Crohn's disease may lead to one or more of the following complications:

  • Inflammation. Inflammation may be confined to the bowel wall, which can lead to diarrhea and bleeding. Inflammation can also lead to scarring and narrowing (stenosis) or may spread through the bowel wall (fistula).
  • Bowel obstruction. Crohn's disease affects the full thickness of the intestinal wall. Over time, parts of the bowel can thicken and narrow, which may block the flow of digestive contents. You may require surgery to remove the diseased portion of your bowel.
  • Ulcers. Chronic inflammation can lead to open sores (ulcers) anywhere in your digestive tract, including your mouth and anus, and in the genital area (perineum).
  • Fistulas. Sometimes ulcers can extend completely through the intestinal wall, creating a fistula — an abnormal connection between different body parts. Fistulas can develop between your intestine and skin or between your intestine and another organ. Fistulas near or around the anal area (perianal) are the most common kind.

    When fistulas develop in the abdomen, food may bypass areas of the bowel that are necessary for absorption. Fistulas may occur between loops of bowel, into the bladder or vagina, or out through the skin, causing continuous drainage of bowel contents to your skin.

    In some cases, a fistula may become infected and form an abscess, which can be life-threatening if not treated.

  • Anal fissure. This is a small tear in the tissue that lines the anus or in the skin around the anus where infections can occur. It's often associated with painful bowel movements and may lead to a perianal fistula.
  • Malnutrition. Diarrhea, abdominal pain and cramping may make it difficult for you to eat or for your intestine to absorb enough nutrients to keep you nourished. It's also common to develop anemia due to low iron or vitamin B12 caused by the disease.
  • Colon cancer. Having Crohn's disease that affects your colon increases your risk of colon cancer. General colon cancer screening guidelines for people without Crohn's disease call for a colonoscopy every 10 years beginning at age 50. However, depending on how long you have had Crohn's disease and how much of your colon is involved, you may need a colonoscopy as often as every one to two years. Ask your doctor how often you should have a colonoscopy.
  • Other health problems. Crohn's disease can cause problems in other parts of the body, such as inflammation of the eyes, skin or joints; anemia; osteoporosis; inflammation of the liver or bile ducts; and delayed growth or sexual development in children.
  • Medications. Certain medications for Crohn's disease that act by blocking functions of the immune system are associated with a small risk of developing cancers such as lymphoma and skin cancers. They also increase risk of infection.

    Corticosteroids can be associated with a risk of osteoporosis, bone fractures, cataracts, glaucoma, diabetes and high blood pressure. Work with your doctor to determine risks and benefits of medications.

Possible complications of ulcerative colitis include:

  • Severe bleeding
  • A hole in the colon (perforated colon)
  • Severe dehydration
  • Liver disease (rare)
  • Bone loss (osteoporosis)
  • Inflammation of your skin, joints and eyes
  • Sores in the lining of your mouth
  • An increased risk of colon cancer
  • A rapidly swelling colon (toxic megacolon)
  • Increased risk of blood clots in veins and arteries
Sep. 27, 2014

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