Anal fistulae

An anal fistula is an abnormal tunnel between a gland inside the anus and an opening on the skin around the anus. Anal fistulae frequently drain pus and sometimes form an abscess. They usually require surgical treatment.

from symptoms to treatment

What should I know about the anal canal?

The anal canal is the final segment of the rectum. It connects to the skin in the anal margin and is surrounded by the anal sphincter. The middle of the canal has valves, at the bottom of which are located the anal glands (first described by Hermann and Desfosses). The sphincter is a group of muscles that form the internal sphincter, which is not under voluntary control, and the external sphincter, which can be contracted voluntarily.

  • What are the symptoms of an anal fistula?

    A fistula is an abnormal tunnel between an infected gland which drains its contents into a subcutaneous cavity, or abscess.

    There are two types of fistula: acute fistula, which is an abscess; and chronic fistula, characterized by drainage (permanent or intermittent, purulent and/or reddish and hemorrhagic, which causes staining, local irritation and itching).

    In its abscess form, a fistula appears as a growth around the anus, often covered with very red skin, triggering acute pain while sitting or when touched. Other symptoms may include tiredness and a high temperature.

  • What are the risk factors of anal fistulae?

    Some people with specific conditions are more likely to develop a fistula and so must be extra cautious. These conditions include Crohn’s disease (an inflammatory bowel disease), tuberculosis and certain sexually transmitted diseases (gonorrhea, chlamydia).

  • How is an anal fistula diagnosed?

        When an anal fistula is suspected, a palpation might reveal a hard tract. An abscess appears as a tight, red mass near the anal margin, which is either visible or felt with palpation. The fistula tract can also be detected through an MRI or endoanal ultrasound, or by injecting a dye during the surgical procedure.

  • What are the treatment options for anal fistulae?

    Abscesses require urgent treatment. The patient receives local or general anesthesia before the doctor makes an incision to the abscess. Antibiotics are not systematically prescribed.

    Several techniques are used to treat the fistula tract, such as fistulotomy, injection of a biological glue, ligature of the fistula within the intersphincteric space, and laser. If the anal fistula is located deep inside the anus, the first step is to insert a flexible drainage device inside the fistula tract. Laxatives and painkillers are also frequently prescribed to help the patient resume normal intestinal transit and to manage pain.

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American Hospital of Paris