Practice Rational Testing

Investigating young adults with chronic diarrhoea in primary care

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h573 (Published 25 February 2015) Cite this as: BMJ 2015;350:h573
  1. Thomas P Chapman, gastroenterology clinical research fellow1,
  2. Lucia Y Chen, foundation year 1 doctor2,
  3. Laurence Leaver, general practitioner3
  1. 1Translational Gastroenterology Unit, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
  2. 2Maidstone Hospital, Maidstone and Tunbridge Wells NHS Trust, Maidstone, UK
  3. 3Department of Primary Care Health Sciences and Green Templeton College, University of Oxford, Oxford, UK
  1. Correspondence to: T P Chapman tomchap{at}doctors.org.uk
  • Accepted 12 December 2014

The bottom line

  • A focused history is key, with organic disease suggested by continuous or nocturnal diarrhoea, significant weight loss, and symptoms for less than three months

  • Refer urgently to secondary care if there are any red flags (such as weight loss, rectal bleeding, or anaemia)

  • Irritable bowel syndrome is the most common cause of chronic diarrhoea and can be diagnosed clinically with minimal testing (normal full blood count and C reactive protein with negative coeliac serology)

  • Consider checking faecal calprotectin if there is diagnostic uncertainty between irritable bowel syndrome and inflammatory bowel disease—a concentration below 50 µg/g makes inflammatory bowel disease unlikely. Do not perform the test if there are red flag indicators or a high suspicion of inflammatory bowel disease, or in older patients, as these patients require referral

A previously well 25 year old man presents to his general practitioner with a six month history of crampy abdominal pain, bloating, and diarrhoea, with passage of loose stools up to six times a day. There is urgency but no incontinence. On clinical examination he has mild lower abdominal tenderness, but digital rectal examination is normal.

What are the next investigations?

Chronic diarrhoea can be defined pragmatically as the passage of loose stools more than three times a day for at least four weeks.1 A patient’s own perception of diarrhoea may be markedly different, and it is essential to clarify—for example, faecal incontinence is commonly misconstrued as diarrhoea.1

Irritable bowel syndrome (IBS), a functional disorder, is the most prevalent cause of chronic diarrhoea.2 Other important causes include inflammation (inflammatory bowel disease (IBD), microscopic colitis, and more rarely infection), bile acid diarrhoea, malabsorption (coeliac disease, lactose intolerance, and pancreatic insufficiency), drugs, food additives, and endocrine conditions (thyrotoxicosis and diabetes). Clinicians should always be mindful of an underlying cancer, particularly in patients over 45 years, and …

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