Bladder Exstrophy

Classic exstrophy of the urinary bladder occurs in about 1/35,000-40,000 births. The male:female ratio is 2 : 1. The severity ranges from simple epispadias (in boys) to complete exstrophy of the cloaca involving exposure of the entire hindgut and the bladder (termed cloacal exstrophy).

Clinical Manifestations

Anomalies of the bladder are hypothesized to result when the mesoderm fails to invade the cephalad extension of the cloacal membrane; the extent of this failure determines the degree of the anomaly. In classic bladder exstrophy (Fig. 535-1), the bladder protrudes from the abdominal wall and its mucosa is exposed. The umbilicus is displaced downward, the pubic rami are widely separated in the midline, and the rectus muscles are separated. In boys, there is complete epispadias with dorsal chordee, and the overall penile length is approximately half that of unaffected boys. The scrotum typically is separated slightly from the penis and is wide and shallow. Undescended testes and inguinal hernias are common. Girls also have epispadias, with separation of the two halves of the clitoris and wide separation of the labia. The anus is displaced anteriorly in both sexes, and there may be rectal prolapse. The pubic rami are widely separated. Persons with exstrophy tend to be shorter than normal.

Figure 535-1 Classic bladder exstrophy in a newborn boy. The bladder is exposed in the midline, the umbilical cord is displaced caudad, the penis is epispadiac, and the scrotum is broad.

The consequences of untreated bladder exstrophy are total urinary incontinence and an increased incidence of bladder cancer, usually adenocarcinoma. The genital deformities can produce sexual disability in both sexes, particularly in males. The wide separation of the pubic rami causes a characteristic broad-based gait but no significant disability. In classic bladder exstrophy, the upper urinary tracts usually are normal.

Other Exstrophy Anomalies

Children with more complex cases of cloacal exstrophy, which has an incidence of 1/400,000, have an omphalocele and severe abnormalities of the colon and the rectum and often have short bowel syndrome, the most devastating anomaly managed by pediatric urologists. Approximately 50% of patients have an upper urinary tract anomaly, and 50% have spina bifida. Children with cloacal exstrophy do not achieve normal urine or stool continence. Reconstructive techniques result in a satisfactory outcome in most patients with permanent urinary diversion (either ileal conduit or continent urinary diversion) and a colostomy. Because the penis in boys with cloacal exstrophy usually is diminutive, genital reconstruction in boys with cloacal exstrophy has been unsatisfactory. Previously, most specialists recommended assigning a female gender to such infants, but currently there is debate whether these children, who have a 46,XY karyotype and androgen imprinting in utero, can have a satisfactory female gender identity. Many assume male gender characteristics by adolescence. Decisions regarding gender assignment should be made jointly by the physicians caring for the infant (surgical team, pediatric endocrinologist, child psychiatrist, and ethicist) and family.

Epispadias is in the spectrum of exstrophy anomalies, affecting approximately 1/117,000 boys and 1/480,000 girls. In boys, the diagnosis is obvious because the prepuce is distributed primarily on the ventral aspect of the penile shaft and the urethral meatus is on the dorsum of the penis. Distal epispadias in boys usually is associated with normal urinary control and normal upper urinary tracts and should be repaired by 6-12 mo of age. In girls, the clitoris is bifid and the urethra is split dorsally (Fig. 535-2). In more severely affected boys and in all girls with epispadias, there is total urinary incontinence because the sphincter is incompletely formed, and there is wide separation of the pubic rami. These children require surgical reconstruction of the bladder neck, similar to the final management stage in children with classic bladder exstrophy.

Figure 535-2 Girl with complete epispadias.

(From Gearhart JP, Rink RC, Mouriquand PDE, editors: Pediatric urology, ed 2, Philadelphia, 2010, Saunders.)

Bladder Diverticula

Bladder diverticula develop as herniations of bladder mucosa between defects of bladder smooth muscle fibers. Primary bladder diverticula usually develop at the ureterovesical junction and may be associated with vesicoureteral reflux, because the diverticulum interferes with the normal flap-valve attachment between the ureter and bladder. In rare circumstances the diverticulum is so large that it interferes with normal micturition by obstructing the bladder neck. Bladder diverticula also commonly are associated with distal urethral obstruction such as posterior urethral valves or neurogenic bladder dysfunction. They occur commonly in children with connective tissue disorders including Williams syndrome, Ehlers-Danlos syndrome, and Menkes syndrome (Fig. 535-3). Small diverticula require no treatment other than that of the primary disease, whereas large diverticula can contribute to inefficient voiding, residual urine, urinary stasis, and urinary tract infections and should be excised.

Figure 535-3 Girl with Menkes syndrome with multiple large bladder diverticula causing inability to void and recurrent urinary tract infections. The condition was managed by bladder diverticulectomy.

Urachal Anomalies

The urachus is an embryologic canal connecting the dome of the fetal bladder with the allantois, a structure that contributes to the formation of the umbilical cord. The lumen of the urachus is normally obliterated during embryonic development, transforming the urachus into a solid cord. Urachal abnormalities are more common in boys than in girls. A patent urachus can occur as an isolated anomaly; it may be associated with prune-belly syndrome or posterior urethral valves (Chapter 534). In this condition there is continuous urinary drainage from the umbilicus. The tract should be excised. Another urachal anomaly is the urachal cyst, which can become infected. Typical symptoms and physical findings include suprapubic pain, fever, irritative voiding symptoms, and an infraumbilical mass, which can be erythematous. Diagnosis is made by ultrasonography or CT (Fig. 535-4). Treatment is intravenous antibiotic therapy and drainage and excision. Other urachal anomalies include the vesicourachal diverticulum, which is a diverticulum of the bladder dome, and umbilical-urachal sinus, which is a blind external sinus that opens at the umbilicus. These lesions should be excised.

Figure 535-4 CT scan demonstrating infected urachal abscess in an 8 yr old girl. The condition was managed by drainage and excision.