Imperforate Anus (Anal Atresia)

Imperforate Anus is a genetic abnormality of the rectum and anus, which is evident at birth and can affect any person. Imperforate anus means that the opening of the rectum, the anus, is not perforated, which may mean there is no hole, the hole is in an abnormal position or the anus is blocked. The deformity means that the person will not be able to release faeces or stools unless the defect is corrected with surgery.

How does imperforate anus occur?

The imperforate anus deformity is present at birth and is a congenital or genetic abnormality, occurring due to defective DNA / Chromosomal development.

Are there different kinds of imperforate anus?

Imperforate anus can present differently depending on the type of genetic abnormality. There are three main categories of deformity:

  1. The colon and rectum are not attached because the rectum ends in a blind pouch without an anus.
  2. There may be no anus present at all or a narrowing of the anus, also known as stenosis, due to a low lesion near the colon.
  3. Depending on gender the rectum may have an opening, but instead of it being the anus it is the vagina in girls or either the scrotum, urethra or bladder in boys. In boys the fistula connecting to the rectum elevates the colon in the pelvis and in girls the rectum urinary tract and vagina may form one channel known as persistent cloaca.

What are the symptoms of imperforate anus?

Usually, imperforate anus is identified during or shortly after birth as any of the three categories listed above. However, if missed at birth an imperforate anus may be recognised when the baby is unable to defecate between a day or two after birth or has a swollen belly. Another symptom may be that the baby passes faeces via the vagina (girls), scrotum or urethra (boys). The most apparent symptom is the absence of an anus or the anus is present in an abnormal place, such as near the bladder or genital organ.

How is imperforate anus diagnosed?

At birth medical practitioners examine the baby physically to look for abnormalities, such as anorectal malformation. Usually imperforate anus is noticeable during physical examination if there is no anus. However, due to the small size of the baby this can be missed and symptoms may be identified within 24 to 48 hours after birth. Another medical examination, which includes imaging tests or sonography, may then be used to check the spine, urinary tract and genitals for diagnosis and type of imperforate anus abnormality.

How is imperforate anus treated?

All forms of imperforate anus can be treated, whether the rectum and colon are not connected, the anus does not exist or if the rectum opens into the genital area. Initially, until the baby is strong enough to have surgery, a colostomy to allow removal of stool may be necessary at first. Perineal anoplasty surgery includes detaching the rectum from other structures and repairing organs, creating an external anus opening and then using pull-through procedures to attach the rectum to the new anus.

How does imperforate anus affect healthy development?

Surgery can easily rectify most imperforate anus conditions, though health complications may be a result, such as constipation. Some children need to adhere to medical recommendations to prevent complications, which may include:

  • A bowel program.
  • High-fibre diet
  • Taking laxatives to soften stools.
  • Using enemas to prevent blockage.

If irregular bowel movements and constipation persist throughout childhood development, further surgery may be necessary.

Imperforate anus and associated defects affecting health

At birth, along with imperforate anus, other abnormalities may also be evident, such as limb, renal, heart, spinal and oesophageal atresia defects. These abnormalities are medically categorised as VACTERL, standing for: Vertebral (V); Anal atresia (A); Cardiovascular (C); Tracheoesophageal fistula (T); Oesophageal atresia (E); Renal and Radial (R); and Limb (L). Surgery to correct imperforate anus may include correcting VACTERL defects too. Being born with such abnormalities will affect normal and healthy body function. Having corrective surgery and treatment immediately will help the person affected manage their health better as they develop in life.

What can be done to prevent imperforate anus?

Since perforated anus is a genetic birth defect there is nothing that can be done to prevent the abnormality. However, there is hope as research into genetics progresses.

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