Ulcerative Colitis

How does the digestive system work?

Your digestive system, or GI tract, is made up of several organs that together help your body take in food, break it down, distribute nutrients and get rid of waste.

The upper GI tract includes the mouth, pharynx, oesophagus and stomach. Food is taken in through the mouth, chewed and swallowed down past the pharynx, then passed down through the esophagus and into the stomach.

The lower GI tract includes the large intestine, small intestine and anus. The small intestine has three parts: the duodenum (the first and shortest part of the small intestine, where most chemical digestion takes place), the jejunum (the middle part of the small intestine, largely responsible for absorption of nutrients), and the ileum (mainly responsible for absorbing vitamin B12, bile salts and other nutrients).

The large intestine includes the cecum (a pouch that connects the ileum to the large intestine, which aids in the breakdown of materials such as cellulose), colon (which removes water and salt and stores wastes) and rectum (the final part of the large intestine which serves as a storage area for waste).

The anus is the outer opening of the rectum and is mainly responsible for getting rid of waste from the body.

Ulcerative colitis only affects the colon (large intestine) and rectum. The inflammation (swelling) affects the mucosa (lining) of the colon.

In comparison, Crohn's disease can affect any area of the GI tract, from the mouth to the anus. The inflammation (swelling) extends deeper into the lining of the affected area than in ulcerative colitis. There can also be normal healthy bowel in between patches of diseased bowel in Crohn's disease.

Here is a list of the different types of ulcerative colitis and how they might affect you.

• Ulcerative proctitis: This only affects the rectum and tends to be a milder form of ulcerative colitis.

• Proctosigmoiditis: Colitis affecting the rectum and the sigmoid colon (the lower part of colon located above the rectum). Symptoms include bloody diarrhoea, cramps and an urge to use the toilet. There may also be pain on the lower left side of the abdomen.

• Left-sided colitis: Continuous inflammation starting at the rectum and reaching as far as the splenic flexure (a bend in the colon near the spleen). Symptoms may include weight loss, loss of appetite, diarrhoea, severe pain on the left side of the abdomen, and bleeding.
• Pan-ulcerative (total) colitis: This affects the entire colon. Symptoms can include diarrhoea, severe abdominal pain, cramps and extreme weight loss.

In severe cases

In severe total colitis, possible complications may include severe bleeding and sudden, severe dilation (widening) of the colon (toxic megacolon), which can lead to a perforation, or a small hole in the bowel which can let the contents pass through and cause infection. Although not many people have these problems, when they do happen they need urgent medical attention, and may need surgery.