Crohn's disease is a type of inflammatory bowel disease, causing swelling and inflammation of the digestive tract. One of the symptoms of Crohn's disease is the formation of fistulas, which are small tunnels or openings, either connecting one loop of the intestines to another loop or to another part of the body, such as the bladder or vagina. These fistulas are caused by the inflammation and other changes in the intestines caused by Crohn's disease.
Inflammation
Inflammation of the lining of the digestive tract is the first step towards the development of a fistula. The inflammation causes the intestines to form scar tissue and become abnormally thick. This thickening and distortion of the intestines can lead to the formation of ulcers, or sores, on the inside lining of the intestines. When these ulcers grow deeper, they can begin to tunnel through the wall of the intestine, forming a gap or tunnel that leads to whatever tissue is next to the sore, such as the vagina, bladder or the skin, explains the National Digestive Diseases Information Clearinghouse.
Abscesses
Abscesses, small infected cavities filled with pus, are often linked with fistulas, particularly fistulas in the area of the anus or rectum. Approximately 25 percent of patients with Crohn's disease will develop a fistula or abscess at some point during their lifetimes, reports the Crohn's and Colitis Foundation of America. Anal abscesses result from infection of the small glands inside the anus. Crohn's disease increases the risk of infection of these glands, explains Jackson Siegelbaum Gastroenterology.
Draining Abscesses
In some cases, an anorectal abscess will rupture, causing the pus to drain out. The infected abscess may then turn into a sore or ulcer, which can deepen and grow into a fistula, the Merck Manuals Online Medical Library explains. When a fistula forms from an anorectal abscess, it often leads to the skin on the buttocks, causing an opening leading from the anus out of the body, reports the American Society of Colon and Rectal Surgeons.
References
- Crohn's and Colitis Foundation of America: Surgery for Crohn's Disease
- American Society of Colon and Rectal Surgeons: Anal Abscess/Fistula
- Jackson Siegelbaum Gastroenterology: Anal Fissure, Abscess and Fistula
- The Merck Manuals Online Medical Library: Anorectal Fistula(Fistula in Ano)
- National Digestive Diseases Information Clearinghouse: Crohn's Disease
