Week 4.1 - Bowel Pathology Flashcards
What is though to be the cause of inflammatory bowel disease?
chronic immune condition due to inappropriate and persistent activation of immune system in the presence of normal intraluminal flora
What is the pathophysiology of IBD?
defect in mucosal barrier allows microbes to get behind epithelial surface to immune cells which respond as if its an invader
How do you diagnose IBD?
- clinical history
- xray exam
- pathological corruption
- pANCA positive in 75% UC patients but only 11% CD patients
What is ulcerative colitis?
continuous inflammation along large intestine and rectum, with blood and mucus
What is a mneumonic for ulcerative colitis?
(uc) CLOSEUP
- continuous
- limited to rectum and large bowel
- only superficial mucosa and submucosa affected
- smoking protective?
- excrete blood and mucus
- use aminosalicitates
- PSC causes it
What is crohns disease?
inflammation affecting entire GIT, with skip lesions, and no mucus or bleeding but fistulas and strictures present
What is a mneumonic for crohns disease?
crows NESTS
- No mucus or blood
- entire GIT
- skip lesions
- Terminal ileum most affected and Transmural (full thickness of colon affected)
- smoking is a risk factor
What are the chances of developing cancer in IBD?
- 10 years with pancolitis has 20/30x higher chance in 20 years
- CD has 5x greater risk as someone else age matched
How does ulcerative colitis lead to cancer?
mucosa inflammation, epithelial layer eventually becomes reactive and atypical, leading to dysplasia and then neoplasia and malignancy.
What histological features do you see in crohns disease?
- mesentary inflamed, thickened and oedematous as it wraps itself around bowel in protective way.
- fibrosis and strictures, and fistulas from bowel loops merging. possible perforation
Which granulomas do we see in CD and UC?
CD - non-caesiating granulomas
UC - NO granulomas
what ulceration do we see in CD and UC?
UC - ulceration into submucosa and pseudopolyps
CD - ulceration deeper than UC right into muscularis propria. transmural. can be anywhere along GIT
What are long term consequences of crohns disease?
- if in small intestine, malabsorbtive issues.
- if severe, fibrosis, strictures, abscesses and fistulas
What is ischaemic enteritis?
blood supply to bowel is insufficient so bowel dies. can be large, small intestine, small infarct etc.
What are predisposing conditions to ischaemic enteritis?
- thrombosis,
- emboli,
- cardiac failure,
- shock,
- low Bp
What is acute ischaemic enteritis?
- acute serious and splenic fixture vulnerable. affected area spreads to non-affected. see oedema, necrosis, gangrene, perforation
What is chronic ischaemic enteritis?
- chronic has inflammation and ischaemia long enough for inflammatory cells to enter and fix damage. ulceration, fibrosis, stricture
What is radiation colitis?
abdominal radiation may impair normal epithelial activity. presents with anorexia, nausea, cramps, diarrhoea, malapsorption. mimics IBD.
What is appendicitis?
obstruction typically by faeces or worm, leads to increased intraluminal pressure, and ischaemia of mucosa, leading to inflammation which may perforate
What is large bowel neoplasia?
epithelial cells start dividing in less controlled way - dysplasia. known as polyps - 50% are solitary and 30% of post mortem find them. can be low grade or high grade
What is low grade vs high grade dysplasia?
- low grade looks similar to normal, with less mucin production.
- high grade nuclei are bigger and divide more uncontrollably, with very little mucin produced. may become invasive (cancerous)
What is the cause of colorectal adenocarcinoma?
- 98% of colorectal carcinomas.
- caused by lifestyle, diet, alcohol, lack of fibre and fruit, genetic.
- IBD’s lead to destructive infl. processes - more chance of mutation
What is colorectal adenocarcinoma presentation?
tumour. affects right and left differently.
- right less likely obstructive due to fluidy faeces, anaemia, vague pain, weakness, exophytic polyp
- left more likely obstructive due to hard faeces - altered bowel habit and fresh bleeding per rectum, annular cancer.
What is the diagnosis and prognosis of colorectal adenocarcinoma?
TNM, check for extramural invasion in mesenteric fat - pick through fat and check all lymph nodes for invasion.
