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.

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
  • Tuberculosis
  • Gonorrhea
  • Cancer of the large intestine.

Symptoms of anal fistula may include:

  • Itching
  • Discharge of watery pus
  • Irritation of tissue around the anus
  • Discomfort
  • Pain.

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
  • MRI Scan is a good modality to deliniate Fistulas
  • 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) barium, 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.

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 as a daycare procedure . 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.

Using LASER, FiLaC (Fistula Laser Closure) Surgery can be done.

DLPL (DiIstal Laser Proximal Ligation) is also a LASER Modality of treatment.

High level fistulas require a seton therapy in which a thread is passed through the fistula and tied on itself. This thread is then tightened on a biweekly basis and the fistula is thus cut and allowed to simultaneously heal.

After a fistulotomy, the doctor will prescribe stool softeners and rest. In addition, the doctor may prescribe antibiotics to fight any infection.

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. 

Home care may include:

  • Using stool softeners
  • Adding fiber to your diet
  • Drinking plenty of water, up to 3.5 lts per 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.

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  
  • 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.