Irritable bowel syndrome (IBS)

What is irritable bowel syndrome (IBS)?

Irritable bowel syndrome is a common disorder of the gut that can cause bloating, cramps, diarrhoea and constipation.

IBS has a great impact on quality of life and work productivity. It affects approximately 10% of the general population and most commonly affects young people, particularly women. Patients often feel anxious and depressed and unable to carry out daily tasks.

What causes IBS?

The precise cause or causes of IBS are unknown but it is thought to be due to effects on the gut and brain pathways, between which there are thought to be strong links. There are thought to be a number of various factors involved in the development of IBS including:

• Possible triggers include infections, inflammation, food antigens and medications
• Changes in intestinal permeability (‘leaky gut’)
• Changes in the gut microbiome (the bacteria species which reside in the gut)
• Changes in central nervous system function
• Stress and anxiety
• Change in diet

What are the symptoms of IBS?

Common symptoms include:

• Abdominal pain 
• Stomach cramping
• Irregular bowel function - patients may experience diarrhoea or constipation, or a mixture
• Abdominal swelling

Other symptoms may include:

• Farting
• Mucus in your faeces
• Tiredness
• bBack pain
• Nausea

How is IBS diagnosed?

You should see your GP in the first instance. They may recommend tests to rule out any other gastrointestinal disorders or coeliac disease (gluten intolerance).

Further tests may include:

• Blood tests including full blood count, C-reactive protein, coeliac serology tests and liver function tests.
• Faecal calprotectin samples are a very useful marker of intestinal inflammation. A negative result makes the diagnosis of IBS very likely.
• Stool microscopy & culture sensitivity samples can be useful to check for infections such as gastroenteritis. Gut infections can lead to post-infectious IBS.
• Endoscopy tests include gastroscopy and lower gastrointestinal endoscopy constituting flexible sigmoidoscopy and colonoscopy. These are invasive tests and so may not be required usually being reserved for equivocal or difficult cases.
• Radiological tests include abdominal ultrasound and CT scanning. These may be performed to check for other causes of abdominal pain such as gallstone disease and diverticulitis.

What is the treatment for IBS?

IBS treatment will depend on your particular symptoms, sometimes symptoms of IBS can ease or settle without treatment. Treatment for IBS may include dietary restrictions. You may be asked to keep a food diary to help identify foods that may trigger symptoms. 

Psychological counselling may be effective for certain individuals with abdominal pain.

If conservative treatment is not successful your GP may refer you to a specialist consultant.

Medical treatment

The right drug needs to be selected to help specifically target and treat the patient’s symptoms. A trial and error approach may need to be adopted with different drugs combined to improve their effectiveness:

• Probiotics may be effective but more robust evidence is needed to prove their effectiveness.
• Antispasmodic drugs may be effective for abdominal pains and particularly spasm-type pains. Probiotics may be effective but more robust evidence is needed to prove their effectiveness.
• Peppermint oil has been shown to be a simple treatment that is effective for most IBS symptoms.
• Linaclotide is a drug that has been shown to be effective in reducing abdominal pain and improving constipation.
• Prucalopride is a drug that has been shown to be effective in treating young women with IBS and constipation.
• Eluxadoline is a relatively new drug that has been shown to be effective in treating IBS with diarrhoea symptoms.
• Rifaxamin is an antibiotic treatment that has been shown to possibly improve IBS symptoms.
• Amitriptyline is a drug that acts on the nervous system and acts as a nerve painkiller. It has been shown to help improve IBS symptoms, particularly abdominal pain.

Self-help measures for IBS

There are some lifestyle changes that you can make to help relieve your symptoms of IBS. These include:

• Get regular exercise
• Try to manage your stress
• Keep a symptom tracker - this may help you to identify any foods or triggers that make your symptoms worse so you can try and avoid these triggers. A FODMAP diet may also improve symptoms of IBS.