Inflammatory Bowel Disease
Inflammatory Bowel Disease (IBD) is a term usually used to describe Crohn’s Disease (CD) and Ulcerative Colitis (UC). Both are chronic diseases that cause inflammation of the gastrointestinal tract. In 5-10% of patients, in which IBD affects the colon (large bowel) alone, it can be difficult to make a definite diagnosis of either UC or CD in which case the term indeterminate colitis, or IBD-unclassified are used.
What causes IBD?
A single cause for IBD has not been identified. We do know that both genes and environmental factors (for example, smoking and childhood exposure to infections) are likely to play a role.
How common is IBD?
There are between 180,000 and 200,000 people in the UK with IBD. Of these 60-80,000 will have CD and 120,000 UC. An average sized UK hospital sees 45-50 new cases of IBD per year and has around 500 people with IBD under follow up. The number of newly diagnosed cases is relatively stable although the incidence of CD may be increasing.
Can I pass on IBD to my children?
Recent studies show that there is a genetic component to both diseases. For UC, having a first degree relative increases the risk of developing the disease by 10-15 fold which equates roughly to a 5% risk. This does mean however that there is a 95% chance of not developing the disease. There is a similar 10 fold increase in risk in CD, though this is greater in some ethnic groups such as Ashkenazi Jews.
What is Ulcerative Colitis?
Ulcerative Colitis causes inflammation of the mucosa (the inside surface) of the colon. Generally speaking the inflammation is continuous and starts in the rectum, extending up the colon to varying degrees. UC most commonly starts in young people, with a peak incidence between 10 and 40yrs. However, some can develop it later in life.
Any cause of inflammation of the colon, (for example infection) can cause diarrhoea and occasionally blood. However, unlike infections, which normally resolve within a few days or weeks, ulcerative colitis tends to cause symptoms for long periods of time.
How is UC diagnosed
The diagnosis of UC is made with a combination of medical history, clinical evaluation and endoscopy. Blood tests (for example to check for anaemia) and stool sample tests (to rule out infection) are also normally taken.
Of these tests, the most important is a colonoscopy. This shows how far the disease extends (which affects how the condition is treated) and allows biopsies to be taken so a firm diagnosis is made. Colonoscopy helps to differentiate between Crohn’s and UC and also helps to rule out other causes of bloody diarrhoea.
How is UC treated?
The treatment depends on the severity and extent of disease. The treatment of UC and Crohn’s disease is similar but not identical. A limited number of drugs are effective, including:
5- Aminosalicylic Acid (5-ASA)
The first line of therapy in UC is a group of drugs called 5-ASAs (short for 5-AminoSalicylic Acid). These anti-inflammatory drugs can be taken either by mouth (as tablets or granules) or inserted directly into the large bowel through the anus (as suppositories, liquid enemas or foam).
For inflammation limited to the last few centimetres of the bowel (known as proctitis) suppositories are normally the most effective treatment as they deliver the drug in high concentration directly to where it is needed. For more extensive disease, enemas, tablets, or a combination of the two are required.
Steroids, such as prednisolone, are a very effective treatment in the short-term to control acute inflammation, and used in this way have few serious side effects. However, they should not be used to suppress the disease for long periods as the side effects become more of a problem with increasing usage.
As well as tablets, steroids can also be given as injections, suppositories and enemas. If the disease is severe, intravenous steroids may be needed in hospital.
Decreasing the dose of steroids too quickly may cause the disease to relapse. However, more importantly, it can be dangerous and should not be done without prior consultation with a doctor.
A variety of drugs which affect the immune system are used to treat IBD; these are termed immunosuppressants. The most commonly used are azathioprine, mercaptopurine, cyclosporine and methotrexate.
Immunosuppressants are normally used in people who need frequent steroid treatment. As they take 2-3 months to have their full effect, they are generally used to keep the disease in remission rather than to get it under control. As such, they are often started once a flare up has been controlled and the dose of steroids is being reduced.
These drugs require close monitoring with regular blood tests. We will discuss the potential side effects of these medications fully with you if they are needed.
Other therapies in UC
There has been a huge explosion of the use of drugs called biologics in the treatment of inflammatory bowel disease. These appear to be less effective in UC than in Crohn’s disease.
Probiotic therapies in UC show promise but experience of their use is limited. There is some study evidence that aloe vera may be helpful in mild or moderately active disease.
While some of these may be effective, they are generally only suitable for mild or perhaps moderate disease and do not represent an alternative to steroids or immunosuppressants for most people.
Colorectal Cancer risk and UC
Colorectal cancer (CRC) is a common disease affecting between 1 in 20 and 1 in 25 of the population in the UK. Patients with longstanding UC have a higher risk of developing CRC than the average population. The degree to which the risk is increased is debatable. However, the risk is highest in those with extensive active colitis and intermediate in those with left sided disease. People with proctitis have no increase in risk. The risk is increased in people who also have a condition called primary sclerosing cholangitis (a disease of the liver associated with IBD).
Current guidelines suggest that a colonoscopy is carried out about 8-10 years after diagnosis to check the extent of the disease. Further procedures are then performed at intervals of 1-3 years depending on individual circumstances.
When is surgery needed in people with UC?
Surgery was previously the only effective treatment for ulcerative colitis. Even with the enormous advances made over the last few years in the treatment of UC, surgery still has a very important role to play. Generally speaking, surgery is recommended if the condition is not responding to medical therapy or if pre-cancerous cells or colorectal cancer is found at colonoscopy. In patients who have a severe attack of UC and are in hospital, urgent surgery is sometimes required. Indeed, deferring surgery in favour of more medical therapy in patients with severe illness who are not responding to treatment may be detrimental.
If you are one of the small proportion of people who requires surgery to control your condition, you will be referred to a specialist colorectal surgeon who is experienced in treating IBD. They will be able to advise you about what surgery involves and the different operations that can be performed.
What is Crohn’s disease?
Crohn’s disease is another disease that causes inflammation of the bowel. However, unlike UC, Crohn’s disease can affect any part of gastrointestinal tract from the mouth to the anus. Most commonly it affects the end of the small bowel (terminal ileum) and colon.
The cause is unknown, but is currently thought to be related to an imbalance between the bacteria in the gut and the host’s immune system. Genetic factors are also important.
Like UC, the most common presenting feature of CD is chronic diarrhoea. However, many of patients present with predominantly abdominal pain and weight loss and some with rectal bleeding or a combination of all of these symptoms. CD can be a debilitating disease. Chronic diarrhoea is very common. Crohn’s disease can cause strictures (narrowings) in the bowel, which may lead to blockages. Inflammation around the anus can cause fistulas (connections between the bowel and the skin) to occur.
However, Crohn’s disease isn’t always severe. Most people with the condition lead normal lives and are relatively untroubled by their disease, to the extent that it never diagnosed.
Endoscopy is very important in establishing the diagnosis of Crohn’s disease. Most commonly this will be a colonoscopy unless there are symptoms consistent with possible upper gut involvement, in which case a gastroscopy will be useful.
Viewing the small bowel is also important in Crohn’s disease. Barium tests of the small bowel are being replaced by CT and MRI scans. We can now also perform a capsule endoscopy; this has become a very useful tool in finding out exactly how much bowel is affected, and is also useful for finding subtle disease changes.
As in UC, blood tests and stool cultures are useful for assessing severity and response to treatment.
What drugs are used to treat Crohn’s disease?
Many of the drugs used to treat CD are the same as those described for use in UC. However, there are some important differences that we will now discuss.
Unlike in UC, there is evidence that special polymeric or elemental liquid diets, are an effective treatment for CD. Because they are most effective if all normal food is eliminated, they are not used commonly for adults. However, your doctor will be happy to discuss the pros and cons of dietary treatment with you and you may need to see our specialist dietitian.
5-ASAs have a limited role to play in Crohn’s disease being at best mildly effective in some people. However, they are still used because they have few side effects.
Antibiotics are commonly used to treat abscesses inside the abdomen or in the skin if they have fistulas. Drugs like ciprofloxacin and metronidazole are also used to treat fistulas and sometimes to treat active inflammation in the bowel (for which they may be slightly effective).
Prednisolone is a highly effective treatment for active Crohn’s disease. However, if used in the long term, steroids cause multiple side effects including weight gain, hypertension, diabetes and osteoporosis. As they are also ineffective at keeping Crohn's disease in remission, they are only used for short periods of time.
A newer type of steroid, budesonide, is slightly less effective but has fewer side effects. It is used to treat Crohn’s disease affecting the last bit of the small bowel.
As with UC, azathioprine, mercaptopurine and methotrexate are used to treat Crohn’s disease. Again, it is important to remember that these drugs take 2-3 months to work and are generally used to keep the condition in remission rather than to get it under control.
Biologic therapy and Crohn’s disease
The use of biologic therapy in CD has increased exponentially in the last few years. Infliximab and adalimumab are the most commonly used. They are antibodies to an inflammatory molecule in the body called Tumour Necrosis Factor (TNF), so these drugs are sometimes termed anti-TNF therapy. Infliximab is given as an intravenous infusion in hospital every few weeks, whereas adalimumab is taken at home as an injection under the skin once a fortnight. In the UK, infliximab and adalimumab are generally used in patients in whom other therapies have failed.
As with the immunosuppressants, these are powerful drugs that affect the immune system. They require close follow up and regular review and have potential side effects that we will need to discuss if this treatment is proposed.
A wide variety of other treatments have been used to treat Crohn’s disease. Many of these are undergoing clinical trials as possible future treatments. However, for the moment at least, your treatment is likely to be based on the drugs outlined above.
Is there anything I can do myself to improve my Crohn's disease?
Yes – if you smoke. Smoking not only worsens active disease but makes drugs used to treat Crohn’s disease less effective. If you have Crohn’s disease and you smoke, you should definitely stop.
Colorectal Cancer risk and CD
As with UC, there is an increased risk of developing colorectal cancer in people who have Crohn’s disease that affects much of the large bowel. We tend to start screening colonoscopies 8-10 years after diagnosis.
Surgery for UC is described as curative, since the whole colon is removed. However, since CD can affect any part of the gastrointestinal tract this is not the case for CD. Surgery may be necessary for a variety of reasons. The removal of isolated disease of the last bit of the small bowel can be a very effective treatment. However, because the disease tends to recur, normally at the site that the bowel is joined, long term treatment with drugs is still often necessary.
Surgery may also involve the treatment of strictures that can either be resected or treated or opened up. Disease around the anus is often treated surgically to relieve areas of infection or to open fistulas so they can drain and heal.
We always work in close cooperation with surgeons with special expertise in IBD if our patients require surgery.
Where can I get further information?
The National Association for Colitis and Crohn’s Disease (NACC) is the patient organisation for people with IBD. This is a charitable organisation which provides support and sensible, patient-centred information to people with IBD. The website is excellent (www.nacc.org.uk) and provides a wealth of information about IBD.
There are several books aimed at providing information to people with IBD and their families. We would highly recommend Inflammatory Bowel Disease (The Facts), which was co-authored by one of the members of London Digestive Health; all royalties go to NACC.