Key learning points:
- Our understanding of IBS has improved immeasurably in the last decade, enabling us to diagnose the condition more rapidly and offer scientifically-proven therapies
- Dietary and lifestyle advice is at the heart of evidence-based treatment guidelines, with probiotics, laxatives, antispasmodics, soluble fibre, antidepressants, and psychological interventions among the other recommended options
- Nurses are integral members of the multidisciplinary team and can play a key role in identifying and managing patients with IBS in primary care
Irritable bowel syndrome (IBS) is a common and debilitating functional bowel disorder that is characterised by abdominal pain or discomfort accompanied by diarrhoea, constipation or both.
The prevalence of IBS varies greatly depending on which diagnostic criteria are used, however, it has been estimated that around one in 10 adults may have the condition, with almost twice as many women as men affected (1).
Irritable bowel syndrome can have a profound effect on an individual’s well-being, with frequent, unpredictable symptoms impacting every aspect of daily life.
Our understanding of IBS has grown immeasurably over the past decade, enabling us to positively diagnose the condition more promptly, identify potential triggers or exacerbating factors, and initiate scientifically-proven therapies with good rates of success.
Scientific progress has led us to understand that IBS has multiple contributing factors and that there are different sub-groups of patients that should be treated differently.
New pharmacological therapies have emerged and the evidence-base supporting existing therapies has expanded considerably.
What causes IBS?
Irritable bowel syndrome is a multifactorial condition that involves a combination of genetic and environmental factors.
The condition is known to have a genetic component, although exactly which genes are involved has not yet been determined.
Many different pathophysiological mechanisms have been implicated in the development of IBS including disturbances in gut motility, visceral hypersensitivity, mucosal inflammation, and altered central pain processing (2).
Common precipitants of IBS symptoms include food intake, psychological distress, and acute infectious gastroenteritis (3). The role of dysbiosis in IBS – where an imbalance of gut bacteria occurs after an infection, food poisoning, foreign travel or antibiotic use – is a relatively new concept that has captured scientific interest.
Overgrowth of bacteria in the small intestine and changes in faecal microbiota have been linked to IBS (4) and, while the relative contribution of dysbiosis to the pathogenesis of IBS is still unclear, probiotic supplementation appears to have a clear, beneficial effect on symptoms and quality of life (5).
Signs and symptoms of IBS
The cardinal symptoms of IBS are abdominal pain or discomfort associated with altered bowel habits. Other gastrointestinal (GI) signs and symptoms include hard, lumpy, loose or watery stools, bloating, passing of mucus, straining to defecate, bowel urgency, and a feeling of incomplete bowel evacuation.
In addition to the GI symptoms, patients with IBS often report symptoms such as headache, fatigue, nausea, backache, bladder problems, depression and anxiety.
Establishing a diagnosis of IBS relies primarily on symptom assessments, but the emphasis should be on making a rapid, confident and ‘positive’ diagnosis, linked to defined treatment plans that can be presented as a ‘tailored’ approach to each patient.
The most recent, universal diagnostic criteria for IBS IS the Rome III criteria (Box 1) (6), which are widely used in clinical studies, but rarely applied systematically in clinical practice. Patients with IBS are usually classified according to their most prominent bowel symptom, with around one-third of patients having diarrhoea-predominant IBS (IBS-D), one-third having constipation-predominant IBS (IBS-C), and remaining one-third having a mixture of both (IBS-M). It is important to remember, however, that patients frequently shift between the different IBS types.
The National Institute for Health and Clinical Excellence (NICE) recommends that healthcare professionals should consider assessing a patient for IBS if he or she presents with at least a six-month history of any of the following: (7)
- Abdominal pain or discomfort.
- Change in bowel habit.
‘Red-flag’ indicators for referral to secondary care are shown in Box 2. According to the NICE guidelines, a diagnosis of IBS should only be considered if the individual has abdominal pain or discomfort that is either relieved by defecation or associated with altered bowel frequency or stool form, which should be accompanied by at least two of the following:
- Altered stool passage (straining, urgency, incomplete evacuation).
- Abdominal bloating (more common in women than men), distention, tension or hardness.
- Symptoms made worse by eating.
- Passage of mucus.
Other investigations should be restricted to the minimum required to exclude other diagnoses: a full blood count (FBC), erythrocyte sedimentation rate (ESR) and antibody testing for coeliac disease are all recommended (7).
For patients with diarrhoea-predominant symptoms, faecal calprotectin testing will help to rule out inflammatory bowel disease; colonic transit studies (X-ray) and pelvic floor studies may be very helpful for patients with constipation-predominant symptoms. In particular, a pelvic ultrasound should always be considered in women presenting with non-specific symptoms like bloating (to rule out ovarian pathology).
Management of IBS
Guidelines for the diagnosis and management of IBS in adults in primary care were published by NICE in 2008 (7) and, on the whole, are still current (Box 3). Self-care is a particularly important aspect of IBS management, with nurses playing a critical role in educating patients and providing dietary and lifestyle advice.
Current recommended treatments include laxatives, antispasmodics (e.g. peppermint, colpermin, mebeverine, buscopan), soluble fibre, probiotics, some antidepressants, and psychological therapies such as cognitive behavioural therapy (CBT) and gut-directed hypnotherapy. Indeed, CBT can be as effective as medication in this regard (8).
Since the NICE guidelines were published, two new medications – linaclotide and lubiprostone – have been licensed in the UK for the symptomatic treatment of IBS-C. These medications have a good body of evidence indicating that they may be of benefit in IBS-C, and it seems likely that they will be included as recommended treatments when the NICE guidelines are next updated.
Evidence for the benefits of probiotics on a range of IBS symptoms has also expanded since the NICE guidelines were published in 2008. A recent systematic review and meta-analysis identified significant beneficial effects of probiotics on global symptoms of IBS, abdominal pain, bloating and flatulence, (9) and the NICE guidelines suggest at least a four-week trial of a chosen probiotic at the manufacturer’s recommended dose (7).
Currently, it is unclear which individual species or strains of probiotic are most effective in IBS, although recent evidence suggests that liquid-based products are more likely than freeze-dried products to survive the acidic environment of the stomach and that one product in particular (Symprove) has the best survival potential (10).
A recently-reported 12-week, randomised, placebo-controlled study of Symprove conducted in the UK demonstrated significant reductions in pain and other IBS symptoms, with some study participants becoming symptom-free during treatment (5).
Nurses can play a key role in identifying and managing patients with IBS. Primary care nurses are particularly well placed to recognise the signs and symptoms of IBS in their patients, obtain an accurate medical history, identify ‘red flag’ indicators, and advise on diet, lifestyle, and other interventions as well as bringing in specialists where needed (doctors, dietitians, psychologists).
Scientific advances have paved the way for us to offer our patients a more confident and reassuring diagnosis early in the consultation process, facilitating the initiation of scientifically-proven treatments with good results.
In clinical practice, nurses have the potential to improve diagnostic accuracy, clinical outcomes, quality of life and overall satisfaction for patients with IBS11 and they should be at the heart of every multidisciplinary team managing this condition.
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2. Lee YJ, Park KS. Irritable bowel syndrome: emerging paradigm in pathophysiology. World J Gastroenterol 2014;20:2456-69.
3. Spiller R, Aziz Q, Creed F, et al. Guidelines on the irritable bowel syndrome: mechanisms and practical management. Gut 2007;56:1770-98.
4. Spiegel BM. Questioning the bacterial overgrowth hypothesis in irritable bowel syndrome: an epidemiologic and evolutionary perspective. Clin Gastroenterol Hepatol 2011;9:461-9.
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6. Drossman D, ed. Rome III: The Functional Gastrointestinal Disorders. 3rd ed. McLean, VA: Degnon Associates; 2006.
7. National Institute for Health and Care Excellence. Irritable bowel syndrome in adults: diagnosis and management of irritable bowel syndrome in primary care. NICE clinical guideline 61. 2008.
8. Hayee BH, Forgacs I. A psychological approach to managing irritable bowel syndrome. BMJ 2007;334:1105-9
9. Ford AC, Quigley EM, Lacy BE, et al. Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome: systematic review and meta-analysis. Am J Gastrenterol 2014;109:1547-61.
10. Fredua-Agyeman M, Gaisford S. Comparative survival of commercial probiotic formulations: tests in biorelevant gastric fluids and real-time measurements using microcalorimetry. Benefic Microbes 2015;6:
11. Moore JS, Gagan MJ, Perry RE. The benefits of a nurse-led service in the identification and management of symptoms of irritable bowel syndrome. Gastrenter
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