THE DIFFERENCES BETWEEN CROHN'S DISEASE AND ULCERATIVE COLITIS

THE DIFFERENCES BETWEEN CROHN'S DISEASE
AND ULCERATIVE COLITIS

Factor	Crohn's Disease	Ulcerative Colitis
Distribution	Affects small bowel and large bowel	Affects large bowel only
Endoscopy findings	Rectum frequently spared Inflammation not continuous (presence of skip lesions) Bowel wall is thickened and has a 'cobblestoned' appearance due to deep ulcers and swelling of the tissue	Rectum always affected Inflammation is uniform Bowel wall is thin with loss of vascular pattern (blood vessels not visible)
Radiology	Strictures are common Deep fissures and fistulae are common Asymmetrical inflammation	Occur less commonly Occur less commonly Symmetrical inflammation
Histology	Presence of granulomas are almost diagnostic Inflammation extends through the mucosa and muscle of the bowel The increase in white cells tend to be lymphocytes	Inflammation usually confined to mucosa The increase in white cells tend to be polymorphs
Diet	Remission achieved with enteral feed followed by exclusion/ eliminatio diet	Unaffected by diet
Clinical appearance	Patients often thin and may be malnourished due to intestinal malabsorption of nutrients Diarrhoea - only sometimes with blood Abdominal mass common	Weight loss usually related to the severity of active disease Bloody diarrhoea Rarely occurs
Smoking	Strongly associated with smoking Predicts a worse course of disease Increases risk of surgery & further surgery	Associated with non-smokers or ex-smokers Appears to protect against disease
Genetic Factors	Susceptibility genes on chromosomes 12, 7,3 & 2 Chromosome 16 strongly associated with Crohns	Shares similar susceptibility genes HLA factors (Like those that determine blood groups) appear to be important in predicting disease extent & behaviour