Posterior urethral valves

Posterior urethral valves is the most common congenital cause of lower urinary tract obstruction in males, and a common cause (15–17%) for end-stage renal disease in childhood. Most commonly, posterior urethral valves is suspected on basis of a screening antenatal ultrasound. Ultrasound will not detect posterior urethral valves itself, but recognizes the consequences of lower urinary tract obstruction with a dilated thick-walled bladder and dilation of the prostatic portion of the urethra. After birth, urine drainage has to be secured by placement of a bladder catheter, and imaging is needed to confirm the presence of the urethral valves and estimate the degree of damage to the kidney. Consequences of posterior urethral valves depend on the degree of renal dysplasia and bladder dysfunction. Prevention or minimization of such consequences by intrauterine urine drainage has not definitively shown a benefit of early vesico-amniotic shunting.