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.

Fistulas usually don’t go away unless they are treated.

What is the cause?

An anal fistula is usually caused by a bacterial infection in the anus. It may happen as a result of:

• passing hard bowel movements
• diarrhea
• childbirth
• injury to the anus
• frequent use of laxatives
• diseases of the colon or rectum, such as Crohn's disease (chronic inflammation of the bowel)
• other diseases or infections

What are the symptoms?

Symptoms may include:

• itching
• watery pus, sometimes mixed with blood
• irritated skin around the anus
• pain in the rectal area, especially when you have a bowel movement
• leaking of bowel movement

How is it diagnosed?

Your healthcare provider will ask about your symptoms and examine you. You may have 1 or more of the following tests:

• swab of the anus to test for infection
• an exam of the anus and rectum with a small scope (anoscopy)
• an X-ray exam with a fluid put into the anus to make it easier to see a fistula
• an ultrasound or MRI scan of the rectal area
• a colonoscopy (a way to look at all of the colon and rectum with a slim, flexible tube and tiny camera)

Tissue may be removed (biopsied) during the colonoscopy. The tissue can be tested for signs of disease, such as infection, irritation, or cancer.

How is it treated?

An anal fistula may be treated with surgery to open and drain the infected area. The surgery is called a fistulotomy.

• Small fistulas may be treated in your healthcare provider's office after you are given a local anesthetic to numb the area. In some cases your provider may be able to use stitches and a gluelike chemical or other substance to seal and heal the fistula instead of cutting it open.
• If the fistula is large, you will be given regional or general anesthesia to keep you from feeling pain during the surgery and you may need to stay at the hospital overnight.

After surgery, your provider will prescribe stool softeners and rest. Your provider may also prescribe antibiotics and pain medicine.

If the fistula is small and easy to treat, you may be better in a few days or weeks. If your fistula is deep or long and more difficult to treat, it may take more than 1 surgery and a longer time for the fistula to completely heal. If you have a medical problem like inflammatory bowel disease, you may keep getting fistulas.

How can I take care of myself?

To care for yourself at home after treatment:

• Keep your bowel movements soft:
  • Follow your healthcare provider's instructions for taking stool-softening medicines.
  • Drink plenty of water.
  • Add more fiber to your diet with whole-grain foods, bran, and fruits and vegetables.
• After bowel movements, gently wipe the area around the anus with clean, moist pads. This will remove irritating particles and fluid from the anal area.
• Soak in warm baths to help relieve pain and keep the area clean. Warm baths help increase blood flow to the area. Blood brings infection-fighting cells and nutrients to the area.
• Be as physically active as your healthcare provider recommends.
• Follow any other instructions your provider gives you.

How can I help prevent an anal fistula?

There is no sure way to prevent anal fistulas. However, it may help to:

• Keep your digestive tract healthy by eating plenty of fiber.
• Get regular exercise.
• Get any rectal problems, especially infections, treated right away.