What is Inflammatory Bowel Disease? (IBD)
Inflammatory Bowel Disease describes two diseases, ulcerative colitis and Crohn's disease, which cause inflammation of the bowel. Ulcerative colitis causes inflammation of the inner lining of the large bowel (colon and rectum). When only the rectum is involved it is called proctitis, and when the entire colon is involved it is called total colitis. Crohn's disease often causes inflammation of the full thickness of the bowel wall and may involve any part of the digestive tract from the mouth to the anus. Most frequently the ileum, which is lower part of the small bowel, and the large bowel are involved.
The cause is unknown, but many studies have shown the importance of normal gastro-intestinal bacteria in the pathogenesis of IBD.
Approximately 2 x 10^14 bacteria reside in the gastrointestinal tract, and there are more than 500 different types of bacteria
There is a complex barrier which prevents the bacteria from penetrating the bowel wall. The barrier includes mucus and IgA antibodies which are in the lumen of the bowel, and prevent bacteria attaching to the bowel wall. Epithelial cells, (surface cells of the bowel wall), are also effective in preventing bacteria invading as they produce anti-bacterial substances.
The bacteria which break through this barrier are destroyed by the cellular immune system which is made up of lymphocytes and leucocytes.
IBD occurs in areas of the gastrointestinal tract exposed to the highest concentration of bacteria, i.e. at the junction of the small and large bowel.
The most plausible hypothesis is that when the barrier breaks down due to one or more genetic mutations, bacteria enter the bowel wall and produce chronic inflammation and ulceration, i.e. inflammatory bowel disease.
Common symptoms include disabling abdominal pain, diarrhoea and weight loss. Many patients have chronic abscesses and leakage around the anus, causing severe pain and impairing sexual activity. See the personal stories for a fuller description of how IBD affects young lives.
What Tests are used to Make the Diagnosis
Blood tests to confirm anaemia, inflammation, vitamin and mineral deficiencies. Most people, however, require colonoscopy, (a flexible tube inserted through the anus), or a gastroscopy, (via the mouth) .