Patients may experience a variety of medical complications as a result of Crohn’s disease (CD). These include:

• Obstruction. Created when scar tissue or swelling from the chronic inflammation of CD narrows gastrointestinal passageways. The intestines may become completely or partially obstructed. This may block digestion and require surgery to remove the diseased portion of the bowel. Obstruction is the most common complication in patients with CD.
  
  
• Fistulae. Abnormal tunnels that develop when ulcers break through intestinal walls, creating a tract that connects to nearby tissue (e.g., other parts of the intestines, the bladder, vagina or skin). These tunnels may become infected and abscesses (collection of pus) may develop, which require drainage. Fistulae often appear in areas around the rectum and anus. Medication is sometimes used to treat fistulae, although some cases require surgery. Fistulae occur in approximately 30 percent of patients with CD, according to the Crohn’s & Colitis Foundation of America (CCFA).
  

  

• Anal fissures. Tears in the lining of the anus where infections may occur. Patients with CD may develop fissures, which can cause pain, itching and bleeding, especially during bowel movements. Most fissures heal on their own and do not require treatment.
  

  

• Malnutrition. Insufficient amounts of calories, proteins and vitamins. Patients with CD may find it difficult to eat, or their intestines may fail to absorb enough nutrients (malabsorption), due to abdominal pain and diarrhea common in CD. Treatment involves the replacements of nutrients, either through injections or supplements in tablet or liquid form.
  
  
• Toxic megacolon. Occurs when the large intestine widens, losing muscle tone. This inflammation may cause the colon to rupture. Symptoms include abdominal distention, fever, pain and shock. This life-threatening condition requires immediate medical attention and usually surgery.
  
  
• Impaired development in children. Children 18 and under who have CD may experience stunted or delayed physical growth as well as delayed sexual development. The use of steroids to treat CD in children may also retard growth. Aggressive nutritional therapy with supplements (e.g., enteral and parenteral nutrition) can help normalize growth in children with CD.
  
  
• Osteoporosis. A decrease in bone mass that causes bones to be weak and easily fractured. Thirty to 60 percent of patients with inflammatory bowel disease have low bone density, according to the CCFA. Patients who have had CD for a long time, postmenopausal women and people using steroids have a greater risk of developing osteoporosis. Blood tests can identify vitamin deficiencies that may indicate osteoporosis and periodic bone density testing can identify early osteoporosis in patients with CD. Osteoporosis develops in many patients with CD at the age when bones are normally the densest (early 20s and 30s). Nutritional supplements (e.g., calcium and vitamin D) and weight-bearing exercises can help build bone strength.
  
  
• Liver and biliary function problems. Gallstones, kidney stones and other diseases of the liver and bile ducts may occur in patients with CD. Gallstones may require surgical removal. Kidney stones may be passed during urination or require urology consultation.

  

• Clotting problems. In some cases CD may cause problems with blood clotting (deep vein thrombosis).
  
  
• Short bowel syndrome. Patients who have surgery to remove large portions of the small intestine may be at risk for short bowel syndrome. It can cause serious problems in the ability to absorb nutrients, and requires treatment with parenteral nutrition.