Anal Fistula

What is an anal fistula?

An anal fistula is an abnormal tunnel between the anal canal and the outer skin of the anus. The anus is the opening of the rectum where bowel movements (BMs) leave the body.

How does it occur?

An anal fistula usually results from an infection that forms in the tissue lining the anal canal. The infection may be caused by the bacteria that normally exist in the rectum. Sometimes an anal fistula may occur as a result of:

a healed sore in the rectal area
ulcerative colitis, a disease that damages the colon and rectum
diverticulitis, inflammation of small, harmless pouches in the wall of the intestines
Crohn's disease, a chronic inflammation of the intestines
tuberculosis of the bowel
gonorrhea in the rectum
cancer of the large intestine (colon or rectum).

What are the symptoms?

Symptoms of anal fistula may include:

itching
discharge of watery pus
irritation of the skin around the anus
pain in the rectal area
leakage of stool between bowel movements.

How is it diagnosed?

Your healthcare provider will review your symptoms and examine you. You may have one or more of the following procedures:

anoscopy, a procedure in which your provider inserts an instrument with a light into the rectum to look at the anus and lower part of the rectum
sigmoidoscopy, a procedure in which your healthcare provider uses a flexible scope to inspect the lower part of the intestine for inflammation or disease
a biopsy of any abnormal tissue to check for inflammation or cancer
lower gastrointestinal (GI) series, a procedure that uses a special fluid to show the intestines better on X-ray.
colonoscopy, an exam of the entire lower intestine with a slim, flexible, lighted tube to look for causes.

How is it treated?

The procedure used to treat an anal fistula is called a fistulotomy. Your healthcare provider opens the infected area and allows the fistula to drain. Stitches usually are not needed.

Small or shallow fistulas may be treated in your healthcare provider's office after you are given a local anesthetic to numb the area. Larger fistulas must be treated surgically under regional or general anesthesia. If the fistula is complex and goes through both anal sphincter muscles, more than one procedure may be necessary.

After a fistulotomy, your healthcare provider will prescribe stool softeners and rest. In addition, your provider may prescribe antibiotics to fight any infection.

How long will the effects last?

An anal fistula usually lasts until it is surgically removed.

How can I take care of myself?

Follow your healthcare provider's instructions.

Caring for yourself at home after surgery may include:

using stool softeners
adding fiber to your diet
drinking plenty of water
taking warm baths to keep the anal area clean and to increase blood circulation to the area (blood brings infection-fighting cells and nutrients to the area)
using clean, moist pads to wipe the area around the anus gently to remove irritating particles and fluid from the fistula.

How can I help prevent an anal fistula?

There is no known way to prevent an anal fistula. However, there are ways to try to keep your lower GI tract healthy.

Eat food high in fiber.
Drink plenty of water.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File GASE4002.HTM Release 11.0/2008