Posterior Urethral Valves

What are posterior urethral valves?

Urethral valves occur when a boy is born with extra flaps of tissue that have grown in his urethra, the tube through which urine exits the urinary tract. This extra tissue prevents the urethra from properly carrying urine from the bladder to the tip of the penis and out of the body. When urine can’t be normally expelled from the body, the organs of the urinary tract (the kidneys, ureters, bladder, and urethra) may become dilated, or swollen. If this dilation occurs, it may cause serious damage to the tissues and cells within those organs.

What are anterior urethral valves?

The two main types of urethral valves are posterior urethral valves and anterior urethral valves. Of the two, posterior urethral valves are much more common than anterior urethral valves. The severity of these disorders depends on the degree of obstruction in the urethra. Symptoms and care of anterior urethral valves are similar to that of posterior urethral valves.

What causes posterior urethral valves?

Urethral valves are congenital, which means that boys are born with these extra flaps of tissue. It’s still not clear what causes these disorders, but they are believed to occur early on in male fetal development and may have a genetic component. Normally, the flaps of tissue in the urethra are very small structures. Researchers suspect that during fetal development, the body sends signals that tell the tissue to stop growing or help the tissue decrease in size. In boys with posterior or anterior urethral valves, this signal never gets sent or picked up, which causes the tissue to keep on growing.

What are the symptoms of posterior urethral valves?

In mild cases of urethral valves, a boy’s symptoms may not surface until the age of 10 years or older. In more serious circumstances, they can present as hydronephrosis (severe dilation of the kidneys) in newborns. Symptoms of urethral valves can vary from child to child and may include:

  • an enlarged bladder, which may be detectable through the abdomen as a large mass
  • urinary tract infection
  • painful urination
  • weak urine stream
  • urinary frequency
  • bedwetting or wetting pants after your child has been toilet trained
  • poor weight gain
  • difficulty with urination

Severe cases can lead to the following medical complications:

  • respiratory distress
  • hydronephrosis (dilation of the kidneys)
  • bladder dysfunction
  • renal function impairment and an increased risk of kidney failure
  • vesicoureteral reflux (when urine flows backwards from the bladder up to the kidneys).

How we care for posterior urethral valves

At Boston Children’s Hospital, we take a team approach to treating urethral valves. Your child will be evaluated and treated by a group of skilled specialists from many different disciplines, including nephrology, urology, and radiology. Depending on the severity of the abnormality, posterior or anterior urethral valves can be treated with various surgical interventions and medical management.

Since boys with urethral valves have an up to 25 percent chance of kidney failure over the course of their lifetime, our specialists in Boston Children's Department of Urology make maintaining optimal bladder function the primary goal of treatment. We will help your child prevent bladder function issues, incontinence, and urinary tract infections by regularly monitoring his kidney function, bladder functioning, and voiding ability (emptying of the bladder).