The most common cause of congenital urethral obstruction in children is on the PUV, with an incidence of 1 case per 3000-8000 live births, affecting only boys. Currently, the diagnosis for 60% to 80% of the cases is still done at the prenatal exams.
The valve is characterized by a membranous structure, originating from the floor lining of the prostatic urethra, which blocks the flow of urine.
The obstruction of urinary flow causes dilation, lengthening of the posterior urethra and thickening of the bladder muscle, as shown in the following figure.
In older children, the most obvious symptoms are: urinary incontinence, urinary urgency, squirt changes and dripping.
Voiding cystourethrography(VCU) is the best available test (gold standard) for the diagnosis of PUV, especially when associated with secondary vesicoureteral reflux (VUR).
The association with the urinary tract infection appears in more than 50% of children over one year of age suffering from PUV.
The overall evaluation of the newborn is extremely important, with special attention to the pulmonary and renal functions, and possible connection with the urinary tract infection.
After confirming the PUV, the initial approach, usually with a short stay, must be the bladder urinary drainage through a gavage.
A final treatment for VUP should be considered for boys born at term with normal weight, good general condition and absence of infection, through valve endoscopic cauterization.
Vesicostomy, which is a temporary deviation of the urine, by making a small surgical subumbilical incision, is indicated for patients with small diameter ureters, urinary tract infection or even sepsis, disorder of the excreta eliminated by the kidneys and renal failure.
In neonates with severe renal impairment, a higher urinary diversion may be indicated – ureteral or renal pelvis.
