What is Inflammatory Bowel Disease or “IBD”?
Inflammatory bowel disease (IBD) is a term used to describe two main diseases, ulcerative colitis and Crohn’s disease, which cause inflammation of the bowel. This inflammation is thought to be due to dysfunction of your immune system, and is not due to an infection.
Ulcerative colitis causes inflammation of only the inner lining of the colon and rectum (large bowel). When only the rectum is involved it is sometimes called ulcerative proctitis or just proctitis. When the entire colon is involved it is sometimes called pan-colitis. Crohn’s disease 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 (back passage). Most frequently the ileum, which is the last part of the small bowel, the colon or both are involved. These patterns of disease location are referred to as ileitis, colitis and ileo-colitis respectively. Sometimes people get confused between Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS).
The two conditions are quite different and so are their treatments. Inflammatory Bowel Disease is where there is visible inflammation or damage to the bowel, whereas in Irritable Bowel Syndrome there are multiple symptoms related to the bowel (abdominal pain, diarrhoea, constipation, bloating), but blood tests are normal and nothing can be seen with endoscopy / colonoscopy or x-rays. It is thought to be due to nerve sensitivity, hence the use of the word irritable. The two conditions IBD and IBS can, however, occur in the same person.
What causes ulcerative colitis and Crohn’s disease?
Despite a great deal of research, the precise causes of ulcerative colitis and Crohn’s disease are unknown. There is evidence, however, that genetic, environmental, immunological and infectious (bacterial) factors are all involved to a degree, and it may be their interaction in susceptible people that causes IBD to develop. Ulcerative colitis and Crohn’s disease are not contagious diseases.
Relatives of people with IBD have a slightly greater risk of developing either disease, but even if both parents have IBD you still have a greater than 60% chance of NOT having it. Stress and/or diet alone are not thought to cause IBD, although attention to both these factors improves quality of life with IBD. Both diseases are more common in the Western world, although their incidence is also rising in developing countries.
Who gets IBD?
IBD often develops between the ages of 15 and 30 but can start at any age; it is uncommon, but becoming increasingly seen, in children. It is slightly more common in women in Australia than in men. It is estimated that about 61,000 Australians have IBD, approximately 28,000 have Crohn’s disease and 33,000 have ulcerative colitis.
What are the symptoms of IBD?
People with either ulcerative colitis or Crohn’s disease can develop pain in the abdomen, diarrhoea (usually with blood and mucus when you have ulcerative colitis), tiredness and weight loss (especially with Crohn’s disease). Some people may also experience fever, mouth ulcers or nausea and vomiting. People with Crohn’s disease may also get pain or swelling around the anus, with or without a discharge.
A few people have disease affecting other parts of the body and may experience swollen joints, inflamed eyes, skin lumps or rashes, or jaundice (yellow discolouration of the skin). The symptoms and their severity vary from person to person and usually flare up or improve over time. Many people will experience periods of remission when they are completely free of symptoms. Medical therapy these days aims to prolong these periods of remission, rather than allowing repeated flares of disease activity. With current medical treatment, life expectancy is normal.
What tests are used to confirm the diagnosis of ulcerative colitis or Crohn’s disease?
The diagnosis of Crohn’s disease or ulcerative colitis is often delayed as the same symptoms can occur with other diseases. When symptoms and signs are severe, the diagnosis is usually made promptly, but in milder cases delays are usual. In general, unless symptoms have been going for more than 8 weeks, it is usually necessary to exclude bowel infections or gastroenteritis (which may occur from contaminated food or after a prolonged course of antibiotics). In mild cases, without rectal bleeding or weight loss, IBS is often first diagnosed, as IBS is far more common than IBD. Any abnormal test result, however, should guide the diagnosis away from IBS.
Tests which help point towards a diagnosis of IBD include blood tests which may show anaemia, raised white cell or platelet count and elevation in CRP or ESR, which are markers of inflammation in the body. Blood tests are also useful to look for complications of IBD, such as iron deficiency or other vitamin or mineral deficiencies. A faecal (bowel motion) specimen may need to be examined to exclude infection.
Most people require an examination of part of the bowel, either by direct inspection via a flexible tube inserted through the back passage (colonoscopy or sigmoidoscopy) or mouth (gastroscopy), or by x-rays, which may include CT or MRI scan and/or barium small bowel series (where dye is swallowed and x-rays are taken). There is no one test that can reliably diagnose all cases of IBD, and many people require several tests, although the diagnosis of IBD is usually strongly suspected from a careful medical history.
Depending on the severity of your symptoms, it is common for it to take 6-18 months from the first onset of symptoms until a positive diagnosis of IBD is made. In most cases this delay does not lead to any additional problems.
How is IBD treated?
The type of treatment you will be offered depends on whether you have ulcerative colitis or Crohn’s disease, which part of your gut is affected and how severe your disease is. There are also some opportunities for you and your doctor to choose between treatments that are similarly effective, but may have different actions and side effect profiles.
When more of the bowel is affected, your doctor may suggest you take medicine by mouth. Medicines used to treat IBD include sulphasalazine (Salazopyrin), coated mesalazine (Mesasal, Salofalk granules and tablets, Pentasa tablets and granules), Mezavant tablets, balsalazide sodium (Colazide) or olsalazine sodium (Dipentum). Steroid tablets (usually prednisolone) may be required if the inflammation is more severe or if more extensive amounts of the bowel are involved.