A fistula is an opening in the skin near the anus that leads into a blind pouch or may connect through a tunnel with the anal canal. An anal fistula is almost always the result of a previous abscess. Just inside the anus are small glands. When these glands get clogged, they may become infected and an abscess can develop. A fistula is a small tunnel that forms under the skin and connects a previously infected anal gland to the skin on the buttocks outside the anus.
What causes an abscess?
An abscess results from an acute infection of a small gland just inside the anus, when bacteria or foreign matter enters the tissue through the gland. Certain conditions – colitis or other inflammation of the intestine, for example – can sometimes make these infections more likely.
What causes a fistula?
After an abscess has been drained, a tunnel may persist connecting the anal gland from which the abscess arose to the skin. If this occurs, persistent drainage from the outside opening may indicate the persistence of this tunnel. If the outside opening of the tunnel heals, recurrent abscess may develop.
What are the symptoms of an abscess or fistula?
An abscess is usually associated with symptoms of pain and swelling around the anus. Individuals may also experience fatigue, fevers and chills. Symptoms related to the fistula include irritation of skin around the anus, drainage of pus (which often relieves the pain), fever, and feeling poorly in general.
Does an abscess always become a fistula?
No. A fistula develops in about 50 percent of all abscess cases, and there is really no way to predict if this will occur.
How is an abscess treated?
An abscess is treated by making an opening in the skin near the anus to drain the pus from the infected cavity and thereby relieve the pressure. Often, this can be done in the doctor’s office using a local anesthetic. A large or deep abscess may require hospitalization and the assistance of an anesthesiologist. Hospitalization may also be necessary for patients prone to more serious infections, such as diabetics or people with decreased immunity. Antibiotics are a poor alternative to draining the pus, because antibiotics do not penetrate the fluid within an abscess.
What about treatment for a fistula?
Surgery is necessary to cure an anal fistula. Although fistula surgery is usually relatively straightforward, the potential for complication exists, and is preferably performed by a specialist in colon and rectal surgery. It may be performed at the same time as the abscess surgery, although fistulas often develop four to six weeks after an abscess is drained, sometimes even months or years later.
Fistula surgery usually involves opening up the fistula tunnel. Often this will require cutting a small portion of the anal sphincter, the muscle that helps to control bowel movements. Joining the external and internal openings of the tunnel and con-verting it to a groove will then allow it to heal from the inside out. Most of the time, fistula surgery can be performed on an outpatient basis. Treatment of a deep or extensive fistula may require a short hospital stay.
How long does it take before patients feel better?
Discomfort after fistula surgery can be mild to moderate for the first week and can be controlled with pain pills. The amount of time lost from work or school is usually minimal.
Treatment of an abscess or fistula is followed by a period of time at home, when soaking
the affected area in warm water (sitz bath) is recommended three or four times a day. Stool softeners or a bulk fiber laxative may also be recommended. It may be necessary to wear a gauze pad or mini-pad to prevent the drainage from soiling clothes. Bowel movements will not affect healing.
What are the chances of a recurrence of an abscess or fistula?
If properly healed, the problem will usually not return. However, it is important to follow the directions of a colon and rectal surgeon to help prevent recurrence.