In the latest on our series of myths and facts in general practice, three specialists from St George’s University Hospitals run through some misconceptions about IBS – and some facts you might not know…
Myths
Myth 1: IBS is caused by stress
IBS was previously labelled as a functional disorder, but more contemporary nomenclature describes it as a ‘Disorder of the Gut-Brain interaction’ (DGBI). In simple terms this is where the normal bidirectional communication and co-ordination between the enteric nervous system and the central nervous system is disrupted resulting in a wide array of symptoms and pathologies including IBS; please see Mayer et al for an excellent review. While stress does not directly cause IBS, it is one of multiple factors that is known to exacerbate symptoms along with others such as poor mental health, infections, medications and diet. Identifying these triggers, which are individual for each patient, and discussing and addressing them is key to managing IBS and improving symptoms.
Myth 2: It’s not IBS if you’re constipated
The presenting symptoms and phenotype of IBS can be extremely variable and can certainly result in constipation as the predominant symptom, described as IBS-C where >25% of motions are type 1 or 2 on the Bristol stool chart and <25% of motions are type 6 or 7. These patients should be initially managed with positive validation and explanation of their symptoms and lifestyle advice including a gradual increase in dietary fibre – too rapid will lead to bloating – and good hydration. A bulk forming laxative such as Ispaghula husk (Fybogel) is a useful first step and additional laxatives such as Movicol or Senna could be added after this. If, despite these measures, they are still symptomatic then a 5HT4 agonist such as Prucalopride can be beneficial. If the constipation is associated with significant bloating then Linaclotide therapy should be considered and the response reviewed at four weeks.
Myth 3: IBS is trivial
IBS does not result in a structural abnormality within the bowel that we can detect on imaging or endoscopy and does not result in malabsorption or have any serious long-term complications. However, the impact it can have on patient’s quality of life can be profound. Concern about diarrhoea or abdominal pain can lead to sufferers avoiding eating, which can result in weight loss, avoiding socialising or missing work due to fear of their symptoms. This can also then have a significant effect on mental health. Therefore, whilst it has often been labelled historically as trivial and something patients simply have to ‘get on with’, our current knowledge and understanding refutes this and IBS should be managed aggressively to improve patients’ symptoms and quality of life as much as possible.
Myth 4: Intermittent fasting can be used to treat IBS
Intermittent fasting has emerged as a popular dietary technique for multiple pathologies in the last few years. Different variations exist:
- Alternate day fasting – where you eat normally every other day and fast in between
- Modified fasting or 5:2 – where you eat 500-600 calories for non-consecutive days in the week and normally for the remaining five –
- Time restricted eating – most commonly where you only eat between midday and 8pm.
There is emerging evidence that these strategies can be helpful in treating obesity, type 2 diabetes and fatty liver disease. However, there is as of yet no evidence that it has benefits in IBS. Diet is a crucial element of management of IBS but, while some basic advice can be beneficial to most patients, it is most effective when tailored to the patient and their symptoms and simply advising all IBS patients to use intermittent fasting is not correct.
Myth 5: IBS does not require re-investigation
Generally speaking, once the diagnosis of IBS is made using the Rome IV criteria further investigations are not required and treatment should be tailored to the patient’s symptoms in order to improve their quality of life. However, whilst the sub-type and symptoms of IBS can vary and change, if patients re-present with altered or new symptoms then careful history taking and examination should be performed in order to ensure a more sinister pathology is not missed. A high index of suspicion should be maintained for older patients over 50, a history of autoimmune or other systemic medical disorders or patients with significant weight loss. Even with a known diagnosis of IBS, any red flag symptoms should be referred urgently under an appropriate pathway.
Facts
Fact 1: IBS is a clinical diagnosis – but beware mimics
IBS is a clinical syndrome. It can be diagnosed based upon the Rome IV Criteria which consists of:
- Recurrent abdominal pain on average at least 1 day per week in the last 3 months, associated with two or more of the following:
- Related to defecation
- Associated with a change in the frequency of stool
- Associated with a change in form (appearance) of stool
However, there are a number of mimics that can produce similar symptoms of pain, bloating or diarrhoea. Common examples are Crohn’s disease, Coeliac disease or chronic infections such as Giardia or Whipple’s disease which are typically contracted in the tropics. It is therefore reasonable for patients to undergo non-invasive tests to ensure a mimic or more sinister pathology is not missed. Blood tests including a full blood count, ESR, CRP, renal profile, liver profile, bone profile, coeliac serology, thyroid function and haematinics to look for malabsorption and stool tests including a stool culture, with any recent travel history supplied, and faecal calprotectin are useful tests.
Fact 2: Treatment needs tailoring to each sub-type of IBS the patient presents with
The British Society of Gastroenterology produced a thorough guideline on diagnosing and managing IBS both in primary care and secondary care. It emphasises the importance of making a positive diagnosis of IBS and not using the previous mantra of ‘it is in your head’ when discussing it with patients; this in itself can be affirming to patients and provide therapeutic benefit. Whilst simple lifestyle interventions such as exercise, relaxation techniques and probiotics as well as basic dietary changes (available in the NICE CG61[8]) should be offered to everyone the guideline also clearly divides pharmacological therapies into groups based upon the sub-type of IBS. Symptoms of pain can be treated with anti-spasmodics such as hyoscine or peppermint oil, diarrhoea with loperamide and constipation with ispaghula husk. Second line treatments include TCAs or SSRIs, Prucalopride for constipation or Ondansetron for diarrhoea; these are usually initiated in secondary care following further assessment and investigation and it should be noted that ondansetron is used off-licence in this scenario. Gut-directed hypnotherapy and CBT are both useful treatments if patients are amenable but national provision of this is very variable.
Fact 3: Dietary changes in IBS need to be individualised
As well as the initial dietary measures discussed above there is more thorough advice available from the British Association of Dietitians. However, for some these changes remain insufficient and for these patients more advanced dietary interventions are indicated. Even in those without coeliac disease, some patients are advised to go on to a gluten-free diet to improve symptoms in IBS particularly if there is a clear temporal link to symptoms and gluten intake; although it should be noted there is currently insufficient evidence to support this approach. Whilst expensive, this is a relatively easy dietary change to make for patients and without risks provided their new diet is balanced. More comprehensive dietary strategies are the FODMAP diet which has been shown to be effective in IBS-D and IBS-C however it can be difficult to implement without dietetic support and challenging to adhere to given the restrictive nature of it. Whilst there are multiple websites discussing a FODMAP diet and how to do so, we recommend all patients do so with the support of a dietitian.
Fact 4: IBS is associated with mental health disorders particularly anxiety and depression
A large systemic review with meta-analysis examined 73 papers and found that patients with IBS are three times as likely to suffer from either anxiety or depression. The bidirectional nature of communication between enteric and central nervous systems means that there is a complex interaction between IBS and mental health disorders. Whilst mental health disorders do not cause IBS, nor vice versa, both can worsen or improve each other’s symptoms. Managing any co-existing mental health is a key facet to managing IBS and should be clearly explained and discussed with patients.
Fact 5: Not all exercise is good for IBS
All modern guidelines with regards to IBS describe lifestyle changes that can help with patients’ symptoms and there is a wealth of good quality evidence demonstrating that exercise has wide health benefits for physical and mental health. However, there is also evidence that over-exercising can actually have negative impact upon our gut health and therefore worsen IBS symptoms. A systematic review published in 2017 showed that strenuous exercise worsens the indices of intestinal injury, particularly mucosal permeability and endotoxaemia, slows gastric and intestinal transit and can cause malabsorption. Performing strenuous exercise in hot conditions also worsened all these effects. The majority of the studies included defined strenuous exercise by examining VO2max which is clearly not practical for patients. However, a suggested approach is to advise patients to pursue moderate exercise and that if they notice they are getting significant worsening of their IBS symptoms, to reduce the intensity and duration of this but continue exercising. They can gradually increase the intensity and duration over time as they find appropriate. Ensuring good hydration with increased exercise, particularly for IBS-C patients, is also crucial.
Dr Michael Colwill is a gastroenterology research fellow, Dr Kevin Jacob is a gastroenterology fellow, and Dr Andrew Poullis is a consultant gastroenterologist, all at St George’s University Hospitals NHS Foundation Trust
