I am 19 years old and was diagnosed with Crohn's disease two years ago. I often get stomach pains accompanied by diarrhea. I've also noticed blood in my stool and coming from my bottom. My doctor did tell me that along with Crohn's some people get a condition called an anal fistula. What is that? Do you think I need to get checked out?

Trisha

Crohn's disease (CD) is a chronic inflammatory disease typically affecting the lower small intestine (ileum) and/or the colon. It can involve any part of the intestinal tract from the mouth to the anus. Typical symptoms include abdominal pain, diarrhea, weight loss, fevers and sometimes bleeding from the rectum.

The complications of Crohn's disease include bowel obstruction (due to scarring from the long-term inflammation), abscess formation in the abdomen, increased risk of colon cancer and, as your doctor mentioned, fistulas. Fistulas are simply abnormal connections between the bowel and another organ. They occur when inflammation in a bowel segment spreads to involve adjacent organs. Fistulas commonly occur in Crohn's disease because the inflammation in the intestinal segments involves their entire thickness, including the muscle and outer layer of the intestine. Typically, fistulas occur between two bowel loops, or from bowel to bladder, vagina, skin or other structures. The treatments for fistulas include medications (immunosuppressive drugs and antibiotics) and, if medications are ineffective, surgical procedures.

Up to one-third of patients with Crohn's suffer from perianal fistulas. In this situation, the opening of the fistula is located near the anus. It is unclear why the anus is so predisposed to fistulas in Crohn's. Typically, the symptoms of a perianal fistula include pain in the anal region (especially with defecation) and a discharge that may be foul-smelling (due to infection or abscess). Bleeding is not a common symptom of a fistula, however.

In your case, if the bleeding is a new symptom, it should be evaluated. This is especially true if you have not had a recent colonoscopy. If you have not had colonic involvement as part of your CD, it may be starting. Also, your gastroenterologist can closely examine the perianal area to look for a possible fistula.