Anal Fistula

General Illness Information

Common Name:

Medical Term: None Specified.

Description: An abnormal channel from the anus or rectum to the skin near the anal opening but may occasionally be to another organ such as the vagina. Most fistulas begin from a deep gland in the wall of the anus or rectum. However, fistulas may sometimes result from drainage of an ano-rectal abscess. The fistula may be painful and it may discharge pus. Fistulas in infants are usually congenital and are more common in boys than girls.


  • Anal fistula can be caused by an infection, which starts in the anorectal crypts forming an abscess.
  • Abscess bursts, leaving behind a tract from the interior to the anal opening.
  • Other causes include injury to the anus or rectum, inflammation of the bowel (e.g. crohn’s diverticulitis) or cancer of the bowel.

Prevention: No particular preventive steps.

Signs & Symptoms

  • Constant or intermittent purulent discharge.
  • Firm-tender lump.
  • Pain during or after bowel movement.
  • Discoloration of skin surrounding fistula.

Risk Factors

  • Inflammatory bowel disease, such as crohn’s disease.
  • Infection (e.g. tuberculosis, diverticulitis)
  • Puncture wound in anal canal lining or injury from an enema tip, injury during childbirth.
  • Cancer of the bowel.
  • Injection treatment for internal hemorrhoids.

Diagnosis & Treatment

  • Examination may reveal one or more openings around the anus and the doctor may be able to palpate a cord-like tract. A probe may be inserted to determine the depth and the direction of the fistula.
  • Anoscopy (examination of the anus with an instrument) with probing may help reveal the primary opening. Sigmoidoscopy is also required to rule out concurrent bowel disorder.

General Measures:

  • Minor surgical procedure to excise fistula. Usually with local anesthetic (occasionally general anesthetic required).
  • Warm sitz baths after surgery to help relieve any discomfort.


  • Stool softeners may be prescribed to prevent constipation.
  • Antibiotics may be prescribed if an infection is present.


Resume work and normal activity as soon as possible.


Regular diet, high in fiber.

Possible Complications :

  • Constipation.
  • Post-surgical bowel sphincter incompetence.
  • Delayed wound healing in cases of underlying bowel disorder such as crohn’s disease.


This condition is usually effectively treated by surgery unless underlying bowel disorder complicates it.

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