What it actually is
Irritable bowel syndrome is a disorder of gut-brain interaction. The bowel becomes more sensitive than normal and moves in an uncoordinated way, producing abdominal pain related to defecation together with changes in stool consistency or frequency.
Two points change how it feels to live with. First: it is a positive diagnosis, made on well-defined clinical criteria, not by endless exclusion. Second: a normal colonoscopy does not mean nothing is happening. The mechanisms are real and measurable, and treatments do work.
First, rule out what does matter
Before assuming irritable bowel syndrome, we need to be sure nothing else is being missed. That does not mean running every test available, only the ones your case calls for.
- Coeliac disease, very frequently mistaken for IBS for years
- Inflammatory bowel disease, using faecal calprotectin
- Thyroid disorders and anaemia, with a simple blood test
- Microscopic colitis, in persistent watery diarrhoea, particularly in middle-aged women
- Bile acid malabsorption, a treatable and strikingly underdiagnosed cause
- Lactose or fructose intolerance, where the pattern suggests it
Signs that call for fuller investigation
Unintentional weight loss, blood in the stool, anaemia, fever, symptoms starting after the age of 50, waking at night with pain or diarrhoea, or a family history of bowel cancer or inflammatory bowel disease. Any of these changes the approach entirely.
Why identifying your subtype matters
Treating every patient the same is the commonest mistake, because management changes radically depending on whether constipation, diarrhoea or alternation between the two predominates. A drug that suits one subtype can clearly worsen another.
On top of that comes your individual pattern: whether pain dominates everything else, whether urgency is the main problem, whether it worsens at particular times. From that comes a plan that fits your case rather than a generic protocol.
What actually works
- Structured dietary intervention. The low FODMAP diet works, but it must be done in phases and with support, including an orderly reintroduction. Following it indefinitely and unsupervised impoverishes the diet and alters the gut flora
- Treating the dominant symptom. Antispasmodics for pain, and specific drugs depending on whether constipation or diarrhoea predominates
- Low-dose neuromodulators. Prescribed not because the problem is psychological but because they act on visceral hypersensitivity. One of the most effective and worst explained tools available
- Gut-brain directed therapies. With solid evidence in cases that do not respond to the above
- Reviewing your regular medication. Some commonly used drugs perpetuate symptoms without anyone making the connection
How I approach this consultation
With an idea that is not always welcome: run fewer tests and think more. In irritable bowel syndrome the temptation is to chain together ever more expensive investigations looking for something that is almost never there, while the patient stays the same and every normal result adds to their anxiety.
What I do is different. I rule out what needs ruling out in a targeted way, explain what is happening in your gut and why, and we build a written plan with concrete steps and a defined point at which to review whether it is working. No endless lists of forbidden foods and no unsupported supplements.