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).
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.
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.
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.
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.
Version Info
Last reviewed on: 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.
