Lecture 13 Lower GI tract disease Flashcards
Name the parts of the large intestine
Ileum, Cecum, ascending colon, transverse colon and descending colon, rectum.
Large intestine membranes
Mucosa -> submucosa -> taeniae coli
Define appendicitis
Acute bacterial infection of the appendix caused by lumen obstruction
What are clinical symptoms of appendicitis?
Pain, rebound tenderness, systemic symptoms
Define pseudomembranous colitis
Acute inflammation of the colon presenting with the formation of plaque like fibrinous exudate (pseudomembranes) covering parts of mucosa
What causes pseudomembranous colitis?
Toxin produced by overgrowth of C.diff, replacing normal intestinal flora
Who is more likely to develop pseudomembranous colitis
patients treated with broad spectrum antibiotics
What are symptoms of pseudomembranous colitis?
Fever and lower abdo tenderness
How is pseudomembranous colitis treated?
Stopping antibiotics, hydration, specifical antibacteria therapy
Define inflammatory bowel disease
Chronic inflammatory conditions of unknown aetiology affecting the gastrointestinal tract
What is the pathogenesis of IBD?
Genetics, environment, constitutional susceptibility
What are the two types of IBD?
Crohn’s disease and ulcerative colitis
What is crohn’s disease?
Idiopathic IBD, affects any part of GIT from mouth to anus. Has skip lesions
What are the percentages of the areas affected by crohns disease?
50% ileum and colon, 30% terminal ileum and 20% colon alone. Perianal skin involvement (75%)
Pathology of Crohns disease?
Mucosal ulceration, fissures, Oedema of adjacent epithelium (cobblestone), pseudopolyp formation regen. Transmural inflam, non-caseating
Complications of Crohns disease?
Anaemia, malabsorption, fistulas, extra-intestinal. ^risk of bowel carcinoma.
Define colitis?
Disease affecting only colon, starts in rectum spreading proximally, continuous mucosal disease.
Microscopy findings for ulcerative colitis?
Affects mucosa only above muscularis mucosae, cryptitis, crypt abscess, goblet cell depletion, pseudopolp formation regeneration
What is pseudopolyp formation regeneration found in?
Crohn’s and ulcerative colitis
Complications of ulcerative colitis
Anaemia, electrolyte loss, extra-interstinal disease, ^ carcinoma risk.
What mimic IBD?
Ischaemic colitis, radiation colitis, Behcet’s disease, pouchitis, diversion colitis,
What genetic factors can lead to colorectal carcinoma?
Familial adenomatous polyposis & lynch syndrome
What dietary factors can lead to colorectal carcinoma?
Low, fibre, bile aerobes, red meat, lack of vits and antioxidants
What is involved in the National Bowel Cancer Screening Programme?
60-75 years old, faecal occult blood test (FOBT) -> colonoscopy looking for polyps
What is a polyp?
Projection above an epithelial surface
Define adenoma
benign tumour of glandular epithelium
What does the quantity and size of the polyps mean?
The more polyps -> ^ the risk. The larger the polyp -> ^ likely to be malignant
Notes on familial adenomatous polyposis (FAP)
Autosomal dominant, chromosome 5, polyps from mid-teens onwards, Carcinoma inevitable (15 years). Needs genetic counselling.
Which condition needs genetic counselling?
Familial adeonmatous polyposis
What are the variants of familial adenomatous polyposis?
Gardner’s and Turcot syndromes
Define lynch syndrome
hereditary non-polyposis colorectal carcinoma
Notes on lynch syndrome?
autosomal dominant, associated with CRCa (70-85%)
What disease is microsatellite instability is linked to?
Lynch syndrome
Define TEMS
transanal endoscopic microsurgery
What is the staging of colorecatal carcinoma?
Dukes stage A (above muscle 95%survival) B into serosal fat (66%) C LN involved (33%)
Define desmoplasic response
Growth of fibres or connective tissue.
