Bladder distention and pyelectasis in the male fetus: causes, comparisons, and contrasts.

Abstract

The objective of this paper was to determine if prenatal sonographic findings can accurately differentiate between the causes of bladder distention and pyelectasis in the male fetus. Twenty‐one cases were evaluated for the presence of oligohydramnios, posterior urethral dilation, bladder wall thickening, urachal patency, cortical thinning, cortical cysts, and increased renal echogenicity. Postnatal diagnosis included posterior urethral valves (10 cases), prune belly syndrome (four cases), vesicoureteral reflux (four cases), left ureterovesical junction obstruction (one case), and nonrefluxing, nonobstructive megacystis‐megaureter (two cases). Oligohydramnios was present in eight of 10 cases of posterior urethral valves and in one of four cases of prune belly syndrome. A dilated posterior urethra was noted in seven of 10 cases of posterior urethral valves and transiently in two of four cases of prune belly syndrome. Bladder wall thickening developed in all cases of posterior urethral valves and was noted in two of four patients with prune belly syndrome. A patent urachus likewise was identified in two of four cases of prune belly syndrome. The presence of oligohydramnios, progressive bladder wall thickening, and dilated posterior urethra was most suggestive of posterior urethral valves, whereas the presence of a patent urachus was most suggestive of prune belly syndrome. The presence of pyelectasis and megacystis without additional amniotic fluid, bladder, urethral, or renal abnormalities was most suggestive of vesicoureteral reflux, ureterovesical junction obstruction, or nonrefluxing, nonobstructive megacystis‐megaureter. Owing to the overlap and evolution of these findings, close follow‐up evaluation is recommended.

Predictive Factors of Fetal Urethral Obstruction: A Multivariate Analysis

“…The authors documented that the simultaneous presence of oligohydramnios and increased renal echogenicity was highly predictive of infravesical obstruction with 100% sensitivity and 93% specificity. Montemarano et al [9] reported as most suggestive of PUV the presence of oligohydramnios, progressive bladder thickening and a dilated posterior urethra. Nevertheless, the data obtained in all of these studies were submitted to univariate analyses that did not evaluate the combined effects of two or more factors.…”

“…Dilatation was considered to be present if the maximum anteroposterior diameter of the fetal renal pelvis was 65 mm. Bladder distention (megacystis) was defined as an abnormally large appearing bladder with failure of the bladder to empty over a period of time greater than 45 min [9]. Oligohydramnios was determined on the basis of the amniotic fluid index [11,12].…”

“…Nevertheless, the combination of these findings in the fetus can result from other pathological processes, including megacystismegaureter syndrome, prune-belly syndrome and bladder neck obstruction due to ectopic ureterocele [7]. Previous studies have shown that some findings may represent increased sensitivity of sonography to predicting PUV [7][8][9].…”

Síndrome de abdomen en ciruela pasa y dextrocardia, asociación infrecuente

“…Montemarano (13), describe dilatación de la uretra posterior en dos de 4 casos de síndrome de Prune belly, observadas con ecografías obstétricas a las 16 y 19 semanas de gestación respectivamente. Osborne y col (14), describen que la dilatación de las vías urinarias resulta de la obstrucción a diferentes niveles, pero se dan casos de dilatación sin evidencia de obstrucción.…”

Congenital urinary tract obstruction

“…In the second and third trimester, the obstruction at the level of bladder neck Previous studies found this ultrasonographic sign very specific to LUTO especially in a fetus with posterior urethral valves (23,24). However, a retrospective study showed that it was only present in 51.6% of fetus with proven posterior urethral valve and could be seen in 34.8% of other non-obstructive pathologies including vesicoureteric reflux and primary megaureter (25).…”