Posterior urethral valves

At Children’s Hospital Boston, 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:

• Voiding cystourethrogram (VCUG), a minimally invasive test that uses special x-ray technology to examine the urinary tract and bladder.

• 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 involvesevaluation of bladder storage and emptying function.

Learn more about the different methods that Children’s uses to diagnose urinary issues such as PUV.