Inflammatory Bowel Disease

Studies using interleukin-10 deficient mice - which develop a form of colitis similar to UC - show that the disease can be prevented by raising the mice in a sterile environment, which prevents naturally-occurring gut colonisation. No single infectious organism has been reliably identified as the trigger for IBD, but Mycobacterium paratuberculosis, Helicobacter hepaticus and the measles vaccine have all been cited as possible candidates. Genetics Recent breakthroughs in IBD genetics may hold the key to understanding these diseases. Several gene loci are linked to Crohn's disease susceptibility and the best characterised of these is the NOD2/CARD 15 gene on chromosome 16, which accounts for about 15 per cent of Crohn's disease in Western countries.2 This gene codes for an intracellular protein that recognises a bacterial cell wall antigen muramyl dipeptide. Therefore, mutations result in impairment of bacterial handling in the gut. The protein is found in epithelial cells, macrophages and Paneth cells: Paneth cells are particularly plentiful in the distal small bowel, the most common site for Crohn's disease. Section 2: Diagnosis The symptoms of IBD are dependent on the site of inflammation and can therefore present with an array of gastrointestinal problems. In some patients the diagnosis can be delayed for years as there is a significant symptomatic overlap with irritable bowel syndrome (IBS), which is much more common. Early diagnosis is a particular problem for patients with small bowel Crohn's disease and those with colitis but without rectal bleeding. IBD should always be considered in patients with unresponsive symptoms. Presentation UC usually presents with diarrhoea, rectal bleeding, urgency and tenesmus. Many of the symptoms arise from inflammation in the rectum, and patients with localised rectal disease (proctitis) may be just as symptomatic as those with more extensive disease. Crohn's colitis may mimic UC but if there is no rectal involvement there will be less urgency and tenesmus, and pain and weight loss may be the presenting symptoms. Some 70 per cent of patients with Crohn's will have disease in the terminal ileum. This may be picked up asymptomatically (e.g. click this site http://www.gponline.com/Clinical/article/886370/inflammatory-bowel-disease/