The usual symptoms of fistula in ano are intermittent perianal swelling and drainage or continuous mucoid or brown-stained drainage from a site in the perianal skin, which results from a communication between the anal canal and the perianal tissues. The cause is unknown.

Fistula in ano is sometimes preceded by perianal abscess, but not always. Persistent drainage 6-8 weeks after drainage of a perianal or perirectal abscess is a sign of an underlying anal fistula.

Although some patients with inflammatory bowel disease have fistulas, the vast majority of patients with fistula-in-ano do not have inflammatory bowel disease.

The treatment is surgical. Surgical consultation is indicated for any patient with suspected fistula-in-ano.

Antibiotics are of no value in the absence of acute infection, which is rare.

If patient has history of constipation or hard bowel movements, attempt should be made to correct this, as it may have been causative.

A high fiber diet can be achieved by daily use of a high fiber cereal (i.e., All-Bran, Fiber One, Bran Buds, Kashi cereals with >10 grams of fiber per serving) ½ to 1 cup of cereal daily.

by using a fiber supplement (i.e., Metamucil, Citrucel, Benefiber, etc.). A sufficient amount must be taken daily to give 10-20 grams of fiber. This usually means tablespoons not teaspoons of supplement.

The added fiber must be taken every day. It is not a cathartic. Beneficial effects take days to weeks as the colon adapts to the new diet.

Miralax is another alternative, but should be reserved for patients who cannot tolerate or are unable to manage a high fiber diet.

For patients with severe, chronic constipation, or in whom one is concerned about dysmotility, referral to the Michigan Bowel Control Program is suggested.