Prune Belly Syndrome (Early urethral obstruction sequence)


Severe obstruction is fatal in fetal life unless the urinary bladder is decompressed. This can occur in utero though rupture. In some centers, prenatal decompression of the bladder by vesicoamniotic shunt placement, which also increases amniotic fluid volume to promote lung development, has been attempted. Infants who are born alive frequently have renal damage, although the abdominal musculature usually develops postnatally.

Prognosis correlates with extent of renal dysplasia. Severe dysplasia associated with maternal oligohydraminios and pulmonary hypoplasia results in perinatal demise in 20% of cases.

Chronic amniotic fluid leakage and renal agenesis result in the oligohydramnios sequence, which causes pulmonary hypoplasia and fetal compression. However, prune belly is not an associated feature because the bladder is not distended. Extrophy of the bladder refers to exposure of the bladder due to failure of the infra-umbilical mesoderm to invade the cloacal membrane. Polycystic kidneys do not cause an obstructive uropathy, although in some cases they are associated with oligohydramnios.

CHLA Board Review 2005
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