The cause of IBS is not known. Doctors call it a functional disorder because there is no sign of diseases such as inflammation or infection when the colon is examined.
With aggressive research done in this area over a period of time, scientists have come to the conclusion that the cause of IBS may be multifactorial, the cumulative effect of which results in the derangement of the normal functioning of the bowel.
The underlying cause of this disorder is an abnormality of the intestinal muscles contraction. In IBS the intestines may not function normally, either contracting too forcefully or weakly, too slowly or rapidly.
The factors that can adversely affect the job of the bowel are as follows:
1. Psychological factors: Patients with IBS report of increasing symptoms during the events of stress and many patients with IBS report that their symptoms began during periods of major life stressors such as a divorce, death of a loved one, school exams, or after moving to a new job or city. About 50% of patients exhibit a range of emotional disturbance including anxiety, depression, and neurosis.
It is a known fact that our emotions and intestines are interwoven. The brain and the intestines are closely connected by nerve fibres that control the functioning of the intestines. It is believed that in IBS the communication between brain and gut may be impaired.
2. Sensitivity to food: Symptoms of IBS have also been known to be triggered by the ingestion of certain foods to which the individual is sensitive. Chocolate, milk products, caffeine, or large amounts of alcohol are frequent offenders.
One theory states that lack of fibre in the diet can have a detrimental effect. This lack of fibre causes irregular contractions of the large intestines.
3. Genetics and heredity: Some studies indicate that there are more chances of IBS running in a family. It is believed that there are some inborn tendencies of an individual that make him/her react adversely to stress or certain food and resulting in IBS.
4. Some patients develop IBS following an episode of gastroenteritis or abdominal surgeries like removal of the gallbladder.
5. Researchers have also found that women with IBS may have more symptoms during their menstrual periods, suggesting that reproductive hormones can increase IBS symptoms
6. Conventional medicines: Many patients with IBS report worsening of their symptoms following the use of some of the conventional medicines like antibiotics, steroids, anti-inflammatory medicines etc.
Abdomen: The area of the stomach.
Barium Enema: An x-ray examination of the colon and rectum after liquid barium has been infused through the rectum.
Bowel: The part of the digestive system that makes and stores stool. It is also called the large intestine.
Colon: The large intestine.
Colonoscopy: A test in which a flexible, lighted tube is inserted through the rectum to examine the colon.
Distension: An uncomfortable swelling feeling in the abdomen, often caused by excessive amounts of gas and fluids in the intestine.
Endoscopy: The examination of the inside of a hollow organ, such as the bowel, using special lighted tubes.
Exacerbation: Aggravation of symptoms or an increase in disease activity; a relapse.
Fissure: A crack in the skin, usually in an area of the anus.
Functional: Refers to how something works.
Gastroenterologist: A physician specially trained in the diagnosis and treatment of patients with gastrointestinal disease.
Gut: General word for intestine or bowel.
IBD: Acronym for inflammatory bowel disease.
Inflammatory Bowel Disease (IBD): A collective term for Crohn’s disease and ulcerative colitis.
Irritable Bowel Syndrome: Altered motility of the small and large intestine, causing diarrhoea and abdominal discomfort. Sometimes mistakenly called “spastic colitis,” this condition does not cause inflammation of the colon and has no relationship to ulcerative colitis.
Lactose Deficiency/Lactose Intolerance: A condition caused by a decrease or absence of the enzyme lactase, which aids in the digestion of milk sugar (lactose).
Motility: Movement of the muscles that propel food through the intestinal tract.
Mucus: A whitish substance produced by the intestine, which may be found in the stool.
Upper G.I. Series: An x-ray exam of the oesophagus, stomach, and duodenum performed in the fasting patients after the ingestion of liquid barium. The duration of the exam can be prolonged to allow for visualization of the entire small intestine, including the terminal ileum. The x-ray is then known as an upper G.I. series with small-bowel follow-through.