Posterior Urethral Valve

What are posterior urethral valves (PUV)?

PUV is an abnormality of the urethra, which is the tube that drains urine from the bladder to the outside of the body for elimination. The abnormality occurs when the urethral valves, which are small leaflets of tissue, have a narrow, slit-like opening that partially impedes urine outflow. Reverse flow occurs and can affect all of the urinary tract organs including the urethra, bladder, ureters, and kidneys. The organs of the urinary tract become engorged with urine and swell, causing tissue and cell damage. The degree of urinary outflow obstruction will determine the severity of the urinary tract problems.

Prevention & Risk Treatment

Prevention & Risk Treatment

What causes posterior urethral valves?

PUV is the most common cause of severe types of urinary tract obstruction in children. It is thought to develop in the early stages of fetal development. The abnormality affects only males and occurs in about one in 8,000 births. This disorder is usually sporadic (occurs by chance). However, some cases have been seen in twins and siblings, suggesting a genetic component.

What are the symptoms of posterior urethral valves?

The syndrome may occur in varying degrees from mild to severe. The following are the most common symptoms of posterior urethral valves. However, each child may experience symptoms differently. Symptoms may include:

  • An enlarged bladder that may be detectable through the abdomen as a large mass
  • Urinary tract infection (usually uncommon in children younger than age 5 and unlikely in boys at any age, unless an obstruction is present)
  • Painful urination
  • Weak urine stream
  • Urinary frequency
  • Bedwetting or wetting pants after the child has been toilet trained
  • Poor weight gain
  • Difficulty with urination

The symptoms of PUV may resemble other conditions or medical problems. Always consult your child's doctor for a diagnosis.

Diagnosis

Diagnosis

How are posterior urethral valves diagnosed?

The severity of the obstruction often determines how a diagnosis is made. Often, PUV is diagnosed by fetal ultrasound while a woman is still pregnant. Children who are diagnosed later often have developed urinary tract infections that require evaluation by a doctor. This may prompt your doctor to perform further diagnostic tests, which may include:

  • Abdominal ultrasound. A diagnostic imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
  • Voiding cystourethrogram (VCUG). A specific X-ray that examines the urinary tract. A catheter (hollow tube) is placed in the urethra (tube that drains urine from the bladder to the outside of the body) and the bladder is filled with a liquid dye. X-ray images will be taken as the bladder fills and empties. The images will show if there is any reverse flow of urine into the ureters and kidneys.
  • Endoscopy. A test that uses a small, flexible tube with a light and a camera lens at the end (endoscope) to examine the inside of part of the urinary tract. Tissue samples from inside the urinary tract may also be taken for examination and testing.
  • Blood test. A blood test may be ordered to assess your child's electrolytes and to determine kidney function.
Children's Team

Children's Team

Providers

Departments

Departments

Urology

At Children’s National in Washington, DC, our pediatric urologists provide comprehensive care for disorders affecting reproductive and urinary organs.

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