Fistulas

A fistula is an abnormal passageway between two areas of the digestive tract. An internal fistula occurs between two areas of intestine or an area of intestine and another organ. An external fistula occurs between the intestine and the outside of the body. Both internal and external fistulas may be characterised by abdominal pain and swelling. External fistulas may discharge pus or intestinal contents. Internal fistulas can be associated with diarrhoea.

The most common types of fistulas develop around the anus, colon, and small bowel. These types are

• ileosigmoid—occurs between the sigmoid colon and the end of the small bowel, which is also called the ileum



• ileocecal—occurs between the ileum and caecum



• anorectal—occurs between the anal canal and the skin around the anus



• anovaginal—occurs between the rectum and vagina



• colovesical—occurs between the colon and bladder



• cutaneous—occurs between the colon or small bowel and the outside of the body

Fistulas can occur at any age. Some fistulas are congenital, which means they occur during the development of a baby. They are seen in infants and are more common in boys. Other fistulas develop suddenly due to diseases or after trauma, surgery, or local infection. A fistula can form when diseased or damaged tissue comes into contact with other damaged or nondamaged tissue, as seen in Crohn's disease (intestinal inflammation) and diverticulitis. Childbirth can lead to fistulas between the rectum and vagina in women.

External fistulas are found during a physical examination. Internal fistulas can be seen by colonoscopy, upper and lower GI series, or CT scan.

Fistulas may be treated by surgery to remove the portion of the intestine causing the fistula, along with antibiotics to treat any associated infection.