Prune Belly
Jamie C. Harris
Fizan Abdullah
Prune belly is an extremely rare disease, occurring in 1/35 000 live births. The majority of patients are male (FIG 1).
It is characterized by three components: abdominal wall flaccidity, bilateral undescended testes, and urologic anomalies.
Abdominal wall laxity is associated with increased rates of respiratory infections, due to a poor cough mechanism, as well as increased incidence of lordosis.
Urinary tract anomalies lead to increased rates of infectious complications as well as ureteral obstruction; 81% of patients have megaureter.
Urinary tract abnormalities can include renal dysplasia and ureteral enlargement.
Additionally, both testes are intra-abdominal in the majority of patients.
Overall outcome of the children is variable, with some not surviving past the neonatal period due to complications to some with minimal disease complications.
DIFFERENTIAL DIAGNOSIS
Prune bellylike variant: abdominal flaccidity. However, unlike in prune belly, the rectus muscles are not involved.
Patient History and Physical Findings3
Prenatal history is often unremarkable. However, oligohydramnios may be present.
Physical examination
A wrinkled abdomen with more laxity noted in the medial and inferior regions. This is a distinctive feature of prune belly. There will be redundant skin over the abdomen.
FIG 1 • This demonstrates the laxity in the abdominal wall of prune belly.
As the children age, the abdomen will look more protuberant and less wrinkled.
If portions of the urinary system are massively dilated, these can sometimes be palpated on abdominal exam.4
Scrotal exam will reveal bilateral absence of testes in the majority of cases.
Cardiac anomalies can be associated with prune belly; a cardiopulmonary exam should be included to listen for murmurs.
Close monitoring of urine output is important to identify any obstructive uropathy that may be present. If present, nephrostomy tubes can be considered for urinary decompression.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Prenatal ultrasound
Hydroureteronephrosis, bladder distension, oligohydramnios, and cryptorchidism can be seen on prenatal ultrasound.5
Postnatal urinary tract evaluation
Serum creatinine measurements
This will identify any worsening renal function.
Baseline measurements should be obtained at birth and trended to determine changes in function, creatinine greater than 0.7 mg/dL has a higher rate of developing renal failure.6
Kidney Ureter Bladder radiograph (KUB):
Evaluation of the bowel for dilatation can be done using a KUB. Bowel will extend over the lateral edge of the abdominal wall, which is diagnostic of prune belly.
Due to the lack of abdominal wall structure, intestinal malrotation can occur due to poor fixation to the abdominal wall.4
Renal and bladder ultrasound4:
An ultrasound will demonstrate atresia or absent kidney, hydronephrosis, megaureter, tortuous ureters, or megabladder.7Related posts:
