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
For a doctor to make a diagnosis of IBS, a person must have had recurrent abdominal pain on average at least one day per week during the previous three months that is associated with two or more of the following:
- The pain is increased or unchanged after a bowel movement
- A change in frequency of bowel movements
- A change in stool form or appearance.
- Anti-spasmodic drugs: relax the muscles in the wall of your intestines to stop painful spasms. They include mebeverine (Colofac), and hyoscine (Buscopan, Gastrosoothe).
- Anti-diarrhea medications: over the counter medicines like loperamide may help control diarrhea.
- Antidepressants: if symptoms include pain or depression a doctor may recommend medications that relieve depression.
- Fibre supplements: 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) may help with digestion.
Support and further informationFor further support and information:
National Institute of Diabetes and Digestive and Kidney Diseases (2015). Irritable Bowel Syndrome (IBS) (Web Page). Bethesda, MD: NIDDK, National Institutes of Health of the U.S. Department of Health and Human Services. https://www.niddk.nih.gov/health-information/digestive-diseases/irritable-bowel-syndrome [Accessed: 19/08/17]
O’Toole, M.T. (Ed.) (2013). Irritable Bowel Syndrome. Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis MI: Elsevier Mosby.
Sperber, A.D., et al. (2017). The global prevalence of IBS in adults remains elusive due to the heterogeneity of studies: a Rome Foundation working team literature review. Gut. 2017;66(6):1075–1082.