Address correspondence to Carlo A. Dell"Agnola, MD, University of Milan - Italy, Dept. of Pediatric Surgery - Istituti Clinici di Perfezionamento, Via Petrarca 18, 20123 - Milano, Italy; Ph: 39-2-4800-2063; Fax: 39-2-5830-9597; ¶ Dept. of Urology - Ospedale S.Gerardo-Monza, ºDept. of Ob-Gyn, Ospedale S.Paolo
Synonyms: None.
Definition: Obstruction of the urinary tract at the junction of the renal pelvis and the ureter.
Prevalence: Unknown. M5:F1 in cases diagnosed postnatally.
Etiology: Sporadic, but familial cases have been reported.
Pathogenesis: In most cases, ureteropelvic junction obstruction seems to be of functional nature. Abnormalities in the development of the innervation of the muscularis of the ureter seem to play an important role in the pathogenesis of ureteropelvic junction obstruction.
Associated anomalies: Extraurinary anomalies in up to 19% of cases and include: Hirschsprung"s disease, cardiovascular abnormalities, neural tube defects, sagittal synostosis, mandibular hypoplasia, esophageal atresia and distal fistula, imperforate anus, syndactiyly.
Differential diagnosis: Includes multicystic dysplastic kidneys and perinephric urinoma secondary to rupture of the severely dilated renal pelvis.
Prognosis: Good.
Management: Unilateral ureteropelvic junction obstruction should not alter standard obstetrical management as long as the contralateral kidney looks normal. Management of bilateral ureteropelvic junction obstruction depends upon the gestational age, amount of amniotic fluid and functional renal reserve provided by chemical analysis of a fetal urine sample. Associated anomalies should always be searched for and rapid fetal karyotyping is indicated.
MESH Ureteral obstruction ICD9 753.2 CDC 753.210
Introduction
Invasive procedures or fetal surgery to drain obstructed urinary tract appear as an attractive extension of prenatal diagnosis but mixed results may decrease the value of these prenatal interventions1. Even a less invasive procedure such as fetal urine sampling for the evaluation of renal function may be questionable, and the predictive value of urine testing is controversial2. Moreover, a high incidence of maternal and fetal complications has been reported after these procedures3 (Table 1). Major neonatal complications related to prenatal procedures can also occur. The following case illustrates limits and possible complications that must be taken into account by the obstetrician planning invasive intervention on fetal uropathy.
Table 1: Complications of fetal intervention3
g shunt migration
|
g poor drainage
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g onset of labor within 48 hours
|
g urinary ascites
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g chorioamnionitis
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g extrusion of shunt into peritoneal cavity
|
g amniotic fluid leak
|
g perforated jejunum
|
g placental hemorrhage
|
g periureteral scarring
|
Case report
Prenatal management
A 25-year-old white woman G1P0 was referred to our Perinatal Unit after a routine ultrasound scan raised the suspicion of unilateral obstructive uropathy at 32 weeks. On our ultrasound examination, the diagnosis of renal cyst (41 x 46 mm) and severe hydronephrosis was made (fig. 1).