Irritable Bowel Syndrome (IBS) is a disorder that interferes with the normal functioning of the large intestine. It is characterised by a group of symptoms – bloating, abdominal cramps or pains, constipation and diarrhoea, feelings that you have not completely emptied the bowel, and alternating constipation and diarrhoea. It is a condition that is highly undiagnosed in many people. It is not a disease but a functional disorder, meaning that the bowels do not work as they should. Irritable bowel syndrome may cause discomfort and distress to people, but it does not permanently harm the intestines or lead to any severe diseases like cancer or intestinal bleeding.
What causes the symptoms of irritable bowel syndrome? The large bowel which is mainly involved in IBS is a muscular tube measuring about 6 feet long. It connects the small intestine with the rectum and anus. Its function includes absorbing water and salts from digestive meals that have travelled from the stomach through the small intestine. The muscles of the large intestine contract (tighten or squeeze) to move digestive material towards the rectum and anus. It is this contracting action that creates the order and eventual bowel motion. Nerves, hormones and muscular activities control the contraction of the large intestine.
IBS affects the motility or movement of stool and gas and influences how fluids are absorbed. When stool remains in the large bowel for a long time, too much water gets to be absorbed, and this results in passage of hard stools and constipation. If, however, there are spasms, this push stool through the large bowel so fast that the fluids do not get adequately absorbed and result in diarrhoea. In other situations, in which there are spasms, gas may get trapped in one area or stool may collect in one place temporarily. In some other cases, the nerves and muscles have been found to be extra sensitive. For example, the muscles may contract too much after a meal resulting in pain and diarrhoea, or the nerves may become overly sensitive to the stretching of the bowels because of gas resulting in abdominal cramps. The bloaty feelings result from the gas build-up in such situations.
Irritable bowel syndrome which is commoner in women has been known to be worse during menstruation. How is IBS diagnosed? Irritable bowel syndrome is mostly a diagnosis of exclusion. The implication of this is that no one test dictates this condition. However, diagnosis is made when other similarly presenting conditions have been excluded. The diagnosis involves a complete medical history which will include a careful description of symptoms and a physical examination. Associated bleeding, weight loss, and persistent severe pains are indeed not symptoms of IBS and may indicate other problems like cancer or inflammation. Some useful criteria are helpful in reaching a diagnosis:
- Abdominal pain or discomfort for at least 12 weeks out of the last 12 calendar months.
- The abdominal pain or discomfort in IBS have these peculiar features –
(a) There is a relief after a bowel motion
(b) an ongoing episode causes an alteration in the form of the stool
(c) there is a change in how often you have bowel motions. It may be less or more.
How do diet and stress affect IBS? People with IBS commonly have symptoms associated with diet and stress. Many, report that their symptoms occur after a meal or when under stress. The reasons are not known. Eating courses spasms of the large bowel. Usually, this response may cause an urge to have a bowel movement within 30 to 60 minutes after a meal. In people with IBS, the urge may come sooner with cramps and diarrhoea. Contractions or spasms may be stronger after a fatty meal. Other foods implicated include milk products like cheese, ice cream (especially in people who are lactose intolerant), chocolate, alcohol, caffeine, carbonated drinks, and gas producing foods like beans and some types of vegetables like cabbage. Stress, extremes of emotions like anger, anxiety, all overwhelming situations, could stimulate the large bowel in people with IBS.