinical and therapeutic approaches of VUR in pediatric population as published throughout the years. With the introduction of Deflux injection as a minimally invasive procedure, we identify a beginning of a new trend that further extends the indications for endoscopic injections, including its introduction to adult patients as well.

Current status of Gil-Vernet trigonoplasty technique

Significant controversy exists regarding vesicoureteral reflux (VUR) management, due to lack of sufficient prospective studies. The rationale for surgical management is that VUR can cause recurrent episodes of pyelonephritis and long-term renal damage. Several surgical techniques have been introduced during the past decades. Open anti-reflux operations have high success rate, exceeding 95%, and long durability. The goal of this article is to review the Gil-Vernet trigonoplasty technique, which is a simple and highly successful technique but has not gained the attention it deserves. The mainstay of this technique is approximation of medial aspects of ureteral orifices to midline by one mattress suture. A unique advantage of Gil-Vernet trigonoplasty is its bilateral nature, which results in prevention from contralateral new reflux. Regarding not altering the normal course of the ureter in Gil-Vernet procedure, later catheterization of and retrograde access to the ureter can be performed normally. There is no report of ureterovesical junction obstruction following Gil-Vernet procedure. Gil-Vernet trigonoplasty can be performed without inserting a bladder catheter and drain on an outpatient setting. Several exclusive advantages of Gil-Vernet trigonoplasty make it necessary to reconsider the technique role in VUR management.

A genome-wide scan for genes involved in primary vesicoureteric reflux

BACKGROUND

Vesicoureteric reflux (VUR) is the retrograde flow of urine from the bladder into the ureters. It is the most common urological anomaly in children, and a major cause of end-stage renal failure and hypertension in both children and adults. VUR is seen in approximately 1-2% of Caucasian newborns and is frequently familial.

OBJECTIVE AND METHODS

In order to search for genetic loci involved in VUR, we performed a genome-wide linkage scan using 4710 single-nucleotide polymorphisms (SNPs) in 609 individuals from 129 Irish families with >1 affected member.

RESULTS

Nonparametric linkage (NPL) analysis of the dataset yielded moderately suggestive linkage at chromosome 2q37 (NPL(max) = 2.67, p<0.001). Analysis of a subset without any additional features, such as duplex kidneys, yielded a maximum NPL score of 4.1 (p = 0.001), reaching levels of genome-wide statistical significance. Suggestive linkage was also seen at 10q26 and 6q27, and there were several smaller peaks.

CONCLUSION

Our results confirm the previous conclusion that VUR is genetically heterogeneous, and support the identification of several disease-associated regions indicated by smaller studies, as well as indicating new regions of interest for investigation.

A Comparison of Single-Dose Caudal Clonidine, Morphine, or Hydromorphone Combined with Ropivacaine in Pediatric Patients Undergoing Ureteral Reimplantation

BACKGROUND

Caudal blockade is a common technique for pediatric postoperative analgesia. While safe and effective, caudal opioids are associated with troublesome side effects. Caudal clonidine may offer significant analgesic benefits. We prospectively compared the analgesic, side effect, and rehabilitation profiles of caudal clonidine, hydromorphone, or morphine in a group of 60 pediatric patients undergoing ureteral reimplantation.

METHODS

Patients aged 6 mo to 6 yr were evenly and randomly enrolled in a double-blind manner. Patients received a single caudal dose of 2 mcg/kg of clonidine, 10 mcg/kg of hydromorphone, or 50 mcg/kg of morphine, combined with 1.0 mL/kg of 0.2% ropivacaine with epinephrine. After sevoflurane in oxygen/air anesthesia, all subjects received proxy nurse-controlled analgesia with morphine. Postoperative pain intensity, use of IV morphine, and side effects were assessed during the first 24 h. Oral intake and discharge home were recorded.

RESULTS

Caudal clonidine resulted in less postoperative nausea and vomiting (P = 0.01) and pruritus (P = 0.007) than did caudal hydromorphone or caudal morphine. Caudal morphine produced more sustained initial analgesia than did caudal clonidine (P = 0.02). No difference was observed in pain scores, total morphine use, time to first oral intake or discharge home. No postoperative respiratory depression, excessive sedation, hypotension, or bradycardia was identified.

CONCLUSIONS

Although caudal morphine may result in more sustained initial analgesia, caudal clonidine combined with nurse-controlled analgesia appears to provide comparable analgesia with fewer side effects. Based on these results, the use of caudal clonidine may be superior to caudal opioids after pediatric ureteral reimplantation.