|Classification and external resources|
Bladder exstrophy (also known as Ectopia vesicae) is a congenital anomaly in which part of the urinary bladder is present outside the body. It is rare, occurring once every 10,000 to 50,000 live births with a 2:1 male:female ratio. The diagnosis involves a spectrum of anomalies of the lower abdominal wall, bladder, anterior bony pelvis, and external genitalia. It occurs due to failure of the abdominal wall to close during fetal development and results in protrusion of the anterior bladder wall through the lower abdominal wall.
Treatment is with surgical correction of the defect, but patients can still have long term issues with urinary tract infections and urinary incontinence.
The cause of bladder exstrophy is maldevelopment of the lower abdominal wall, leading to a rupture which causes the bladder to communicate with the amniotic fluid.
Recently, Cheng et al. proposed possible genetic factor in the pathogenesis of bladder exstrophy. Based on their knock-out mouse model, the group screened bladder exstrophy patients' DNA and found that abnormality of the gene P63 may be involved in the pathogenesis of bladder exstrophy.
DeltaNp63 plays an anti-apoptotic role in ventral bladder development.Cheng W, et al. Development. 2006
Insertion/deletion polymorphisms in the ΔNp63 promoter are a risk factor for bladder exstrophy epispadias complex.Wilkins S, Zhang KW, Mahfuz I, Quantin R, D'Cruz N, Hutson J, Ee M, Bagli D, Aitken K, Fong FN, Ng PK, Tsui SK, Fung WY, Banu T, Thakre A, Johar K, Jaureguizar E, Li L, Cheng W.PLoS Genet. 2012;8(12)
New insights into the pathogenesis of bladder exstrophy-epispadias complex.Mahfuz I, Darling T, Wilkins S, White S, Cheng W.J Pediatr Urol. 2013 Jun 3. pii: S1477-5131(13)00111-3.
Spectrum of anomalies
The typical manifestation of exstrophy-epispadias complex is
- bladder everted through a midline lower abdominal wall defect
- widening of the pubic symphysis
- epispadias in males (dorsal cleft in the penis, exposing the urethral mucosa)
- the anus and vagina appear anteriorly displaced
- the testicles may be undescended.
- bifid clitoris in females, with a short "urethral strip" indistinguishable from bladder mucosa.
Prenatal diagnosis of bladder exstrophy is difficult and sometimes impossible. Feature on prenatal ultrasound can include the absence of bladder filling, a low-set umbilicus, widening of the pubic ramus, small external genitalia and a lower abdominal mass. It can be found if the Sonographer cannot identify a normal bladder filling and emptying, despite adequate time spent looking. Most often the diagnosis is made after birth with the finding of an exposed bladder.
Evaluation and Management at Birth
At birth, the bladder mucosa is exposed and is quite sensitive. The umbilical cord should be tied with a 2-0 silk suture rather than a clamp to prevent trauma to the delicate mucosa. In addition, the bladder should be covered with a non-adherent film (Plastic Wrap) to prevent sticking of the bladder to diapers or clothing. With each diaper change the plastic wrap should be removed and the bladder irrigated with sterile saline and a clean wrap should be placed. The child should then be transferred to a tertiary care pediatric hospital for management of their bladder exstrophy.
Modern therapy is aimed at surgical reconstruction of the bladder and genitalia, most often through a staged approach. The initial surgical management consists of bladder, posterior urethral and abdominal wall closure (with or without osteotomies). Bladder closure may be delayed if the bladder is deemed too small to close. The surgical management epispadius usually occurs at approximately 6–12 months of age. Reconstruction of the bladder neck is typically done at toilet training age (approximately age 4-5), once the child is able to and interested in participating in a bladder retraining program. In very carefully selected patients surgical management may be carried out in a single stage or in combined procedures.
Even with successful surgery, patients may have long-term problems with
- urinary reflux (see Vesicoureteral reflux)
- repeated urinary tract infections
- bladder adenocarcinoma
- colonic adenocarcinoma
- uterine prolapse
Sexual function and libido are normal in exstrophy patients. Successful pregnancies and delivery in exstrophy patients have been reported.
- Gearhart et al., 1995a. Gearhart JP, Ben-Chaim J, Jeffs RD, et al.: Criteria for the prenatal diagnosis of classic bladder exstrophy. Obstet Gynecol 1995; 85:961.
- Gearhart and Jeffs, 2007. Gearhart JP, Jeffs RD: The bladder exstrophy-epispadias complex. In: Walsh PC, et al. ed. Campbell's Urology, 9th ed.. Philadelphia: WB Saunders; 2007; Chapter 119.
- Exstrophy of the Bladder - The Children's Hospita of Philadelphia
- Bladder exstrophy page at Children's Hospital Boston
- http://www.bladderexstrophy.com/patient_support.htm#Canada. Bladder exstrophy support groups by region