It is not known what causes intestinal muscles to stop working properly in IBS. One suggestion is that communication signals between the brain and the intestine are disrupted and this results in abnormal function of the intestinal muscles. Potential causes of IBS include:
- Hypersensitivity: some people with IBS have a lower pain threshold to bloating and cramping in their intestines.
- Infection: bacterial gastroenteritis may trigger IBS in some people.
- Stress: stressful events, such as work or marriage difficulties, or the death of someone close, may also trigger symptoms of IBS. Psychological stress can be expressed through physical symptoms. Stress can also worsen IBS.
- Body chemicals: levels of neurotransmitters (chemicals that transmit nerve signals) and digestive tract hormones are altered in some people with IBS. Reproductive hormones appear to worsen symptoms.
- Food sensitivity: many people with IBS report that some foods and beverages can cause symptoms.
Signs and symptoms
There is no test that can confirm a diagnosis of irritable bowel syndrome. A diagnosis is made by a doctor asking questions about symptoms and other health problems, and ruling out other illnesses. For a doctor to make a diagnosis of IBS one of the following must also be true:
- You have pain or discomfort that is relieved by going to the toilet
- You have pain or discomfort that is accompanied by a change in frequency of bowel movements or in stool form (appearance), i.e. harder or softer.
And two of the following must be true:
- You experience a change in how you pass stools, eg: you feel an urgency to go to the toilet, strain to pass stools, or feel as if you have not completely emptied your bowels
- You have bloating or hardness in your abdomen
- Your symptoms tend to feel worse after you eat
- Your stools may have mucous in them.
- Anti-spasmodic drugs: relax the muscles in the wall of your intestines to stop painful spasms. They include mebeverine (Colofac), and hyoscine (Buscopan, Gastrosoothe).
- Loperamide (Diamide Relief): is sometimes used to treat diarrhoea in people with IBS.
- Antidepressants: although normally used to treat depression, these medications may have benefits in some people with IBS. Examples include, amitriptyline (Amitrip), clomipramine (Apo-Clomipramine), and doxepin (Anten).
- Fibre supplements: such as sterculia (Normacol), can be used to treat constipation and possibly some of the other symptoms of IBS.
- Peppermint oil: which can relax the muscles in your intestine, is sometimes used to treat symptoms of IBS.
- Probiotics: products, such as probiotic yoghurts, soy drinks, and tablets and capsules (which contain live ‘friendly’ bacteria similar to those that live in your bowels) can help with digestion.
Support and further informationFor further support and information: Crohn’s & Colitis New Zealand Charitable Trust
Phone: 0800 ASK IBD (0800 275 423)
Phone: +61 (07) 3376-2496