Consultant gastroenterologist Dr Kieran Moriarty tackles burning questions on this distressing condition from GP Dr Linden Ruckert
Consultant gastroenterologist Dr Kieran Moriarty tackles burning questions on this distressing condition from GP Dr Linden Ruckert
1. It has been said IBS affects 20 per cent of the population. Are we any nearer to understanding why this is – or perhaps why 80 per cent don't have it? Is it just a disease of modern times (and lifestyle)?
IBS is a disorder or syndrome, rather than a disease, and affects around 20 per cent of adults in industrialised countries.
Even more people have at least one of its symptoms, namely abdominal pain, constipation, diarrhoea or bloating. Three-quarters of people with symptoms do not consult a doctor.
Of those that do, only about 20 per cent are referred to a gastroenterologist. Some 50 per cent of these have depression or anxiety.
Psychological factors and healthcare seeking behaviour, as well as sociocultural and dietary factors, influence who goes to the physician.
In Western countries, it is seen more frequently in women than men. The prevalence may decline with advancing age.
IBS is associated with a considerable health and economic burden. It is seen in all cultures and ethnic groups and is not just a disease of modern times and lifestyle.
2. Patients often say after I have explained it: 'OK, but I've been an anxious, stressed person for many years and I've been through worse times than this. Why have I got it now?' The same sort of comment is made by people who develop it after a stressful time. What do you say to patients?
Why should some people develop IBS, whereas others do not? We do not know all the answers to that question, although some factors have been identified that are associated with an increased likelihood that an individual will have IBS.
• Psychological factors
• Abnormal activity of the bowel muscles and nerves
• Increased sensitivity of the gut
• Gastrointestinal infections
• Diet, food intolerance and food allergy
Studies have shown a link between the onset of IBS symptoms and a preceding stressful event such as employment difficulties, bereavement, marital stress or an operation.
Some studies have also linked social problems relating to work, finances, housing or personal relationships.
These findings suggest a person's mood and emotions influence the way they respond to their symptoms (for example, whether they consult a doctor) as well as having a direct effect on their intestines.
Stress also plays an important role in causing intestinal pain. I explain these facts to the patient and also add that many people with IBS do not have any obvious psychological or personality problems.
3. The foregut symptoms seem to be particularly difficult to help and standard prokinetics are not terribly effective. Do you have any tips on how to deal with this?
Functional gastrointestinal disorders, of which IBS is one type, may arise from the oesophagus or gastroduodenal region. They are indeed particularly difficult to treat.
Oesophageal disorders include globus, rumination syndrome, functional heartburn and functional dysphagia.
Gastroduodenal disorders include functional dyspepsia, ulcer-like dyspepsia, unspecified dyspepsia, aerophagia and functional vomiting.
The key aspect to management is explanation of the condition and reassurance, particularly that there is no underlying sinister pathology.
Investigations may include gastroscopy, barium swallow and meal, oesophageal pH and manometry studies, and isotope or ultrasound gastric emptying studies.
Chest X-ray and ECG may provide reassurance with oesophageal pain.
Calcium channel blockers may help oesophageal pain and prokinetics, such as metoclopramide or domperidone, may alleviate nausea and vomiting. Generally, however, drug therapy is disappointing.
Underlying psychological factors are common and may respond to psychological therapies, such as relaxation therapy.
4. I am a bit confused about the role of fibre sometimes, particularly soluble versus insoluble and whether the sources ought to vary.
Are 'prescribable' sources effective long-term? One gastroenterologist once said to me that such treatment wasn't helpful and especially young women referred to him actually had constipation due to living on sandwiches/not exercising.
Dietary fibre is found in the tough fibrous part of fruit and vegetables, particularly the stalk, and on the outside of fruits, seeds or grain (bran is the outer covering of wheat grains).
It is also in the soft parts of fruit and vegetables that are not digested by the small intestine.
Fibre is not broken down in the stomach and small intestine, but passes to the colon, where it acts like blotting paper, keeping water in the stool.
Both soluble and insoluble fibre are present in all plant foods. Soluble fibre readily dissolves in water. Insoluble means lack of solubility in water, but with passive water-attracting properties that help to increase bulk, soften stools and shorten intestinal transit time.
Soluble fibre sources include psyllium seed husk and ß-glucan from oat bran, whole oats, whole grain or dry-milled barley.
Sources of insoluble fibre include whole grain foods, bran, nuts and seeds, vegetables such as green beans, cauliflower and celery, and the skins of some fruits, including tomatoes.
The optimal diet contains a mixture of both sources. Prescribable sources of fibre vary in their long-term efficacy. The usual types of constipation are caused by (a) lack of dietary fibre; (b) ignoring the call to stool and (c) uncoordinated straining.
5. What do you think about diet? Is there a standard exclusion diet we can recommend?
Some mention unabsorbable fibres, such as inulin, citrus fruit and caffeine-containing drinks. Many patients do believe that lactose intolerance is involved, and I read one study that said that up to 200ml/day of milk was fine but higher levels could trigger symptoms.
Healthy eating is the cornerstone of treatment. It is important to eat breakfast, since this helps the bowel to start working in the morning.
Dietary fibre or bran may ease constipation, but can exacerbate diarrhoea, gas or bloating. Each person therefore needs to find their optimal fibre intake.
Eating, especially fatty food, triggers pain in around 75 per cent of people with IBS. It is important to distinguish this generalised food intolerance from intolerance to specific foods, which may produce symptoms in certain individuals.
The role of specific intolerance as a cause of IBS is debatable. Exclusion of wheat and dairy products and caffeine-containing drinks may benefit some people.
Some people develop typical IBS symptoms after eating carbohydrates that they are unable to absorb. Examples are lactose (milk sugar) and fructose (fruit sugar).
If they are not absorbed, they may ferment in the gut and produce gas. Excluding these from the diet can reduce symptoms and colonic gas production.
Reduced levels of lactase in the lining of the small intestine affects around 10 per cent of those of northern European descent, rising to 60 per cent in people of Asian origin and 90 per cent in people of Chinese descent.
People consuming a substantial amount of lactose (equivalent to more than half a pint of milk per day) may benefit from lactose restriction, while those with lower lactose intakes may not, because a low intake does not usually cause symptoms of intolerance.
6. Do you find any drug therapy works? Is there a rationale for SSRIs rather than low-dose tricyclics (which some do seem to find constipating)?
I have seen there are 5HT3 receptors in the gut that alter function in response to the experience of pain – raising the possibility of almost an 'end organ' disease.
Unfortunately, drug treatments are of only limited value and many have side-effects.
Anti-spasmodic drugs, such as mebeverine, dicycloverine, alverine citrate and hyoscine butylbromide, relax intestinal smooth muscle and relieve pain due to colonic spasm.
Combination with a fibre preparation may enhance efficacy. Low-dose tricyclic antidepressants, such as amitriptyline and nortriptyline, may relieve pain due to their action on the 'gating' of pain impulses. Their use is limited by side-effects, such as drowsiness, dry mouth and constipation.
The side-effect profile of the antidepressant SSRIs may be a little better, but these drugs are much more expensive than the tricyclics.
Serotonin plays an important role in the motor and secretory responses of the gut to the ingestion of food.
Alosetron antagonises type 3 serotonin receptors in the gut and is effective in diarrhoea-predominant IBS, although vascular damage to the colon has been linked to its use.
Tegaserod, which stimulates type 4 serotonin receptors, is available in the US and some other countries, but not in the UK, for constipation-predominant IBS in women.
Given its prevalence in the community, IBS may be considered a disorder rather than a disease. Its manifestations depend on the interaction of the enteric nervous system and the central nervous system.
7. Is it useful to think of IBS as a wider pain syndrome that might include fibromyalgia, for example?
It may be useful to think of IBS as a wider pain syndrome. This may be due to a more generalised smooth muscle hyperactivity or visceral hypersensitivity in the abdominal organs. A wide range of other problems may occur along with the more typical ones of IBS.
• Premenstrual tension.
• Incomplete emptying of bladder.
• Back pain
• Bad breath
• Unpleasant taste in the mouth
• Poor quality of sleep
• Constant tiredness
Alleviation of the symptoms of IBS may be associated with an improvement in the non-gastrointestinal symptoms. Sometimes, however, these features may develop as substitution symptoms.
8. Do any complementary therapies work – for example, aloe vera, acupuncture, biofeedback?
A variety of complementary therapies is commonly used by IBS patients, both together with and instead of conventional treatment.
As many of these therapies have not been subjected to controlled clinical trials, at least some of their efficacy may reflect the high placebo response seen in IBS.
But there is evidence to support the efficacy of hypnotherapy.
Hypnosis induces a state of relaxation to try to alter underlying abnormalities of gut motility and/or sensation.
The ultimate aim is to help people to control symptoms on their own, using what they have learned during the treatment sessions.
Probiotics, such as lactobacilli and bifidobacteria, have several actions that may be of benefit in IBS. These include antibacterial effects, protection of the gut lining and influencing immune reactions in the gut.
Biofeedback is used in the treatment of faecal incontinence and constipation. Therapy aims to increase sensitivity to rectal sensation and avoid inappropriate straining.
It also provides a detailed explanation of how the body normally works and helps retrain the action of the bowel.
Aloe vera is a herbal remedy. In the absence of properly conducted clinical trials showing any benefit, its routine use cannot be recommended. Similarly, scientific evidence for a role for candida in IBS is lacking.
Acupuncture, possibly through the release of endorphins, may relieve abdominal pain.
9. Which patient books and online resources do you recommend? Can you suggest anything that might change the way we approach IBS?
I would suggest the following books and online resources:
• CORE (Digestive Disorders Foundation), 3 St Andrew's Place, Regent's Park, London NW1 4LB. Tel 020 7486 0341; e-mail email@example.com; website www.corecharity.org.uk.CORE provides a range of leaflets about the cause, symptoms and treatment of digestive disorders on receipt of an SAE.
• The Irritable Bowel Syndrome Network, Unit 5, 53 Mowbray Street, Sheffield S3 8EN. Tel 0114 272 3253; e-mail firstname.lastname@example.org; website www.ibsnetwork.org.uk.The IBS Network publishes factsheets and quarterly newsletters and co-ordinates local self-help groups, which offer a befriending scheme giving support to fellow sufferers. Helpline staffed by IBS nurse specialists. An SAE is required for information by post.
• Understanding Irritable Bowel Syndrome by Dr Kieran Moriarty. This is a book written for patients and is available from many pharmacists or Family Doctor Publications.
So how might we change the way we approach IBS?
Some 75 per cent of people with symptoms of IBS remain in the community and do not contact their GP.
Healthcare seeking is associated more with psychological rather than gastroenterological features.We therefore need to explore psychological issues as well as treating gastroenterological symptoms.
10. How likely are IBS-type symptoms to be coeliac disease?
We are told it may have an incidence of 1:300 and not have classical symptoms – should we screen all patients presenting with IBS-like symptoms?
Coeliac disease can mimic IBS, presenting with abdominal pain, bloating and constipation or diarrhoea. Recent studies suggest the prevalence of coeliac disease in the UK is about 1:100.
It is therefore reasonable to screen patients with suggestive symptoms by testing for anti-endomysial antibody or tissue transglutaminase.
Anti-gliadin antibody is not specific or sensitive enough for coeliac disease. Anti-endomysial antibody may be negative in IgA deficiency. Thus one should measure immunoglobulins as well.
If anti-endomysial antibody or tissue transglutaminase are positive, it is important to perform gastroscopy and duodenal biopsy to confirm the diagnosis of coeliac disease histologically, before commencing a gluten-free diet.
Kieran Moriarty is a consultant gastroenterologist at Royal Bolton Hospital, Farnworth, Bolton
Competing interests None declared
• IBS remains poorly understood: mood and emotion influence the response to symptoms as well as having a direct effect on the gut
• An optimum diet contains a balance of soluble and insoluble fibre; prescribable fibre varies in long-term efficacy
• Unabsorbable carbohydrate, eg lactose (milk sugar) and fructose (fruit sugar), may cause fermentation in the gut and gas, leading to symptoms
• Manifestations depend on the interaction of the enteric and central nervous systems, so antidepressants may relieve pain by gating the pain response
• It may be useful to think of IBS as a pain syndrome and check for non-GI features
• There is evidence for hypnotherapy, biofeedback and probiotics use; acupuncture may have some effect through endorphin release
What I will do now
Dr Ruckert comments on the answers to her questions
• I will consider the use of calcium channel blockers for oesophageal pain, which can be so difficult to help
• It may be worth telling patients that fatty food may be more likely to trigger pain
• I will remember to note ethnicity and ask about lactose intake and remind those who may be affected that a small amount will not trigger symptoms
• Probiotics are the most readily accessible form of complementary therapy and I will suggest patients try them
• I will feel less guilty when ticking the box for a coeliac disease screen in patients with IBS, as the prevalence in the UK is about one in 100
Linden Ruckert is a GP in north London