Imperforate anus

Anorectal malformation; Anal atresia

Imperforate anus is a defect in which the opening to the anus is missing or blocked. The anus is the opening to the rectum through which stools leave the body. This is present from birth (congenital).

Causes

Imperforate anus may occur in several forms:

The rectum may end in a pouch that does not connect with the colon.
The rectum may have openings to other structures. These may include the urethra, bladder, base of the penis or scrotum in boys, or vagina in girls.
There may be narrowing (stenosis) of the anus or no anus.

It is caused by abnormal development of the fetus. Many forms of imperforate anus occur with other birth defects.

Symptoms

Symptoms of the problem may include:

Anal opening very near the vagina opening in girls
First stool is not passed within 24 to 48 hours after birth
Missing or moved opening to the anus
Stool passes out of the vagina, base of penis, scrotum, or urethra
Swollen belly area

Treatment

A health care provider can diagnose this condition during a physical exam. Imaging tests may be ordered.

The infant should be checked for other problems, such as abnormalities of the genitals, urinary tract, and spine.

Surgery to correct the defect is needed. If the rectum connects with other organs, these organs will also need to be repaired. A temporary colostomy (connecting the end of the large intestine to the abdomen wall so that stool can be collected in a bag) is often needed.

Outlook (Prognosis)

Most defects can successfully be corrected with surgery. Most children with mild defects do very well. However, constipation can be a problem.

Children who have more complex surgeries still have control over their bowel movements most of the time. However, they often need to follow a bowel program. This includes eating high-fiber foods, taking stool softeners, and sometimes using enemas.

Some children may need more surgery.

When to Contact a Medical Professional

This problem is often found when the newborn infant is first examined.

Comtact your provider if a child treated for imperforate anus has:

Abdominal pain
Constipation that is difficult to manage
Failure to develop any bowel control by the age of 3

Prevention

There is no known prevention. Parents with a family history of this defect may seek genetic counseling.

Open References

References

Dingelsein M. Selected gastrointestinal anomalies in the neonate. In: Martin RJ, Fanaroff AA, Walsh MC, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 84.

Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Surgical conditions of the anus and rectum. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 371.

Imperforate anus - illustration
Imperforate anus is a malformation of the anorectal region that may occur in several forms. The rectum may end in a blind pouch that does not connect with the colon, or it may have openings to the urethra, bladder, or vagina. A condition of stenosis, or narrowing of the anus, or absence of the anus may be present.
Imperforate anus
illustration
Imperforate anus repair - series
Presentation

<strong>Imperforate anus repair - series</strong><p>In individuals with a normal anatomy, the large intestine (colon) empties into a pouch-like portion of bowel (rectum). Through complex nerve and muscle structures, the rectum releases stool through the anus out of the body. </p>

<strong>Indications</strong><p>This surgery is recommended to repair cases of imperforate anus and other anorectal malformations. There are two types of imperforate anus; a low type and a high type. The low type imperforate anus repair is illustrated.</p>

<strong>Procedure</strong><p>Surgical repair involves creating an opening for passage of stool. Complete absence of an anal opening requires emergency surgery for the newborn. Surgical repairs are done while the baby is deep asleep and pain-free (using general anesthesia). Surgery for a high type imperforate anus defect usually involves creation of a temporary opening of the large intestine (colon) onto the abdomen to allow passage of stool (this is called a colostomy). The baby is allowed to grow for several months before attempting the more complex anal repair. The anal repair involves an abdominal incision, loosening the colon from its attachments in the abdomen to allow it to be repositioned. Through an anal incision, the rectal pouch is pulled down into place, and the anal opening is completed. The colostomy may be closed during this stage or may be left in place for a few more months and closed at a later stage. Surgery for the low type imperforate anus (which frequently includes a fistula) involves closure of the fistula, creation of an anal opening, and repositioning the rectal pouch into the anal opening. A major challenge for either type of defect and repair is finding, using, or creating adequate nerve and muscle structures around the rectum and anus to provide the child with the capacity for bowel control.</p>

<strong>Aftercare</strong><p>The child may require several days in the hospital. Dilatation of the new anus (to improve muscle tone and prevent narrowing) will begin in the hospital and continue for some months. Stool softeners and a high-residue diet will need to continue throughout childhood.</p>

Imperforate anus - illustration
Imperforate anus is a malformation of the anorectal region that may occur in several forms. The rectum may end in a blind pouch that does not connect with the colon, or it may have openings to the urethra, bladder, or vagina. A condition of stenosis, or narrowing of the anus, or absence of the anus may be present.
Imperforate anus
illustration
Imperforate anus repair - series
Presentation

Self Care

Tests for Imperforate anus

Review Date: 4/28/2023

Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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Health Library

Imperforate anus

Causes

Symptoms

Treatment

Outlook (Prognosis)

When to Contact a Medical Professional

Prevention

References

Imperforate anus - illustration

Imperforate anus

Imperforate anus repair - series

Imperforate anus - illustration

Imperforate anus

Imperforate anus repair - series

Self Care

Tests for Imperforate anus

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