Irritable Bowel Syndrome, GP Tips

GP Tips for IBS

Thanks to Dr Simon Travis, Consultant Gastroenterologist at the John Radcliffe Hospital in Oxford for his expert advice and the GPs of the19 Beaumont Street Journal Club.

 Symptoms and differentials

·         Mucus discharge is a benign symptom, common in IBS

·         Morning diarrhoea/bowel disturbance implies IBS but if diarrhoea persists throughout the day consider referral to exclude other pathology, such as microscopic colitis

·         Nocturnal diarrhoea is pathological until proved otherwise

·         Bacterial overgrowth is implied by previous bowel resection and/or underlying bowel disease and explosive, malodorous diarrhoea with gas and wind and normal CRP. Also seen in elderly and with autonomic neuropathy. A treatment trial with cipro or metronidazole is reasonable if clinical suspicion is strong

Tests

·         FBC, CRP and EMA only essentials. In active Crohn’s a CRP will be raised 90% of the time i.e. few false negatives. ESR is more expensive, and gives little extra value

·         Fancy faecal tests

o   Faecal calprotectin levels. Marketed as a new test for intestinal inflammation, and thus to distinguish IBS from IBD. But at this stage probably not suitable for primary care

o   Faecal fats. Not very useful as false positive rate high. If negative can help rule out malabsorption, but a malabsorption syndrome is clinically diagnosed on basis of diarrhoea and weight loss

o   Faecal elastase (send to biochemistry) is a good test for pancreatic insufficiency

 Gut flora and IBS

·         Huge area of interest at present and highly significant in some types of IBS

·        we are 10% human and 90% gut bacteria…there are so many billions of bacteria in the gut a little pot of yoghurt or single course of antibiotics is unlikely to have much meaningful impact, hence the indifferent results in trials

·     What is more clinically relevant is the substrate the bacteria feed on. Bacteria in the gut ferment carbohydrate, which produces gas. Therefore if bloating is a problem…

 Bloating and IBS

·         Aim to alter the substrate the bacteria feed on, by reducing the amount of resistant starch

·        Resistant starch is more resistant to digestion, and hence will be more likely to be fermented in the colon producing bloating

·         Dietary manipulation therefore aims to reduce resistant starches

o   The longer the shelf-life of the food, the more resistant the starch! E.g. fresh egg pasta will have much less resistant starch than dried pasta, French white bread (goes stale quickly) will have much less than brown, granary bread etc

o   Simple tips: if bloating cut down on carbs, especially complex carbs and resistant starches e.g. low calorie sweeteners/diet drinks, have fresh new potatoes rather than old, eat ripe soft fruit, avoid seeds, avoid preserved and unripe fruit etc. Toasting and cooling carbs increases starch resistance.

o   This explains why some people feel they are gluten intolerant when they do not have coeliac; do not go gluten free, just cut down on complex carbs

·         Golden linseed is effective as it is water soluble fibre. Mix into foods.

Self-help and dietary manipulation

·         Read and recommend the excellent Irritable Bowel Solutions by Prof John Hunter

Simon Curtis