cloacal exstrophy

Cloacal exstrophy is a rare malformation which includes phallic separation with epispadias, pubic diastasis, bladder exstrophy, and cloacal exstrophy.

Cloacal exstrophy is a feature of the OEIS (omphalocele-exstrophy-imperforate anus-spinal defects) complex (MIM.258040). In this complex, exstrophy of the cloaca includes the persistence and exstrophy of a common cloaca that receives ureters, ileum, and a rudimentary hindgut and is associated with failure of fusion of the genital tubercles and pubic rami, incomplete development of the lumbosacral vertebrae with spinal dysraphism, imperforate anus, cryptorchidism and epispadias in males and anomalies of the mullerian duct derivatives in females, and a wide range of urinary tract anomalies. Omphalocele is common, and most patients have a single umbilical artery.

Synopsis

 large infraumbilical, anterior midline defect
 protruding large omphalocele
 bladder agenesis
 narrow thorax
 fetal bowel floating in a large amount of ascites within the omphalocele sac
 olyhydramnios

Associations

 distorted spine (7651659)
 spinal dysraphism (15300529)
 sacral meningomyelocele (7651659)
 bilateral clubfeet (7651659)

 OEIS complex (O = omphalocele, E = bladder exstrophy, I = imperforate anus, S = spinal defects)
 association: cloacal exstrophy, exomphalos, renal agenesis, ambiguous external genitalia, axial hypotonia withg 9q34.1-qter deletion (15054847)

Differential diagnosis

 midline anterior abdominal wall defects

• gastroschisis
• amniotic band syndrome
• limb-body wall complex (body-stalk syndrome).

Etiology

 unknown

• single defect of early blastogenesis ?
• defect of mesodermal migration during the primitive streak period ?

Epidemiology

Exstrophy of the cloaca sequence occurs approximately 1 in 200’000 to 400’000 births (1). Both sexes are affected with a male to female ratio of 2.5:1.

Physiopathology

Embryogenesis of exstrophy of the cloaca sequence is still unclear. The primary defect is thought to be in the development of early mesoderm which will later contribute to the infraumbilical mesenchyme, cloacal septum and caudal vertebra. This results in
 (a) failure of cloacal septation, with persistence of a common cloaca;
 (b) complete breakdown of the cloacal membrane with the exstrophy of the cloaca, failure of fusion of genital tubercles and pubic rami, and often in the formation of an omphalocele;
 (c) incomplete development of lumbosacral vertebrae with herniation of a grossly dilated central canal of the spinal cord.

The exstrophied bowel is usually the ileocecal region with little or no large bowel distally.

Associations

 cryptorchidism
 urinary tract anomalies

• pelvic kidneys

 large ovarian cysts (9607477)

Prognosis - Management

Excellent survival with surgical repair is possible. Genetic females do not raise a problem as they will be raised as females. Gender assignment is one of the difficult tasks in the management of newborns with cloacal exstrophy.

In genotypic males with exstrophy of cloaca sequence, the phallic size is usually small and reconstruction of an adequate penis is nearly impossible. Testes are usually undescended and abnormal. Males with unilateral or bilateral phallic structures should be raised as males. There is general consensus that in genetic males with insufficient phallus reassignment as phenotypic females with early orchidectomy to minimize testosterone imprinting on central nervous system should be considered.

Surgical management of babies born with cloacal extrophy sequence has progressed over the years and reasonably good outcome is being reported in the literature. Interestingly the reported case is doing well even though he has marked tonsillar herniation.

A fiel developemental defect

However, Bladder exstrophy and cloacal exstrophy seem to be distinct clinical entities. Exstrophy of the cloaca includes the persistence and exstrophy of a common cloaca that receives ureters, ileum, and a rudimentary hindgut, and is associated with failure of fusion of the genital tubercles and pubic rami, incomplete development of the lumbosacral vertebrae with spinal dysraphism, imperforate anus, cryptorchidism and epispadias in males and anomalies of the mullerian duct derivatives in females, and a wide range of urinary tract anomalies.

See also

 Malformations

References

 Matta H, Hemes A, Nawaz A, Jacobz A, Shawis R N, Salem AHA. An unusual variant of Cloacal exstrophy. Annals of Saudi Medicine 2002;22:204-205 (no abstract available)

 Lund DP, Hendren WH.Cloacal exstrophy: a 25-year experience with 50 cases. J Pediatr Surg. 2001 Jan;36(1):68-75. PMID: 11150440

 Lund DP, Hendren WH. Cloacal exstrophy: experience with 20 cases. J Pediatr Surg 1993;28:1360-9

 Bruch SW, Adzick NS, Goldstein RB, Harrison MR. Challenging the embryogenesis of cloacal exstrophy. J Pediatr Surg. 1996 Jun;31(6):768-70. PMID: 8783098