Summary content1. To understand normal physiology of the gastrointestinal tract
2. To review the etiopathogenesis of Inflammatory Bowel Diseases
3. To emphasize the different modalities to diagnose Inflammatory Bowel Diseases
4. To have an overview of the most commonly used clinical and endoscopic activity scores for Inflammatory Bowel Diseases
Although extra-intestinal manifestations are common, inflammatory bowel diseases (IBD) typically affect the intestine. Where ulcerative colitis (UC) is limited to the colon, Crohn’s disease (CD) may involve all parts of the gastrointestinal tract (mouth, oesophagus, stomach, small intestine, colon and rectum). Consequently, the function of all these segments may be compromised.
Although the exact etiopathogenesis of IBD has not been unravelled, the prevailing model states that IBD is driven by environmental factors in genetically susceptible individuals, resulting in a dysregulated immune response towards the intestinal microbiome.
Besides a good clinical history and physical examination, several diagnostic tools will help the physician to diagnose IBD. These tools include lab test (both blood and faeces), radiological examination (ultrasound, CT and MR scan), and endoscopy with biopsies for histological examination.
Clinical disease activity of CD and UC, are most commonly assessed using the Harvey-Bradshaw index and the Mayo score, respectively. However, patient reported outcomes become more frequently implemented. Also endoscopic disease activity indices have been introduced in daily clinical care. For CD, the Crohn’s disease endoscopic index of severity (CDEIS), the simple endoscopic score for Crohn’s disease (SES-CD), and the Rutgeerts score are used. For UC, the Mayo score and the ulcerative colitis endoscopic index of severity (UCEIS) are employed. C-reactive protein (CRP) and faecal calprotectin could be regarded as surrogate markers for endoscopic disease activity, but their accuracy is not optimal.