Prune Belly Syndrome Workup

Updated: Jan 17, 2020
  • Author: Israel Franco, MD, FAAP, FACS; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Laboratory Studies

Obtain a sequential multiple analysis (SMA-6; ie, 6 different serum tests and creatinine tests to evaluate renal function in a serial fashion) because many children with prune belly syndrome may have renal compromise.

Urinary output and electrolytes must be carefully observed in newborns. A rise in blood urea nitrogen (BUN) and creatinine levels associated with decreased urine output indicates obstruction.


Imaging Studies

With the routine use of maternal ultrasonography, prune belly syndrome is most often diagnosed prenatally. Cases have been identified as early as at 11–12 weeks of gestation, but the characteristic anomalies may not be consistently evident until later in the pregnancy. The diagnosis of prune belly syndrome should be considered when the following are clearly identified on a prenatal ultrasound [1] :

  • Oligohydramnios
  • Urinary abnormalities (dilatation of the urinary tract, megacystis, bilateral hydroureteronephrosis)
  • Absence of abdominal musculature

Radiologic studies should be performed in the newborn period, regardless of whether obstruction is present. The first study that should be performed is renal and bladder ultrasonography, which is noninvasive and can be used later to noninvasively monitor the child's progress. Perform ultrasonography of the kidneys as early as possible to evaluate the upper tracts. Kidney, ureter, and bladder (KUB) test findings can usually be used for diagnosis based on the typical appearance of the bowels hanging over the lateral edge of the abdominal wall.

Renal scan is necessary after renal function stabilizes to evaluate renal function and drainage.

Contrast voiding cystourethrography (VCUG) should be performed. VCUG is used to delineate the prostate-membranous urethra and the bladder and to detect the presence of an urachal remnant. The presence of a patent urachus is a hint that stenosis is present. Urethral stenosis must be ruled out immediately.

In addition, VCUG will identify whether vesicoureteral reflux is present and if so, determine its degree and extent. Patients with vesicoureteral reflux are placed on antibiotic prophylaxis. If evidence of upper-tract dilatation or obstruction is found, a renal Hippuran or diethylenetriamine pentaacetic acid (DTPA) study should be performed.

Careful radiologic evaluation is essential before committing to any type of diverting procedure. Children with only megaureter, megacystis, and the prostatic abnormalities who have no evidence of obstruction or reflux can be managed conservatively with close observation.

For full discussion, see Prune Belly Syndrome Imaging.