Bladder dysfunction depends on many variables in children with posterior urethral valves

Abstract

We congratulate the authors for a very good paper on an important topic about what the Pediatric Urologists community still has many unanswered questions.The paper compares neonates (6-18 days) to young children (3-19 months), and conclusions should apply only to these age groups: late diagnosis in older children may present other characteristics (1). The dynamic nature of the problem implies that valve bladders differ according to age, so that overactivity predominates in the first 5 years of life, while detrusor failure typically appears in late school-aged children or adolescents, complicating the analysis of bladder functions in papers that adopt follow-up periods including different ages. Age also affects the epidemiology of kidney failure (especially end-stage failure), that predominates in the first years of life and adolescence/ young adulthood.The only statistically significant finding of the paper (higher % PVR in the late treatment group) remains to be proved as clinically meaningful, as the differences between the two groups are small. An important secondary result is the confirmation that definitive harming to renal function relates to late diagnosis, even when late diagnosis is defined as diagnosis in the first two years of life. Unfortunately, diagnostic delay of posterior urethral valves remains common in low-medium income countries, relating mainly to inappropriate prenatal care.Bladder dysfunction depends on many variables, so that defining the factors that modulate this problem is difficult in practice. Different patients may show varying degrees of bladder dysfunction depending on the degree of obstruction (posterior urethral valves may vary anatomically from short sub-occlusive valves to almost complete urethral occlusion), polyuria, severity of secondary vesicoureteral reflux (2), and the detrusor response to compensate high voiding pressures. Interestingly, tissue response for aggressions and tissue remodeling differ between fetuses, neonates/ children younger than 3 months, and older pediatric patients/adults. Profiles of proteoglycans, collagens, growth factors, and inflammatory reaction differ from adults. Linear incisions usually heal without scarring in fetuses. Collagen deposition in fetal wounds is quick, highly organized and the proportion of collagen types differs from older individuals (3). Perinatal treatment histological results may differ from those corresponding to treatment after the first trimester of life. Despite most research referring to skin mechanisms of scarring, the process of bladder remodeling may differ between very young children and older ones, which may explain differing results concerning bladder function whenever the relief of urethral obstruction occurs beyond the very first months of life.