Bladder dysfunction as a prognostic factor in patients with posterior urethral valves

Chronic Kidney Disease in Boys with Posterior Urethral Valves-Pathogenesis, Prognosis and Management

Posterior urethral valves (PUV) are the most common form of lower urinary tract obstructions (LUTO). The valves can be surgically corrected postnatally; however, the impairment of kidney and bladder development is irreversible and has lifelong implications. Chronic kidney disease (CKD) and bladder dysfunction are frequent problems. Approximately 20% of PUV patients will reach end-stage kidney disease (ESKD). The subvesical obstruction in PUV leads to muscular hypertrophy and fibrotic remodelling in the bladder, which both impair its function. Kidney development is disturbed and results in dysplasia, hypoplasia, inflammation and renal fibrosis, which are hallmarks of CKD. The prognoses of PUV patients are based on prenatal and postnatal parameters. Prenatal parameters include signs of renal hypodysplasia in the analysis of fetal urine. Postnatally, the most robust predictor of PUV is the nadir serum creatinine after valve ablation. A value that is below 0.4 mg/dl implies a very low risk for ESKD, whereas a value above 0.85 mg/dl indicates a high risk for ESKD. In addition, bladder dysfunction and renal dysplasia point towards an unbeneficial kidney outcome. Experimental urinary markers such as MCP-1 and TGF-β, as well as microalbuminuria, indicate progression to CKD. Until now, prenatal intervention may improve survival but yields no renal benefit. The management of PUV patients includes control of bladder dysfunction and CKD treatment to slow down progression by controlling hypertension, proteinuria and infections. In kidney transplantation, aggressive bladder management is essential to ensure optimal graft survival.

Nadir creatinine predicts long-term bladder function in boys with posterior urethral valves

INTRODUCTION

Posterior urethral valves (PUV) cause lower urinary tract obstruction leading to increased intravesical pressure during fetal urinary tract development. Though the bladder and kidneys are separate organs, with different embryological origins, they are complementary and influence each other both before and after birth. We aimed to assess the relationship between renal and bladder function in boys with PUV and whether early renal markers could predict future bladder function.

PATIENTS AND METHODS

We included all boys with prenatally suspected lower urinary tract obstruction, born between 2000 and 2013, in two University Hospitals, with at least 5 years follow-up. We excluded patients who presented a Lower Urinary Tract Obstruction other than PUV, children who presented multiple birth defects and neonatal deaths and those with incomplete long-term renal or bladder function data. We included data on nadir creatinine (NC), long-term renal function and long-term bladder function (defined by Uroflow parameters). Boys with PUV were divided into three severity groups for renal function according to their NC and three severity groups for bladder function as determined by Uroflow.

RESULTS

We included 73 boys. Average nadir creatinine was 43.4 ± 26.1 μmol/L. Twenty-nine boys (49.3%) presented a NC < 35 μmol/L, thirty-eight (52.1%) a NC between 35 and 75 μmol/L, and 6 (8.2%) a NC > 75 μmol/L. Thirty-eight (52.1%) presented normal bladder function, 23 (31.5%) presented moderately impaired bladder function and 12 (16.4%) presented severely impaired bladder function. 41.4% of boys with NC < 35 had abnormal bladder function vs 46.2% of those with an NC between 35 and 75 μmol/L and 83.3% of boys with NC > 75 μmol/L. Nadir creatinine both predicted both bladder function and renal status (table 1). Correlation between presence of grade 3-5 CKD and poor uroflow was also significant (p < 0.005).

DISCUSSION

Nadir creatinine was significantly correlated to bladder function at 5 years of age. What this study suggests is that as nadir creatinine increases so does the risk of severe bladder dysfunction. Our results, though limited to flowmeter and renal function, could help pediatric urologist tailor bladder function monitoring, and indicate which patients could benefit from more aggressive bladder therapy.

CONCLUSION

Bladder and renal function are linked in boys with posterior urethral valves. Boys with high nadir creatinine could benefit from early bladder function evaluation and management.

A Data-Driven Memory-Dependent Modeling Framework for Anomalous Rheology: Application to Urinary Bladder Tissue

We introduce a data-driven fractional modeling framework for complex materials, and particularly bio-tissues. From multi-step relaxation experiments of distinct anatomical locations of porcine urinary bladder, we identify an anomalous relaxation character, with two power-law-like behaviors for short/long long times, and nonlinearity for strains greater than 25%. The first component of our framework is an existence study, to determine admissible fractional viscoelastic models that qualitatively describe linear relaxation. After the linear viscoelastic model is selected, the second stage adds large-strain effects to the framework through a fractional quasi-linear viscoelastic approach for the nonlinear elastic response of the bio-tissue of interest. From single-step relaxation data of the urinary bladder, a fractional Maxwell model captures both short/long-term behaviors with two fractional orders, being the most suitable model for small strains at the first stage. For the second stage, multi-step relaxation data under large strains were employed to calibrate a four-parameter fractional quasi-linear viscoelastic model, that combines a Scott-Blair relaxation function and an exponential instantaneous stress response, to describe the elastin/collagen phases of bladder rheology. Our obtained results demonstrate that the employed fractional quasi-linear model, with a single fractional order in the range α = 0.25–0.30, is suitable for the porcine urinary bladder, producing errors below 2% without need for recalibration over subsequent applied strains. We conclude that fractional models are attractive tools to capture the bladder tissue behavior under small-to-large strains and multiple time scales, therefore being potential alternatives to describe multiple stages of bladder functionality.

Bladder function in children with posterior urethral valves: impact of antenatal versus postnatal diagnosis

Purpose:

Posterior urethral valves (PUVs) are the most common cause of congenital bladder obstruction in boys. Our aim was to assess the impact of early diagnosis and fulguration of PUVs on bladder function and compare their functional and urodynamic outcome with children who underwent delayed intervention.

Materials and Methods:

We retrospectively evaluated 153 patients who underwent primary valve ablation from two tertiary hospitals between 2001 and 2018. Patients have been divided into 2 groups, group 1 included 69 patients who were detected antenatally and underwent early fulguration of PUVs while group 2 included 84 children presented postnatally and underwent delayed valve ablation. The recorded data throughout follow-up in renal function tests, urodynamics and changes in the upper urinary tracts were evaluated and compared.

Results:

Median age at time of valve ablation was 10 days in group 1 and 7 months in group 2. The median follow-up period was 6.5 and 7 years in group 1 and 2, respectively. Chronic kidney disease (CKD) developed in 15 (22%) boys in group 1 while in group 2 it was observed in 31 (37%), p=0.04. While Q-max, mean bladder capacity and post-void residual (PVR) volumes were comparable in both groups, percent PVR was significantly higher in group 2 (3.27 vs. 1.44, p=0.002). Detrusor overactivity was slightly different in both groups (p = 0.07).

Conclusions:

Compared to delayed intervention, primary ablation of PUVs during the early neonatal life possibly provides the optimum chance to have optimum renal function without impact on bladder function.

Renal Replacement Therapy and Intermittent Catheterization Risk in Posterior Urethral Valves

OBJECTIVES

Posterior urethral valves predispose children to renal replacement therapy (RRT) and bladder dysfunction. Researchers of single-institutional series were unable to refine risk stratification because of rarity of the disease. We aimed to identify clinical variables associated with the risk of RRT and clean intermittent catheterization (CIC) in a large multicenter cohort study.

METHODS

Children with posterior urethral valves born between 1995 and 2005 who were treated before 90 days of life at 5 children's hospitals were retrospectively reviewed. Outcomes included RRT and recommendation for CIC. Predictors and outcomes were assessed by using survival analysis.

RESULTS

A total of 274 patients were managed for a median of 6.3 years, and 42 progressed to RRT. On survival analysis, 16% progressed to RRT by 10 years of age. RRT varied by the serum nadir creatinine level in the first year of life (SNC1) (log-rank P < .001). After stratifying by the SNC1, the estimated risk of progressing to RRT by 10 years of age was 0%, 2%, 27%, and 100% for an SNC1 of <0.4, an SNC1 of 0.4 to 0.69, an SNC1 of 0.7 to 0.99, and an SNC1 of ≥1.0 mg/dL, respectively. CIC was recommended in 60 patients, which translated on survival analysis to a risk of 26% by 10 years of age.

CONCLUSIONS

Risk of RRT and CIC recommendation increased with age. The SNC1 strongly predicted need for RRT. These results allow for both improved family counseling and the potential for more appropriate screening and intervention strategies for those identified in higher-risk groups.

Current strategies to predict and manage sequelae of posterior urethral valves in children

Posterior urethral valves (PUV) constitute a significant urological cause of chronic kidney disease (CKD) in children. The condition is characterised by the unique pathophysiology of the evolution of bladder dysfunction after relief of obstruction, which contributes to CKD. Improvements in prenatal diagnosis followed by selective foetal intervention have not yet produced improvement in long-term renal outcomes, although better patient selection may alter this in the future. Proactive management with surveillance, pharmacotherapy, timed voiding, double voiding, and/or assisted bladder-emptying, is being increasingly offered to those with severe bladder dysfunction and has the potential of reducing the burden of renal disease. Clinicians are currently able to counsel regarding the prognosis using serum creatinine and other emerging markers. However, much of this work remains to be validated. Satisfactory graft survival rates are now reported with aggressive management of bladder dysfunction in children who are candidates for renal transplantation. Knowledge gaps exist in identifying early markers of renal injury, risk stratification, and in understanding patient and carer perspectives in PUV.

Long-term outcomes of kidney and bladder function in patients with a posterior urethral valve

We investigated long-term functional changes in the kidney and bladder of patients with posterior urethral valve (PUV) who underwent fetal intervention or postnatal surgery.We retrospectively reviewed the medical records of 28 consecutive patients treated for PUV at our institution. Detailed data on medical and surgical histories, particularly on pre- and postnatal treatment modality, including fetal vesicoamniotic shunt, endoscopic valve ablation, and vesicostomy, were collected and analyzed. Long-term renal function was evaluated based on serum levels of creatinine (sCr), estimated glomerular filtration rate (eGFR), and renal scans. Voiding function was evaluated in urodynamic tests.Vesicoamniotic shunting was performed in 12 (42.8%) patients. Although the mean initial sCr was significantly higher in patients in whom a fetal shunt was placed than in others (2.04 vs 1.17 mg/L, P = .038), the sCr at long-term follow-up was not significantly different between them (0.64 vs 0.40 mg/L, P = .186). The mean maximum detrusor pressure was significantly lower in patients with a fetal shunt than in others (37.7 vs 73.0 cm H2O, P = .019). Postnatal vesicostomy was performed in 14 patients, and primary valve ablation was performed in 13 patients. The mean initial sCr was higher in patients in the vesicostomy group than in the primary valve ablation group (2.08 vs 0.86 mg/L, P = .014). However, no significant differences were found in sCr (0.9 vs 0.3 mg/L, P = .252) or GFR (59.1 vs 68.5 mL/min/1.73 m, P = .338) at long-term follow-up. Bladder capacity was greater and residual urine volume was less in the vesicostomy group than in the primary valve ablation group, but without statistical significance.Vesicostomy is more beneficial in the recovery of renal function and is not inferior in terms of bladder function, even in patients with severe PUV disorder. It is a reliable surgical option that can spare renal function and guarantee adequate bladder function in the long term.

Cystometrogram appearance in PUV is reliably quantified by the shape,wall, reflux and diverticuli (SWRD) score, and presages the need for intervention

OBJECTIVE

Radiological bladder abnormalities in boys with posterior urethral valves (PUV) are well recognised; however, the assessment is subjective. The shape, wall, reflux and diverticuli (SWRD) score objectively assesses shape, wall, reflux and diverticuli in a simple way. This study was undertaken to demonstrate that the SWRD score is reliable, reproducible and correlates with bladder outcome and videourodynamic (VUD) assessment in boys with PUV.

MATERIALS AND METHODS

Three blinded assessors determined the SWRD scores of PUV bladders from cystometrograms taken during VUD from September 2012 to October 2013. The scores were correlated with clinical outcome and VUD pressure measurements. Data were given as median (interquartile range), non-parametric tests used as appropriate (Mann-Whitney U test, or Kruskall-Wallis) and P < 0.05 was taken as significant.

RESULTS

A total of 55 boys with PUV underwent VUD assessment, for which 52 cystometrograms were available. The SWRD score for non-operative management was 1.0 (0.1-1.9) vs 2.0 (1.0-3.3) for operative intervention, P = 0.018 (Summary Figure). The SWRD score for compliant bladders was 1.1 (0.6-2.0) vs hypercompliant 1.7 (0.5-2.8) vs non-compliant 3.3 (2.8-5.0), Kruskall-Wallis P = 0.011. The hostile detrusor overactivity (DO) bladders (Pdet >40 cmH₂O) had a SWRD score of 2.0 (1.3-3.7) vs 1.0 (0.5-2.5) for low-pressure DO bladders, P < 0.05.

DISCUSSION

In this series of patients, increasingly distorted bladder shape was seen to be associated with poor bladder dynamics on VUD. Patients with poorly compliant bladders had a significantly higher SWRD score than normal or megacystis patients. Severe DO was also significantly associated with a high SWRD score. Therefore, the radiological appearance of a hostile bladder represented a marker for high intravesical pressure. VUR and bladder diverticuli may lead to spurious pressure measurements during VUD; however, the SWRD score provided an independent mechanism with which to objectively assess these patients, even in the presence of gross VUR.

CONCLUSIONS

The SWRD score is a simple and objective scoring system for the radiological abnormalities of PUV bladders. It correlates with clinical outcome and VUD assessment of compliance and DO, but is independent of pressure measurements and so not confounded by VUR acting as a 'pop-off' mechanism.

Posterior Urethral Valves in Children: Pattern of Presentation and Outcome of Initial Treatment in Ile-Ife, Nigeria

Background:

The management of posterior urethral valves (PUV) and its sequelae is still a challenge to most pediatric surgeons in our environment due to late presentation and inadequate facilities for long-term evaluation and treatment. Despite initial successful treatment about 40% would develop chronic renal failure. The aim is to describe the presentation, management and outcome of the initial treatment in boys with PUV.

Materials and Methods:

It is a retrospective analysis of PUV in boys 8 years and below over a 17 years period. Demographic characteristics, clinical features, investigations, and treatment outcome were reviewed.

Results:

Thirty-seven cases were analyzed. The median age was 5 months (range from birth to 8 years). Three (8.1%) patients had prenatal ultrasound diagnosis. The most common presentation was voiding dysfunction 37 (100%). Part of the preoperative investigation included micturating cystourethrogram (n = 31: 83.8%) and abdomino-pelvic ultrasonography (n = 37:(100%). The mean serum creatinine value of those who presented within the first 30 days of life and those who presented afterwards were 325 (±251) µmol/L and 141 (±100) µmol/L respectively, P = 0.003. Surgical interventions included trans-vesical excision of valves (n = 9: 28.1%), valvotomy (n = 10: 31.3%), balloon avulsion (n = 8: 25.0%), vesicostomy (n = 4: 12.5%) and endoscopic valve avulsion (n = 1: 3.1%). Seventeen (56.7%) patients had serum creatinine >70.4 µmol/L after 1-month of valve excision. Five (13.5%) patients had postrelief complications and 5 (13.5%) died on admission. Ninety percentage (27/30) of patients had poor prognostic indices.

Conclusions:

The initial treatment outcome was good but most had poor prognostic factors.

[Urodynamic profile of voiding disorders persisting after treatment of posterior urethral valve]

PURPOSE

Posterior urethral valves (PUV) are the most common cause of bladder outlet obstruction in infancy that impairs renal and bladder function.

MATERIAL AND METHODS

We realize a retrospective study and examined 35 boys with urinary disorders post-treatment of PUV, seen at the urodynamic consultation.

RESULTS

The mean age: 7.56 years, urinary problems are dominated by recurrent urinary tract infections and urinary leakage, morphological assessment is marked by the constant expansion of the urinary tract and bladder, 18 children have end-stage renal disease of which 8 are candidates for transplantation. About urodynamic, the uroflowmetry with measure of post-void urine residue: dysuria with significant residual urine in 14 children; for cystometry, 20 children with bladder hyperactivity, 9 bladders are hypotonic hypoactive with high capacity, 6 explorations are normal.

CONCLUSION

Urodynamic explorations are all interest when voiding symptoms persist after endoscopic section valves and despite a good radiological result.

Long-term consequences of posterior urethral valves

Posterior urethral valves (PUV) are the most common congenital cause of bladder outlet obstruction in infancy, and it is the effect of this obstruction on the bladder and the kidneys that will decide a patient's prognosis. With the improvements in diagnosis and treatments, what was previously a poor prognosis for boys with PUV has improved, and more patients will encounter the long-term sequelae of PUV during puberty and adulthood. In these patients the long-term prognosis in terms of renal and bladder function and fertility, as well as the risk of malignancy in those whose bladders were augmented with gastrointestinal segments, is still a matter of great concern and all of these topics will be discussed in this article.

The significance of detrusor wall thickness as a prognostic factor in pediatric bladder outlet obstruction

PURPOSE

The purpose of this study is to determine detrusor thickness as a prognostic factor in posterior urethral valves.

METHODS

The medical information of 41 patients diagnosed with posterior urethral valves at our institute was retrospectively reviewed. The serum creatinine level after bladder decompression, results of ultrasonography, and voiding cystourethrography were compared between groups divided according to the final bladder and renal function. Detrusor thickness was measured using Müller's method.

RESULTS

The median detrusor thickness was 1.3 mm (0.4-2.5 mm). After median 45.6 months (7.2-96.0 months) of follow-up, impaired bladder function (IBF) was observed in 14 patients. In multivariate analysis, detrusor thickness greater than 1.3 mm (odds ratio, 32.6; 95% confidence interval, 3.1-340.6; P = .004) was the only independent risk factor for later IBF. Final renal function impairment developed in 24 patients (58.5%), and 3 patients (7.3%) were diagnosed with end-stage renal disease after median 66.0 months (32.4-133.2 months) of follow-up period. On multivariate analysis, age-specific elevated serum creatinine level at presentation (odds ratio, 11.1; 95% confidence interval, 1.1-112.5; P = .042) was an independent risk factor.

CONCLUSIONS

Detrusor thickness more than 1.3 mm on ultrasonography was an independent prognostic factor for later IBF.

Reduction of cystometric bladder capacity and bladder compliance with time in patients with end-stage renal disease

BACKGROUND/PURPOSE

Reduced bladder capacity and compliance in patients with end-stage renal disease (ESRD) may affect storage and voiding function after kidney transplantation. This study evaluated the bladder capacity, compliance, and lower urinary tract dysfunction in ESRD patients with duration after dialysis and anuria.

MATERIALS AND METHODS

Adults with ESRD on kidney transplantation waiting list were consecutively enrolled. The survey items included videourodynamic study (VUDS), renal ultrasound, and cystoscopy. The analytical variables assessed included the duration of dialysis, the duration of anuria, cystometric bladder capacity and bladder compliance, voiding phases in VUDS, and cystoscopic findings.

RESULTS

A total of 62 patients with a mean dialysis duration of 58.9 ± 6.3 months were enrolled. The mean cystometric bladder capacity was 178 ± 14 mL and decreased significantly with duration of dialysis (p < 0.001). Anuria was diagnosed in 26 patients, and the mean cystometric bladder capacity decreased significantly with the duration of anuria (p = 0.002). Among the 26 patients with anuria, 16 had a poor bladder compliance. VUDS revealed abnormal storage function in 44 (71.0%) patients and bladder outlet obstruction due to bladder neck dysfunction or urethral narrowing in the voiding phase in 32 (51.6%). Abnormal cystoscopic findings were also noted in 30 (48.4%) patients.

CONCLUSION

Cystometric bladder capacity and bladder compliance decreased with longer duration of dialysis, and the presence of anuria contributed to further decreases in cystometric bladder capacity and bladder compliance. More than two-thirds of patients with ESRD had abnormal findings on VUDS.

Posterior urethral valve

BACKGROUND

Posterior urethral valve (PUV) is a significant cause of morbidity, mortality and ongoing renal damage in children. It accounts for end-stage renal disease in a proportion of children. This article aims at highlighting the current trend in the management of boys with posterior urethral valve.

DATA SOURCES

PubMed/Medline and bibliographic search for posterior urethral valve was done. Relevant literatures on presentation, pathology, evaluation, management and outcomes of PUV were reviewed.

RESULTS

PUV which is increasingly diagnosed prenatally presents a spectrum of severity. The varied severity and degree of obstruction caused by this abnormality depend on the configuration of the obstructive membrane within the urethra. The decision to intervene prenatally is dependent on gestational age, amniotic volume, and renal function of fetal urine aspiration. Identification of the patients who may benefit from early intervention remains inconclusive. Endoscopic ablation of the valve is the gold standard of treatment but use of Mohan's valvotome and other modalities are invaluable in developing countries where endoscopic facilities are limited. Proximal urinary diversion may result in poor bladder compliance and should be reserved for patients with persisting or increasing upper urinary tract dilatation, increasing serum creatinine or inappropriate instruments. The behavior of the bladder and its subsequent management after valve ablation may influence the long-term renal outcome in PUV patients.

CONCLUSIONS

The care of children with PUV continues to improve as a result of earlier diagnosis by ultrasound, developments in surgical technique and meticulous attention to neonatal care. The ultimate goal of management should be to maximize renal function, maintain normal bladder function, minimize morbidity and prevent iatrogenic problems.

Lower urinary tract symptoms in adults treated for posterior urethral valves in childhood: matched cohort study

PURPOSE

We compared the prevalence and bother of lower urinary tract symptoms in adults treated for posterior urethral valves in childhood and population based controls.

MATERIALS AND METHODS

Questionnaires were mailed to patients 18 years and older treated at our institution for posterior urethral valves. Of the 124 patients 68 (64.2%) participated, 18 were unavailable and 38 did not participate. Age and sex matched controls were randomly identified from a population based study (response proportion 62.4%). Danish Prostatic Symptom Score was used to assess occurrence (never/rarely/often/always) and bother (none/small/moderate/major) of 12 different lower urinary tract symptoms. Chi-square test was used for the analyses stratified by patient/control status, with the 4-point ordinal scale as the outcome.

RESULTS

Median age of 68 patients with posterior urethral valves and 272 controls (ratio 1:4) was 38.5 years (range 18 to 57). Overall, at least 1 moderate or severe lower urinary tract symptom was reported by 32.4% of patients with posterior urethral valves and 15.8% of controls (p=0.002). Mild hesitancy, weak stream, incomplete emptying and straining were reported twice as often by patients with posterior urethral valves as by controls (p<0.05). Prevalence of any urgency incontinence (14.7% vs 4.8%, p=0.014) and any stress incontinence (11.8% vs 3.0%, p=0.005) was increased at least 3-fold in patients with posterior urethral valves compared to controls. Furthermore, prevalence of bother from several lower urinary tract symptoms was increased approximately 2-fold in patients with posterior urethral valves compared to controls (p<0.05). However, most patients and controls reported no or small bother.

CONCLUSIONS

In adulthood the occurrence and bother of most lower urinary tract symptoms are increased approximately 2-fold in patients with posterior urethral valves compared to the general population. However, in this cohort of young and middle-aged men most symptoms are mild.

Risk factors for progression to end-stage renal disease in children with posterior urethral valves

OBJECTIVE

To identify the variables which affect long-term renal outcome in children with posterior urethral valves (PUV).

MATERIALS AND METHODS

Retrospective analysis of 260 children with PUV who underwent ablation of valves in 1992-2008 at our tertiary care center. The following risk factors for progression to end-stage renal disease (ESRD) were analyzed: nadir serum creatinine greater than 1.0mg/dl, bilateral grade 3 or higher VUR at diagnosis, recurrent febrile UTIs, and severe bladder dysfunction. Patients were divided into two groups: those who developed ESRD (group 1) and those who did not (group 2).

RESULTS

Forty (17.62%) patients had nadir serum creatinine >1mg/dl. At time of initial presentation, high-grade VUR was seen in 63.1% and 33.5% of groups 1 and 2, respectively (P=0.002). Overall, 77 (34%) of the boys developed breakthrough urinary tract infections: 37.03% and 33.5% in groups 1 and 2, respectively (P=1). Fifty-nine (26%) patients were found to have severe bladder dysfunction: 77.8% and 19% in groups 1 and 2, respectively (P<0.0001). Twenty-seven (11.89%) patients progressed to ESRD, at mean age of 11.21 years (5-16). On univariate analysis, the risk-predicting variables were: nadir serum creatinine value greater than 1mg/dl (P<0.0001), bilateral high-grade VUR (P=0.002) and severe bladder dysfunction (P<0.0001). On multivariate logistic regression analysis, nadir serum creatinine greater than 1mg/dl (OR 23.79; CI 8.20-69.05) and severe bladder dysfunction (OR 5.67; CI 1.90-16.93) were found to be independent risk factors predictive of ultimate progression to ESRD.

CONCLUSIONS

Nadir serum creatinine and bladder dysfunction are the main factors affecting long-term renal outcome in cases of PUV. Early identification and treatment of bladder dysfunction may thus be beneficial.

Detrusor glycogen reflects the functional history of bladders with partial outlet obstruction

OBJECTIVE

To assess the relationship between glycogen content in bladder detrusor tissue and historical bladder function in a guinea-pig model of partial bladder outlet obstruction (PBOO).

MATERIALS AND METHODS

In male immature guinea pigs PBOO was created with a silver ring around the proximal urethra; a control group had a sham operation for comparison. Longitudinal individual urodynamic data were obtained weekly, so that guinea pigs were killed at different levels of bladder dysfunction. Bladder sections were stained with periodic acid-Schiff (PAS) to assess overall morphology and glycogen granule density, scored from 0 (no glycogen) to 3. Glycogen scores were related to both the end-stage and historical extremes of bladder function values.

RESULTS

Glycogen granules were seen only in the detrusor; as their number increased their location expanded from only close to the serosa (glycogen score 1), through the detrusor (score 2) up to the urothelium (score 3). A glycogen score of 0 correlated with normal values for all urodynamic variables. Compared with a glycogen score of 0 a score of 1 correlated with significant (P < 0.05) changes in end-stage compliance (decrease) and contractility (increase) and significantly higher historical values for contractility, pressure and number of unstable contractions (NUC). In the group with a glycogen score of 2 there were significant changes in both the end-stage values and historical extremes for compliance, pressure, contractility and NUC (all P < 0.05). In the group with a glycogen score of 3 all these changes were even more dramatic, except for the end-stage contractility, for which the increase was not significant. From glycogen score 0 to score 3 all changes increased in magnitude.

CONCLUSION

A high glycogen content reflects a history of abnormal urodynamic function. This finding exemplifies the added value of structural analysis to urodynamic studies. Further studies are needed to relate bladder structure to the potential for functional recovery.

Kidney transplantation in abnormal bladder

Structural urologic abnormalities resulting in dysfunctional lower urinary tract leading to end stage renal disease may constitute 15% patients in the adult population and up to 20-30% in the pediatric population. A patient with an abnormal bladder, who is approaching end stage renal disease, needs careful evaluation of the lower urinary tract to plan the most satisfactory technical approach to the transplant procedure. Past experience of different authors can give an insight into the management and outcome of these patients. This review revisits the current literature available on transplantation in abnormal bladder and summarizes the clinical approach towards handling this group of difficult transplant patients. We add on our experience as we discuss the various issues. The outcome of renal transplant in abnormal bladder is not adversely affected when done in a reconstructed bladder. Correct preoperative evaluation, certain technical modification during transplant and postoperative care is mandatory to avoid complications. Knowledge of the abnormal bladder should allow successful transplantation with good outcome.

Does bladder augmentation stabilize serum creatinine in urethral valve disease? A series of 19 cases

OBJECTIVE

This study evaluates the results of bladder augmentation (BA) in 19 boys with posterior urethral valves, especially as regards its efficacy in stabilizing serum creatinine.

PATIENTS AND METHODS

In the period 1995-2005, 188 patients with urethral valves were surgically managed. Nineteen of these had undergone BA as a part of their surgical management after initial endoscopic valve ablation in 15 and diversion in four boys. The mean serum creatinine at the time of BA was 2.11 mg/dl.

RESULTS

BA stabilized the serum creatinine in 14 but failed to do so in five boys. A serum creatinine level of more than 2mg/dl at the time of BA was associated with a significantly worse rate of success. BA as part of an undiversion procedure in three boys was unsuccessful.

CONCLUSION

In an economic milieu where renal transplantation is not available for the majority of deserving children, careful selection is required before BA is considered as a surgical solution for the valve bladder. BA, when otherwise indicated, has been beneficial in children with pre-augmentation creatinine up to 2 mg/dl.

Significance of age-specific creatinine levels at presentation in posterior urethral valve patients

OBJECTIVE

Determination of prognostic factors is of great importance in decision making on therapies and informing parents about the probable outcome of disease. The present study aims to evaluate and assess the prognostic factors in posterior urethral valve (PUV) patients.

MATERIALS AND METHODS

The data of 68 patients treated between 1996 and 2004 were evaluated retrospectively. The mean age at diagnosis was 36.4 months. The serum creatinine levels were standardized using the age-specific creatinine reference (ASCR) levels. The age at diagnosis, clinical presentation, initial serum creatinine, method of treatment, presence of vesicoureteral reflux (VUR) and hydroureteronephrosis (HUN), all of which may effect the prognosis, were evaluated.

RESULTS

The analysis revealed that, of the 36 patients whose initial serum creatinine levels were within ASCR, only one (2.8%) had a final serum creatinine higher than ASCR values. In contrast, of the 32 patients whose initial serum creatinine levels were not within ASCR, 19 (59.4%) had final serum creatinine levels higher than ASCR (P<0.001). The distribution of final serum creatinine according to treatment method, presence of UTI before treatment and age at diagnosis was not statistically significant; however, the difference in distribution for initial serum creatinine (P<0.001), mode of clinical presentation (0.016), presence of HUN (0.019) and state of VUR (0.037) before treatment was statistically significant.

CONCLUSION

Final outcome with regard to renal function in PUV patients is affected by bilateral VUR and most significantly by serum creatinine levels higher than ASCR.

Lower Urinary Tract Symptoms After Renal Transplantation in Children

PURPOSE

We investigated the prevalence and nature of LUTS after renal Tx in children. The focus of the study was the presence of LUTS in children without a history of urological symptoms. We also studied the relationship between the characteristics of these patients and the occurrence of LUTS.

MATERIALS AND METHODS

Data were gathered using a written questionnaire, frequency volume chart, free uroflowmetry, transabdominal ultrasonography and medical records. The study group (30 patients) consisted of 9 children (30%) undergoing renal transplantation with an underlying urological disease and 21 (70%) with an underlying nephrological disease.

RESULTS

In the nephrological group the incidence of high capacity bladder was 75%, residual urine 50%, UTI 43%, hesitancy 38%, intermittent flow 33%, bladder pain 33%, nighttime incontinence 29%, nocturia 24%, feeling of incomplete emptying 15%, daytime incontinence 14%, straining 14%, urgency 10%, burning sensation 10% and intermittency 5%. No substantial difference in the occurrence of LUTS, UTI or high bladder capacity after Tx was found between children with an underlying urological disease and those with an underlying nephrological disease. On average, patients in both groups suffered from 3 different LUTS.

CONCLUSIONS

After renal Tx children with a nephrological disease demonstrated a high incidence of LUTS. The occurrence of LUTS combined with UTI and increased bladder capacity indicates that these children are at risk for development of myogenic failure. This finding emphasizes the importance of close urological followup after Tx in children with urological and nephrological disease.

[Urodynamic investigations in children]

Performing urodynamic investigations in children presents some difficulty due to the lack of any normogram, and due to the results that vary with age. Such investigation is therefore carried out only when clinical examination and radiological assessment fail to explain a voiding dysfunction. The procedure should be performed in a urodynamic unit that has paediatric expertise. A specific paediatric procedure is to be respected when performing uroflowmetry and cystometry in children. Assessing the urethral pressure profile is very difficult since moving a catheter along the urethra causes a reflex activity of the pelvic floor muscles. Main indications are: neuropathic bladders, voiding dysfunctions, urinary infections, anorectal malformations and pelvic tumours. As in adults, urodynamic investigations are useful when selecting a therapeutic strategy.

LONG-TERM FOLLOWUP OF BILATERAL HIGH (SOBER) URINARY DIVERSION IN PATIENTS WITH POSTERIOR URETHRAL VALVES AND ITS EFFECT ON BLADDER FUNCTION

PURPOSE

Although valve ablation is the treatment of choice in patients with posterior urethral valves (PUV), temporary high (ureterostomy) diversion remains controversial. In this study we evaluated the effect of bilateral Sober high urinary diversion on renal and bladder function.

MATERIALS AND METHODS

We retrospectively reviewed the records of 36 patients with PUV who underwent bilateral Sober-type diversion. Following valve ablation urodynamic studies were done in all patients after diversion and repeated after ureterostomy closure. The mean duration of diversion was 55 months. Vesicoureteral reflux (VUR), renal dysplasia, serum creatinine during followup and urodynamic parameters were recorded.

RESULTS

All patients underwent endoscopic valve ablation. Renal function impairment at the end of followup was present in 15 patients. Renal dysplasia was found in 10 patients, while VUR was present in 16 at the time of the first urodynamic studies. Urodynamic studies after ureterostomy closure showed well preserved bladder capacity or compliance in 80% and 69% of cases, respectively. About a third of patients showed increased capacity and normal compliance. Univariate analysis showed that VUR, urinary tract infection and renal dysplasia significantly correlated with impaired renal function. On multivariate analysis renal dysplasia was an independent prognostic factor for poor prognosis.

CONCLUSIONS

In patients with PUV temporary high diversion of the Sober type does not have a negative influence on bladder function. It immediately releases high intrarenal pressures but only improves renal function temporarily and may contribute to postpone the time of end stage renal failure. Renal dysplasia dictates long-term renal outcomes in this group.

Initial and long-term management of posterior urethral valves

Posterior urethral valves are the most common cause of congenital obstructive uropathy, resulting in renal failure in childhood. Nowadays, in most cases, diagnosis is suggested by antenatal ultrasound. However, antenatal intervention has not resulted in a significantly improved outcome. Endoscopic valve ablation is the initial treatment in most of these neonates, but others procedures, like vesicostomy or ureterostomy, can also be justified in some particular cases in order to improve renal function prognosis. Different factors like bladder dysfunction, VUR, polyuria and proteinuria, can be responsible for the slow and progressive deterioration in renal function that some of these patients show over the years. By treating them all, we may prevent or delay the onset of end stage renal disease.

LONG-TERM BLADDER DYSFUNCTION AND RENAL FUNCTION IN BOYS WITH POSTERIOR URETHRAL VALVES BASED ON URODYNAMIC FINDINGS

PURPOSE

Posterior urethral valves are the most common cause of congenital obstructive uropathy leading to renal failure in childhood. We investigate the influence of bladder dysfunction on renal function impairment.

MATERIALS AND METHODS

We retrospectively reviewed the records of 116 patients with posterior urethral valves. After valve ablation urodynamic studies were performed in all patients. The presence of vesicoureteral reflux (VUR), renal dysplasia, serum creatinine during followup as well as urodynamic abnormalities were recorded. Mean followup was 10.3 years after valve ablation.

RESULTS

All patients underwent endoscopic valve ablation and urinary diversion was performed in 32. Renal dysplasia was found in 9 patients. Renal function impairment at the end of followup was present in 35 patients. Urodynamic studies showed poor compliance in 30 boys, detrusor overactivity in 44, and poor compliance and detrusor overactivity in 17. Bilateral VUR was found in 17 boys at the time of diagnosis. Urodynamic studies were normal in 23 (20%) patients, of whom 4 had renal failure. Univariate analysis showed that poor compliance and detrusor overactivity had a significant correlation to renal function impairment in addition to bilateral VUR and renal dysplasia. In a multivariate analysis bilateral VUR was an independent prognostic factor for poor prognosis.

CONCLUSIONS

Bladder dysfunction may contribute to renal function impairment eventually but normal urodynamic findings do not preclude renal deterioration. It is likely that loss of compliance and detrusor overactivity would actually result in a valve bladder reaching its end point function.

RENAL TRANSPLANTATION IN CHILDREN WITH RECONSTRUCTED BLADDERS

In this article, we review the outcome and complications of renal transplantation in patients with reconstructed bladders and address specific issues and controversies regarding the management of such cases. Twenty-five articles covering the subjects of renal transplantation, lower urinary tract anomalies, and bladder reconstruction have been selected. Although urologic complications are higher when kidneys are transplanted into reconstructed bladders or urinary diversions, the graft and patient survival rates in most series are comparable with those transplanted into nonreconstructed bladders. The reported series of renal transplantation into abnormal bladders are small, and controlled studies are lacking. Bladder reconstruction should be performed before transplantation when clinically indicated.

Urinary outflow obstruction increases apoptosis and deregulates Bcl-2 and Bax expression in the fetal ovine bladder

During organogenesis, net growth of tissues is determined by a balance between proliferation, hypertrophy, and apoptotic death. Human fetal bladder outflow obstruction is a major cause of end-stage renal failure in children and is associated with complex pathology in the kidney and lower urinary tract. Experimental manipulation of the fetal sheep urinary tract has proved informative in understanding the pathobiology of congenital obstructive uropathy. In this study we used an ovine model of fetal bladder outflow obstruction to examine effects on apoptotic cell death in the developing urinary bladder. While 30 days of obstruction in utero between 75 and 105 days gestation resulted in overall growth of the fetal bladder as assessed by weight, protein, and DNA measurements, we found that apoptosis, as assessed by in situ end-labeling, was up-regulated in fetal bladder detrusor muscle and lamina propria cells and that this was accompanied by a down-regulation of the anti-death protein Bcl-2 and an up-regulation of the pro-death protein Bax. Moreover, activated caspase-3, an effector of apoptotic death, was increased in obstructed bladders. This is the first study to define altered death in an experimental fetal model of bladder dysmorphogenesis. We speculate that enhanced apoptosis in detrusor smooth muscle cells is part of a remodeling response during compensatory hyperplasia and hypertrophy. Conversely, in the lamina propria, an imbalance between death and proliferation leads to a relative depletion of cells.

The valve bladder: etiology and outcome

The infravesical obstruction created by posterior urethral valves produces a series of structural, biochemical, and functional changes in these boys' bladders that begins during fetal life. Any change can be irreversible and result in the alterations in bladder function that can be found in some of these patients. Bladder instability, poor compliance, and myogenic failure are the three most common urodynamic patterns and are also responsible for some of these patients' poor long-term prognosis. Treatment of bladder dysfunction in these patients is basically directed toward improving their kidney function prognosis and also to avoid the urinary incontinence presented secondarily by some valve bladders.