Direct lower abdominal ureteral jet as sonographic sign of bladder exstrophy

Bladder exstrophy is a rare malformation characterized by an infra-umbilical abdominal wall defect, incomplete closure of the bladder with mucosa continuous with the abdominal wall, epispadias and alterations in the pelvic bones. Its incidence is low at 1 in 20 000–50 000 live births. It is diagnosed easily at birth but rarely in utero. Previous reports have identified four prenatal sonographic findings associated with bladder exstrophy: (1) the bladder is not visualized on ultrasound; (2) presence of a lower abdominal bulge representing the exstrophied bladder; (3) a small penis with anteriorly displaced scrotum; and (4) short umbilical cord insertion-to-genital tubercle length1-4. In this report, we suggest a novel auxiliary sign for the diagnosis of bladder exstrophy using power Doppler ultrasound. In the normal fetus, the ureters arise from the pelvis of each kidney and enter the bladder posteriorly on the left and right sides. A urine jet from the ureters into the bladder can often be seen by ultrasound. In cases of bladder exstrophy, the posterior urinary bladder wall is continuous with the abdominal wall and urine from the ureters passes directly into the amniotic sac. We hypothesized that, since the urine production and ureteral function in cases of bladder exstrophy are normal, visualization of urine jets directly into the amniotic cavity would be diagnostic. Using power Doppler ultrasound (Philips iU 22; 3–9-MHz transvaginal probe; CPA, 77%; MED, 1500 Hz; WF, 90 Hz; 3–6-MHz transabdominal probe; CPA, 77%; MED, 1500 Hz, WF, 90 Hz), we were indeed able to observe a urine jet coursing from the abdominal wall into the amniotic cavity, confirming the presence of bladder exstrophy. During a 5-year study period, we diagnosed bladder exstrophy in four fetuses (three at 15 weeks and one at 23 weeks). In these cases, the bladder was not visualized in the presence of normal kidneys, there was no lower abdominal bulge and cord insertion was slightly lower in the abdomen. In all four cases, the urine jet was seen flowing from the ureters directly into the amniotic cavity using color Doppler ultrasound (Figures 1a and 2, Videoclips S1–S3). In all cases the pregnancy was terminated on parental request and the autopsies confirmed the diagnosis of bladder exstrophy (Figure 1b). Our findings suggest that visualization of ureteral urine jets from the lower fetal abdomen is a useful sonographic sign for bladder exstrophy and should be included in the investigation when this anomaly is suspected. Moreover, inclusion of this sign in the differential diagnosis may shorten the examination by avoiding time spent waiting for possible bladder filling and the need for serial targeted ultrasound to establish the diagnosis5. M. Bronshtein†‡, Y. Gilboa§, A. Gover¶ and R. Beloosesky*† †Department of Obstetrics and Gynecology, Rambam Medical Center, Ha'alya Ha'Shnya 8, Haifa, Israel; ‡Social Welfare & Health Sciences, University of Haifa, Haifa, Israel; §Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, Tel Hashomer, Ramat-Gan, Israel; ¶Neonatal Intensive Care Unit, Lady Davis Carmel Medical Center, Haifa, Israel *Correspondence. (e-mail: ronbel3@gmail.com) Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.