Prune belly syndrome

Prune belly syndrome is also known as triad syndrome or Eagle-Barrett syndrome. It is characterized by a triad of abnormalities that include the following:

• Absence of abdominal muscles
• Undescended testicles - a condition seen in newborns whereby one (or both) of the male testes has not passed down into the scrotal sac.
• An abnormal, expanded bladder and problems in the upper urinary tract, which may include the bladder, ureters, and kidneys.

Because of the substantial involvement of the urinary tract, children with prune belly syndrome are usually unable to completely empty their bladders and have serious bladder, ureter, and kidney impairment.

A child with prune belly syndrome may also have other birth defects. Most commonly, these defects involve the skeletal system, intestines, and heart. Girls may have defects in their external genitalia, as well.

Some infants who have prune belly syndrome may be stillborn or die within a few months of birth.

What causes prune belly syndrome?

Prune belly syndrome is an uncommon birth defect occurring in about one in 40,000 births. In 95 percent of the cases, it occurs in males. It may occur if there is a urethral obstruction during fetal development preventing any urine from flowing through the urinary tract. The urethra is the tube that drains urine from the bladder to the outside of the body for elimination. If there is obstruction, urine can reverse flow and cause an expanded bladder.

The cause of prune belly syndrome is unknown, however, some cases have been reported in siblings, suggesting a genetic component.

What are the symptoms of prune belly syndrome?

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

• The abdomen may have a wrinkly appearance with multiple folds of skin
• An abdominal mass may sit above the pubic bones - this is a result of an expanded bladder
• The urinary tract organs may be easy to feel through the abdominal area
• An outline of the intestines may be visualized through the abdomen including visualization of peristalsis (the worm-like movements of the intestines shifting food forward)
• Absence of testes in the scrotum may be present in males
• There may be underdeveloped muscles of the abdomen preventing a child from sitting upright
• A child may experience frequent urinary tract infections (usually uncommon in children younger than 5 years and unlikely in boys at any age, unless an obstruction is present)

The symptoms of prune belly syndrome may resemble other conditions and medical problems. Always consult your child's physician for a diagnosis.

How is prune belly syndrome diagnosed?

The severity of the defects often determines how a diagnosis is made. Often prune belly syndrome is diagnosed by fetal ultrasound while a woman is still pregnant. Because of the distinct abnormalities of prune belly syndrome, a physician is usually able to make a diagnosis after initial examination during the newborn period. A child who may not have the outward signs of prune belly syndrome may experience a urinary tract infection, which will prompt further testing by your child's physician. Additional diagnostic procedures may include the following:

• Renal 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.
• Intravenous pyelogram (IVP) - a diagnostic imaging technique which uses an x-ray to view the structures of the urinary tract. An intravenous contrast of dye is given so that the structures can be seen on film. An IVP also reveals the rate and path of urine flow through the urinary tract.
• Blood tests (to determine how well the kidneys may be functioning)

Treatment for prune belly syndrome:

Specific treatment for prune belly syndrome will be determined by your child's physician based on:

• Your child's age, overall health, and medical history
• The extent of the disease
• Your child's tolerance for specific medications, procedures, or therapies
• Expectations for the course of the disease
• Your opinion or preference

Treatment for the syndrome depends on the severity of symptoms. If your child has mild prune belly syndrome, he/she may be maintained on precautionary antibiotic therapy to prevent upper and lower urinary tract infections.

Your child may be referred to an urologist (physician who specializes in disorders and care of the urinary tract and the male genital tract). Some children may require a vesicostomy (a small opening made in the bladder through the abdomen) to facilitate emptying the bladder of urine. Other children may need to undergo extensive surgical remodeling of the abdominal wall and urinary tract. In boys, a surgical procedure to advance the testes into the scrotum may be performed, called an orchiopexy.

Despite available surgical interventions, some children may develop extensive kidney failure.