Which of the following is not present at the presentation of a child with bladder exstrophy?
A. Umbilicus adjacent to bladder plateAnswer D
The abnormalities seen in bladder exstrophy represent a failure of development of the lower abdominal wall; possibly because of the failure of mesoderm to migrate into the cloacal membrane. In classic bladder exstrophy the abnormalities seen all follow from this failure. The bladder lies open and exposed as a bladder plate. The umbilicus lies immediately adjacent to the bladder plate. When the bladder plate is mobilised for closure the umbilicus becomes ischaemic and is subsequently lost. The ureters do not enter the bladder obliquely and there is an increased tendency to subsequent vesicoureteric reflux. There is diastasis of the pubic rami, (i.e., they fail to meet in the midline). The lower abdominal wall demonstrates a series of characteristic features: the rectus muscle divaricates inferiorly, the umbilicus is sited rather low, and the perineum is foreshortened resulting in a slightly anterior anus. The separated pubic rami result in the bony attachments of the corpora cavernosa being widely separated. This contributes to a rather short and wide penis in boys, and a bifid clitoris in girls. In contrast to cloacal exstrophy, there tend not to be other associated anomalies in classic bladder exstrophy, (i.e., there is no increased association with developmental problems, cardiac or spinal disease).
Although bladder exstrophy is a devastating anomaly of the lower urinary tract, the upper urinary tract is not usually affected at presentation. Closure of the abdominal wall and bladder are difficult. To achieve urinary continence, some mechanism to control the bladder outlet needs to be surgically created, as well as ensuring that the bladder has adequate storage. One of the most common ways of controlling the bladder outlet is to create a fixed resistance that then has to be overcome during voiding. Care of these complex patients is performed in specialist centres where the goal of urinary continence is perused without jeopardising the upper tracts.