Inflammatory bowel disease: ulcerative colitis & Crohn's disease
Inflammatory bowel disease (IBD) is a chronic inflammation of the intestines due to an abnormal immune response attacking the intestines. The two types of IBD are ulcerative colitis (UC) and Crohn’s disease (CD). Both diseases are commoner in the Western population but are gradually increasing in Asian countries. Genetic and environmental factors are involved in the cause of IBD. One interesting theory is the “hygiene hypothesis”. Worms are believed to regulate the immune response in the intestine in a helpful way. Improvement in hygiene levels results in less worm infestation, which reduces the beneficial effect of worms on the immune system, which in turn lead to an abnormal immune response, resulting in IBD.

What are the symptoms of inflammatory bowel disease?

1    Diarrhea persisting longer than 2-4 weeks. Diarrhea due to infections (called gastroenteritis) is self-limiting and resolves quickly in a few days, even without antibiotic treatment. Sometimes, the diarrhea can be prolonged beyond a few weeks and can be due to irritable bowel syndrome (IBS), a totally harmless but bothersome condition. This needs to be distinguished from conditions such as chronic infections (due to ameba, tuberculosis), malabsorption (tropical sprue and celiac sprue), cancer and inflammatory bowel disease (IBD). The number of stools passed per day correlates with the severity of the IBD.

2    Abdomen crampy pains. Chronic pains with altered bowel habit which last longer than 2 weeks may be a sign of IBD. Severe abdomen pain that is persistent, severe, or increasing in intensity needs to be evaluated quickly. This acute abdomen pain may be due to inflammation, obstruction, perforation of one portion of the involved intestine and can be a medical emergency. It needs to be distinguished from other causes such as gallbladder inflammation due to gallstones, pancreas inflammation and diverticulitis.

3    Blood in the stools. Bleeding to IBD usually occurs mixed with stools and mucus, accompanied by urgent sensation to move the bowels due to inflammation of the rectum lining. This contrasts to bleeding from piles which is bright red in color, usually occurs at the end of bowel movement and may be accompanied by pain or a small lump around the anus.

4    Weight loss and fever. The more severe forms of IBD are accompanied by nutritional deficiencies, weight loss and fever.

5    Other features. Mouth ulcers, joint and back pain (arthritis, ankylosing spondylitis), eye redness (uveitis), skin ulcers (pyoderma gangrenosum) and liver involvement (sclerosing cholangitis) are some of the complications that can occur in patients with IBD.

Ulcerative colitis (UC) affects only the large intestine, starting from the rectum and may extend to the cecum. Crohn’s disease (CD) can affect the entire digestive tract from the mouth, esophagus, stomach, duodenum, small intestine, large intestine and anus. The commonest areas of involvement in CD are the terminal ileum and colon.

Which diagnostic tests are needed?

1    Colonoscopy is needed to confirm the diagnosis of IBD, assess the extent of involvement and exclude other conditions such as tuberculosis, amebic infection, cancer and ischemic colitis.

2    Imaging of the small intestine in suspected Crohn’s disease may be required using barium studies, CT scan or MRI. In cases where only the small intestine is involved, video capsule endoscopy or small bowel enteroscopy may be required.

3    Additional tests to determine complications of IBD include blood tests, x-rays and CT scans.

What treatments are available?

Many factors are considered in making treatment decisions. These include: severity of disease, extent of involvement in the colon, involvement in the small intestine, cost considerations, patient’s preference and special considerations such as pregnancy and in children. Initially medicines such as steroids and 5-amino-salicylate (ASA) preparations are used. In severe or recurrent disease, stronger suppression of the immune system may be required with azathioprine, 6-mercaptupurine or anti-TNF injections (infliximab, adalimumab) to control the disease. Surgery may be needed in severe cases that do not respond to medical treatment.

[A] Colonoscopy appearance of a patient with active Crohn's disease. There are deep ulcers and a "cobblestone" appearance.

[B] Colonoscopy appearance of a normal colon. Note the smooth, glistening lining with a fine pattern of blood vessels.

[C] Barium X-ray of a patient with Crohn's disease involving the small intestine.  There is short narrowing of the intestine (stricture) due to inflammation. The patient was successfully treated with azathioprine.
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Dr Yap Chin Kong


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