A 26-year-old woman presents with symptoms of intermittent abdominal pain, bloating and looser stools for the past few months. You consider a diagnosis of irritable bowel syndrome (IBS), but plan to organise some investigations first to exclude more serious pathology.

  1. According to the current NICE guidelines, which tests should be arranged?
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A diagnosis of IBS should be considered in any patient having had any of the following symptoms for greater than 6 months:

  • A – abdominal pain
  • B – bloating
  • C – change in bowel habit


A diagnosis of IBS should only be considered if the person has abdominal pain or discomfort that is either relieved by defecation or associated with altered bowel frequency. This should be accompanied by at least two of the following symptoms:

  • Altered stool passage (straining, urgency, incomplete evacuation)
  • Abdominal bloating, distension, tension or hardness
  • Symptoms made worse by eating
  • Passage of mucus


Patients who meet the diagnostic criteria for IBS should undergo the following tests to exclude other diagnoses:

  • Full blood count (FBC)
  • Erythrocyte sedimentation rate (ESR) or plasma viscosity
  • C‑reactive protein (CRP)
  • Antibody testing for coeliac disease (endomysial antibodies or tissue transglutaminase)
  1. According to the current NICE guidelines, which tests are NOT necessary and should not be routinely offered?
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The following tests are not necessary and should not be routinely offered:

  • Ultrasound
  • Rigid/flexible sigmoidoscopy
  • Colonoscopy and/or barium enema
  • Thyroid function test
  • Faecal ova and parasite test
  • Faecal occult blood and faecal immunochemical tests
  • Hydrogen breath test (for lactose intolerance and bacterial overgrowth)
  1. What are the ‘red flag’ indicators that warrant urgent referral to secondary care in patients with a potential diagnosis of IBS?
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All patients presenting with a potential diagnosis of IBS should be screened for the presence of the following ‘red flag’ indicators. If any are present an urgent referral to secondary care is warranted:

  • Unexplained or unintentional weight loss
  • Rectal bleeding
  • A change of bowel habit to looser / more frequent stool for >6 weeks in patients aged over 60
  • Family history of bowel cancer
  1. What are the first-line therapies for the treatment of IBS?
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The first-line therapy for IBS should be:

  • Antispasmodics, e.g. mebeverine hydrochloride
  • Laxatives, but lactulose should be avoided/discouraged
  • Loperamide, if diarrhoea is a feature


Tricyclic antidepressants (TCAs), such as amitriptyline, should be considered as a second-line therapy for patients with IBS if laxatives, loperamide or antispasmodics have not helped. Treatment should be started at a low-dose (5-10 mg amitriptyline) and taken at night. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, should be considered in patients where TCAs have been ineffective.


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