The Prune Belly Syndrome

The classic prune belly syndrome is essentially a male condition which also goes by the title of Eagle Barrett Syndrome or the triad syndrome. The prune belly syndrome gets its name from the characteristic wrinkled appearance of the abdominal wall because of variable degrees of muscle hypoplasia. In addition, there are associated major urinary tract abnormalities and undescended testes in male patients. Rarely, female cases of prune belly syndrome are associated with major genital tract abnormalities.

There is good evidence to support the view that this condition is secondary to fetal lower urinary tract obstruction. Also, the distended bladder or possibly the megaureters hinder the descent of the testes from the abdomen to the scrotum.

An alternative view to the etiology of this condition is that it is secondary to abnormal mesenchymal development.

ANATOMIC FEATURES

The abdominal wall defect is variable.

Above the umbilicus, the oblique muscles and the rectus abdominis are usually affected.

Below the umbilicus, the transverse abdominis and the rectus abdominal muscles are affected, and there may be little lower abdominal wall muscle, if any.

In general, the prostatic urethra is elongated, the bladder neck is wide and ill-defined, and the trigone is large, with large, widely separated ureteric orifices allowing reflux. The bladder is usually large, smooth and thick-walled.

Renal involvement in prune belly syndrome varies from case to case. There may be renal agenesis, and over 50% of cases show features of renal dysplasia, including multicystic kidneys.

The intra-abdominal testes vary in position.

In about 75% of the cases of prune belly syndrome, there are other associated anomalies apart from those of the urinary tract. Pulmonary abnormalities are common, as are chest wall and cardiac abnormalities. Growth retardation and developmental delay with end-stage renal failure have also been reported.

CLINICAL PRESENTATION

The prune belly syndrome is an important cause of fetal uropathy, and about 20% of cases are stillborn or die early in the neonatal period from severe renal dysplasia or pulmonary hypoplasia.

MANAGEMENT

In the newborn, an urgent chest x-ray is necessary to exclude pulmonary abnormalities, including pneumothorax. Cardiac investigations may be advisable.

Serum renal function studies are important, as are electrolytes and a renal ultrasound. Nuclear scans may be useful in differentiating between obstructive and non-obstructive hydronephrosis. A voiding cysto-urethrogram will identify reflux and other lower tract causes for obstruction.

Children with advanced cases of prune belly syndrome with renal dysplasia and lung hypoplasia do not survive the neonatal period. The mild or incomplete forms of the syndrome require long-term follow up.

In some, non-operative management may be reasonable; but in many others, a multitude of various reconstructive procedures will be required on the urinary tract.

Operative management may be necessary to correct urinary stasis in order to prevent urinary tract infections, which significantly contribute to morbidity, loss of renal function and mortality. Surgery may be required to correct reflux, and often reduction cystoplasty is also performed.

Bladder function may deteriorate with age, and careful surveillance is advised.

Some patients will also require abdominal wall reconstruction; however, routine abdominal wall reconstruction is not recommended, as the cosmetic appearance tends to improve somewhat with growth.

Orchiopexy is justifiable in patients with prune belly syndrome, although no cases of paternity have been recorded.

PROGNOSIS

Prune belly syndrome patients require careful, lifelong follow up with regular assessment of kidney and bladder function and palpation of the testes. The prognosis of this disorder depends upon the degree of renal involvement, bladder function, pulmonary function as well as the impact of associated abnormalities.