Dr Anton Emmanuel shows how grouping people with irritable bowel syndrome into diagnostic sub-types can help determine a suitable care plan or the need for referral

Symptoms relating to irritable bowel syndrome (IBS) are one of the most common reasons for presentation to gastroenterologists, and are encountered even more frequently in primary care. Epidemiological data from the UK suggest annual incidence rates of 370 cases per average-sized clinical commissioning group.1 Yet, despite the high prevalence of IBS, the diagnosis and management of the condition remains frustrating for both patients and healthcare professionals alike. In patients with refractory IBS, a pattern of multiple consultations and investigations develops, placing a considerable strain on resources.

A pathway that centres on diagnosis and management in primary care would help to achieve two goals:

  • improve efficiency of clinicians’ time, reducing the overall cost of IBS management
  • provide an effective, continuous support system for the patient.

This article explores the diagnosis and management of IBS in primary care, with reference to existing guidance; it also provides updates from recent research, which offer the prospect of a new diagnostic test available to primary care, and new approaches to the management and treatment of people with IBS.

Diagnostic tests

The lack of an identifiable organic cause, specific diagnostic markers, or a universally agreed treatment algorithm all contribute to the challenges in the effective management of IBS. Additionally, a sensitive and cost-effective alternative is needed to endoscopy and radiology tests currently undertaken to exclude cancer and inflammatory bowel disease. One recent development, with potentially major impact for primary care, is a diagnostic test using faecal biomarkers.2 The faecal biomarkers calprotectin and lactoferrin are cytosolic glycoproteins found in neutrophils, which resist metabolic degradation by intestinal bacteria. Several studies have evaluated the ability of faecal calprotectin, in particular, to distinguish IBS from inflammatory bowel disease. Sensitivity and specificity data of 80% or higher are reported, with positive and negative predictive values of 70%–90%.2 It is likely that this diagnostic test will soon be available to primary care, possibly allied to a positive IBS symptom questionnaire score, in order to improve cost-effective referral for endoscopy and radiology.3

In the meantime, expert advice from primary and secondary care guideline development groups (for NICE Clinical Guideline [CG] 61 on Irritable bowel syndrome in adults: diagnosis and management of irritable bowel syndrome in primary care4 and The British Society of Gastroenterology’s IBS guidance5) suggests that a positive diagnosis of IBS may generally be made in primary care on the basis of the patient’s symptoms, a lack of alarm features, and minimal laboratory tests (e.g. a full blood count and tests to exclude inflammation and coeliac disease). ‘Safety netting’ is core to UK general practice and is critical here to ensure that the patient is monitored over time; symptoms need to be reappraised regularly to avoid missing a serious diagnosis.

Key diagnostic features

The key features of IBS are:

  • abdominal pain
  • change in bowel habit
  • a temporal association between these two features (e.g. pain exacerbations when constipated, or easing by defaecation).

The above features are often associated with:

  • abdominal bloating
  • exacerbation by stress

The features need to be chronic (i.e. present for at least 6 months) for there to be a diagnosis of IBS.4,6

Sub-typing

Sub-typing is an important component of the diagnostic process, as it is key to determining an appropriate treatment plan. Patients are divided into three sub-types, based on their predominant stool form:6

  • IBS constipation-predominant (IBS-C): patients have hard/lumpy stools ≥25% of the time and loose/watery stools ≤25% of the time
  • IBS with diarrhoea (IBS-D): patients have loose/watery stools ≥25% of the time and hard/lumpy stools ≤25%
  • IBS-mixed (IBS-M): patients have both hard and loose stools ≥25% of the time.

When to refer

Certain patients will require onward referral because of:

  • alarm features:5
    • age >50 years (males especially)
    • short symptom history
    • nocturnal symptoms
    • unintentional weight loss
    • rectal bleeding
    • anaemia
    • family history of cancer
    • abdominal mass
    • recent antibiotic use (C. difficile)
  • uncertainty regarding the diagnosis despite apparent absence of alarm features
  • persisting patient concerns despite primary care interventions.

In addition, patients in whom diet or stress plays a major role may require referral to a dietitian or psychologist for further evaluation or management.

Patient support

Offering empathic reassurance is a major factor both in making a positive diagnosis and in the long-term management of people with IBS. A continuous, supportive relationship with the patient, allowing them to voice their ideas and concerns about IBS, is essential.7 Use of explanatory models may assist in gaining patient trust and helping them to understand their condition. As IBS is a chronic condition, involvement of specialist nurses may aid continuity of patient care. Organisations such as IBS Network8 and Core9 provide online tools, information, and support to help patients manage their condition over time.

Recent developments have targeted a better understanding of aetiopathogenic mechanisms of the symptoms, and hence improved treatments. The approach taken in this article is to suggest that treatment options are divided into three levels, depending on the severity of symptoms, as discussed below.

Treatment—level 1

All patients with IBS are assumed to benefit from the treatment options in level 1, regardless of symptom severity and psychological co-morbidity.

Dietary factors

Guidance in NICE CG61 suggests that addressing diet and nutrition is important in patients with IBS. Suggested interventions include:4

  • having regular meals and taking time to eat
  • drinking at least 8 cups of fluid per day, especially water or other non-caffeinated drinks
  • restricting tea and coffee to 3 cups per day and reducing intake of alcohol and fizzy drinks
  • limiting high-fibre food, especially insoluble fibre (cereal starches), which often exacerbate bloating and pain
  • limiting fresh fruit to three portions per day
  • restricting sorbitol for patients with IBS-D.

Food allergy. There is no convincing evidence that immunoglobulin-mediated food allergy is the mechanism underlying symptom deterioration, and similarly no role for widespread use of food allergy tests. Despite the modest evidence supporting dietary intervention,5 assessment of diet is important to rationalise occasionally unhelpful diets, and also because patients often perceive diet as an important factor in their symptoms.

Lactose intolerance and its relationship with IBS symptoms is an area of controversy.10 Most patients do not consume sufficient lactose in their diet to exceed the functional capacity of intestinal lactase. However, dietary lactose, and artificial sweeteners such as mannitol and sorbitol, may be significant in bloating and gas-related symptoms. Moreover, emerging evidence suggests that reduced intake of fermentable carbohydrates (FODMAPs— fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) might be helpful for subgroups of patients with IBS. A diet low in FODMAPs has both less osmotic and less fermentable content, and unsurprisingly, is most effective in improving diarrhoea and bloating symptoms.11

Probiotics. The use of probiotics is popular in many patients with IBS. The accepted advice is that treatment is taken for at least 4 weeks;4 however, strain specificity means that the therapeutic activity varies between products. Recent meta-analyses suggest that probiotics have a positive, if modest, effect in IBS.12 There is a limit, of course, to what can be concluded from this wide range of mostly short-term studies on a variety of probiotic agents. Of the effects on individual IBS symptoms reported as an outcome, those on abdominal pain and bloating after probiotic treatment are the most convincing. Regarding individual bacteria, Bifidobacterium infantis 35624 has been shown to be effective in two well-designed clinical trials, but positive effects with other probiotic products have also been demonstrated. 13,14

Lifestyle factors

NICE CG61 recommends optimising physical activity and relaxation time as part of the lifestyle advice offered to a patient.4

Treatment—level 2

The recommendations at this treatment level may benefit patients:

  • with moderate symptom severity, or
  • who present frequently despite apparently mild symptoms.

At this level, drug treatment is directed towards the nature and severity of specific symptoms. It is recommended to change one drug at a time, with a predefined time point for evaluation.5 It is also advisable temporarily to stop a treatment from time to time, in order to assess whether it is still needed.

Constipation

Fibre supplementation and bulking agents rather than stimulant laxatives or prokinetics are used as first-line treatment options for patients with IBS-C. In order to avoid common side-effects like bloating, flatulence, and pain, a gradual dose titration is recommended. If bulking agents fail, a trial of osmotic polyethylene glycol (PEG) based laxatives or lactulose is indicated to ease passage of stool, even if formal trial evidence for efficacy of these agents in IBS is lacking.15 NICE guidance suggests that, in view of their potential to exacerbate bloating and flatulence symptoms, intake of lactulose and insoluble fibre is less preferable in IBS-C.4

Newer prokinetic drugs differ from laxatives in that they target specific mechanisms in the gut. Linaclotide is a novel 14-amino acid peptide that is minimally absorbed and has been shown to reduce measures of intestinal pain and improve bowel function.16 Prucalopride is a selective, high-affinity 5-hydroxytryptamine receptor agonist approved by NICE15 for symptomatic treatment of females with chronic constipation in whom laxatives fail to provide adequate relief.15

Diarrhoea

The anti-diarrhoeal agent loperamide is first choice for intermittent or chronic use in patients with IBS-D, with a dose-range of 2–16 mg/day.4,5 It is of particular value in incontinence since it may increase the anal sphincter tone without anticholinergic side-effects.

Patients should titrate the dose of an antidiarrhoeal agent according to their needs, and be reassured that regular use is not injurious to the bowel. Diphenoxylate is an alternative, but codeine phosphate is not recommended because of its potential to induce dependence and dysphoria.5

It has recently been suggested that patients with IBS-D who do not respond to loperamide treatment may have bile acid malabsorption and that their symptoms would respond to bile-acid binding agents like cholestyramine or cholestagel.18 Nocturnal diarrhoea and the presence of steatorrhoea are features of bile acid malabsorption.

Abdominal pain

Meta-analyses of antimuscarinics (mebeverine and hyoscine) show minor advantage over placebo in terms of pain, but with no benefit for other IBS symptoms.19 However antimuscarinics are well tolerated and can be used on an as-required basis. Peppermint oil is an over-the-counter, non-specific, smooth muscle relaxant, and randomised trials have shown its superiority over placebo.20

Tricyclic antidepressants (TCAs) have an analgesic role in IBS. Treatment is started at a low dose (5–10 mg). The dose (typically <30 mg) should be taken once at night, reviewed regularly, and increased if needed.4 Antidepressants are useful in patients with more or less daily abdominal pain of a troublesome nature. Owing to their side-effect profiles, it has been suggested that selective serotonin re-uptake inhibitors (SSRIs) may be beneficial in treating IBS-C, and TCAs favoured for IBS-D.21,22 Whether switching non-responders from one TCA to another is beneficial has not been studied.

Patients need to be well informed about the side-effects of TCAs and SSRIs (e.g. dry mouth, constipation, drowsiness, and fatigue), that there is a time lag of 2–4 weeks for response, and that the drugs have been prescribed for their effect on the gut.5 (Please note that, at the time of publication of this article, TCAs and SSRIs do not have marketing authorisation for the indication described above. Informed consent should be obtained and documented.)

Abdominal gas and bloating

Currently, dietary advice, and possibly probiotics (as discussed under treatment level 1), are likely to be the most effective recommendation for these symptoms. A trial of a TCA may help in some individuals.4,5

Psychological aspects

NICE CG61 states that: ‘Referral for psychological interventions (cognitive behavioural therapy [CBT], hypnotherapy and/or psychological therapy) should be considered for people with IBS who do not respond to pharmacological treatments after 12 months and who develop a continuing symptom profile (described as refractory IBS).’ Gut-directed hypnotherapy, a type of medical hypnosis, has been the subject of randomised controlled trials in patients with IBS, both in the short- and long-term, with the majority of trials indicating significant improvement in IBS symptoms.23 A large number of psychological treatments have been studied in patients with refractory IBS—these are summarised in Table 1 (above), which shows the patient subtypes most likely to respond.4,5 Health economic data also suggests that such approaches are cost effective.23

Table 1: Psychotherapy for IBS: mode of action and patient selection
Therapy Mode of action Effective in patients with Less effective in patients with
Relaxation training Progressive muscle relaxation, biofeedback, and meditation for stress relief
  • Diarrhoea
  • Psychological comorbidity
No data
Gut-directed hypnotherapy Deep relaxation through hypnosis
  • Constipation
  • Flatulence and pain
  • Anxiety
No data
Cognitive behavioural therapy Identifying symptom triggers and learning more appropriate responses
  • Abdominal pain
  • Bloating and flatulence
  • Depression
  • Somatisation beliefs
Psychodynamic interpersonal therapy Helps patient understand relationship between emotions and bowel symptoms
  • Abuse history
  • Constipation
  • Chronic pain
  • Depression

Treatment—level 3

Treatment level 3 is aimed at patients with:

  • abdominal pain predominance
  • severe IBS symptoms
  • a complex situation (i.e. several extra-intestinal complaints), or
  • a difficult psychosocial situation (e.g. psychiatric illness or drug-dependence).

Psychiatric and psychosocial aspects

A significant proportion of patients with refractory IBS experience psychiatric co-morbidities. In certain cases, the use of multiple drugs (especially analgesics and laxatives), taken at excessive doses, may have become part of the problem. It is important to determine whether IBS is the sole problem, or if there are parallel problems (e.g. a primary psychiatric disease, psychosocial problems, drug dependency, or use of opioid analgesics) that will need specific intervention. A multidisciplinary approach, focusing on patient-centred care undertaken by a range of healthcare providers, is the key here.4,5 For some patients, the main focus may be on specific problems according to what dominates the clinical picture, such as treating psychiatric co-morbidity or focusing on pain management. Continuity of care is of great importance for this group of patients, in order to avoid ‘doctor-shopping’. Clearly, the role of primary care is important here—in terms of engagement with, and containment of, the patient.

Conclusion

A positive IBS diagnosis in primary care should minimise the need for referral and unnecessary, costly investigations in secondary care. The decommissioning of IBS to primary care now provides an opportunity for the development of new roles for this ‘Cinderella’ disorder (e.g. digestive health practitioners, specialist-run community services, and group dietetic or behavioural sessions).

  • IBS is suitable for management in primary and community care but specialist help in performing tests to exclude other causes, especially malignancy, is often required
  • Commissioners should investigate the cost and quality benefits of introducing faecal calcoprotectin as a diagnostic test in primary care with its potential to reduce secondary care specialist referrals and invasive investigations
  • A local care pathway crafted between commissioners and providers summarising latest research and NICE guidance would help primary care have confidence in managing this condition
  • Commissioners should consider funding community based specialist
    IBS nurses to assist with those patients who have ongoing and refractory IBS
  • Tariff costs for gastroenterology outpatients = £181 (new), £103 (follow up).a

awww.gov.uk/government/publications/payment-by-results-pbr-operational-guidance-and-tariffs

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