Jeremy

Woodward

Gastroenterologist

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“Psychoanalysts are not occupied with the minds of their patients; they do not believe in the mind but in a cerebral intestine.” Bernard Berenson

Irritable Bowel Syndrome

What is Irritable Bowel Syndrome? 'Irritable Bowel Syndrome' (or 'IBS') is the name given to a collection of abdominal symptoms that are not caused by any other defined gastrointestinal conditions and do not lead to any detectable abnormality on standard tests.

Irritable bowel syndrome symptoms include bloating, cramping abdominal pain, diarrhoea, constipation, and flatulence. Blood in the bowel motions or unintentional weight loss are not symptoms of IBS.

How common is IBS? It is extremely common - affecting about 10% of the adult population every year - about 4 million people. Because of concerns about possible underlying causes, about half of those people experiencing symptoms attend their General Practitioner and IBS accounts for about 50% of all outpatient appointments made with specialist gastroenterologists. Most people will have experienced some symptoms of IBS at some stage in their lives.

How is IBS diagnosed? It is a mistake to think that IBS is only diagnosed after every other test has been carried out and found to be negative - IBS is not a 'diagnosis of exclusion'. IBS has characteristic features that include spasmodic abdominal pain (which may be after eating or in the early hours of the morning), bloating, loose motions associated with abdominal pain, alternating constipation and diarrhoea. The symptoms are characteristically intermittent and may move around the abdomen. These are not features of other conditions. It is usually possible to be fairly certain that the diagnosis is IBS without carrying out lots of tests.

What tests are carried out for IBS? In certain patients it may be necessary to carry out some tests to make sure that there is no underlying condition that is causing similar IBS-like symptoms. Simple blood tests for anaemia, inflammation, Coeliac disease and thyroid malfunction will be normal in IBS. Most younger patients do not require any further investigation, and can usually be started on a trial of treatment. Some patients may require an ultrasound to exclude gallstones, or an upper gastrointetsinal endoscopy (gastroscopy) to exclude peptic ulcer. However, in patients over 50 years of age it is often sensible to carry out a colonoscopy to make sure that there is no evidence of colonic polyps or cancer (which may not cause any symptoms at all).

How severe is IBS? IBS is one of the most under-rated conditions that doctors see and treat. This is because mild symptoms of IBS are experienced by almost everyone at some stage and few appreciate how severe the symptoms can become. IBS can cause severely debilitating symptoms that can prevent people from working or going about their everyday lives. One of the worst features of the condition is that the symptoms can be completely out of keeping with the test results - it can seem unbelievable to sufferers that despite such severe symptoms there may be absolutely nothing to show on any of the investigations that are carried out. Similarly, the severity of the symptoms can lead patients to believe that they must be suffering from a serious or life threatening disease.

Does IBS lead to any serious complications? IBS is not life threatening and is not associated with any serious conditions or complications. Possibly the worst complications may be the anxiety caused by the condition or even the side effects of unecessary investigations. Nevertheless, the condition is very seriously quality of life - threatening. Sometimes patients who have previously been diagnosed with IBS develop another gastrointestinal complaint. This does not necessarily mean that they were initially misdiagnosed as having IBS, as it is quite possible - even likely - that IBS will occur with other conditions as it is so very common.

What causes IBS? There are many theories about the causes of IBS, and this is currently under investigation. IBS can be triggered by an infection such as gastroenteritis or after antibiotics. It is closely associated with psychological stress and anxiety (as we might expect from experience - for instance having to dash to the toilet before an exam or work interview). Abdominal pain that persists after another condition (such as appendicitis or diverticulitis) has been treated may be due to IBS.

  • Low grade inflammation may persist after an infection and lead to 'post infective IBS'. This usually just causes diarrhoea but may be associated with cramping pains and an increase in inflammatory cells in the lining of the colon may be detected on tests. This may represent a particular sub-type of IBS.
  • Nerve Hypersensitivity is very clearly described as a cause of pain in IBS. In experiments, patients with IBS are very aware of a small balloon that is inflated inside the colon and may experience pain, whilst patients who do not have IBS may not even notice that the balloon has been inflated. The sensitivity of the nerves may be altered by inflammation or infection in the bowel, by anxiety or increased conscious awareness of nerve signals sent from the bowel to the brain - 'hypervigilance'.
  • Diet and colonic bacteria may affect the function of the bowel. Fibre is the generic term given to indigestible residues - usually of plant origin - that pass through our upper intestine and into the colon. Here fibre is fermented by the bacteria that live in the large bowel, with the side effect of producing gas. Distension triggers nerve signals from the bowel that may be interpreted as pain.
    • Can IBS be treated? There are many who do not believe that there are any effective treatments for IBS. This is not the case and it can be enormously satisfying - for both doctor and patient! - to get rid of symptoms of IBS that have been troublesome for many years with simple interventions. It is important for patients to realise that there is no single cure, and that treatment may require a period of trial and error with a number of different approaches being tried. Similarly, whilst symptoms can sometimes be treated very quickly, it is usual to see a gradual reduction, with the aim of reducing the severity to a level that makes it possible for patients to resume their everyday lives without disturbance.

      How is IBS treated? The treatment of IBS depends very much on the type of symptoms experienced. A combination of the following interventions is usually beneficial:

      • Diet. Contrary to common belief, a low fibre diet may be beneficial by reducing colonic fermentation and distension that can lead to pain. The downside of this may be constipation, and it is therefore useful to balance the low fibre diet with a non-fermentable fibre substitute in order to maintain bowel frequency.
      • Stool bulking agent. A non-fermentable fibre preparation may increase the size and the fluid content of the bowel motion and change the function of the colon.
      • Anti-spasmodic drugs may be extremely beneficial for patients with cramping abdominal pains. These agents are extremely safe and not associated with any significant side effects.
      • Nerve desensitising drugs. Patients who are experiencing constant discomfort, particularly at night, may be helped by a drug that reduces the hypersensitivity of the nerves in the bowel. These drugs were originally designed used - in much higher doses - as anti depressant agents which can occasionally lead to problems if this is not carefully explained to patients! At the low doses used in IBS, there are no mood altering effects, nor is there any likelihood of developing dependence on the drug and the only side effect is of mild drowsiness. This can help patients experience a proper night's sleeo if they are often disturbed in the night by pain.
      • Psychological approaches. Given the very close links of the bowel with the subconscious brain, it is not surprising that psychological approaches can often be very helpful. Techniques such as relaxation therapy, hypnotherapy or cognitive therapy are frequently used. Patients sometimes worry about such treatments being effective as if it means that 'it is all in the mind' and not a 'proper' illness. In actual fact, the subconscious brain can be tapped as a very powerful resource to change bodily functions - as demonstrated by extraordinary tales of patients who have been able to undergo open abdominal operations under hypnosis without any anaesthetic!
        • What about probiotics? There are a large number of treatments for IBS that are undergoing evaluation at the moment. The most important aspect of any new drug or treatment for this condition is that it is safe and without significant side effects. Contrary to current belief, there is actually very little evidence to suggest that live bacterial preparations are of great help in IBS. Studies that show benefit are very specific to the type of bacterium and only improve certain symptoms. As our understanding of the incredible complexity of the bacterial population of the colon improves, we may be able to use probiotics more intelligently to treat conditions such as IBS.

          What resources are available?

          The IBS Network is the UK charity for patients with IBS and has useful information and resources available.

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