Irritable Bowel Syndrome

Question 1

What is the epidemiology of IBS?

Answer 1

· Affects 10-20% of adults.
· More common in women.
· 20-30 years of age most common.

Question 2

What is the pathophysiology of IBS?

Answer 2

· Dysfunction with the motor and sensory aspects of the GI tract.
· Altered gut reactivity (motility and secretion) in response to stimuli, which can be:
- Environmental - life stresses or abuse.
- Luminal - certain foods, bacterial overgrowth or toxins, gut distension or inflammation.
· This altered reactivity can lead to pain as well as constipation or diarrhoea.

Question 3

What is the prognosis of IBS?

Answer 3

· Normal life expectancy.
· No long-term (or very low likelihood of) complications.
· Symptoms do tend to recur for much of adulthood, particularly at times of stress, emotional difficulty or dietary changes.

Question 4

What two diagnostic criterias are used in IBS?

Answer 4

Manning and Rome II criteria to help establish a diagnosis

No test for IBS, but you might need some tests to rule out other possible causes of yoursymptoms:

Question 5

What are the risk factors for IBS?

Answer 5

· Physical or sexual abuse.
· Age <50 years.
· Female.
· Previous enteric infection (acute bacterial gastroenteritis). 
· Family and job stress.

Question 6

What are the signs and symptoms of IBS?

Answer 6

· Abdominal discomfort.
· Morning rush
· Alteration of bowel habits associated with pain:
· Abdominal bloating or distension
· Normal examination of abdomen. 
· Psychological - anxiety, depression.

Question 7

What investigations would you do if IBS was suspected?

Answer 7

· FBC.
· Stool studies.

· Anti-endomysial antibodies:

• Performed if patient has diarrhoea and/or weight loss, and coeliac disease is suspected.
• Negative in IBS, positive in coeliac disease.

· Anti-tTG antibodies:
- Negative in IBS, positive in coeliac disease.

· AXR (abdo x-ray):

• Useful in evaluation of a patient with bloating.
• Should be normal. Used to rule out obstruction.

· Flexible sigmoidoscopy / colonoscopy.

Question 8

Suggest some differential diagnoses.

Answer 8

· Crohn's disease . 
· Ulcerative colitis.
· Coeliac disease.
· Colon cancer.
· Bowel infections.

Question 9

What are the treatment options for IBS?

Answer 9

· Constipation predominant:

• Without pain or bloating:
  > 1st line - Lifestyle and dietary modifications.
  > Plus - Laxatives.
  > 2nd line - Lifestyle and dietary modifications.
  > Plus - Lubiprostone or Linaclotide.

- With pain or bloating:
   > 1st line - Lifestyle and dietary modifications. 
   > Plus - Laxatives.
   > Plus - Anti-spasmodic.
   > 2nd line - Lifestyle and dietary modifications. 
   > Plus - SSRI. 
   > Plus - Linaclotide.
   > Adjunct - CBT or hypnotherapy. 

· Diarrhoea predominant:

• Without pain or bloating:
  > 1st line - Lifestyle and dietary modifications.
  > Plus - Anti-diarrhoeals.
• With pain or bloating:
  > 1st line - Lifestyle and dietary modifications.
  > Plus - Anti-diarrhoeals.
  > Plus - Anti-spasmodic.
  > 2nd line - Lifestyle and dietary modifications.
  > Plus - Tricyclic antidepressants.
  > Adjunct - CBT or hypnotherapy.

· Alternating constipation and diarrhoea:

• Without pain or bloating:
  > 1st line - Lifestyle and dietary modifications.
  > Adjunct - Laxatives.
  > Adjunct - Loperamide.
• With pain or bloating:
  > 1st line - Lifestyle and dietary modifications.
  > Plus - Anti-spasmodic.
  > Adjunct - Laxatives.
  > Adjunct - Loperamide.
  > 2nd line - Lifestyle and dietary modifications.
  > Plus - Tricyclic antidepressant or SSRI.
  > Adjunct - CBT or hypnotherapy.

Question 10

What complications can occur as a result of IBS?

Answer 10

· Damage to family and work relationships.

· Diverticulosis (not diverticular disease) - diarrhoea-predominant IBS.