Inflammatory bowel disease (IBD) involves the chronic inflammation of the digestive tract. Both ulcerative colitis and Crohn's disease are classified as a type of IBD. Ulcerative Colitis is a chronic disease of the large intestine in which the lining of the colon becomes inflamed and develops ulcers. Crohn's disease is the chronic inflammation of the entire gastrointestinal tract. Although they can have similar symptoms, such as diarrhea, ulcerative colitis only affects the inner lining of the colon and large intestine whereas in Crohn's disease inflammation can occur anywhere in the digestive tract and most commonly affects the last part of the small intestine (called the terminal ileum) and parts of the large intestine. Inflammation in Crohn's disease generally extends much deeper and affects all the layers of the bowel walls. Patients may develop colon ulcers, fissures and/or fistulas due to the severe damage to the bowel walls.
While both ulcerative colitis and Crohn's disease involve inflammation of the digestive tract, their symptoms can be similar but there are also distinguishable differences. Since ulcerative colitis involves inflammation as well as ulcers in the innermost lining of the large intestine, rectal bleeding is a common symptom. Ulcerative colitis also involves symptoms of lower left-sided abdominal pain, frequent stools, and mucous discharge. Crohn's disease involves symptoms of reoccurring abdominal pain and diarrhea usually followed by remission of symptoms. These conditions also share similar symptoms such as: diarrhea, bloating, abdominal cramps, nausea, weight loss. Mucus and blood can also be found in the stool if the lining of the colon is damaged.
Although the exact cause of IBD is unknown, researchers have tied the condition to a flawed immune system. It is thought that IBD can be caused by either an immune-mediated response, in which our immune system is working but working overtime or from an autoimmune condition, in which the immune system is defective and starts attacking healthy tissues. An autoimmune condition in IBD can come from the body making a specific type of antibody that attacks normal colonic proteins, like p40. The p40 protein helps aid in normal colon function. When the p40 protein and others like it get destroyed by the immune system, the symptoms of IBD arise such as discomfort and distress. More recent research shows another mechanism that may be involved in the pathogenesis of IBD. The body may be developing an intolerance to an important colonic auto-antigen called hTM5. If this is occurring, when the body develops intolerances to crucial colonic cells it causes an initiation of an expansive immune response in healthy tissues which leads to the destruction of parts of the epithelial cells in the colon and causes them to lose their function.
Toxicity may also be a cause of IBD. Mycobacterium avium, subspecies paratuberculosis (MAP) has been consistently identified in biopsies of the intestinal lining of Crohn's disease patients. Research results also suggest that ulcerative colitis may be caused by MAP. Although the mechanism on how this gram-positive intracellular pathogen triggers autoimmunity is not fully understood, MAP has been viewed as the common culprit for both Crohn's disease and ulcerative colitis. Infection of MAP causes a chronic intestinal immune inflammatory response which results in intestinal ulcerations. MAP is harbored in the ileocolonic mucosa of a proportion of normal people and can be detected in a high proportion of full thickness samples of inflamed Crohn's disease gut samples. Humans can get the MAP infection through consumption of contaminated milk, products made from contaminated milk, or via contaminated water caused by facet from infected cattle, cows, pigs and other domestic animals. MAP is more robust than tuberculosis, and therefore the risk conveyed to human populations in retail milk and domestic water supplies are high.