Irritable bowel syndrome

I can never remember the Rome criteria, so it came as something of a relief to know that they haven’t actually been validated for accuracy of diagnosis (what’s more, they’ve been updated anyway and now differ slightly from the ones I was trying to remember). The Manning criteria have, but, in practice, it seems to be more a case of looking at patterns – longstanding symptoms with no red flags aren’t likely to be due to anything serious.

The additional symptoms in the current Rome criteria (two out of three required) are:

  • Pain/discomfort onset associated with change in stool frequency
  • Pain/discomfort onset associated with change in stool form
  • Pain/discomfort improves with defaecation

The Manning criteria, as well as the above, have:

  • Passage of mucus per rectum
  • Feeling of incomplete emptying
  • Reported visible abdominal distension

(any of those symptoms for any length of time, which sounds rather vague to me)

Alarm symptoms to consider:

  • Age >50 with no previous colonic screening
  • Recent onset of/change in symptoms
  • Weight loss
  • Rectal bleeding (overt, or positive FOB)
  • Abdominal mass
  • Iron-deficiency anaemia

The things to avoid in diet, it seems, are FODMAPs – Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols. Since foods containing these substances include most lactose-containing foods as well as several green vegetables and some fruits, this could be the unifying factor that explains why exclusion diets for those items have previously proved successful. Low-FODMAP diets are associated with decreased abdominal pain/discomfort, flatus, & bloating.

Gluten avoidence may also help symptoms, even in patients who screen negative for coeliac disease.

Medical treatments: Tailor to either predominant stool form or most troublesome symptom.

Pain/diarrhoea:

  • Peppermint oil (lower NNT than for antispasmodics, and adverse events much less common)
  • Antispasmodics. I normally use hyoscine – other recommended antispasmodics are otilonium, cimetropium, pinaverium, and dicycloverine.
  • Probiotics – some benefit for abdo pain – not clear which ones are helpful, but possibly bifidobacteria
  • Tricyclics – 2nd-line

Constipation:

  • Soluble fibre supplement (ispaghula) +/- osmotic laxative
  • SSRIs

Bloating:

  • Probiotics – possibly helpful, although the best that could be said was that there was a trend towards benefit in a meta-analysis
  • Rifaximin – non-absorbable oral antibiotic which has been shown in an RCT to improve symptoms, including bloating, at 12 week follow-up after a 2-week course, with no increase in C. diff risk.

Psychological therapies have not been found to be effective.

(BMJ 2012;345:e5836)

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About Dr Sarah

I'm a GP with a husband and two young children.
This entry was posted in BMJ, Credits 2012, Gastroenterology. Bookmark the permalink.

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