Synonym:Eagle-Barrett syndrome.
Definition: Prune-belly syndrome is a rare congenital disorder, more common in males, consisting of deficiency of abdominal wall muscles (absent or hypoplastic), cryptorchidism, and genitourinary malformations.
Etiology: Many theories have been proposed to explain the pathogenesis of this anomaly. The first one proposes that occurs an abnormal mesodermal development. The development of the urinary tract. The second one is urethral obstruction malformation complex. It proposes that pressure atrophy of the abdominal wall muscles occurs when urethral obstruction leads to massive distention of the bladder and ureter. Bladder distention would also interfere with descent of the tests and thus be responsible for the bilateral cryptorchidism. The mechanism responsible for the urinary tract dilatation and distention is a flap valve mechanism that results from a hypoplasia of the stromal and epithelial elements of the prostatic urethra. The hypoplasia of these elements leads to an underlying weakness and subsequent sacculation of the prostatic urethra. The last theory is the genetic defect that is suspected because of the predominance in males and few familial cases.
Incidence: One in 40,000 live births, almost exclusively in males (M20:F1). The higher incidence of this syndrome in males has been explained on the basis of the more complex morphogenesis of the male urethra, possibly resulting in obstructive anomalies at several levels. Twinning is associated with PBS; 4% of all cases are products of twin pregnancies. PBS is associated with trisomy 18 and 21. Patients with PBS also have an increased incidence of Tetralogy of Fallot (TF) and ventriculoseptal defects.
Diagnosis: The diagnosis should be suspected in fetuses with very large abdominal masses. These are, most typically, bladder obstruction caused by urethral valves, urethral agenesis, but also other abdominal masses such as ovarian cyst. Possible results are oligohydramnios with consequent pulmonary hypoplasia and urinary ascites. The oligohydramnios, usually, makes impossible the detection of cryptorchidism. Other findings could be: Potter face, pulmonary hypoplasia, gastric dilatation, short bowel, micro ileum, Microcolon, malrotation of the intestines imperforate anus, arthrogryposis and clubfoot. Additional information can be gained by addition three-dimensional ultrasonography scanning and could be useful for more-efficient counseling and therapeutic planning.
Lab Studies: Serum creatinine, BUN, Serum Electrolyte for Renal Function.
Imaging Studies: 1. KUB-USG, 2. Contrast voiding Cystouretrogram, 3. DTPA Scan.
Surgical Therapy is the Mainstay of t/t.
- For Undescended Testis.
- Abdominal wall reconstruction: Abdominal wall reconstruction is performed in most boys to improve respiratory function and for cosmetic reasons.
- Placement of a percutaneous nephrostomy
Obstruction at the ureteropelvic junction (UPJ) has been observed in patients with PBS. In some cases, making the diagnosis can be difficult; however, the diagnosis can be confirmed with placement of a percutaneous nephrostomy.
Placement of a percutaneous nephrostomy provides the surgeon with several options. The surgeon can confirm the diagnosis of UPJ obstruction. The urinary tract can be decompressed in al ill child or in a child that is too small to safety undergo reconstructive surgery at the time. The technique also allows the surgeon to evaluate the renal function of the obstructed unit. Finally, it provides the surgeon with the opportunity to obtain a renal biopsy at the time of placement of the percutaneous nephrostomy.
Standard Pyeloplasty
If conditions are right and the child is stable, a standard pyeloplasty can be performed as another means of treating the obstructed UPJ.
Infravesical obstruction or obstruction at the prostatic urethra
Patient with documented obstruction can be treated by several means - Blocksom Vesicostomy Posterior urethral valves are observed occasionally in patient with PBS, and the valves are best managed by transurethral resection.
Ureteral reimplantation in patients with megaureters, reflux and ureteral transplantation requires an aggressive approach in removing as much of the abnormal distal ureter as possible and preserving the blood supply to the proximal ureter.
Prognosis: The prognosis for patients with PBS can be quite variable. The spectrum runs from still birth to a male with just undescended testicles and a minimal degree of abdominal wall laxity.
The long-term prognosis is clearly dependent on renal function, which, in general, is dependent on the amount of renal dysplasia present at the time.
Men with PBS are not fertile for 2 reasons. The intra-abdominal testis is at greater risk for progressive tubular fibrosis, which, in turn, leads to reduced sperm counts. Also, these patients have prostatic hypoplasia, which leads to retrograde ejaculation.
Many patients have significant respiratory problems that have an impact on long-term prognosis.
Patients can have significant psychological issues because of abdominal laxity.
Future and Controversies : Persistent advances in laparoscopic surgery may continue to improve the outlook for patients with PBS. As more is learned about the history of obstructive uropathy, treatment for these children will be adjusted to offer the most benefit with least amount of intervention. The debate will continue between aggressive early intervention group and no intervention group until all the information is in on the true pathophysiology of PBS.
