What are IBD and IBS?

There are two types of inflammatory bowel disease:

• Ulcerative Colitis
• Crohn's Disease

These are both autoimmune disorders, meaning that the body's immune system is attacking the bowel. Nobody really knows why this happens, though there does seem to be a genetic component - at least with Crohn's Disease. Some recent reseach suggests that the problem in Ulcerative Colitis is that the body mistakes the beneficial bacteria in the large bowel as a threat, and in attacking it harms the bowel.

Like most autoimmune diseases, IBD can be triggered or worsened by stress, which is not to say it's "all in your head". Stress affects the immune system, so why shouldn't it affect an immune system disorder? But nobody really understands why this happens, either.

Ulcerative Colitis (UC) is an inflammation of the intestinal mucosa, generally affecting the large bowel. The inflammation usually starts near the rectum (ulcerative proctitis) and if the disease worsens it spreads upward. Some people have only "left-sided disease" (inflammation only in the sigmoid colon). An unlikely 10% (that would include me) have inflammation throughout the entire bowel, called "universal ulcerative colitis" or "pancolitis". UC is characterized by bloody diarrhea mucous (white stuff streaking the stool or in the toilet).

Crohn's Disease (CD) is an inflammation that extends deeper into the intestinal wall than UC. It usually affects the small bowel rather than the large bowel, and for both these reasons can be a more serious condition. The small bowel is where most nutrients are absorbed, so CD patients can have nutritional deficiencies. CD is characterized by chronic diarrhea, but there may be little or no blood.

Irritable Bowel Syndrome (IBS) is "functional bowel disease" with no obvious physical problem. There's no inflammation in the colon or any other obvious physical dysfunction. That is not to say, however, that there is no physical dysfunction. There is a whole separate nervous system in the bowel, and there is research that suggests the spasms of IBS are caused by problems in the enteric nervous system (see "The Second Brain"). Unlike UC and CD, IBS is not life threatening.