Irritable bowel syndrome (IBS)
Irritable bowel syndrome (IBS) is a common condition that affects about one in every five people in the UK at some point in their lives. The condition is twice as common in women as it is in men.
The condition is a combination of abdominal discomfort or pain and altered bowel habits: either altered frequency ( diarrhoea or constipation) or altered stool form (thin, hard, or soft and liquid).
IBS is not a life-threatening condition and it does not make a person more likely to develop other colon conditions, such as ulcerative colitis, Crohn’s disease, or colon cancer or any diseases of the heart or nerves. Yet IBS can be a chronic problem that can significantly impair quality of life in those that have it. For example, people with IBS miss work more than people without IBS and the condition is associated with absenteeism from school, decreased participation in activities of daily living, alterations of one's work setting (shifting to working at home, changing hours) or giving up work altogether.
What are the symptoms of IBS?
Among the symptoms associated with IBS are:
- Diarrhoea (often described as violent episodes of diarrhoea)
- Constipation alternating with diarrhoea
- Abdominal pains or cramps, usually in the lower half of the abdomen that are aggravated by meals and relieved by having a bowel movement. Often the person has more frequent bowel movements when they have pain and the stools are looser
- Excess wind or bloating
- Harder or looser stools than normal (rabbit-like pellets or flat ribbon stools)
- Visible abdominal distension.
Some people with IBS have other symptoms not related to their digestive tract, such as urinary symptoms or sexual problems.
Symptoms of IBS tend to worsen with stress.
People with IBS have traditionally been described as having "constipation-predominant", "diarrhoea-predominant", or an alternating pattern of constipation and diarrhoea. Each type represents about a third of the overall IBS population.
What causes IBS?
Two hundred years after the condition was first described, experts still don't completely understand what causes IBS symptoms.
Many experts think that it is a problem of bowel motility, the muscles in the bowels don't contract normally, affecting the movement of stool. But some studies don't show that the poor bowel motility correlates with symptoms. Also, drugs that alter motility don't seem to benefit most people with IBS.
Newer studies suggest that in IBS, the colon is hypersensitive, overreacting to mild stimulation by going into spasms. Instead of slow, rhythmic muscle contractions, the bowel muscles spasm. That can either cause diarrhoea or constipation.
Another theory suggests that a number of substances that regulate the transmission of nerve signals between the brain and GI tract may be involved. These include serotonin, gastrin and others.
Some have also suggested that there is a hormonal component to the condition, as it occurs in women much more frequently than in men. So far, studies have not borne this out.
A number of factors can trigger IBS symptoms, including certain foods, medicines, the presence of gas or stool and emotional stress.