Testing & Diagnosis for Posterior Urethral Valves in Children

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.