Fetal posterior urethral valve syndrome: a prospective application of antenatal prognostic criteria.

A case of posterior urethral valve syndrome is presented. Four weeks after a normal 24-week ultrasound examination, diminished amniotic fluid, megacystis, and renal hyperechogenicity were observed. A repeat ultrasound examination at 30 weeks' gestation identified oligohydramnios and increased renal echogenicity. These findings prompted the performance of a percutaneous cystocentesis to assess fetal renal function indirectly. The specimen was evaluated for osmolality and sodium and chloride concentrations. The urine electrolyte concentrations (sodium 115 mEq/L; chloride 93 mEq/L) and the osmolality (230 mOsm/L) were elevated, suggesting impaired renal function and a poor prognosis. Despite these findings, aggressive management was used, including administration of antenatal corticosteroids and elective preterm delivery. A percutaneous cystocentesis was required during the infant's initial resuscitation, followed by a difficult urethral catheterization. Ultimately, a vesicostomy performed on day 4 of life was associated with prompt return of renal function (serum creatinine 0.7 mg/dL at the time of discharge). At 6 months of age, normal renal function has been documented and the vesicostomy has been closed. This case demonstrates the potential limitations of available prognostic criteria in evaluating fetal urinary obstruction and residual renal function. In selected cases (when the onset of obstruction is documented in the third trimester), refinement of these prognostic criteria may be indicated. Similar cases may be best managed by preterm delivery and prompt postnatal decompression.

Duke Scholars

Author Wesley A. Cook Jr. Neurosurgery