KidsMD Health Topics

Posterior Urethral Valves

  • If your son has posterior urethral valves (PUV), it means that he was born with extra flaps of tissue that have grown in his urethra, the tube that leads from the bladder to the tip of his penis. These extra flaps of tissue block the normal flow of urine, which can damage organs such as the bladder and kidneys. Early diagnosis, intervention and long-term follow up care are the keys to successful management of this condition.

    Here is some basic information about PUV:

    •  PUV are extra flaps of tissue that grow in a boy’s urethra.
    •  This congenital (present at birth) condition affects about one in 8,000 baby boys.
    • The severity of the condition depends on the degree of obstruction in the urethra.
    • Symptoms of PUV are related to the urinary tract and may cause painful urination or difficulty emptying the bladder.
    • Depending on the severity of the abnormality, PUV can be treated with various surgical interventions. Endoscopic incision of valves is the most common surgical procedure.
    • With medical management, most boys with PUV will lead healthy lives and have normal kidney function, bladder function and continence.

    How Boston Children’s Hospital approaches posterior urethral valves (PUV):

    At Children’s, we take a multidisciplinary approach to treating a child’s posterior urethra valves (PUV). After an accurate diagnosis is made, boys are carefully assessed and treated by specialists in many different disciplines, including Nephrology, Urology and Radiology. With each appointment, our team of experts monitors your child’s kidney function, bladder functioning and voiding ability (emptying of the bladder). 

    Posterior urethral valves: Reviewed by Joseph G. Borer, MD
    © Children’s Hospital Boston; posted in 2012


    Boston Children's Hospital
    300 Longwood Avenue
    Hunnewell 3
    Boston, MA  02115


  • If your son has been diagnosed with posterior urethral valves (PUV), you may have questions and concerns about your child’s health and future, such as:

    • Will my son have normal bladder and kidney functioning?
    • Will he be able to have children?
    • What is the long-term outlook for my son?

    At Boston Children’s Hospital, we know how important it is for parents to understand their child’s medical concerns. That’s why we’ve provided answers to commonly asked questions such as these following pages. During your appointment, our doctors will explain your child’s condition and discuss management options with you in more detail.

    What are posterior urethral valves (PUV)?

    • PUV are an extra growth of tissue beyond what should normally develop in the area of the urethra, near the urinary bladder.
    • This extra tissue prevents the urethra from doing its job in a normal manner, which is carrying urine from the bladder to the tip of the penis where urine is emptied out of the body.
    • When urine can’t be normally expelled from the body, the organs of the urinary tract (the kidneys, bladder, ureters, and urethra) may become dilated, or swollen.
    • This dilation of the urinary tract organs, if it occurs, may cause serious damage to the tissues and cells within those organs.

    How serious is PUV?

    • Just as is the case with many other diseases, there’s a wide spectrum of severity when it comes to PUV. The severity of your son’s PUV depends on the degree of obstruction in his urethra.
    • In mild cases of PUV, a boy’s symptoms may not surface until the age of 10 years or older.  The symptoms in these boys are mild and may include urinary tract infections (UTIs), difficulty urinating or urinary incontinence.
    •  In more serious circumstances, PUV is diagnosed shortly after birth if the newborn presents hydronephrosis (severe dilation of the kidneys).
    • Today, more and more cases of PUV are being detected during pregnancy, as prenatal ultrasounds become more common. This early detection means that a baby’s symptoms, and the posterior urethral valves themselves, can be treated before they become more serious or cause more injury.


    What causes PUV?

    • PUV is congenital, which means that children are born with the extra flaps of tissue that causes the disorder, even though it’s not always diagnosed at birth.
    • Parents do not pass PUV down to their child. However, PUV has been seen in twins and siblings, suggesting that there is a possible genetic component.
    • The reason why the tissue in the urethra grows more than it should is unknown. However, it’s believed to occur early on in male fetal development.
    • Normally, the flaps of tissue in the urethra are very small structures. It’s believed that during a fetus’ development, the body sends signals that tell the tissue to stop growing or help the tissue decrease in size.
    • In boys with PUV, this signal is thought to be missing. The signal never gets sent or picked up, which causes the tissue to keep on growing.


    Symptoms that may result from PUV often vary in terms of their severity, and range from mild to severe. Therefore, each child experiences symptoms differently. Your son's symptoms may include:

    • an enlarged bladder that may be detectable through the abdomen as a large mass
    • urinary tract infection, or UTI (usually uncommon in children younger than 5 and unlikely in boys at any age, unless an obstruction is present)
    • painful urination
    • weak urine stream
    • urinary frequency
    • poor weight gain
    • difficulty with urination

    Are there any medical complications associated with PUV?

    Severe cases of PUV can lead to the following medical complications:

    • bladder dysfunction
    • renal function impairment
    • About 50 percent of boys with PUV will have vesicoureteral reflux (VUR).
    • In 50 percent of the cases, VUR can be treated with endoscopic incision of the valves.
    • The other 50 percent of boys may need anti-reflux surgery, also known as ureteral reimplantation

    Is my child at risk for kidney failure?

    The risk of kidney failure in a boy with PUV is fairly significant. Kidney failure might present in different stages of the boy’s life: either as a fetus, a neonate, or later on in life. Over the course of their lifetime, boys have a 15-20% chance of kidney failure.

  • At Boston Children’s Hospital, we know that an early and accurate diagnosis is the key for successful treatment and long-term management of posterior urethral valves (PUV).

    When are PUV detected?

    How early PUV can be detected usually depends on the severity of the condition:

    Severe cases

    • In severe cases, PUV may be identified during pregnancy through an ultrasound, a non-invasive imagining technique that uses sound waves to generate an image of the fetus.
    • Serious symptoms of PUV such as hydronephrosis (build up of urine in the kidney) can show up on this prenatal ultrasound.
    • A dilated kidney-collecting system or dilated ureter (the tube that goes from the kidney up above to the bladder below) in a male fetus can alert doctors to a possible diagnosis of PUV

    Mild and moderate cases

    • In mild to moderate cases of PUV, fetal imaging may look relatively normal.
    • In these cases, PUV can have a gradual effect on the bladder and therefore go undetected for years until the child is older and presents with symptoms.
    • In this case, a diagnosis is made after a series of diagnostics tests are performed.

    How is PUV diagnosed?

    Although findings from prenatal tests can make doctors suspect PUV, a formal diagnosis can only made after the baby is born. 

    A definitive diagnosis of PUV is made using:

    • During this procedure, a radiologist will gently slide a very small catheter (tube) coated with numbing gel into your child’s urethra and into the bladder. 
    • The tube will be used to fill the bladder with a contrast material that illuminates the urinary tract by using x-ray images.
    • Using fluoroscopy, a special x-ray technique, the radiologist will obtain images of your child's bladder during filling and emptying.
    • The images from a VCUG can be used to:
    • diagnose vesicoureteral reflux: the reverse flow of urine into the ureters and kidneys, and how well the bladder empties.
    • determine why your child has recurring urinary tract infections
    • discover if antibiotic treatment or anti-reflux surgery was effective
    • determine if there are any abnormalities or obstructions in the urethra

    Other tests used to evaluate a boy with PUV include:

    • direct endoscopic visualization (cystourethroscopy), a test that uses an endoscope (a small flexible telescopic tubewith a light and a camera lens at the end) to examine the urethra.
    • blood tests to check for abnormalities such as elevated creatinine, a waste product that the body makes each day. Since it can only leave the body through the kidneys, a high creatinine level in the blood is a sign of decreased kidney functioning.
    • urodynamic study (UDS) which involves evaluation of bladder storage and emptying function.
  • At Boston Children's Hospital, we take a multidisciplinary approach to treating posterior urethra valves (PUV). From your first visit, you'll work with a team of specialists from various disciplines who are dedicated to helping your family find the best care for your child—when he is first diagnosed, throughout treatment and as he grows.

    How is PUV treated?

    In 95 percent of cases, PUV is treated with a surgical procedure called endoscopic incision of the valves

    • endoscopic incision of the valves, also known as valve ablation or posterior urethral valve ablation, is a surgical procedure that trims down excessive tissue of the valves.
    • This is a minor and minimally invasive procedure and only requires a small incision at the site of the ablation (removal) of the valves.
    • While your child is under general anesthesia, doctors will insert a small telescope called a cystoscope into the urethra. With the cystoscope, doctors are able to view the interior lining of the bladder and the urethra on a monitor.
    • Doctors will use the imaging to examine the obstruction and remove the valves.

    Emergency surgery may be used if your child has:

    • respiratory distress (difficulty breathing on his own). A newborn with respiratory distress may need:
    • ventilation
    • endotracheal intubation: a general term referring to the placement of a tube into a patient's body.
    • hydronephrosis (dilation of the kidneys, at times severe). A newborn with hydronephrosis may need the following surgical treatments:
    • urinary diversion, a procedure that diverts the urine before it reaches the urethra. This is done with a vesicostomy, an operation performed on infants who are too small to undergo endoscopic valve ablation. This procedure creates an opening from the bladder to the outside of the body so the urine can drain directly into a diaper.
    • proximal diversion, a is a less common procedure in which the ureter is brought out to the skin, allowing the urine to be brought out (diverted) to the side of the body. This procedure is done for boys with more severe presentations of the disease. For example, when there are very thick bladder walls or if the bladder itself shows marked abnormality.


    Although medication alone can't treat PUV, it may be used in addition to surgery to treat more severe problems.

    For example, the wall of the bladder has two layers: a soft inner lining and an outer layer of muscle. Some boys have severe hyperactivity of that muscle, which makes the bladder muscle stiff. These boys may benefit from medications that help relax and soften the bladder muscle.

    The most common classes of medication used to help relax the bladder muscle include:

    • anticholinergics / antimuscarinics
    • antispasmotics
    • sympathomimmetics

    How often do children with PUV need to be seen?

    Ongoing medical management is very important for boys with PUV. Due to the varying degrees of severity, some boys will need to be followed more closely than others. For the most part, boys will need to be monitored for kidney function, bladder functioning and voiding ability (emptying of the bladder).

    Generally, after the initial surgery is performed, a child will receive another voiding cystourethrogram (VCUG) to ensure that the appearance of the valves is gone or much less significant.

    Six months after the valves have been ablated, doctors will continue to monitor the child's bladder function using a urodynamic study:

    • a urodynamic study monitors bladder function and gives specific objective information about the bladder's capacity, storage pressures, bladder (detrusor) muscle, and emptying function of the bladder.

    How might PUV affect my child's long-term health?

    There could be some long-term problems, so it's important for your son's doctor to see him periodically.

    Some of these problems could include:

    Even after surgery, your son may continue to experience mild symptoms of urinary incontinence, frequency and urgency. A simple outpatient procedure can often cure these symptoms.

    If your son's urinary tract is severely affected, extensive reconstructive surgery may be helpful in preventing damage to the kidneys.

    It's essential that you keep in close contact with your son's physician so that she can monitor your son for any sign of developing problems.

     Will my child be OK?

    Most boys with PUV will have normal kidney function, normal bladder function and normal continence. In most cases, these boys will also be able to have normal sexual development and normal fertility. 

    Since boys have a 20-25% chance of kidney failure over the course of their lifetime, our specialists in Urology make maintaining optimal bladder function the primary goal of treatment. We help these boys throughout their lifetime with bladder function issues, incontinence and decreasing the risk of urinary tract infections (UTIs). This is done through urodynamic testing to objectively study the bladder function.

    Coping and support

    If you are feeling overwhelmed by your child's diagnosis of posterior urethral valves (PUV), remember that Children's is here to help. We're dedicated to helping families locate the information and resources they need to better understand their child's particular condition and take part in their care.

    This list outlines some of our resources at Children's and in the wider community that may be helpful to you:

    Resources for children and families:

    • The Bladder Exstrophy Program focuses on children, teens and families who are affected by a urinary disorder such as PUV. The support group, which meets three or four times a year on Saturday, offers guest speakers and teen chats. We also puts parents in touch with other families whose children have similar issues.

    For teens

    Adolescence can be stressful time—even for physically healthy teens. Having a condition like PUV may present further difficulties for teenage boys. 


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