Bladder exstrophy – CT

Case Report– 16 years male presents for CECT abdomen&  pelvis with swelling in lower abdomen & difficulty in passing urine since very long time. No past surgical history.

CT findings –

-     Marked widening of the symphysis pubis with absence of normal urinary bladder.

-     Focal defect seen in anterior abdominal wall near midline in suprapubic region with small protrusion of pelvic mesentry into it leading to external bulge in the abdominal wall with overlying thickening of the soft tissue planes.

-     Normal kidneys & bilateral upper 2/3 of ureters in location, contour, size & enhancement without any hydronephrosis. Delayed phase shows normal contrast excretion in both kidneys & ureters. Distal 1/3 of both ureters show mild dilatation with acute anteromedial course in lateral  pelvis reaching upto the abdominal wall defect in suprapubic region with further short segment of severe narrowing of caliber of ureters coursing anteriorly near midline upto the superior margin of base of penis simulating epispadias.  Penile shaft is blunted & smaller in size. Scrotum is unremarkable.

Findings are suggestive of urinary bladder exstrophy with epispadias.

DISCUSSION BY DR MGK MURTHY & DR GA PRASAD

Bladder exstrophy is a rare congenital birth defect  occurring about 3 in 100, 000 births with males to female ratio of 3:1 & includes  malformation of the bladder and urethra in which the bladder is turned inside out, flattened and exposed to  outside the body & bladder neck fails to form.

The condition is caused by incomplete development of the infra- umbilical part of the anterior abdominal wall, associated with incomplete development of the anterior wall of the bladder owing to delayed rupture of the cloacal membrane. Persistence of the cloacal membrane prevents medial mesenchymal ingrowth, causing the abdominal wall to remain lateral and the posterior bladder wall to be exposed to the external surface . Trigone of the bladder and ureteral openings are exposed and sometimes there is mild prolapse.

The pubic symphysis is widened  with diastasis of rectus abdominis. Umbilicus is low set. In males the penis is short, stubby, curved upwards and is drawn into the exstrophic area. Unilateral or bilateral cryptorchidism  or Inguinal hernia may be present . In females, the urethra is short, often buried in the exstrophied bladder. The clitoris tends to be bifid. The labia are also widely separated. The vagina is short and orifice may be stenotic. Uterine prolapse or unicornuate uterus may be present Anus is anteriorly placed.

Antenatal USG findings of exstrophy - epispadias complex include –

-     Repeated failure to visualize the bladder.

-     Lower anterior abdominal wall mass.

-     Low set umbilicus with omphalocoele.

-     Abnormal genitalia.

-     Increased pelvic diameter.

-      Associated renal anomalies, myelomeningocoele and limb anomalies, which are more common in cloacal exstrophy.

Surgical steps include closing the bony pelvic ring & bladder / posterior urethra and / anterior abdominal wall defect and reconstruct the genitalia. Osteotomy of both iliac bones just lateral to SI joints. Later reconstruction of bladder neck and sphincter is done. Another option is urinary diversion if continence is poor following bladder reconstruction. This can be done by ureterosigmoid anastomosis or formation of ileal conduit, colonic conduit or continent urinary diversion.