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