Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder of unknown cause. Common symptoms include abdominal cramping or pain, bloating and gassiness, and altered bowel habits.
Irritable bowel syndrome has also been called spastic colon, functional bowel disease, and mucous colitis. However, IBS is not a true “colitis.” The term colitis refers to a different group of conditions known as inflammatory bowel disease (IBD).
Irritable bowel syndrome is not contagious, inherited, or cancerous. It occurs more often in women than in men, and the onset occurs before the age of 35 in about half of the cases.
Irritable Bowel Syndrome Causes
The cause of irritable bowel syndrome is currently unknown. IBS is thought to result from an interplay of abnormal gastrointestinal (GI) tract movements, increased awareness of normal bodily functions, and a change in the nervous system communication between the brain and the GI tract. A
bnormal movements of the colon, whether too fast or too slow, are seen in some, but not all, people who have IBS.
Irritable bowel syndrome has also developed after episodes of gastroenteritis.
It has been suggested that IBS is caused by dietary allergies or food sensitivities, but this has never been proven.
Symptoms of irritable bowel syndrome may worsen during periods of stress or menses, but these factors are unlikely to be the cause that leads to the development of IBS.
What is irritable bowel syndrome (IBS) and who gets it?
IBS is a common functional disorder of the gut. A functional disorder means there is a problem with the function of a part of the body, but there is no abnormality in the structure.
So, in IBS, the function of the gut is upset, but all parts of the gut look normal, even when looked at under a microscope. IBS causes various symptoms (listed below).
Up to 1 in 5 people in the UK develop IBS at some stage in their life. IBS can affect anyone at any age, but it commonly first develops in young adults. IBS is slightly more common in women than it is in men.
What are the symptoms of irritable bowel syndrome (IBS)?
Pain and discomfort may occur in different parts of the tummy (abdomen). Pain usually comes and goes. The length of each bout of pain can vary greatly. The pain often eases when you pass stools (faeces) or wind. Many people with IBS describe the pain as a spasm or colic.
The severity of the pain can vary from mild to severe, both from person to person, and from time to time in the same person.
Bloating and swelling of your abdomen may develop from time to time. You may pass more wind than usual.
Changes in stools:
- Some people have bouts of diarrhoea, and some have bouts of constipation.
- Some people have bouts of diarrhoea that alternate with bouts of constipation.
- Sometimes the stools become small and pellet-like. Sometimes the stools become watery or more loose. At times, mucus may be mixed with the stools.
- There may have a feeling of not emptying the back passage (rectum) after going to the toilet.Some people have urgency, which means they have to get to the toilet quickly. A morning rush is common. That is, they feel an urgent need to go to the toilet several times shortly after getting up. This is often during and after breakfast.
Other symptoms which sometimes occur – include:
- Feeling sick (nausea).
- Poor appetite.
- Muscle pains.
- Feeling quickly full after eating.
Bladder symptoms (an associated irritable bladder).
Some people have occasional mild symptoms. Others have unpleasant symptoms for long periods. Many people fall somewhere in between, with flare-ups of symptoms from time to time.
Some doctors group people with IBS into one of three categories:
- Those with abdominal pain or discomfort, and the other symptoms are mainly bloating and constipation.
- Those with abdominal pain or discomfort, and the other symptoms are mainly urgency to get to the toilet, and diarrhoea.
- Those who alternate between constipation and diarrhoea.
However, in practice, many people will not fall neatly into any one category, and considerable overlap occurs.
Note: passing blood is not a symptom of IBS. You should tell a doctor if you pass blood.
Do I need any tests for irritable bowel syndrome (IBS)?
There is no test that confirms the diagnosis of IBS. A doctor can usually diagnose IBS from the typical symptoms.
However, a blood sample or stool (faeces) test is commonly taken to do some tests to help rule out other conditions such as Crohn’s disease, ulcerative colitis, coeliac disease, cancer of the ovary, gut infections, etc.
The symptoms of these other diseases can sometimes be confused with IBS. Tests done commonly include:
- Full blood count (FBC) – to rule out lack of iron in the blood (anaemia), which is associated with various gut disorders.
- Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) – which can show if there is inflammation in the body (which does not occur with IBS).
- A blood test for coeliac disease.
In women, a blood test to rule out cancer of the ovary, called CA-125.
A stool test to look for a protein called faecal calprotectin. This may be present if you have Crohn’s disease or ulcerative colitis, but is not present in IBS.
More complicated tests such as gastroscopy (a look into the bowel with a special telescope) are not usually needed.
However, they may be done if symptoms are not typical, or if you develop symptoms of IBS in later life (over the age of about 50) when other conditions need to be ruled out.
What are the treatments for irritable bowel syndrome (IBS)?
Many people are reassured that their condition is IBS, and not something more serious such as colitis. Simply understanding about IBS may help you to be less anxious about the condition, which may ease the severity of symptoms.
Symptoms often settle for long periods without any treatment. In some cases, symptoms are mild and do not require treatment.
There are many different treatments that may be tried for IBS. All will have an effect on some people, but none will help in every person with IBS.
No treatment is likely to take away symptoms completely, but treatment can often ease symptoms and improve your quality of life.
Irritable Bowel Syndrome Diagnosis
Irritable bowel syndrome can be a very difficult diagnosis to make. IBS is called a diagnosis of exclusion, which means a doctor considers many other alternatives first, performing tests to rule out other medical problems.
Some of these tests may include laboratory studies, imaging studies (such as a CT scan or small intestinal X-rays), or a lower GI endoscopy (colonoscopy).
An endoscopy is a procedure in which a flexible tube with a tiny camera on one end is passed into the GI tract while the patient is under conscious sedation.
A combination of history, physical examination, and selected tests are used to help diagnose irritable bowel syndrome.
No single blood test or x-ray study confirms a diagnosis of IBS.
What is the outlook (prognosis)?
In most people with irritable bowel syndrome (IBS), the condition tends to persist long-term. However, the severity of symptoms tends to wax and wane.
You may have long spells without any symptoms, or with only mild symptoms. Treatment can often help to ease symptoms when they flare up.
In some cases, symptoms clear for good at some stage. This is more likely if your IBS started after an infection (gastroenteritis).
IBS does not shorten your expected lifespan, it does not lead to cancer of the bowel, and does not cause blockages of the gut, or other serious conditions.