Anorectal Malformation

Question 1

Clinical presentation of anorectal malformations in antenatal period

Answer 1

Polyhydramnios

Question 2

Clinical presentation of anorectal malformation postnatal

Answer 2

Imperforate anus in inspection (no opening, an anal dimple without opening, fistula to peritoneum)
Signs of progressive abdo distension and bowel obstruction:
-abdo distension
-vomiting
-failure to pass meconium

Other: flattened buttocks, sacral dimple, in case of cloaca-single orifice

Question 3

Differentiate between high lesions and low lesions in anorectal malformations

Answer 3

High lesions the rectum does not pass through puborectalis muscle vs in low lesions it does
High lesions associated with long term continence problems
High lesions have poor prognosis (assc maldevelopment of sacrum, anal and urethral musculature impaired innervation and bladder&bowel dysfunction)

Question 4

Which anorectal malformation is most common in boys

Answer 4

Imperforate anus with Perineal fistula

Question 5

Which anorectal malformation is most common in girls

Answer 5

Imperforate anus Vestibular fistula

Question 6

Name the 3 types of imperforate anus rectal fistulas that can occur in boys

Answer 6

1. Perineal fistula
2. Recto urethral fistulas:
   -Bulbar/membranous urethral fistula
   -Prostatic urethra fistula
3. Rectovesical fistula

Question 7

Name the 2 types of rectal fistulas in imperforate anus seen in girls

Answer 7

Vestibular fistula (commonest)
Perineal fistula

Question 8

What special investigations are done in case of suspected imperforate anus with or without fistula

Answer 8

After 24 hours of no meconium

1. Cross-table lateral shoot- baby positioned with buttocks up and a radio-opaque marker along where anal opening is supposed to be. Swallowed air used as contrast medium to see distance between rectum and skin where anal dimple is marked.
2. Neonatal xray/ babygram
   -if perforation is suspected free air can be seen
   -in TOF or atresia NG tube seen curled up, many other assc abnormalities
3. CXR to look at lungs fields, cardiac
4. echocardiogram and ecg if there are no murmurs
5. US of Kidney, ureter and bladder
6. MRI of spine 3-6 months

Work the baby up for all the systems

Question 9

Discuss management of anorectal malformations(fistulas)

Answer 9

(Relieve obstruction)

Primary divided colostomy then,
Sunsequent Posterior Sagitta Anorectoplasty (PARP) then,
Colonoscopy closure

PSARP: Definitive surgery to dissect out the atretic anorectal canal, divide the fistula, and
place the anorectal canal and neo-anus within the funnel-shaped anal sphincter
fibres is performed at 3-6 months.

Stroma is closed after neo-anus has healed completely and is confirmed to be the correct size for the patient’s age

Question 10

Complications of surgical repair of anorectal malformations/fistula or atresia

Answer 10

Stomal prolapse
Peri-stomal skin excoriation by stool
Constipation
Long term incontinence

Question 11

What causes descent of testes

Answer 11

Not yet fully understood

-traction on the testes by scrotal attachments
-Intraabdominal pressure
-differential growth of the body wall
-Maturation of epididymis
-Hormonal influences

Question 12

Long term complication of undiscended tests

Answer 12

Testicular cancer