Prune belly syndrome, also called Eagle-Barrett syndrome, is a rare congenital disorder that occurs in approximately 1 in 30,000 to 40,000 live births. It is identified by a specific combination of birth defects and primarily affects males, who account for about 95% of cases. The condition’s name comes from the wrinkled appearance of the abdomen, which is one of its most noticeable features. The severity of the syndrome can vary significantly from one individual to another, influencing both treatment and long-term health.
Defining Characteristics of Prune Belly Syndrome
The syndrome is defined by a classic triad of issues. The first characteristic is the partial or complete absence of abdominal wall muscles, such as the rectus and oblique muscles. This deficiency causes the skin on the infant’s belly to appear thin and wrinkled, similar to a prune. The weakness of these core muscles can make it difficult for a child to sit upright or walk.
A second feature involves abnormalities within the urinary tract. Children frequently have an abnormally large bladder that does not empty completely, along with dilated and twisted ureters. This can lead to vesicoureteral reflux, a condition where urine flows backward from the bladder toward the kidneys, increasing the risk of infection and kidney damage.
The third component, seen in nearly all male cases, is bilateral cryptorchidism, meaning both testicles fail to descend from the abdomen into the scrotum. This occurs because the malformed urinary tract and abdominal wall disrupt the normal path of descent.
Underlying Causes and Development
The specific cause of prune belly syndrome is unknown, but researchers have theories based on its presentation. The leading hypothesis suggests an early fetal urethral obstruction is the initial event. This blockage causes urine to accumulate, leading to a distended bladder that pressures surrounding structures.
This pressure is thought to impede the development of the abdominal wall muscles and block the testicles from descending. While the trigger for the obstruction is not understood, its downstream consequences appear to explain the triad of symptoms.
The condition is congenital but not considered a directly inherited disorder. Some cases in siblings suggest a possible genetic predisposition, but for most individuals, it appears to occur sporadically.
The Diagnostic Process
Prune belly syndrome is often detected before birth during routine prenatal appointments. An ultrasound may reveal key indicators, such as an unusually large fetal bladder, dilated ureters, and hydronephrosis (the swelling of kidneys due to urine buildup). Another sign can be oligohydramnios, a lower-than-normal level of amniotic fluid, and a fetal MRI might be used to confirm the diagnosis.
After birth, the diagnosis is confirmed through a physical examination. A doctor observes the characteristic wrinkled appearance of the abdomen and checks for undescended testicles in males. The weak abdominal muscles may also allow the infant’s organs to be easily felt through the skin.
To understand the full extent of the urinary tract issues, physicians will order additional imaging tests. A renal ultrasound provides a detailed picture of the kidneys and bladder. A voiding cystourethrogram (VCUG) is also performed to evaluate the bladder’s structure and function and to check for vesicoureteral reflux.
Multidisciplinary Treatment Approaches
Treatment for prune belly syndrome is individualized based on the severity of symptoms and requires a team of specialists, including pediatric urologists, nephrologists, and pulmonologists. The primary goal is to protect kidney function by ensuring the bladder can drain effectively. In some infants, a vesicostomy is performed, creating an opening on the abdomen for urine to drain directly from the bladder.
Later in childhood, more extensive reconstructive surgeries may be undertaken. Ureteral reimplantation can be performed to correct the backward flow of urine, and procedures to reconstruct the urethra may be necessary. Another surgical intervention is the orchiopexy, which moves the undescended testicles into the scrotum. An abdominoplasty may also be performed to reconstruct the abdominal wall.
Medical management is another component of treatment. Because of urinary stasis and reflux, children with this syndrome are at high risk for urinary tract infections (UTIs). Prophylactic, low-dose antibiotics are often prescribed to reduce this risk. Regular monitoring of kidney function through blood and urine tests is also standard care.
Long-Term Management and Outlook
The long-term outlook varies widely and depends on the health of the kidneys and lungs. With mild forms of the syndrome, a relatively normal life is possible with consistent medical supervision. Lifelong follow-up with urologists and nephrologists is necessary to manage urinary drainage and prevent infections.
A primary long-term risk is chronic kidney disease. Some individuals experience a gradual decline in kidney function that can progress to kidney failure, requiring dialysis or a kidney transplant.
Pulmonary issues can also affect health, as underdeveloped abdominal muscles lead to a less effective cough and susceptibility to respiratory infections. Despite these challenges, advances in medical management have improved outcomes, allowing many to lead full lives.