Posterior urethral valves are developed in boys in early foetal life. They consist of very thin membranes in the upper part of the urethra and may cause problems with the urinary flow to a varying degree.
More pronounced cases are often diagnosed by prenatal ultrasound where a large bladder and a dilated upper urinary tract is seen together with a reduced amount of amniotic fluid. Depending on the degree of bladder outlet hindrance the valves may affect bladder and kidney function. In unborn boys, lung function after birth may also be affected. However, in a number of boys, the diagnosis is made later in life when they seek medical advice due to voiding symptoms or urinary tract infections.
The treatment is a simple valve removal with a cystoscope through the urethra. However, damage to the bladder and kidney may have been caused by the value not working properly. While mild cases often just require observation, in more serious cases the bladder may shrink, recurrent urinary tract infections may occur and together with high bladder pressure, this may cause damage to the kidney function. The function of urinary flow and the bladder in boys with posterior urethral valves changes throughout childhood and needs regular follow-up. Some of the bladder problems can be handled by medication while others may require extensive surgery with bladder enlargement, external catheterization channel and incontinence surgery. However, only few boys suffer from serious kidney deficiency which may require dialysis and kidney transplantation.