What is irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a common 'functional' disorder of the gut. The gut includes the bowels. A functional disorder is one where there is a problem with the function of a part of the body, but where there is no abnormality in the structure. So, in IBS, the function of the gut is upset, but all parts of the gut look normal, even when looked at under a microscope.

Who can get it?

Up to 1 in 5 people in the UK develop IBS at some stage in their life.
IBS can affect anyone at any age, but it commonly first develops in young adults and teenagers. Women are affected more often than men.

What are the symptoms?

  • Pain and discomfort may occur in different parts of the abdomen. Pain usually 'comes and goes'. The length of each bout of pain can vary greatly. The pain often eases when you pass stools (motions or faeces) or wind. Many people with IBS describe the pain as a 'spasm' or 'colic'. The severity of the pain can vary from mild to severe, both from person to person, and from time to time in the same person.
  • Bloating and swelling of your abdomen may develop from time to time. You may pass more wind than usual.
  • Stools (sometimes called motions or faeces)
    • Some people have bouts of diarrhoea, and some have bouts of constipation.
    • Some people have bouts of diarrhoea that alternate with bouts of constipation.
    • Sometimes the stools become small and pellet like. Sometimes the stools become watery or ribbony.
    • At times, mucus may be mixed with the stools. Occasionally, you may pass mucus alone when you go to the toilet.
    • Many people have a feeling of not fully emptying their rectum after going to the toilet.
    • Some people have urgency, which means you have to get to the toilet quickly. A 'morning rush' is common. That is, you feel an urgent need to go to the toilet several times shortly after getting up. This is often during and after breakfast.
  • Other symptoms sometimes occur and include: nausea (feeling sick), headache, belching, poor appetite, tiredness, backache, muscle pains, feeling quickly 'full' after eating, heartburn, and bladder symptoms (an associated 'irritable bladder').

Symptoms that should not be attributed to IBS are:

  • Short duration of symptoms in those >45y old
  • Rectal bleeding (bleeding from the back passage)
  • Weight loss
  • Fever

If you experience any of these symptoms you should consult your doctor.

What causes it?

As mentioned above, in IBS there is no abnormality of the structure of the gut. IBS is caused by a change in function (activity) of the gut. The cause of change in activity within the gut is not clear, but understanding how the gut works can give us information on what may be causing IBS. 

The gut is a long muscular tube that goes from the mouth to the anus. The small and large bowel (also called the small and large intestine) are parts of the gut inside the abdomen. Food is passed along by regular contractions (squeezes) of the muscles in the wall of the gut. Pain and other symptoms may develop if the contractions become abnormal or overactive. The area of overactivity in the gut may determine whether constipation or diarrhoea develops. The cause of overactivity in parts of the gut is not clear. One or more of the following may play a part:

  1. Overactivity of the nerves or muscles of the gut. It is not known why this may occur. It may have something to do with overactivity of messages sent from the brain to the gut. Stress or emotional upset may play a role. About half of people with IBS can relate the start of symptoms to a stressful event in their life. Symptoms tend to become worse during times of stress or anxiety.
  2. Intolerance to certain foods may play a part in some cases. However, this is thought to be only in a small number of cases.
  3. Infection and bacteria in the gut. IBS is not caused by an ongoing gut infection. However, in about 1 in 6 cases, the onset of symptoms seems to follow a bout of gastroenteritis (a gut infection which can cause diarrhoea and vomiting). So, perhaps a virus or other germ may 'sensitise' or 'trigger' the gut in some way to cause persisting symptoms of IBS.

Do I need any tests?

There is no test that confirms the diagnosis of IBS. A doctor will diagnose IBS from the typical symptoms. However, tests are done in some cases to rule out other conditions. For example, tests may be done if symptoms are not typical, or if you develop symptoms of IBS in later life (over the age of about 45) when other conditions need to be ruled out.

If any tests are needed your doctor will explain and discuss them with you before hand, giving you the chance to ask questions and decide if you would like to go ahead with them. The most common tests are blood tests.  Examination of the gut is necessary for some patients.

What are the treatments for irritable bowel syndrome?

Many people are reassured that their condition is IBS. Simply understanding about IBS may help you to be less anxious about the condition, which may ease the severity of symptoms. Symptoms often settle for long periods without any treatment.

If symptoms are more troublesome or frequent, one or more of the following may help:-

Foods, drinks and lifestyle

Some people with IBS find that one or more foods can trigger symptoms, or make symptoms worse ('food intolerance or sensitivity'). A food intolerance is more common in people with IBS who have diarrhoea as a main symptom. If you are not sure if a food is causing symptoms, it may be worth trying a bland diet if symptoms are difficult to control. Then, add in different foods gradually to your diet to see if any cause the symptoms. It may be possible to identify one or more foods that cause symptoms. This can be a tedious process, and often no problem food is found. However, some people say that they can control their symptoms by identifying one or more foods that cause symptoms, and then not eating them.

The foods that are most commonly reported to cause IBS symptoms in the UK are: wheat (in bread and cereals), rye, barley, dairy products, coffee (and other caffeine-rich drinks such as tea and cola), and onions. Some people report an improvement in symptoms when they cut down from drinking a lot of alcohol, or stop smoking if they smoke. Regular exercise may also help to ease symptoms.

It may help to keep a food and lifestyle diary for 2-4 weeks to monitor symptoms and activities. Note everything that you eat and drink, times that you were stressed, and when you took any formal exercise. This may identify triggers, such as a food, alcohol, or emotional stresses, and may show if exercise helps to ease or prevent symptoms.

Treating constipation

Constipation is sometimes a main symptom of IBS. If so, it often helps to eat foods with plenty of fibre, and to drink plenty of water to keep the stools moist.

You can read more about fibre and fluids in your diet in our patient information leaflet entitled: “Guide to the healthy happy bowel”.

If increasing 'fibre and fluids' does not ease constipation then bulk-forming laxatives (sometimes called fibre supplements) can help. These increase the 'bulk' of your faeces and are not 'medicines' as such.  Unprocessed bran is the cheapest. You can sprinkle bran on breakfast cereals, or mix it with fruit juices, stews, soups, yoghurts, crumbles, scones, etc.

Sometimes other types of laxatives are advised if the measures above are not enough to ease a troublesome bout of constipation. Your doctor will discuss this with you and help you decide on the best treatment for you.

Treating diarrhoea

An anti-diarrhoea medicine may be useful if diarrhoea is a main symptom. Loperamide is the most commonly used anti-diarrhoea medicine for IBS. You can buy this at pharmacies or can also get it on prescription.

The dose of loperamide needed to control diarrhoea varies considerably. Many people use loperamide 'as required' but some take it regularly. Many people learn to take a dose of loperamide in advance when they feel diarrhoea is likely to be a problem. For example, before going out to places where they know it may be difficult to find a toilet.

Antispasmodic medicines

These are medicines that relax the muscles in the wall of the gut. Your doctor may advise one if you have spasm-type pains. There are several types of antispasmodics, and they work in slightly different ways. If one is found to help, then you can take it 'as required' when pain symptoms flare-up. Many people take an antispasmodic medicine for a week or so at a time to control pain when bouts of pain flare-up. Some people take a dose before meals if pains tend to develop after eating.

Antidepressant medicines

An antidepressant medicine in the 'tricyclic' group is sometimes used to treat IBS. In particular, it tends to work best if pain and diarrhoea are the main symptoms. (Tricyclic antidepressants have other actions separate to their action on depression. They are used in a variety of painful conditions, including IBS.) Unlike antispasmodics, you need to take an antidepressant regularly rather than 'as required'. Therefore, an antidepressant is usually only advised if you have persistent symptoms, or frequent bad flare-ups that have not been helped by other treatments.

Psychological treatments (talking treatments)

Situations such as family problems, work stress, exams, recurring thoughts of previous abuse, etc, may trigger symptoms of IBS in some people. People with anxious personalities may find symptoms difficult to control. The relationship between the mind, brain, nervous impulses, and overactivity of internal organs such as the gut is complex. Some people have found such things as relaxation techniques, stress counseling, and other talking therapies useful in controlling symptoms of IBS.

What is the outlook (prognosis)?

In most people with IBS, the condition tends to persist long-term. However, you may have long spells without any symptoms, or with only mild symptoms. Treatment can often help to ease symptoms when they flare-up. In a minority of cases, symptoms clear for good at some stage.

IBS does not shorten your expected life span, it does not lead to cancer of the bowel, and does not cause blockages of the gut or other serious conditions.

Further help and advice

The IBS Network    Tel: 0114 272 32 53    Web: www.ibsnetwork.org.uk
Offers advice, information and support for people with IBS.

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