Kidney disease progression in pediatric and adult posterior urethral valves (PUV) patients

Care of children with posterior urethral valves after initial endoscopic incision/ablation: what a nephrologist needs to know

Posterior urethral valves (PUV) are the most common cause of congenital urethral obstruction and are unique in the challenges they pose in management. Endoscopic ablation/incision of the valves is usually offered as the primary treatment of choice. Following this, a range of different clinical patterns are observed, each with varying bladder dysfunction and continence issues and associated with different grades of chronic kidney disease. This review outlines a systematic approach that could help pediatric nephrologists, pediatricians, and pediatric urologists, as well as nursing and allied health specialists, assess these children and develop well-informed management plans. The need for surveillance for bladder dysfunction (incidence approximately 55%), identification of red flags for progression to kidney failure (incidence approximately 20%), and multidisciplinary approach to care are presented, with a focus on reducing long-term morbidity in patients and difficulties for the families. Where possible, an alternative in resource-constrained situations is suggested. We also briefly outline the role of pharmacotherapy, assisted bladder emptying/drainage, and other interventions that have a role in the medium- to long-term management of these patients.

Long-Term Kidney Outcomes in Children with Posterior Urethral Valves: A Population-Based Cohort Study

Key Points

Among 727 children with posterior urethral valves, 32% had major adverse kidney events (death, kidney failure, or CKD) over a median of 14.2-year follow-up. Children with posterior urethral valves were at substantially higher risks of kidney failure, CKD, and hypertension than the general population. This justifies close kidney health surveillance among children with posterior urethral valves and optimized transitions to adult urologic care.

Background

Posterior urethral valves represent the most common cause of lower urinary tract obstruction in male infants (approximately 1/4000 live births). Long-term kidney outcomes of posterior urethral valves remain uncertain. We aimed to determine the time-varying risk of major adverse kidney events (MAKE) following children with posterior urethral valves into adulthood.

Methods

A population-based retrospective cohort study of all male children (<2 years) diagnosed with posterior urethral valves between 1991 and 2021 in Ontario, Canada. Comparator cohorts were (1 ) male general population and (2 ) male children with pyeloplasty (both <2 years). The primary outcome was MAKE (death, long-term KRT [dialysis or kidney transplant], or CKD). Time to MAKE was analyzed using multivariable-adjusted Cox proportional hazards models. We censored for provincial emigration or administrative censoring (March 31, 2022).

Results

We included 727 children with posterior urethral valves, 855 pyeloplasty comparators, and 1,013,052 general population comparators. The median follow-up time was 16.6 years (Q1–3, 8.6–24.5) overall. Throughout follow-up, 32% of children with posterior urethral valves developed MAKE versus 1% of the general population and 6% of pyeloplasty comparators. Their adjusted hazard ratio for MAKE was 36.6 (95% confidence interval, 31.6 to 42.4) versus the general population. The risk of developing MAKE declined over the first 5 years after posterior urethral valve diagnosis but remained elevated for >30-year follow-up. Children with posterior urethral valves were also at higher risk of death, CKD, long-term KRT, hypertension, and AKI than the general population or pyeloplasty comparators.

Conclusions

Children with posterior urethral valves are at higher risk of adverse long-term kidney outcomes well into adulthood.

[Kidney transplantation in children with complex urogenital malformations-what should be considered?]

BACKGROUND

Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common cause of end-stage renal disease (ESRD) in children. Approximately one third of children with CAKUT have lower urinary tract dysfunction (LUTD).

AIM

This article highlights the important aspects that need to be considered in kidney transplantation of children with complex urogenital malformations.

MATERIALS AND METHODS

The paper reviews the existing literature regarding the evaluation, preparation, perioperative management, and follow-up of children with complex urogenital malformations and ESRD undergoing renal transplantation.

RESULTS

Comprehensive diagnostics are required before any pediatric kidney transplantation. If LUTD is suspected, voiding cystourethrography and a urodynamic examination should be performed. Treatment of symptomatic vesicoureterorenal reflux and LUTD is mandatory prior to pediatric kidney transplantation. Following successful kidney transplantation of children with congenital urogenital malformations, lifelong follow-up is required. Regular reevaluations of the bladder by means of urodynamic examinations are necessary. In patients following bladder augmentation with intestinal segments or urinary diversions in childhood, regular endoscopic examinations of the urinary tract are recommended to rule out secondary malignancy.

CONCLUSION

Treatment of children with complex urogenital malformations should be carried out in centers with appropriate expertise.