Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) is a very common condition which affects the function of the bowel.

It is generally a chronic condition although the symptoms and severity may vary from person to person.

Definitions

Bowel=intestine (in irritable bowel syndrome, this refers to the large intestine)

Syndrome= a group of symptoms

Causes of irritable bowel syndrome

No one knows the exact cause of irritable bowel syndrome. One possible reason one gets IBS is that there is an imbalance between the activity of the nerves and muscle contractions in the bowel wall. For instance, the bowel wall may contract more strongly and food is rushed thorough the intestines more quickly resulting in diarrhea, bloating, flatulence and abdominal pain. In another instance, the opposite may occur and the bowel contracts more slowly leading to constipation.

The presence of food in the bowel may also affect the sensitivity of the nerves hence some people may find that certain food(eg fatty food, alcohol, caffeine) can trigger an attack of abdominal pain.

Symptoms or complaints

The symptoms which varies from person to person include:

  1. abdominal pain or cramping usually relived by going to the toilet
  2. alteration in bowel habit/diarrhoea/constipation (usually painful)
  3. bloating or flatulence
  4. mucus in the stool
  5. feeling that one has not finished a bowel movement

You should always see a doctor if you have any of the above symptoms because these symptoms are also often found in other diseases affecting the colon such as bowel cancer, diverticular disease and inflammatory bowel disease.

Differential diagnoses to consider – What other conditions can mimic symptoms of irritable bowel syndrome?

  1. Diverticular disease
  2. Bowel cancer
  3. Inflammatory bowel disease
  4. Coeliac disease

Management

History and Examination

If you have any of the above symptoms, you should see your doctor. You may need to be referred to a specialist for further assessment.

A thorough careful history and examination needs to be taken in particular to exclude conditions such as bowel cancer.

The examination would consist of an abdominal examination including a rectal examination. A rigid sigmoidoscopy should also performed

Investigations

A colonoscopy may be indicated especially if there is a change in bowel action as this can be a symptom of bowel cancer as well. Unlike other colon conditions, there is no pathology to find in irritable bowel syndrome eg no inflammation of bowel or polyps.

Other tests including blood tests may be necessary.

Treatment

General measures

  1. Diet changes – A high-fibre diet and fibre supplements such as Metamucil (psyllium) or Fybogel (ispaghula husks) may help especially for those with constipation. Eating regular meals may also help.
  2. Avoidance of trigger factors (these may vary from person to person)
  • Caffeine (eg from coffee)
  • Chocolate
  • Fatty foods like chips
  • Milk products
  • Alcohol
  • Carbonated drinks like Coke
  • High-gas food like beans and artichokes
  1. Stress relief – Stress can make the symptoms worse. Counselling and regular exercise may help.

Medications

These should only be used in consultation with your doctor. They include;

  1. Antidiarrhoeal medications (eg loperamide or cholestyramine) for diarrhoea
  2. Laxatives for constipation
  3. Antidepressants (eg fluoxetine, amitriptyline) – these medications affect the neurotransmitter levels in the nerves in the bowel
  4. Antispasmodics can be used for pain relief (eg Mebeverine, hyoscine and peppermint oil)
  5. Medications directly affecting the nerve receptors in the bowel eg Alosetron(an antagonist of serotonin receptors in the bowel) and tegaserod (an agonist of serotonin receptors) (The latter medication has been shown to be effective for short-term use in women but it is expensive)

Other analgesics are generally ineffective and codeine-containing drugs should be avoided.

Other therapy

Counselling, relaxation exercises, deep breathing techniques, cognitive behaviour therapy, biofeedback, hypnotherapy all may help. Complementary therapy such as acupuncture or probiotics may help some people.