Loose bowel motions may be due to an infection (gastroenteritis) but if the symptoms persist for more than 3 weeks then other conditions need to be considered. Sometimes the problem is......

Crohn's Disease

Endoscopic image
Endoscopic image - terminal ileum with ulceration and swelling resulting in narrowing of the lumen
Colonic Crohn's disease - as seen at colonoscopy
Photos of Crohn's disease of the colon taken at colonoscopy
Photos of Crohn's disease of the colon taken at colonoscopy
The main common site for Crohn's diseae is the terminal ileum - that is the last part of the small bowel before it joins the large bowel

What is Crohn's disease?

  • This is an inflammatory condition of the bowel of unknown cause;
    • It affects 1 in 500 - 700 of the population
    • Onset is often in early adult life - 20-40 years but can occur at any age
    • For more information see IBD
  • It may affect any part of the gastrointestinal tract including oesophagus, stomach, small bowel and large bowel
  • The condition starts as small ulcers in the lining of the gut
    • these early ulcers are called "aphthous" ulcers. These have some similarities to mouth ulcers
    • These small ulcers progress to deeper ulcers with fissuring (deeply penetrating areas) - see photo at right
    • The lining of the bowel becomes oedematous (swollen) giving what is described as a "cobblestone" appearance
  • Crohn's disease is often patchy - several different areas of the gut are involved;
    • The diagnosis is generally made by the appearance at colonoscopy
    • Biopsies can be specific for Crohn's disease (if there are granulomas)
    • Usually the inflammation is non-specific (that is there is helpful additional information that is suggestive rather than diagnostic of Crohn's disease)
    The condition cannot be cured but can be well managed with a combination of medication and surgery (see sections on steroids, salicylates (refer to ulcerative colitis on main menu), azathioprine, monoclonal antibodies (infliximab (Remecaide),  adalimumab (Humira or a biosimilar) and also section on surgery. 

What are the main symptoms?

  • There are a great variety of symptoms depending on area of bowel involved;
  • The most site of involvement is the ileum - the end of the small bowel - just before it joins the colon;
    • There may be lower or mid-abdominal pain (usually cramping or gripping in nature), nausea, diarrhoea, weight loss
    • OR / AND pain and localized tenderness in right lower abdomen
  • If the colon is involved there will be more diarrhoea (sometimes mixed with blood and mucus);
    • Pain is most likely to be in the left lower part of the abdomen and occur before and during defaecation
  • Peri-anal disease presents with anal pain and discharge;
    • This may be due to a fissure or fistula.
    • A fissure is a non-healing split in the anus
    • A fistula is a connection or tract between the rectum and the skin immediately adjacent to the anus
  • Tiredness is common because of the chronic inflammation as well as anaemia and nutritional deficiencies
  • Other possible associated symptoms are arthritis - sometimes only joint pains but also swelling and tenderness , mouth ulcers, and some particular skin rashes. Red eyes with blurring of vision is due to iritis and requires urgent attention
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