Red flags for pathology in patients with irritable bowel syndrome (IBS):

• GI bleeding (e.g., melena and rectal bleeding).
• Unexplained weight loss.
• Progressive abdominal pain.
• Onset after age 50.
• Nocturnal diarrhea (unusual in IBS).
• Iron deficiency anemia, elevated CRP or fecal calprotectin/lactoferrin.
• Family history of inflammatory bowel disease (IBD) or colorectal cancer.

Causes of acute abdominal pain should be ruled out – AVOID premature closure bias.

IBS is common: abdominal pain and altered bowel patterns (diarrhea, constipation, or both).

The prevalence of IBS in Canada is ~12%.

IBS is more common in:

• Women aged 20-40.
• Those with psychiatric disorders.
• Those with functional somatic syndromes (e.g., chronic fatigue, fibromyalgia).
• Individuals under the age of 50.

IBS is associated with visceral hypersensitivity and abnormal motility.

• Diagnosis is clinical and relies on patient self-reporting of symptoms as well as ruling out other causes.
  • Consider red flags.
  • Patients may report acute enteric infection prior to onset of IBS symptoms.
  • Assess family history of celiac disease.
• Differential diagnosis:
  • Celiac disease.
  • Inflammatory Bowel Disease (IBD).
  • Colorectal cancer.
  • Microscopic colitis.
  • Small intestinal bacterial overgrowth (SIBO).
• There are different subcategories of IBS:
  • IBS with diarrhea
  • IBS with constipation
  • IBS with mixed stool pattern, and
  • IBS unclassified.

Table 2: Lab and imaging investigations for disorders related to IBS.

Continuity of care and the physician-patient relationship are considered critical in the management of IBS, so consider referral to a longitudinal physician.

Table 3: Non-pharmacological therapy for IBS.

Table 4: Pharmacological therapy option for IBS.

For patients that continue to have refractory symptoms, consider referral for behavioural modification (e.g., cognitive behavioural therapy, gut-directed hypnotherapy, relaxation therapy, dynamic psychotherapy) or use of anxiolytics for less than two weeks to reduce anxiety if present (e.g., benzodiazepines or gabapentin).

1. https://www.researchgate.net/figure/A-The-Bristol-Stool-Form-Scale-BSFS-is-a-useful-tool-to-evaluate-bowel-habit-The_fig1_340532872

   
   

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2. Wald A. Clinical manifestations and diagnosis of irritable bowel syndrome in adults [Internet]. 2023 [cited 2024 Jan 19]. Available from: https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-irritable-bowel-syndrome-in-adults?search=irritable+bowel+syndrome&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2#H2525434223

   
   

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4. Moayyedi P, Andrews CN, MacQueen G, Korownyk C, Marsiglio M, Graff L, et al. Canadian Association of Gastroenterology Clinical Practice Guideline for the management of Irritable Bowel Syndrome (IBS). Journal of the Canadian Association of Gastroenterology. 2019;2(1):6–29. doi:10.1093/jcag/gwy071