What is colitis?

Colitis is an inflammation of your colon, also known as your large intestine. Dr Simon Anderson explains the main symptoms associated with colitis and how it is typically diagnosed.

What is colitis?

The term colitis means inflammation of the lining of the colon (large bowel/intestine) – the last part of the digestive tract. This means that the lining has become red, swollen and ‘angry’. Sometimes the inflammation can lead to the breakdown in parts of the lining causing ulcers. The inflammation can involve the whole of the colon or a part of it. If only the last part of the colon (rectum) is involved, it is called proctitis.

Colitis can occur due to an infection (e.g. salmonella) in which case it is termed ‘infectious colitis’; medication (such as certain anti-cancer drugs, or non-steroidal anti-inflammatory drugs) or it can occur spontaneously due a problem in one’s immune system – called inflammatory bowel disease.

Inflammatory bowel disease comprises two different diseases – Ulcerative Colitis and Crohn’s disease. Ulcerative colitis involves only the colon, whereas Crohn’s disease can involve any part of the digestive tract. When Crohn’s disease involves only the colon, it is termed Crohn’s colitis.

What are the symptoms of colitis?

When the colon is inflamed it is unable to absorb liquids which results in diarrhoea – which is the commonest symptom of colitis. If ulcers are present, bleeding also occurs and sometimes mucus. The symptoms of colitis are variable. They can start suddenly or gradually without any obvious cause. The severity of the diarrhoea and bleeding will depend on the amount of colon that is inflamed. Although colitis is a lifelong condition, it can resolve for long periods before flaring up again. Some patients have persistent symptoms that wax and wane and some have severe symptoms that are associated with nausea, fever and abdominal pain.

Typical symptoms include:

  • Diarrhoea – usually with blood and sometimes also mucus. This is usually unrelated to mealtimes and often associated with an urgent need to pass stool.
  • Loss of appetite, nausea and weight loss due to reduced food intake.
  • Feeling very tired and non-specifically unwell. Tiredness can also be due to a lack of sleep due to waking up to pass stool.
  • If the colitis is more severe, a fever and rapid heartbeat can occur.

How is colitis diagnosed?

Blood tests may show a low blood count (anaemia) due to blood loss. Other findings on blood tests include a low protein (albumin) level and raised inflammation markers. Stool tests are useful to exclude an infection. In addition, the stool inflammation marker, calprotectin, is raised in ulcerative colitis, and is useful to exclude other causes of diarrhoea such as irritable bowel syndrome (IBS), which typically shows a normal calprotectin level.

Endoscopic tests are also a good diagnostic tool. There are three options:

  • Flexible sigmoidoscopy: A flexible tube with a camera in its tip that is passed through the anus (back passage) into the lower (sigmoid) colon. This enables the lining of the lower colon to be examined and biopsies to be taken at the same time which will confirm the diagnosis. The procedure is relatively quick however inhaled Entonox (‘gas and air’) or sedative medication can be used if needed.
  • Colonoscopy: This is similar to a flexible sigmoidoscopy but the scope is inserted through the whole colon. A sedative medication is given as the procedure takes longer than a sigmoidoscopy and sometimes can be mildly uncomfortable.
  • Upper gastrointestinal (GI) endoscopy (gastroscopy): If there are symptoms in the upper part of your digestive system as well as the colon, a upper GI) endoscopy or gastroscopy is needed. In this, an endoscope is inserted through your mouth to examine your oesophagus, stomach and duodenum (the first part of the small intestine or bowel).

How is colitis treated?

Ulcerative colitis and Crohn’s colitis are treated initially with medication which is often very effective. However, if the inflammation does not respond and becomes more severe, surgery may be needed to remove the inflamed bowel.

The medication is initially designed to settle the inflammation down and then to prevent it coming back (called maintenance treatment). Most people with colitis will need to take maintenance treatment for several years with increased doses when the inflammation returns (flare-ups).

Mediation options include:

  • Mesalazine: an anti-inflammatory medication which has a protective coating to prevent it from being absorbed in the upper GI tract, and thus enable it to be delivered, unabsorbed to the lower GI tract (the colon), the site of inflammation.
  • Mesalazine can also be given as a suppository (a large elongated pill which is inserted into the rectum) or as an enema ( a liquid or foam which is inserted into the rectum with a hand-held device).
  • Corticosteroids (steroids) can be given as tablets, enema or intravenously (to treat severe colitis)
  • Immunosuppressant medication dampens down the immune system to reduce the inflammation.
  • Biological drugs are the newest medicines to treat colitis. They are antibodies which block parts of the immune system. These are administered either as an intravenous infusion or as a self-administered injection (like an insulin injection).
  • Other treatments, which do not treat the inflammation, can be used to reduce the frequency of diarrhoea (e.g loperamide), control cramping pain (e.g mebeverine, buscopan) or improve stool frequency and bloating (special diets, and/or probiotics).

Where can I learn more about colitis?

For more information and helpful resources, you can visit the Crohn’s and Colitis UK website.

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Written by Dr Simon Anderson

Dr Anderson founded, and now leads, the video capsule endoscopy and balloon enteroscopy service at Guy’s and St Thomas Hospital. He is one of the foremost practitioners in the field, with dual accreditation in gastroenterology and general medicine.