Prenatally Detected Genito-Urinary Abnormalities

With the increasing use of ultrasonography to monitor the progress of a pregnancy, urinary abnormalities are now detected in many cases prior to birth. Many of these abnormalities would otherwise be undetected until the child presented later in life with some problem. Although prenatal (antenatal) sonography can detect multiple abnormalities, accurate diagnosis is only possible in a few types of disorders. In the majority of cases the abnormalities can be followed through the pregnancy and diagnostic evaluation commences shortly after birth.

Prenatal Evaluation: they types of genito-urinary problems that can be seen on obstetric sonograms are:

• ureteral reflux

• urinary obstructions

• cystic abnormalities of the kidney

• genital abnormalities

  Repeat sonograms at regular intervals are all that is usually needed to monitor the abnormalities for change. In addition, the volume of amniotic fluid and presence of other fetal anomalies are assessed. Specific rare problems are occasionally detected very early in the pregnancy and these may require fetal intervention, such as: severe urinary obstructions with decreased or not amniotic fluid detected before 33 weeks gestation. In these rare cases, fetal testing of the amniotic fluid or bladder urine may be helpful in determining if treatment before birth is necessary. About one third of all prenatally detected problems turn out to have no true pathology.

Postnatal Evaluation: The postnatal evaluation begins in the hospital within 24 to 48 hours after birth. The pediatric urologist should be contacted prior to birth if possible to counsel the family and coordinate the workup, or, at the latest, by 24 hours after birth. If the infant is able to urinate within the first 24 hours, a blood test to evaluate kidney function and a kidney and bladder ultrasound is done at 48 hours. A sonogram performed earlier may miss swelling of the kidney due to dehydration of newborns. Some infants may require other diagnostic tests prior to going home, while most will be followed in four to six weeks as outpatients. The usual adjunctive tests are a voiding cystourethrogram (VCUG) and/or a nuclear renogram (DPTA, DMSA, MAG-III) If the infant has not urinated within 24 hours, the workup may be moved up a day and a catheter will frequently be placed.

The goals of the evaluation are:

• preservation of kidney function

• prevention of urinary infection

• diagnosis and treatment of urinary obstruction or vesico-ureteral reflux (an abnormality that causes urine from the bladder to go back up to the kidney).