Irritable Bowel Syndrome Introduction

What is irritable bowel syndrome?

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, but can be puzzling for those who have it and for the doctors who treat it.

Unlike disorders such as stomach ulcers or arthritis, there is no laboratory test, x-ray, scan or endoscopic investigation that can show whether or not you have irritable bowel syndrome. There is no clear cut cure for the disorder. However, various kinds of treatment can relieve the symptoms and, with the right support from your doctor, you can learn how to treat and manage IBS.

Irritable bowel syndrome is a syndrome, a collection of symptoms with similar features that occur together in a pattern that your doctor can recognise. Irritable bowel syndrome is a syndrome and not a disease. In typical cases, there is rarely any doubt about the diagnosis, although you may have symptoms in any part of your gastrointestinal tract, which stretches from the oesophagus (gullet) to the rectum.

What are the main symptoms?

The term irritable is used to describe the reaction of the muscles in the intestines, which respond to stress with abnormal contractions. These may result in various combinations of the three main symptoms:

  • Pain
  • Diarhoea
  • Constipation.

These symptoms may be worrying. However, if you have been told that you have irritable bowel syndrome, you can take some comfort from the information that this disorder does not increase your chance of developing long term serious conditions such as ulcerative colitis or cancer. Also, there is no evidence that people with irritable bowel syndrome have a shorter life expectancy.

How common is irritable bowel syndrome?

Irritable bowel syndrome affects around one in five adults in the industrialised countries. Even more people have at least one of its symptoms. A study in the USA found that, in one year, as many as 70% of the general population had problems associated with abnormal bowel function, such as abdominal pain, constipation or diarrhoea. Three quarters of people with symptoms of irritable bowel syndrome do not consult a doctor, and yet as many as half the people seen in a hospital outpatient clinic for gastrointestinal disorders have IBS as the cause of their problems. Evidence suggests that half the people with irritable bowel syndrome seen in clinics also have some symptoms of depression or anxiety.

In the UK, around 8 million people have IBS. On average, each of them has 17 days off work a year, at an annual cost to the country of approximately £500 million. Average work days missed in the USA per year were 14.8, compared with 8.7 in those without symptoms of irritable bowel syndrome. Indeed, IBS ranks close to the common cold as a leading cause for absenteeism from work as a result of illness.

Symptoms of irritable bowel syndrome are equally common in men and women, but women consult their doctors about the symptoms more often than men. About half of those with irritable bowel syndrome develop symptoms before the age of 35; 40% of people with IBS are aged 35 to 50 years. There is a tendency for symptoms to occur less often as you get older, but some people do experience them for the first time later in life. Doctors tend to be more cautious about diagnosing irritable bowel syndrome in elderly people. They will usually do so only after excluding other diseases of the gut.

Key points

  • Irritable bowel syndrome is a syndrome, not a disease, affecting about 20% of adults in industrialised countries.
  • Doctors see twice as many women as men with the condition.
  • Irritable bowel syndrome has a major social impact, leading to frequent days off work and restriction of social activities.