GPAtlas
IRRITABLE BOWEL SYNDROME (IBS)
gpatlas.co.uk
🔍 When to Suspect
Recurrent abdominal pain/discomfort for at least 6 months, associated with a change in bowel habit (constipation/diarrhoea/alternating) and feelings of bloating
🩺 Assessment
- ◉ Symptoms + triggers → Abdominal pain relieved by defecation, bloating, change in stool frequency/form, urgency, incomplete evacuation; worse with stress/foods
- ◉ Risk factors/history → Previous gastroenteritis, stress, family history of bowel or ovarian cancer (to exclude, not a risk for IBS)
- ◉ Impact + mimics → Significant impact on social life, work, and quality of life; mimics include IBD, coeliac disease, ovarian cancer
- ◉ Exam findings → Often normal; may have mild, generalized abdominal tenderness; perform DRE if rectal bleeding or change in habit
💊 Management
🔸Key tests:
➤ FBC, CRP/ESR, coeliac screen (IgA tTG) are all essential; also faecal calprotectin to exclude IBD and CA125 in women ≥ 50 with new IBS-type symptoms
🔸Lifestyle:
➤ Regular meals, adequate fluids, limit caffeine/alcohol; advise regular exercise; adjust fibre (soluble fibre e.g., oats may help)
🔸Pharmacological:
➤ 1st line (symptom-specific): Pain (antispasmodics e.g., mebeverine); Constipation (ispaghula, then macrogol); Diarrhoea (loperamide)
➤ 2nd line (pain/global): Low-dose TCA (e.g., amitriptyline 5-10mg at night)
➤ 3rd line: Consider SSRI if TCA fails
🔸Dietary interventions:
➤ Advise a trial of probiotics for 4 weeks; if symptoms persist, refer to a dietitian for a trial of a low FODMAP diet
🔸Follow-up/safety-net:
➤ Reassure and provide positive diagnosis; refer for psychological therapies (CBT/hypnotherapy) if symptoms persist >12 months
⚠️ Red Flags
• Unintentional and unexplained weight loss
• Rectal bleeding
• A family history of bowel or ovarian cancer
• A change in bowel habit to looser/more frequent stools for >6 weeks in a person >60
• An abdominal or rectal mass
➡️ Referral Criteria
Urgent: 2WW referral if any red flags for cancer are present (e.g., weight loss, rectal bleeding, mass)
Routine: To a Dietitian for a low FODMAP diet; to Gastroenterology if diagnosis is uncertain; for psychological therapies if symptoms persist
📌 GP Tips
🔹A full set of normal baseline bloods (FBC, CRP, tTG) and a normal faecal calprotectin strongly support a diagnosis of IBS
🔹For constipation in IBS (IBS-C), avoid lactulose as it often worsens bloating; choose a bulk-forming laxative or a macrogol instead