Posterior Urethral Valves
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. It occurs when the urethral valves, which are small leaflets of tissue, have a narrow, slit-like opening that partially blocks 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. This causes tissue and cell damage. The degree of urinary outflow blockage will determine the severity of the urinary tract problems.
What causes PUV?
PUV is the most common cause of severe types of urinary tract blockage in children. It is thought to develop in the early stages of fetal development. PUV affects only males and occurs in about 1 in 8,000 births. It 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 PUV?
PUV may be mild to severe. These are the most common symptoms:
An enlarged bladder that may be felt 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 a blockage is present)
Weak urine stream
Bedwetting or wetting pants after the child has been toilet trained
Poor weight gain
Trouble with urination
The symptoms of PUV may look like other conditions or medical problems. Always see your child's doctor for a diagnosis.
How is PUV diagnosed?
Often, PUV is diagnosed by fetal ultrasound while a woman is still pregnant. Children diagnosed later often have developed urinary tract infections that require evaluation by a doctor. This may prompt your doctor to do further tests, which may include:
Abdominal ultrasound. This imaging technique 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). This specific X-ray examines the urinary tract. A catheter (hollow tube) is placed in the urethra 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. This test 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 testing.
Blood test. This blood test may be done to check your child's electrolytes and kidney function.
What is the treatment for PUV?
Treatment for PUV depends on the severity of the condition. Treatment may include the following:
Supportive care. At first, treatment may focus on relieving your child's symptoms. If your child has a urinary tract infection, is dehydrated, or has electrolyte irregularities, these conditions will be treated first. Your child may have a catheter placed in his bladder. This is a small hollow tube that is inserted into the penis through the urethra and is threaded up into the bladder. Your child may also get antibiotics and intravenous (IV) fluids.
Endoscopic ablation. Your child may see a urologist. This is a doctor who specializes in the disorders and care of the urinary tract and the male genital tract. The urologist may do a procedure called an endoscopic ablation. During this procedure, the urologist will insert an endoscope, a small, flexible tube with a light and a camera lens at the end. With this tube he or she will examine the blockage and remove the valve leaflets through a small incision.
Vesicostomy. In certain situations, a different procedure called a vesicostomy may be required. In a vesicostomy, a small opening is made in the bladder through the abdomen. Usually this opening is repaired at a later time when the valves can be cut more safely.
Nearly 1 in 3 boys with PUV may have some long-term kidney failure that may need to be addressed. The prognosis for PUV improves when found early.