Pathology of the GI Tract 2 Flashcards
What are diverticulum?
outpouchings/thickenings of muscularis propria
What are true ‘congenital diverticulum’?
present from birth. through all layers of bowel wall
What are ‘pseudo’ diverticulum?
during post natal life. not through all the layers of the bowel wall
Where specifically on the colon are diverticulum located?
protrusion of the mucosa and submucosa through the bowel wall
between the mesenteric and taenia coli
less common in proximal colon e.g. caecum
shortening of the colon due to increased elastin in the taeniae coli
Who is less likely to get diverticulum?
vegetarians
people with high fibre diets
How do diverticulum form?
increased intra-luminal pressure → irregular, uncoordinated peristalsis
points of weakness in the bowel wall
What are the clinical features of diverticular disease?
asymptomatic
cramping abdominal pain
alternating constipation and diarrhoea
What is colitis?
inflammation of the colon. Usually submucosal/muscular
What is colitis divided into?
Acute and chronic
What are the acute types of colitis?
acute infective colitis
antibiotic associated colitis (inc pseudo-membranous colitis)
drug induced colitis
acute ischemic colitis
What are the chronic types of colitis?
chronic idiopathic inflammatory bowel disease microscopic colitis ischemic colitis diverticular colitis chronic infective colitis e.g. TB
What are the 3 idiopathic inflammatory bowel diseases?
ulcerative colitis
crohns disease
indeterminate colitis (overlap between UC and CD)
What are the risk factors for IBD?
smoking (protective in UC) oral contraceptives childhood infections domestic hygeine apendicectomy - protective family history
what are the clinical presentations of UC?
diarrhoea
rectal bleeding (anaemia)
abdominal pain
weight loss
What are the complications of UC?
toxic megacolon/perforation (dilated transverse colon - gas and fluid accumulate)
haemorrhage
stricture (rare)
carcinoma
does UC run a remitting/relaxing course?
yes - flare ups occur
What part of the colon does UC always effect?
appendix, colon and terminal ileum - always rectum
What are the histological features of UC?
crypt abscesses increase in neutrophils crypt distortion granula red mucosa - inflammed flat undetermining ulcers normal serosa inflammatory polyps
What are the clinical features of crohns disease?
chronic relapsing disease - flare ups affects all levels of the GI tracts diarrhoea (bloody) colicky abdominal pain weight loss fever oral ulcers peri-anal disease (fistulas)
What are the histological features of CD?
formation of granulomas
cobblestone appearance
What are the complications of CD?
toxic megacolon perforation apthoid and fissuring ulcers strictures (common) haemorrhage carcinoma short bowel symdrome - repeatedly removing too much bowel makes it too small
What are the hepatic extra-intestinal manifestations of IBD?
fatty changes
granulomas
Primary Sclerosing Cholangitis (bile ducts inside and outside the liver progressively decrease in size due to inflammation and fibrosis)
bile duct carcinoma
What are the skeletal extra-intestinal manifestations of IBD?
polyarthritis
sarco-ileitis
ankylosing spondylitis (a form of spinal arthritis)
What are the muco-cutaneous extra-intestinal manifestations of IBD?
oral apthoid ulcers pyoderma gangrenosum (rare skin condition that causes painful ulcers) erythema nodosum (inflammation of the fat cells under the skin, resulting in tender red nodules or lumps)
What are the ocular extra-intestinal manifestations of IBD?
iritis/uveitis
episcleritis
retinitis
What are the renal extra-intestinal manifestations of IBD?
kidney and bladder stones
What are the haematological extra-intestinal manifestations of IBD?
anaemia
leucocytosis
thrombocytosis
thrombo-embolic disease
What are the systemic extra-intestinal manifestations of IBD?
amyloid
vasculitis
What are the risk factors for colorectal cancer in UC?
early age of onset duration of disease greater than 8 years total/extensive colitis family history severity of inflammation presence of dysplasia
What are colorectal polyps?
mucosal protrusion
varialble size, shape and number
due to mucosal/submucosal pathology or a lesion deeper in the bowel wall
What are examples of non neoplastic polyps in the colo-rectum?
hyperplastic polyps
juveniles polyps
hamartomatous polyps (i.e. peutz-jeghers syndrome)
What are hyperplastic polyps?
multiple polyps
common
in rectum and sigmoid colon
no clinical significance - apart from some large right sided polyps that may give rise to unstable carcinomas
What are juvenile polyps?
spherical/pedunculated
commonest polyp in children
typically in rectum and distil colon
juvenile polyposis (multiple polyps) associated with increased risk of colorectal and gastric cancer
What is peutz-jeghers syndrome?
autosomal domincant - mutation to STK11 gene presents in teens/early 20's abdominal pain, GI bleeding and anaemia multiple polyps muco-cutaneous pigmentation mostly in small bowel
What are adenoma polyps?
benign epithelial tumours
common polypoid but may be flat
precursor of colorectal cancer
evenly distributed around colon but larger in recto-sigmoid and caecum
variable shape, tubular/villous and variable grade
What are the risks of adenoma polyps progressing into adenocarcinoma?
risk with flat adenomas size dependent high grade villous or tubulo-villous HNPCC associated adenomas
what are the risk factors for colorectal cancer?
diet - fibre is good whilst red meat and fat is bad obesity/physical activity alcohol NSAIDs HRT and oral contraceptives schistosomiasis radiation UC and CD
What are the two inherited susceptibilities to colorectal cancer?
Familial adenomatous polyposis (FAD) - autosomal dominant, mutation in APC tumour supressor gene
Hereditary nonpolyposis colorectal cancer (HNPCC) - autosomal dominant, mutation in DNA mismatch repair gene
What staging methods are used for colorectal cancer?
Dukes staging
TNM staging
