Crohn's disease Flashcards
What is Crohn’s disease (CD)?
Disorder of unknown aetiology characterised by transmural inflammation of the GI tract.
CD may involve any or all parts of the entire GI tract from mouth to the perianal area.
Which part of the GI tract does CD usually present?
Terminal ileum and perianal locations.
What is present in CD but not UC?
CD is characterised by skip lesions (where normal bowel mucosa is found between diseased areas)
Aetiology of CD
Remains unclear
Genetic factors
Environmental factors- smoking, contraceptive pill, a diet high in refined sugar and infectious agent (measles virus)
Pathophysiology of CD
The initial lesion starts as an inflammatory infiltrate around intestinal crypts that subsequently develops into ulceration of the superficial mucosa.
Inflammation progresses to involve deeper layers and form non-caseating granulomas.
Early endoscopic findings include hyperaemia and oedema of the inflamed mucosa.
Acute transmural inflammation results in bowel obstruction due to mucosal oedema associated with spasm.
Chronic inflammation thickens the bowel wall and leads to scarring, luminal narrowing and stricture formation.
Complications of CD
Fistulation Sinus tract formation Perforation Abscess formation Malnutrition Dehydration Vitamin and nutrient deficiencies.
Classification of CD
Vienna classifies CD into 24 subgroups based on:
Age at diagnosis
Location- maximum extent of disease involvement at any time before the first resection
Behaviour
Signs & symptoms of CD
Abdominal pain Prolonged diarrhoea Perianal lesions Bowel obstruction Blood in stools Fever Fatigue Abdominal tenderness Weight loss Oral lesions Abdominal mass Extra-intestinal manifestations.
Risk factors of CD
White ancestry Age 15-40 or 60-80 years FHx of CD Weak- Cigarette smoking Diet high in refined sugar Oral contraceptive pill Not breastfed NSAIDs
Investigations of CD
FBC Iron studies Serum vitamin B12 Serum folate Comprehensive metabolic panel (CMP) CRP and ESR Stool testing Yersinia enterocolitica serology Plain abdominal films CT abdomen Colonoscopy Tissue biopsy OGD Wireless capsule endoscopy
Differentials of CD
UC Infectious colitis Pseudomembranous colitis Ischaemic colitis Radiation colitis Yersina enterocolitica Intestinal TB Amoebiasis CMV colitis Diverticular disease Acute appendicitis Ectopic pregnancy Pelvic inflammatory disease Endometriosis IBS
