Colon Pathology Flashcards
What is peristalsis in the small and large intestine mediated by?
Intrinsically- myenteric plexus
Extrinsically- autonomic innervation
Which two plexus’s are found within the myenteric plexus?
Meissner’s plexus
Auerbach plexus
Where would you find Meissner’s plexus?
Base of submucosa
Where would you find Auerbach plexus?
Between circular and longitudal muscularis layers
What is idiopathic inflammatory bowel disease?
Chronic inflammatory conditions which results in constant inappropriate activation of the mucosal immune system because of normal intraluminal flora.
->wordy but read, it makes sense :)
What are the two main types of idiopathic inflammatory bowel diseases?
Crohn’s disease
Ulcerative colitis
Which part of the GIT can Crohn’s affect?
Any
Which part of the body can ulcerative colitis affect?
Colon
Why may there be strong immune defences against normal flora in the body in individuals with idiopathic inflammatory bowel disease?
May be defects in the epithelial barrier function meaning immune cells are exposed to flora which doesn’t usually happen
Genetics can be a cause for both CD’s and UC.
Which gene mutation can cause CD?
NOD2 gene mutation
How can IBD be diagnosed?
Requires-
-Clinical history
-Radiographic examination
-Pathological correlation
Which autoimmune antibody can be found in patients with IBD?
pANCA (perinuclear antineutrophilic cytoplasmic antibody)
What % of Crohn’s patients are pANCA positive?
Only 11%
What % of UC patients are pANCA positive?
75%
->think Panko breadcrumbs, if they get stuck in your throat make you go UC!
gal idk i’m trying to help
Which age groups tend to be more likely to get UC?
Peaks at 20-30yrs AND 70-80yrs
Where can UC be localised to?
Rectum
Which other organ may be affected by UC despite in only affecting the colon?
Appendix
Inflammation may also spread backwards towards small intestine
Describe the pathology of UC
Inflammation affecting rectum to proximal.
Pseudocysts and ulceration
Why are those with UC at a higher risk of cancer?
Epithelial layer gets repaired so many times there starts to be defects. This causes dysplasia, meaning cells divide of their own accord and this is a step towards malignancy.
What are some of the complications of UC?
Perforation
Haemorrhage
Toxic dilatation
Are males or females more likely to be affected by Crohn’s?
Females
-> think of Amy Dowden, only person I am aware of having Crohn’s, she’s a women…sorry, memory aids!
At which age would you be most likely to develop Crohn’s?
Any age but peaks at 20-30 and 60-70
Where do most cases of Crohn’s first present?
Small intestine
Describe the pathology of Crohn’s.
Granular serosa, dull grey colour
Wrapped in mesentery fat, almost in a protective way
Thickened wall
Narrowed lumen
Ulceration causing ‘cobblestone’ appearance
Are there granulomas present in UC?
No
Are there granulomas present in CD?
Yes- non-caseating granulomas
What can be a complication of CD in the small intestine?
Malabsorption
What are some complications of CD?
Strictures
Fistulas, abscesses
Perforation
Increased risk of cancer
Ischaemic enteritis is another type of IBD.
What happens in it?
Impinged blood supply to bowel
->think, ischaemia, lack of blood
What can happen as a result of ischaemic enteritis?
Bowel can die
Where can ischaemic enteritis affect?
Small intestine, large intestine or both
What can cause infarction in ischaemic enteritis?
Occlusion to any one of the main three branches supplying the bowel (coeliac trunk, SMA, IMA)
List some of the predisposing conditions which can lead to ischaemic enteritis.
-Arterial thrombosis (severe atherosclerosis, oral contraceptives, dissecting aneurysms)
-Arterial embolism (cardiac vegetations, acute atheroembolism, cholesterol embolism).
-Non-occlusive ischaemia (cardiac failure, shock, vasoconstrictives drugs like beta blockers)
What happens in radiation colitis?
Inflammation of intestines after radiotherapy as can impair normal proliferating nature of the cells.
Why does radiotherapy affect the cells in the intestines?
It targets rapidly dividing cells, which the colon cells are
What are the symptoms of radiative colitis?
Anorexia
Abdominal cramps
Diarrhoea
Malabsorption
What happens to the appendix with age?
It regresses (gets smaller)
What is acute appendicits?
Inflammation of the appendix
What is a common cause of acute appendicitis?
-Faecal stone blocking and causing inflammation
-Enterobius vermicularis (type of worm)
What can happen to the appendix if it is inflammed?
May perforate
What is dysplasia?
Epithelial cells start dividing in an uncontrolled way
How does dysplasia usually present in the GIT?
In the form of a polyp/adenoma
What would be seen histologically in low grade dysplasia?
Increased number of nucelli
Increased nucelli size
Reduced mucin
What would be seen histologically in high grade dysplasia?
Very crowded
Very irregular
->not yet invasive
What are some of the risk factors for colorectal adenocarcinoma?
Lifestyle
Family history
IBD
Genetics
Describe how a right sided colorectal adenocarcinoma would present.
Anaemia
Vague pain
Weakness
Obstruction
Describe how a left sided colorectal adenocarcinoma would present.
Bleeding
Altered bowel habit
Obstruction
What would a left sided colorectal adenocarcinoma look like?
Would encircle the circumference of the lumen, making it narrower
What would a right sided colorectal adenocarcinoma look like?
Exophytic lesions, polypoid
What type of staging is used for tumours?
TNM
