Irritable Bowel Syndrome
The symptoms of irritable bowel syndrome (IBS) vary between different people, but most sufferers complain of feeling bloated, and having either abdominal discomfort, or pain, which often comes in spasms. Bowel movements can be erratic, with bouts of diarrhoea, then constipation. Many people with IBS also find that their symptoms can be affected by their diet (some foods make the bloating and pain worse), and also their emotions, especially stress. IBS can affect people of any age, but does seem to be more common in young people, and also women. In contrast, bowel cancer is more common in older people, over 50, though it does occasionally affect younger people. The classic symptom is a change in bowel habit, with previous orderly bowels becoming unpredictable, with bouts of constipation or diarrhoea. Some people notice their motions are a different shape (indicating a partial blockage in the bowel) or a different colour – black stool can be a sign that there is bleeding inside the bowel. Unlike IBS, pain is often not a major feature of bowel cancer, though some sufferers do have a vague feeling of discomfort in one area of their abdomen. Unfortunately, in a considerable number of people, bowel cancer does not cause any noticeable bowel symptoms at all – it is only discovered when it causes anaemia, or a burst, or completely blocked bowel. IBS is not related to bowel cancer in any way – but anyone with problems with their bowels should always see a doctor. There is no specific test for IBS – sometimes the diagnosis is fairly obvious, but in others, it can only be diagnosed when other problem – including bowel cancer – have been excluded.
Causes No one knows what causes irritable bowel syndrome. The intestines of people with IBS don’t look any different than those of people without the disorder, although they do seem to react more strongly to foods and stresses. Research has shown that people with IBS have problems with motility, the rhythmic muscle contractions that push fecal matter through the large intestine. In one study, people who had IBS with constipation had almost no contractions in 24 hours, compared with six to eight per day in healthy volunteers. IBS patients with diarrhea, by contrast, had as many as 25 contractions a day. Either problem can cause symptoms of IBS. The longer it takes for the muscle contractions to move the stool through the colon, the harder the stool becomesand the tougher it is to pass. By contrast, water won’t be absorbed from the stool if muscle spasms push it through too rapidly, leading to diarrhea. Gas can also get trapped along the way, causing discomfort. Sometimes people with IBS pass mucus with their bowel movements. People with this disease also appear to be extra sensitive to distention of the colon. Studies using balloons to distend the colon have shown that patients with IBS experience pain and feel bloated at balloon pressures and volumes that are significantly lower than those that cause symptoms in people without the condition. Recent studies also have shown that neurotransmitters, chemicals that pass signals between nerves, are particularly active in the gastrointestinal tracts of people with the condition.