Diseases & Conditions
What is an anal fistula?
Anal fistula, a rare condition, is a chronically inflamed, abnormal tunnel between the anal canal and the outer skin of the anus. It often drains watery pus, which can irritate the outer tissues and cause itching and discomfort.
How does it occur?
An anal fistula usually results from an infection that forms in the tissue lining the anal canal. The infection may be caused by spread of bacteria that normally exist in the rectum. Occasionally, it may occur as a result of:
a healed sore in the rectal area
ulcerative colitis, a disease associated with ongoing breakdown of tissues that causes a sore in the lining of the colon
diverticulitis, inflammation of harmless growths in the wall of the intestines
Crohn's disease, a chronic inflammation of the intestines
cancer of the large intestine.
What are the symptoms?
Symptoms of anal fistula may include:
discharge of watery pus
irritation of tissue around the anus
How is it diagnosed?
To diagnose an anal fistula, the doctor will review your symptoms, give you a physical exam, and may use the following procedures:
anoscopy, a procedure in which the doctor inserts an instrument called an anoscope into the rectum to inspect the anus and lower part of the rectum
sigmoidoscopy, a procedure in which a doctor uses a flexible or rigid scope to inspect the lower part of the intestine for inflammation and/or disease
a biopsy to evaluate for inflammation or cancer
lower gastrointestinal (GI) series, a procedure that uses a special fluid to show the intestines better on x-ray
A lower GI series requires a clean, clear GI tract. The doctor will prescribe a special diet, including plenty of water, for the day before the procedure. In addition, you may be given an enema the morning of the procedure.
How is it treated?
The surgical procedure used to correct an anal fistula is called a fistulotomy. In a fistulotomy the doctor opens the infected area and allows the fistula to drain. Stitches usually aren't needed.
Small or shallow fistulas may be treated in the doctor's office with local anesthetic. Larger fistulas must be treated surgically under regional or general anesthesia. If the fistula is complex and goes through both anal sphincter muscles, more than one procedure may be necessary.
After a fistulotomy, the doctor will prescribe stool softeners and rest. In addition, the doctor may prescribe antibiotics to fight any infection.
How long will the effects last?
An anal fistula usually lasts until it is surgically removed.
Changes in diet, good hygiene, and medications may be used for treatment, but surgery is usually needed to drain the infection and remove the infected tissue.
How can I take care of myself?
Home care may include:
using stool softeners
adding fiber to your diet
drinking plenty of water, up to 8 eight-ounce glasses a day
taking warm baths
using clean, moist pads to wipe the area around the anus, to remove irritating particles and fluid from the fistula
using special skin creams to soothe irritated tissue.
How can I help prevent an anal fistula?
Follow these guidelines to help prevent an anal fistula. They help to keep the lower gastrointestinal tract healthy.
Eat food high in fiber.
Drink plenty of water each day (up to eight 8-ounce glasses).
Have regular physical exams to look for underlying diseases of the rectum.
Be aware of the signs and symptoms of bowel disease, and seek medical attention if any appear.