IBS: diagnosis, treatment and management
1st June 2017

IBS: diagnosis, treatment and management

Gastroenterology Today

According to NICE, Irritable Bowel Syndrome (IBS) is estimated to affect between 10 – 20% of the UK population at any one time, equating to around 12 million people.

IBS causes a significant burden on the NHS, costing £200m annually in the UK  National and international guidance stresses the importance of making a positive diagnosis based on symptom assessment and appropriate investigation. Despite this recent data has shown that a third of people had to visit their GP at least five times before diagnosis, with 44% of sufferers reporting delayed diagnosis and treatment of the condition has impacted their quality of life.

Understanding IBS symptoms

IBS is a chronic disorder of gastrointestinal function with no well-defined structural or biochemical cause. It is a chronic, sometimes debilitating condition that can disrupt many people’s personal and working lives. The causes are thought to be multi-factorial. Psychological stress, gastrointestinal infection, diet and changes in the gut micro-biome have all been postulated to have a role in precipitating symptoms.

Symptoms can include one or a combination of constipation, diarrhoea, abdominal pain and bloating. Over time, patients often move from being constipation predominant to diarrhoea predominant and visa versa. Sufferers often complain of tiredness and fatigue. Approximately 15% of patients who develop IBS have other functional disease, such as fibromyalgia, interstitial cystitis.

Early diagnosis of IBS

With wide variations in symptoms from person to person, and the fact that other conditions can masquerade as IBS, diagnosis is often challenging. Where possible, clinicians are encouraged to make a positive diagnosis of IBS without resorting to complex and invasive procedures. All patients should undergo a thorough symptom assessment documenting the key features and exploring lifestyle and other factors, which are known triggers of disease. All patients should be asked about ‘Red Flags’ (see Figure 1) and if present, these should precipitate a referral to secondary care. A patient presenting with new symptoms of IBS should undergo basic investigations, including full blood count, C reactive protein or other inflammatory marker for Inflammatory Bowel Disease and antibody testing for Coeliac Disease. In those with diarrhea predominance bile salt malabsorption should be considered.

Faecal calprotectin is a heat stable neutrophil granule protein, which is found in elevated levels in the stools of patients with active inflammatory gastrointestinal disease. In patients under 60 years old without Red Flag symptoms referred to secondary care a normal faecal calprotectin has a negative predictive value of 0.964 for excluding symptomatic organic intestinal disease.v It is therefore increasingly used as a non-invasive means of excluding organic disease in patients thought likely to have IBS.


Figure 1 Red Flag symptoms

(See https://www.theibsnetwork.org/have-i-got-ibs/could-it-be-anything-else/)

‘Red Flag’ symptoms:

The following symptoms are warning signs for a person to be referred to their GP:


  • Rectal bleeding. Although in many cases rectal bleeding is caused by haemorrhoids, which often develop in people with IBS, regular loss of blood from the rectum should never be ignored.
  • Unintentional or unexplained weight loss.
  • Persistent fever and malaise.
  • An unexplained change in bowel habit persisting for more than six weeks, in an individual over 50 years old.
  • Family history of bowel or ovarian cancer.
  • Iron Deficiency Anaemia.  

Treating IBS

There are a wide variety of treatments available to relieve symptoms of IBS, however because of the multi-factorial nature of the pathogenesis no single treatment is universally effective. Whilst placebo responses are high, most studies would suggest that drug effects account for improvement in only 15-20% of patients. Helping people with IBS make improvements to diet and lifestyle is key to long-term management. The IBS Network aims to promote greater education awareness and understanding of Irritable Bowel Syndrome and provides useful signposts for many patients in this regard (www.theibsnetwork.org). Medical treatments should be recommended or prescribed according to the predominant symptoms, and in some cases a combination of drugs may be required.

Dietary changes

People with IBS usually find that eating can trigger their symptoms, but it’s often difficult to identify what component, if any, of the meal may be responsible. It may be the act of eating, the context of the meal, or just eating in a rush that is upsetting the gut. For others, certain food and drink may exacerbate their symptoms, such as fizzy drinks, dairy, gluten, fatty foods, onions, garlic, and some fruits, perhaps containing FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols). See the British Dietetic Association food fact sheet (https://www.bda.uk.com/foodfacts/IBSfoodfacts.pdf)  and recommendations on The IBS Network website for additional diet advice (https://www.theibsnetwork.org/diet ).

Encouraging the use of a food diary will help show any patterns (such as irregular eating) where symptoms may be worse. If people are struggling to make changes or are using exclusion diets they should be referred to a Registered Dietitian.

Lifestyle impact on IBS

Understanding physical activity levels and the psychological status of a patient with IBS is important. Emotional context can influence IBS symptoms, even in the absence of psychiatric disease. Physical activity also has a significant impact on bowel function.

Providing advice on managing stress and anxiety whether through adapting work/life balance and talking or complementary therapies can be useful (see https://www.theibsnetwork.org/stress/).


IBS is a complex, long-standing illness which clinicians often find challenging to diagnose because of the fear that IBS is masking a second disease. Failure to make a positive diagnosis can increase the likelihood of repeated visits to GPs and other medical practitioners and can cause psychological distress. Once someone is diagnosed with IBS, and encouraged to gain a better understanding of the potential triggers, whether linked to diet, lifestyle, stress or other factors, and knowing treatments, therapies and changes to make – they can often take control of their own illness through long-term self-management.

For more information and support on managing IBS symptoms, visit www.theibsnetwork.org


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