Imperforate Anus

Signs and Symptoms

Imperforate anus is a birth defect that occurs in about one of every 5,000 newborns. It is somewhat more common in boys than girls and may include a single abnormality or a combination of abnormalities of the rectum and anus. The rectum is the end of intestine that connects with the anus and the anus is the body's opening to dispel solid waste. Although there is no known cause for this condition, there are many forms of this birth defect, including:

• The absence of an anal opening.
• An anal opening in the wrong position, usually a very small opening.
• An abnormal connection or opening, called a fistula, between the rectum and the urethra, bladder or vagina.
• In girls, the rectum, urethra and vagina can join together to form a single opening. This is called a cloaca and is very rare.

If the anus is missing, there is no outlet to release stool after birth. The intestine ends in a blind pouch, so your infant's stool, called meconium, remains in the intestine. This can cause vomiting and an enlarged or swollen abdomen.

In some cases, the rectum may end high in the pelvis or it can end low, closer to the correct position.

If there is a fistula or connection between the intestine and the bladder, stool may be excreted with urine. If there is a fistula between the intestine and the vagina, stool may pass out of the vagina.

Diagnosis

If the anal opening is missing or in the wrong position, the condition can be diagnosed by a physical examination.

The existence of a fistula or abnormal connection between the intestine and bladder would be suspected if stool is excreted through the urine. A fistula or abnormal connection between the intestine and vagina would be suspected if stool is excreted from the vagina.

To confirm the condition, your baby's doctor may request several diagnostic tests including an X-ray and ultrasound.

Treatment

If the anus did not develop correctly, surgery will be performed to create an opening, or new anus, to allow stool to pass. Treatment may differ, depending on if the imperforate anus is high or low in the pelvis.

If the intestine ends high in the pelvis, treatment usually involves three procedures:

• First a stoma, or opening of the intestine to the abdomen, is made in a procedure called a colostomy. Newborns who have a stoma will need a special stoma bag on the abdomen to collect stool.

• The second procedure, called anoplasty, involves pulling down the rectum to the anus where a new anal opening is created. If a fistula or abnormal connection to the bladder or vagina is present, that connection will be closed.

• Several months later after the new anal opening has healed, a third procedure will be performed to close the stoma.

If the intestine ends low in the pelvis, an anal opening often can be made in a single operation. The rectum is pulled down to the anus and a new anal opening created, using a minimally invasive technique called laparoscopy. In these cases, a stoma is not required. If the anal opening is in the wrong position, it will be closed and moved to the correct location.

Following the operation, babies have very frequent bowel movements that can cause severe diaper rash. A protective skin cream is used immediately after surgery.

Babies can go home once they are drinking, having bowel movements, feeling comfortable on pain medication and are free of fever.