Definition: Association of an imperforate anus with confluence of the rectum, vagina, and bladder in a urogenital sinus.

Etymology: Cloaca = sewer in Latin.

Synonyms: Anorectal anomalies, persistent cloaca, cloacal malformations.

Incidence: Cloacal malformations occur in approximately 0.2:10,000 live female births. The incidence in male is not well established which may result from an ascertainment bias.

Etiology: Sporadic. Rare cases have been associated with chromosomal anomalies[2],⁶. In the mouse, a similar type of anomalies occur with mutations of the Hoxa-13 and Hoxd-13[3] and Etretinate, a synthetic retinoid can cause similar anomalies[4].

Diagnosis: The typical appearance is that of a pelvic fluid-filled structure, whose appearance depends on the anatomy involved and the gestational age[5],. In the first trimester, the main finding may be dilated loops of bowel, then megacystis, ascites and oligo/anhydramnios occurs when no external opening is present. The perineum is smooth with absence of anal, urethral, and/or vaginal openings. The labia majora and minora may be absent in females and the scrotum and penis may be absent or hypoplastic in males,[8],.

Cloacal dysgenesis with vesico-rectal fistula (courtesy Peter Twining, Nottingham, UK)

Differential diagnosis: Obstructive uropathy, but a large bladder should be visible and Vacterl.

Associated anomalies: cardiac, pulmonary (hypoplastic lungs), renal (renal agenesis, dysplasia, hydronephrosis, hydroureters), gastrointestinal (intraluminal colonic calcifications) skeletal and vertebral anomalies[10], growth restriction, single umbilical artery9.

Prognosis: in cases with no outlet of the urine into the amniotic cavity, the prognosis is fatal due to lung hypoplasia, but there are exceptions7. Among those surviving to surgery, in a large series of 141 patients:

·        82 have spontaneous bowel movements and satisfactory control,

·        38 use enemas to evacuate,

·        9 have a colostomy,

·        7 have fecal soiling, and

·        5 are too recently operated to evaluate.

Regarding urinary control,

·        83 void spontaneously,

·        40 catheterize to empty,

·        4 have urinary diversion,

·        1 has a continent diversion,

·        5 patients are wet, and

·        8 are too recently operated to judge11.

Twenty-four patients are now adults, 17 of who have experienced coitus and 7 have not. Seven have had babies, all except one by cesarean section 11. Others have also reported normal vaginal deliveries[12].

Management: Prenatal: in the absence of amniotic fluid, the pregnancy can be managed as non-viable. Postnatally, the management depends on the type of anomalies and associated malformations.

References:

[1] Dodson JL, Ferrer FA, Jackman SV, Blakemore KJ, Docimo SG Cloacal outlet obstruction with an ectopic ureter. Urology (Online) 2000 May 1;55(5):775

[2] Chen CP, Chern SR, Lee CC, Town DD Isochromosome 18q in a fetus with congenital megacystis, intra-uterine growth retardation and cloacal dysgenesis sequence. Prenat Diagn 1998 Oct;18(10):1068-74

[3] Warot X, Fromental-Ramain C, Fraulob V, Chambon P, Dolle P Gene dosage-dependent effects of the Hoxa-13 and Hoxd-13 mutations on morphogenesis of the terminal parts of the digestive and urogenital tracts. Development 1997 Dec;124(23):4781-91

[4] Mesrobian HG, Sessions RP, Lloyd RA, Sulik KK Cloacal and urogenital abnormalities induced by etretinate in mice. J Urol 1994 Aug;152(2 Pt 2):675-8

[5] Zaccara A, Gatti C, Silveri M, Rivosecchi M, Bilancioni E, Spina V, Giorlandino C, De Gennaro M, Bagolan P Persistent cloaca: are we ready for a correct prenatal diagnosis? Urology (Online) 1999 Aug;54(2):367

[6] Cacciaguerra S, Lo Presti L, Di Leo L, Grasso S, Gangarossa S, Di Benedetto V, Di Benedetto A Prenatal diagnosis of cloacal anomaly. Scand J Urol Nephrol 1998 Feb;32(1):77-80

[7] Liang X, Ioffe OB, Sun Cloacal dysgenesis sequence: observations in four patients including three fetuses of second trimester gestation. Pediatr Dev Pathol 1998 Jul-Aug;1(4):281-8

[8] Carroll SG, Hyett J, Eustace D, Seller MJ, Nicolaides KH Evolution of sonographic findings in a fetus with agenesis of the urethra, vagina, and rectum. Prenat Diagn 1996 Oct;16(10):931-3

[9] Murr MM, Waziri MH, Schelper RL, Abu-Youself M Case of multivertebral anomalies, cloacal dysgenesis, and other anomalies presenting prenatally as cystic kidneys. Am J Med Genet 1992 Apr 1;42(6):761-5

[10] Qureshi F, Jacques SM, Yaron Y, Kramer RL, Evans MI, Johnson MP Prenatal diagnosis of cloacal dysgenesis sequence: differential diagnosis from other forms of fetal obstructive uropathy. Fetal Diagn Ther 1998 Mar-Apr;13(2):69-74

[11] Hendren WH Cloaca, the most severe degree of imperforate anus: experience with 195 cases. Ann Surg 1998 Sep;228(3):331-46

[12] Ljubic A, Sulovic V, Stankovic A, Cvetkovic A Cloacal dysgenesis and vaginal delivery. J Gynecol Obstet Biol Reprod (Paris) 1993;22(4):417-8