T H E J O U R N A L OF

PEDIATRICS SEPTEMBER

1992

Volume 121

Number 3

MEDICAL PROGRESS Diagnosis and treatment of fetal urinary tract abnormalities R i c h a r d N. Fine, MD From the Department of Pediatrics, State University of New York at Stony Brook

In 1970 Garrett et al. 1 reported the initial case of polycystic kidney disease documented by fetal ultrasonography. Obstructive uropathy in a fetus was subsequently described by Garrett et al. 2 in 1975. This ability to detect intrauterine urinary tract abnormalities by fetal ultrasonography led to increasing use of this method. In 1981 Harrison et al. 3 reviewed the outcome of urinary tract malformations detected by obstetric ultrasonography in 13 fetuses and proposed that the fetus with hydronephrosis may benefit from decompression performed after early delivery or by intrauterine surgical intervention. The proposal was based on the premise that unrelieved urinary tract obstruction interferes with normal fetal development of the kidney and that theseverity of the renal damage depends on the degree and duration of obstruction. After the report by Harrison et al. 4 of the successful decompression of the urinary tract of a 21-week-old fetus with severe hydronephrosis by bilateral cutaneous ureterostomies performed after a hysterotomy, there was anticipation that intrauterine surgery would minimize the potential renal dysplasia and pulmonary hypoplasia associated with fetal urinary tract malformations. However, despite the success of the surgical procedure, the infant died of pulmonary

Reprintrequests: Richard N. Fine, MD, Professor and Chairman, Department of Pediatrics, State University of New York at Stony Brook, Stony Brook, NY 11794-8111. 9/18/37880

hypoplasia within 24 hours of birth. At autopsy the kidneys showed cystic dysplasia. Between 1982 and 1985, a total of 73 placements of catheter shunts for fetal obstructive uropathy (unilateral and bilateral hydronephrosis) were reported to the International Fetal Surgery RegistryS; 30 (41%) of the fetuses survived. The oldest living patient was 5 years of age and reported to be developing normally. Fourteen stillbirths resulted from elective abortions, and there were 29 neonatal deaths, 27 of which were related to pulmonary hypoplasia. The authors of the report suggested that the data be I

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viewed with cautious optimism, that the stage of early technical development had passed, and that it was time for prospective controlled studies to determine definitively the value of intrauterine intervention in the fetus with obstructive uropathy. 5 A decade has passed since Harrison et al. 3 proposed that early decompression would benefit the fetus with hydronephrosis. The purpose of this review is to delineate the current status of the diagnosis and treatment of fetal urinary tract abnormalities. SPECIFIC INDICATIONS FOR FETAL ULTRASONOGRAPHY TO DETECT RENAL ABNORMALITIES The presence of oligohydramnios, an elevated c~-fetoprotein concentration in maternal serum, a small fetus by clin-

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ical examination, or a family history of renal disease are all specific indications to perform fetal ultrasonography. Fetal urine contributes significantly to the amount of amniotic fluid beginning at the second trimester; the presence of oligohydramnios indicates either a substantial diminution in fetal urine production or obstruction of the flow of fetal urine. Elevation of a-fetoprotein in maternal serum has been associated with renal agenesis, congenital nephrotic syndrome, and obstructive uropathy. 6 In a study by Reuss et al. 7 of 141 pregnant women with a family history of hereditary renal disease, 11 (7.8%) had a fetus with an abnormality detected by renal ultrasonography. These incidence data, compared with those individuals without a family history of renal disease of