Irritable Bowel Syndrome

What is IBS?

IBS is a common condition that affects the colon or large bowel. People with IBS seem to have a very sensitive digestive system. It may affect as many as 1 in 10 people with women almost twice as likely to suffer from IBS. IBS is characterised by abdominal pain or discomfort that is related to passing flatus or faeces. There is usually an associated change in either the stool frequency or the consistency of the stool.

Patients typically have diarrhoea, constipation or both at different times and some patients complain of abdominal bloating or fullness. Symptoms that are not caused by IBS include bleeding, fever, weight loss, anaemia and night-time symptoms. These need further investigation to exclude other causes. Patients with new onset after 50, Upper gastrointestinal symptoms (eg nausea/vomiting) and a significant family history also need further tests.

What causes IBS?

No one knows the exact cause of IBS. It is likely a complex interplay of many factors in a patient that is susceptible to developing IBS. These may include

Environmental Factors

  • Infections in the gut
  • Antibiotics
  • Stress

Patient Factors

  • Food intolerance
  • Increase in gut immune activation
  • Gut hypersensitivity
  • Increased pain sensation
  • Increased gut permeability

How is IBS diagnosed?

Many patients are concerned that their symptoms are related to a serious condition such as bowel cancer and seek medical advice. Your doctor may order some tests such as a blood test (Haemoglobin, CRP, celiac serology) and a stool (poo) test (faecal calproctectin) as initial screening to exclude some of the common conditions that may mimic IBS such as Inflammatory Bowel Disease (IBD) and celiac disease. If your symptoms are typical and you are under 40 when you first developed symptoms, you may not need any further tests. Sometimes, a colonoscopy may be recommended.

How do you treat IBS?

Communication is very important. An explanation of the symptoms and diagnosis as well as treatment options can be reassuring.There are a range of treatment options depending on your symptoms. These can include:

  1. Dietary modification – e.g. low FODMAP
  2. Anti-diarrhoea medication – e.g. loperamide
  3. Constipation treatment – e.g. fibre or laxatives
  4. Pain medications – e.g. codeine which may also help with diarrhoea
  5. Anti-spasmodic medications

What is a Low FODMAP Diet?
Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols

FODMAP’s are sugars (carbohydrates) that are poorly absorbed by the gut contained in many common foods such as wheat, garlic, onions, some fruit (eg apple/pear) and some dairy products.

As FODMAP’s are poorly absorbed by the small intestine, they reach the colon and are fermented by colonic bacteria. This leads to increased water secretion into the gut, increased “wind”/gas and an increase in short-chain fatty acids. There is some evidence that a low-FODMAP diet can improve symptoms in patients with IBS. Once a low FODMAP diet has been established, some items such as dairy can be gradually re-introduced to test symptom response. Monash University have developed an app for patients on this topic.