Crohn's disease is one form of inflammatory bowel disease. Patients with this condition have an abnormally activated immune system, which causes it to attack the healthy tissue of the intestines. This leads to intestinal damage and inflammation, which causes the intestines to lose some of their ability to absorb digested food. Crohn's can also cause a number of complications, some of which affect many other parts of the body.
Blockage
According to the National Digestive Diseases Information Clearinghouse (NDDIC), the most common complication of Crohn's disease is blockage of the intestines. Because Crohn's disease causes inflammation of the intestinal walls, the intestines can become swollen or covered in scar tissue. This can lead to an obstruction, causing pain in the abdomen, vomiting and abdominal bloating. Blockage can be treated using anti-inflammatory medications or surgery.
Fistulas
The Crohns's and Colitis Foundation of America (CCFA) notes that another common complication of Crohn's disease is ulcer formation. Ulcers are sores that develop in the tissue of the intestines as a result of the damage done from inflammation. Sometimes the ulcers are deep enough that they turn into small tunnels or tracts, which are called fistulas, between different parts of the intestines. Fistulas become infected very easily because they lack the normal support of other tissues around them and may have to be surgically removed.
Malnutrition
According to the Mayo Clinic, Crohn's disease can also cause patients to suffer from malnutrition. This is because Crohn's disease often saps a patient's interest in eating and limits the intestine's ability to absorb nutrients. This can lead to vitamin deficiencies, sudden weight loss and anemia (from lack of iron).
Anal Fissure
Crohn's can also affect the anus directly or the skin around it. This can lead to the formation of a crack or a cleft in this area, which can become easily infected (often due to contamination from fecal matter). This complication of Crohn's typically manifests itself as pain during bowel movements.
