Cloacal exstrophy is a rare congenital malformation result- ing in exstrophy of the urinary, intestinal and genital systems and is associated with anomalies of other organ systems. The term OEIS complex (omphalocele, exstrophy of the bladder, imperforate anus, and spinal defects) are used to describe the spectrum of malformations in cloacal exstrophy. The incidence of cloacal exstrophy is estimated to be 1/200,000–1/400,000 live births.
GENETICS/BASIC DEFECTS
1. Genetics
a. Recurrence of OEIS complex in siblings can be explained by the following mechanisms:
i. Autosomal recessive inheritance ii. Multifactorial determination
iii. Gonadal mosaicism for a dominant mutation iv. Environmental factors
v. Subclinical maternal disorder
b. Higher incidence of OEIS complex in monozygotic twins than in dizygotic twins suggests a possible genetic contribution to the occurrence of these defects 2. Basic defects of OEIS complex
a. Resulting from a single localized defect in the early caudal mesoderm at approximately 29 days of development
b. Resulting in the following sequence of events:
i. Failure of cloacal septation leading to a persist- ence of the cloaca with a rudimentary mid-gut and imperforate anus
ii. Failure of break down of the cloacal membrane leading to exstrophy of the cloaca, omphalocele, and lack of fusion of the pubic rami
iii. The lumbosacral somites giving rise to abnormal vertebrae in which there is protrusion of the dilated spinal cord (hydromyelia) and a cystic, skin-covered mass in the lumbosacral region 3. Cloaca and cloacal exstrophy
a. Cloaca
i. A transient embryological structures
ii. The term ‘cloaca’ literally means ‘sewer’ in Latin
iii. The term used to represent the emptying of the gastrointestinal and urogenital tracts into a com- mon sinus
iv. Defined as a common chamber (orifice) in the perineum into which the urinary, genital and intestinal tract drain
b. Cloacal exstrophy: the common orifice empties onto the anterior abdominal wall
CLINICAL FEATURES
1. Classic exstrophy of the cloaca a. Lower abdominal defect
b. Exposure of intestinal and bladder mucosa c. Accompanied by the following anomalies
i. Omphalocele ii. Imperforate anus iii. Urogenital anomalies 2. Gastrointestinal malformations
a. Omphalocele b. Imperforate anus
c. Rectovestibular/rectovesical fistula d. Small bowel anomalies
i. Foreshortened small bowel ii. Rotational anomalies e. Meckel diverticulum
f. Inguinal hernias 3. CNS malformations
a. Spina bifida: the most common CNS malformation i. Leptomeningocele
ii. Myelomeningocele iii. Meningocele
iv. Spina bifida occulta v. Cord tethering b. Craniosynostosis 4. Skeletal malformations
a. Vertebral anomalies
i. Presence of extra vertebrae
ii. Hemivertebrae and associated scoliosis iii. Absent vertebrae
b. Pubic diastasis
c. Lower extremity anomalies i. Clubfoot deformities ii. Limb deficiencies 5. Genitourinary malformations
a. Bladder anomaly i. Open
ii. Separated into 2 halves
iii. Flanking the exposed interior of the cecum iv. Openings to the remainder of the hindgut
v. Prolapse of the terminal ileum as a “trunk” of bowel onto the cecal plate
b. Renal anomalies i. A single kidney ii. Rudimentary kidney iii. Pelvic ectopic kidney
iv. Ureteropelvic junction obstruction v. Malrotation
vi. Crossed renal ectopia
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c. Ureteral anomalies i. Duplication ii. Ectopic insertion
iii. Distal stricture and megaureter d. Male genitalia anomalies
i. Small and bifid penis
ii. Hemiglans located caudal to each hemibladder e. Female genitalia anomalies
i. Bifid clitoris ii. Uterine duplication iii. Vaginal duplication
iv. Vaginal agenesis 6. Prognosis
a. Used to be uniformly fatal malformation in its worst form
b. Currently with an 80–100% survival rate due to early surgical repair but accompanied by lifelong severe morbidity
DIAGNOSTIC INVESTIGATIONS
1. Evaluation of associated malformations 2. Karyotyping for genetic sex
3. Renal ultrasonography for renal and upper urinary tract anomalies
4. Voiding cystourethrography to assess bladder capacity in early childhood in preparation for continence reconstruction 5. Radiographic studies to demonstrate spinal dysraphism
a. Plain spinal radiographs b. Myelography
c. CT
d. CT myelography
e. Spinal MRI to identify occult abnormalities that pre- dispose to symptomatic spinal cord tethering
GENETIC COUNSELING
1. Recurrence risk
a. Patient’s sib: recurrence in subsequent pregnancies noted in one report
b. Patient’s offspring: Lack of offspring from patients with cloacal exstrophy making the determination of inheritance difficult
2. Prenatal diagnosis by ultrasonography
a. Elevated maternal serum α-fetoprotein (AFP) in OEIS complex. The open ventral wall defect likely results in AFP leakage
b. Ultrasonography
i. Major ultrasound criteria
a) Nonvisualization of the bladder (91%) b) A large midline infraumbilical anterior wall
defect or cystic anterior wall structure (per- sistent cloacal membrane) (82%)
c) Omphalocele (77%)
d) Lumbosacral myelomeningocele (68%) ii. Minor (less frequent) ultrasound criteria
a) Lower limb defects (23%) b) Renal anomalies (23%) c) Ascites (14%)
d) Widened pubic arches (18%) e) A narrow thorax (9%)
f) Hydrocephalus (9%)
g) A single umbilical artery (9%) 3. Management
a. Appropriate parental counseling and referral to a cen- ter with significant expertise in the management of cloacal exstrophy when prenatal diagnosis is made b. Medical stabilization of the infant
i. Fluid and electrolyte replacement ii. Parenteral nutrition
iii. Moisten the exstrophied bladder and bowel with saline and cover them with a protective plastic dressing
iv. Daily prophylactic antibiotics c. Gender assignment
i. Evaluation of the genitalia
ii. Decision limited to the genetic male patients with cloacal exstrophy
a) Male gender assignment appropriate for male patients with adequate bilateral or uni- lateral phallic structures
b) Male neonates with minimal phallic struc- tures: appropriate to raise as female subjects with early excision of the gonads
c) Appropriate hormonal manipulation to improve psychosexual dysfunction
d) Improvements in phallic reconstruction eventually allow most genetic male patients to be assigned male gender
iii. Initial sexual reassignment to be done in conjunc- tion with extensive family counseling as well as continued counseling for the parents and children d. Management of gastrointestinal malformations
i. Closure of omphalocele
ii. Combined with gastrointestinal diversion or reconstruction
a) Ileostomy with resection of the hindgut rem- nant
b) Colostomy
e. Management of genitourinary malformations i. Bladder closure
ii. Initial bladder excision and urinary diversion iii. Further augmentation or urinary diversions to
achieve continence
f. Management of CNS malformations i. Closure of myelomeningocele ii. Cord untethering
iii. Spinal fusion
iv. Cranial expansion for craniosynostosis g. Management of orthopedic malformations
i. Manage myelodysplasia ii. Pelvic osteotomies
iii. Various orthopedic devices to assist with ambu- lation
REFERENCES
Austin PF, Homsy YL, Gearhart JP, et al.: The prenatal diagnosis of cloacal exstrophy. J Urol 160:1179–1181, 1998.
Baker Towell DM, Towell AD: A preliminary investigation into quality of life, psychological distress and social competence in children with cloacal exstrophy. J Urol 169:1850–1853, 2003.
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Carey JC, Greenbaum B, Hall Arch Dermatol: The OEIS complex (omphalo- cele, exstrophy, imperforate anus, spinal defects). Birth Defects Orig Artic Ser XIV(6B):253–263, 1978.
Chitrit Y, Zorn B, Filidori M, et al.: Cloacal exstrophy in monozygotic twins detected through antenatal ultrasound scanning. J Clin Ultrasound 21:339–342, 1993.
Davidoff AM, Hebra A, Balmer D, et al.: Management of the gastrointestinal tract and nutrition in patients with cloacal exstrophy. J Pediatr Surg 31:771–773, 1996.
Diamond DA, Jeffs RD: Cloacal exstrophy: a 22-year experience. J Urol 133:779–782, 1985.
Dick EA, de Bruyn R, Patel K, et al.: Spinal ultrasound in cloacal exstrophy.
Clin Radiol 56:289–294, 2001.
Flanigan RC, Casale AJ, McRoberts JW: Cloacal exstrophy. Urology 23:227–233, 1984.
Fujiyoshi Y, Nakamura Y, Cho T, et al.: Exstrophy of the cloacal membrane. A pathologic study of four cases. Arch Pathol Lab Med 111:157–160, 1987.
Gosden C, Brock DJH: Prenatal diagnosis of exstrophy of the cloaca. JAMA8:
95, 1981.
Hurwitz RS, Manzoni GA, Ransley PG, et al.: Cloacal exstrophy: a report of 34 cases. J Urol 138:1060–1064, 1987.
Jeffs RD: Exstrophy and cloacal exstrophy. Urol Clin North Am 5:127–140, 1978.
Kaya H, Oral B, Dittrich R, et al.: Prenatal diagnosis of cloacal exstrophy before rupture of the cloacal membrane. Arch Gynecol Obstet 263:
142–144, 2000.
Kutzner DK, Wilson WG, Hogge WA: OEIS complex (cloacal exstrophy): pre- natal diagnosis in the second trimester. Prenat Diagn 8:247–253, 1988.
Lee DH, Cottrell JR, Sanders RC, et al.: OEIS complex (omphalocele-exstrophy- imperforate anus-spinal defects) in monozygotic twins. Am J Med Genet 84:29–33, 1999.
Loder RT, Dayioglu MM: Association of congenital vertebral malformations with bladder and cloacal exstrophy. J Pediatr Orthop 10:389–393, 1990.
Lund DP, Hendren WH: Cloacal exstrophy: experience with 20 cases. J Pediatr Surg 28:1360–1368; discussion 1368–1369, 1993.
Lund DP, Hendren WH: Cloacal exstrophy: a 25-year experience with 50 cases.
J Pediatr Surg 36:68–75, 2001.
Mathews R, Jeffs RD, Reiner WG, et al.: Cloacal exstrophy-improving the quality of life: the Johns Hopkins experience. J Urol 160:2452–2456, 1998.
Meglin AJ, Balotin RJ, Jelinek JS, et al.: Cloacal exstrophy: radiologic findings in 13 patients. AJR Am J Roentgenol 155:1267–1272, 1990.
Mitchell ME, Plaire C: Management of cloacal exstrophy. Adv Exp Med Biol 511:267–270; discussion 270–263, 2002.
Molenaar JC: Cloacal exstrophy. Semin Pediatr Surg 5:133–135, 1996.
Reddy RA, Bharti B, Singhi SC: Cloacal exstrophy. Arch Dis Child 88:277, 2003.
Schober JM, Carmichael PA, Hines M, et al.: The ultimate challenge of cloacal exstrophy. J Urol 167:300–304, 2002.
Smith NM, Chambers HM, Furness ME, et al.: The OEIS complex (omphalocele- exstrophy-imperforate anus-spinal defects): recurrence in sibs. J Med Genet 29:730–732, 1992.
Smith EA, Woodard JR, Broecker BH, et al.: Current urologic management of cloacal exstrophy: experience with 11 patients. J Pediatr Surg 32:
256–261; discussion 261–252, 1997.
Yerkes EB, Rink RC: Exstrophy and epispadias. 2002. www.emedicine.com
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Fig. 1. Two infants (A,B;C) with cloacal exstrophy. The schematic diagram (D) illustrates the anatomy of various defects in the second infant (C).
