Colitis is an uncomfortable and at times painful inflammation of the colon. The colon's main job is to absorb water from the fecal matter and solidify feces. When the cells of the colon get inflamed, water absorption becomes impaired. Consequently, colitis typically causes diarrhea (sometimes bloody), as well as abdominal pain.
Inflammatory Bowel Disease
Inflammatory bowel disease describes auto-immune conditions which can cause colitis. Auto-immune diseases are the result of the immune system accidentally believing that healthy tissue (in this case, tissue from the colon) is actually something foreign. This causes the immune system to attack the colon, leading to inflammation. Two types of inflammatory bowel disease that can lead to colitis are ulcerative colitis and Crohn's disease.
Microscopic Colitis
Microscopic colitis is another form of colitis that is caused by an auto-immune disorder. There are two types of microscopic colitis: collagenous colitis and lymphocytic colitis, which result in a buildup of collagen and white blood cells, respectively, in the walls of the colon. These two diseases are more common in older women and typically have to be diagnosed by taking a look at a tissue sample underneath a microscope.
Infectious Colitis
Infectious colitis describes any sort of colon inflammation that is the result of an infection. These infections are typically from bacteria, including E. Colu, Salmonella, Shigell, and Campylobacteria. These bacteria can access the colon if the patient eats contaminated food (i.e. food poisoning). Another bacteria that can infect the colon, C. dificile, often colonizes the large intestine after other bacteria have been killed off by antibiotics.
Chemical Colitis
The colon can also become inflamed if harsh or abrasive chemicals irritate the lining of the large intestine (also known as the mucosa). This form of colitis is most common in people whose colon's have been irritated by the chemicals in an enema.
Ischemic Colitis
Ischemia is the condition in which blood flow to an organ is interrupted, leading to tissue damage (or death) and inflammation. Sometimes ischemia is caused by narrowing of the arteries which transport blood to the colon, a condition which is known as atherosclerosis or arteriosclerosis. Other times the arteries become blocked off, either by the intestines twisting around themselves (a condition known as volvulus) or from them getting wrapped around an abdominal hernia.
