Conditions & Investigations

Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a common condition that will effect approximately 20% of the population at some point during their lives. IBS has no effect on life expectancy. However, it is a source of chronic pain, fatigue, and other symptoms and contributes to work absenteeism There are a variety of different names that patients will hear such as functional bowel disorder, spastic colon syndrome, spastic bowel or spenic flexure syndrome, all of which come under the umbrella term of IBS.

The Diagnosis of IBS

History taking

The focus of making a diagnosis of IBS comes from taking a detailed history not only of a patient’s symptoms, but also to see whether there are any other medical conditions which could be related. Your doctor should also enquire about your family history of illness, as well as social factors such as your intake of alcohol, coffee or fizzy drinks as well as your current dietary habits. Stress can often be an important factor and again this will usually be discussed in any consultation.

Symptoms  of IBS

The typical symptoms that patients describe are abdominal pain which usually tends to be in the lower half of the abdomen and can be crampy in nature. This is associated with a change in bowel habit passing a motion of variable consistency, ranging from a pellet lumpy type stool to a loose liquid stool.  It is important to accurately describe the stool consistency and some patients may be shown the Bristol Stool Chart which offers a visual aid. Patients will also often describe feeling bloated and windy.  Some patients often find that their abdominal pain is improved by either opening their bowels or  passing wind. Weight loss or bleeding from the back passage are not features of IBS.


The symptoms of IBS vary widely and from patient to patient. Under the umbrella term of IBS, there are various subtypes, such as diarrhoea predominant IBS, constipation predominant IBS, fluctuating (constipation and diarrhoea) IBS  as well as post-infective IBS (where classically the symptoms of IBS start after a gastroenteritis). As is suggested by each subtype, this is very much based on the clinical history .

However, because of the varied  symptoms, it is also important to exclude other conditions such as infections, inflammatory bowel disease, malabsorption type problems such as Coeliac disease (a gluten allergy which leads to problems absorbing nutrients and minerals), or bowel cancer. Therefore your doctor will usually perform several tests to  exclude some o these other conditions:

a) Blood tests:  blood tests will look for signs of anaemia, check your thyroid function and look for evidence of Coeliac disease as well as checking  the level of inflammatory molecules  in your blood called an ESR and CRP – these molecules are non-specific indicators  of infection or inflammation and can be raised in inflammatory bowel disease.

b) Stool samples: You may also be asked to give a stool sample, which will not only look for evidence of infection, but can also sometimes be used to look for evidence of inflammation in the bowel (called the faecal calprotectin test).

c) Colonoscopy: other investigations of the bowel such as a colonoscopy are often indicated – this is a test to examine your large intestine (also called colon), and involves passing  a  thin, flexible, telescope. about as thick as a little finger, up the back passage and into the colon. It is is then manoevered all the way round the colon as far as the caecum which is where the small and large intestine meet. This test involves some preparation by taking a strong laxative the day before the procedure so that clear views of the lining of the colon are obtained. The purpose of the test is to exclude other conditions such as inflammatory bowel disease and early bowel cancer, which can sometimes mimic the symptoms of IBS.

Treatment of IBS

There are a wide variety of treatments for IBS, - sometimes more than one treatment is required, and patients ....It is important that your doctor disusses all the various treatment options with you, so that in consultation with your doctor, you can decide which treatment will be best for you.

Dietary treatments:

a) Fibre

b) Low FODMAP diet