IBS: Bowel Changes in a Young Person

Clinical Scenario

Emma Richardson, 27, presents face-to-face with ongoing tummy problems. She has had 18 months of bloating after eating, loose stools 3-4 times daily, and abdominal pain relieved by defecation. Symptoms occur during the daytime only. She has no red flag features: no rectal bleeding, no weight loss, no nocturnal symptoms, no family history of bowel cancer or IBD. She has tried eliminating gluten and dairy with minimal benefit. She has previously been told it is just stress but feels this has not been taken seriously.

What This Case Tests

Applying Rome IV criteria for IBS diagnosis; excluding red flags for organic disease (IBD, coeliac disease, colorectal cancer); ordering targeted investigations (coeliac serology, faecal calprotectin, basic bloods); explaining IBS as a positive diagnosis rather than a diagnosis of exclusion; providing evidence-based management including dietary, pharmacological, and psychological approaches.

Common Mistakes Trainees Make

The three most common mistakes are: dismissing IBS as a diagnosis of exclusion without taking it seriously (IBS is a positive diagnosis based on Rome IV criteria, not just the absence of other diseases), not ordering faecal calprotectin to exclude IBD (this is the single most important investigation for differentiating IBS from IBD in a young patient), and attributing all symptoms to stress without adequate clinical assessment (Emma has been told this before and felt dismissed).

The Consultation Challenge

Emma has been told her symptoms are stress-related and feels dismissed. Your first task is to take her seriously and conduct a proper clinical assessment — she has been waiting 18 months for someone to do this.

Take a structured bowel history using the Rome IV criteria framework. IBS-D (diarrhoea-predominant) is diagnosed when: recurrent abdominal pain at least 1 day per week for the last 3 months, associated with 2 or more of: related to defecation (pain relieved by opening bowels — present), associated with change in stool frequency (loose stools 3-4 daily — present), associated with change in stool form (loose/watery — present). Symptoms onset at least 6 months before diagnosis. Emma meets all criteria.

Screen for red flags that would suggest organic disease: rectal bleeding (absent), unexplained weight loss (absent), nocturnal symptoms (absent — IBS is characteristically daytime only), family history of bowel cancer or IBD (absent), onset over 50 (no — she is 27), iron deficiency anaemia, and abdominal or rectal masses. The absence of all red flags in a 27-year-old with 18 months of typical symptoms makes IBS the overwhelming diagnosis.

However, targeted investigations are still appropriate to confirm and reassure. Essential: tissue transglutaminase IgA with total IgA (coeliac screen — must confirm she has been eating gluten for 6+ weeks), faecal calprotectin (the key test — normal level effectively excludes IBD, elevated level requires gastroenterology referral), FBC, CRP, and TFTs. These are not fishing expeditions — they are targeted exclusion of the two conditions that most commonly mimic IBS (coeliac disease and IBD).

Explain IBS as a real diagnosis. "This is not just stress and it is not in your head. IBS is a recognised condition where the nerves and muscles of the gut become oversensitive. We know what it is, and there are effective treatments."

Management is multi-layered. First-line dietary advice: NICE recommends regular meals, adequate fluid, reduced caffeine and alcohol, and a trial of the low-FODMAP diet (ideally with dietitian support). Pharmacological: antispasmodics (mebeverine or hyoscine butylbromide) for pain, loperamide for diarrhoea if needed, and consider a low-dose tricyclic (amitriptyline 10mg) for pain modulation if symptoms are persistent. Psychological: CBT and gut-directed hypnotherapy have strong evidence for IBS and should be offered.

Time check: Spend the first 4 minutes on the bowel history and Rome IV assessment. Screen for red flags by minute 6. Arrange investigations between minutes 7-8. Explain the IBS diagnosis positively between minutes 9-10. Use the remaining time for the management plan and follow-up.

How Examiners Mark This Case

Data Gathering and Diagnosis: Examiners assess whether you apply the Rome IV criteria systematically, screen for red flags, and order targeted investigations (faecal calprotectin and coeliac serology as priorities). They look for whether you ask about nocturnal symptoms (their absence supports IBS), stool consistency (Bristol Stool Chart), and previous dietary trials. The diagnosis should be made positively — "you meet the criteria for IBS" — not by exclusion.

Clinical Management and Medical Complexity: Examiners expect a multi-layered management plan: dietary advice (NICE recommendations, low-FODMAP with dietitian), pharmacological options (antispasmodics, loperamide, and consideration of low-dose tricyclic for persistent symptoms), and psychological therapies (CBT, gut-directed hypnotherapy). Knowledge that faecal calprotectin effectively excludes IBD (negative predictive value >95%) demonstrates evidence-based investigation.

Relating to Others: Examiners assess whether you take Emma's symptoms seriously (she has been dismissed before), explain IBS as a genuine medical condition rather than a stress response, and empower her with a clear management plan. Emma should leave feeling validated, diagnosed, and equipped with treatment options — not dismissed again.

Example Opening

Strong opening: "Hello Emma, I can see you have been dealing with these symptoms for quite a while and I want to make sure we get to the bottom of it properly. Can you take me through exactly what has been happening?"

When making the diagnosis: "Based on what you are telling me, your symptoms fit a condition called irritable bowel syndrome — IBS. I want to be clear: this is a real medical condition, not just stress. The nerves and muscles in your gut have become oversensitive, which causes the bloating, pain, and loose stools. There are effective treatments, and I want to run a couple of tests first to make absolutely sure we are not missing anything else."

Avoid: "It sounds like IBS — try to reduce your stress and see if it improves." (Exactly the dismissive response Emma has already received).

How This Appears in the SCA

IBS diagnosis in a young person tests your ability to make a positive diagnosis using recognised criteria rather than treating IBS as a diagnosis of exclusion. Examiners assess whether you use Rome IV criteria, order targeted investigations (particularly faecal calprotectin), and provide a comprehensive management plan. Taking the patient's symptoms seriously after previous dismissal is also specifically assessed.

Key Statistic

IBS affects approximately 10-15% of the UK population and is twice as common in women. A normal faecal calprotectin (<50 mcg/g) has a negative predictive value exceeding 95% for excluding IBD. The low-FODMAP diet improves symptoms in approximately 70% of IBS patients when followed correctly with dietitian guidance.

Relevant Guidelines

• NICE CG61: Irritable bowel syndrome in adults — diagnosis and management
• Rome IV criteria for IBS
• NICE guidance on faecal calprotectin testing
• British Dietetic Association guidance on the low-FODMAP diet.

Frequently Asked Questions

What are the Rome IV criteria for diagnosing IBS?

Recurrent abdominal pain at least 1 day per week for the last 3 months, associated with 2 or more of: related to defecation (improved or worsened by opening bowels), associated with a change in stool frequency, associated with a change in stool form (appearance). Symptoms must have onset at least 6 months before diagnosis. IBS is subtyped as IBS-D (diarrhoea-predominant), IBS-C (constipation-predominant), IBS-M (mixed), or IBS-U (unsubtyped).

Why is faecal calprotectin the key investigation in young patients with bowel symptoms?

Faecal calprotectin is a marker of intestinal inflammation. A normal result (below 50 mcg/g) has a negative predictive value exceeding 95% for excluding inflammatory bowel disease (Crohn's disease and ulcerative colitis). This effectively separates IBS (normal calprotectin) from IBD (elevated calprotectin) without the need for colonoscopy. It is the single most useful test for a young patient with IBS-like symptoms.

Should I refer IBS for colonoscopy?

Not if there are no red flags and the faecal calprotectin is normal. IBS is a positive clinical diagnosis, not a colonoscopy-of-exclusion diagnosis. Colonoscopy is indicated if: red flags are present (rectal bleeding, weight loss, family history of IBD/bowel cancer, nocturnal symptoms), faecal calprotectin is elevated, symptoms began after age 50, or there is a poor response to treatment suggesting an alternative diagnosis. Unnecessary colonoscopy in young patients with typical IBS exposes them to procedural risks without benefit.

What is the low-FODMAP diet and how effective is it for IBS?

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols — short-chain carbohydrates that are poorly absorbed and fermented in the gut, triggering IBS symptoms. The low-FODMAP diet involves eliminating high-FODMAP foods for 2-6 weeks, then systematically reintroducing them to identify individual triggers. It improves symptoms in approximately 70% of IBS patients. NICE recommends it be supervised by a trained dietitian for best results.

When should I consider psychological therapy for IBS?

CBT and gut-directed hypnotherapy have strong evidence for IBS and should be considered when: symptoms persist despite dietary and pharmacological management, there is a clear stress-symptom connection, anxiety about symptoms is driving avoidance behaviours, or the patient prefers a non-pharmacological approach. NICE recommends offering psychological therapy as part of the IBS management pathway, not as a last resort. Frame it as "treating the gut-brain connection" rather than "it is in your head."