Week 4.1 - Bowel Pathology

Question 1

What is though to be the cause of inflammatory bowel disease?

Answer 1

chronic immune condition due to inappropriate and persistent activation of immune system in the presence of normal intraluminal flora

Question 2

What is the pathophysiology of IBD?

Answer 2

defect in mucosal barrier allows microbes to get behind epithelial surface to immune cells which respond as if its an invader

Question 3

How do you diagnose IBD?

Answer 3

• clinical history
• xray exam
• pathological corruption
• pANCA positive in 75% UC patients but only 11% CD patients

Question 4

What is ulcerative colitis?

Answer 4

continuous inflammation along large intestine and rectum, with blood and mucus

Question 5

What is a mneumonic for ulcerative colitis?

Answer 5

(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

Question 6

What is crohns disease?

Answer 6

inflammation affecting entire GIT, with skip lesions, and no mucus or bleeding but fistulas and strictures present

Question 7

What is a mneumonic for crohns disease?

Answer 7

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

Question 8

What are the chances of developing cancer in IBD?

Answer 8

• 10 years with pancolitis has 20/30x higher chance in 20 years
• CD has 5x greater risk as someone else age matched

Question 9

How does ulcerative colitis lead to cancer?

Answer 9

mucosa inflammation, epithelial layer eventually becomes reactive and atypical, leading to dysplasia and then neoplasia and malignancy.

Question 10

What histological features do you see in crohns disease?

Answer 10

• 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

Question 11

Which granulomas do we see in CD and UC?

Answer 11

CD - non-caesiating granulomas
UC - NO granulomas

Question 12

what ulceration do we see in CD and UC?

Answer 12

UC - ulceration into submucosa and pseudopolyps
CD - ulceration deeper than UC right into muscularis propria. transmural. can be anywhere along GIT

Question 13

What are long term consequences of crohns disease?

Answer 13

• if in small intestine, malabsorbtive issues.
• if severe, fibrosis, strictures, abscesses and fistulas

Question 14

What is ischaemic enteritis?

Answer 14

blood supply to bowel is insufficient so bowel dies. can be large, small intestine, small infarct etc.

Question 15

What are predisposing conditions to ischaemic enteritis?

Answer 15

• thrombosis,
• emboli,
• cardiac failure,
• shock,
• low Bp

Question 16

What is acute ischaemic enteritis?

Answer 16

• acute serious and splenic fixture vulnerable. affected area spreads to non-affected. see oedema, necrosis, gangrene, perforation

Question 17

What is chronic ischaemic enteritis?

Answer 17

• chronic has inflammation and ischaemia long enough for inflammatory cells to enter and fix damage. ulceration, fibrosis, stricture

Question 18

What is radiation colitis?

Answer 18

abdominal radiation may impair normal epithelial activity. presents with anorexia, nausea, cramps, diarrhoea, malapsorption. mimics IBD.

Question 19

What is appendicitis?

Answer 19

obstruction typically by faeces or worm, leads to increased intraluminal pressure, and ischaemia of mucosa, leading to inflammation which may perforate

Question 20

What is large bowel neoplasia?

Answer 20

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

Question 21

What is low grade vs high grade dysplasia?

Answer 21

• 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)

Question 22

What is the cause of colorectal adenocarcinoma?

Answer 22

• 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

Question 23

What is colorectal adenocarcinoma presentation?

Answer 23

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.

Question 24

What is the diagnosis and prognosis of colorectal adenocarcinoma?

Answer 24

TNM, check for extramural invasion in mesenteric fat - pick through fat and check all lymph nodes for invasion.