Posterior Urethral Valves (PUV)
What Are Posterior Urethral Valves (PUV)?
Posterior Urethral Valves (PUV) is a condition that occurs exclusively in boys, affecting the urethra—the tube that carries urine from the bladder to the outside. In boys with PUV, a blockage forms in the urethra near the bladder, making it difficult for urine to flow properly. As the bladder struggles to expel urine, the increased pressure can push urine back into the ureters and kidneys, causing them to swell. This pressure can lead to kidney damage if left untreated.
What Are the Symptoms of PUV?
The symptoms of PUV can vary depending on the severity of the blockage. Not all children will exhibit the same symptoms, and the degree of obstruction will affect how serious the symptoms are. Common signs include:
- Enlarged bladder that can be felt as a lump through the abdomen
- Frequent urinary tract infections (UTIs)
- Difficulty urinating or a weak stream
- Unusually frequent urination
- Bedwetting after successful toilet training
- Poor weight gain
These symptoms may overlap with those of other conditions, so it’s important to consult a doctor for an accurate diagnosis.
How Is PUV Diagnosed?
PUV can often be detected through an ultrasound scan during pregnancy if there is swelling in the bladder, ureters, or kidneys. It may also be diagnosed in a newborn if the bladder is swollen and urine is constantly dribbling. In some cases, the condition may remain unnoticed until symptoms emerge later in life.
The diagnostic process typically includes:
- Ultrasound of the abdomen: This scan creates images of internal organs and helps assess their function.
- Micturating Cystourethrogram (MCUG): This test tracks the movement of urine through the urethra and bladder, and checks for urine reflux (backflow to the kidneys).
- Cystoscopy: A procedure where a small tube with a camera is inserted into the bladder to examine its interior.
- Blood tests: To assess kidney function and fluid balance, along with other tests to evaluate the health of the urinary system.
What Causes PUV?
The exact cause of PUV is not well understood. It is not inherited and occurs during the early stages of pregnancy when organs and tissues begin to form. There is no evidence that PUV is caused by anything the mother did or ate during pregnancy.
How Rare Is PUV, and Who Is Affected?
PUV is a rare condition, affecting approximately 1 in 8,000 live male births. It exclusively impacts male infants.
How Can PUV Be Treated?
Treatment for PUV depends on the severity of the symptoms and the impact on the child’s health. The approach typically starts with symptom management, which may involve inserting a catheter into the bladder to drain urine. UTIs and any fluid imbalances are treated with antibiotics and intravenous fluids.
One of the main treatments is Laser PUV Fulguration, which aims to remove the obstructing valve tissue that is causing urine backflow. This is done using a cystoscope (a tube with a light) and a Holmium Laser, which cuts away the valves. This procedure is less invasive than traditional surgery and typically yields positive results, significantly improving urine flow.
What Is the Outlook for Children with PUV?
The outlook for children with PUV depends on how much kidney damage has already occurred by the time the condition is diagnosed. Doctors will monitor kidney function and urinary health through tests and follow-up visits. In many cases, with early diagnosis and appropriate treatment, the prognosis is good, though ongoing follow-up is necessary to monitor for any long-term effects on the urinary system.