Alimentary Tract Pathology

Question 1

what is the length of the small intestine?

Answer 1

6m long

Question 2

how long is th duodenum and what is it peritonised?

Answer 2

25cm

retroperitonised

Question 3

where does the sigmoid colon originate?

Answer 3

pelvic brim

Question 4

how long is the rectum and how it peritonised?

Answer 4

15cm long

the distal 7cm is extraperitoneal

Question 5

if your parent or sibling has an IBD, what is the risk that you may get it?

Answer 5

9% risk

Question 6

what antibody can be used to diagnose IBD and what is the prevalence of this antibody in crohns and UC?

Answer 6

pANCA
75% UC patients
11% CD patients

Question 7

describe the pathology of crohns disease.

Answer 7

transmural inflammation
thickened wall and narrowing of the lumen
granular serosa/dull grey
wrapping mesenteric fat
mesentery is thick, oedematous and fibrotic

Question 8

what cell metaplasia occurs in crohns disease?

Answer 8

paneth cells

Question 9

which IBD has deep ulceration ?

Answer 9

crohns

UC has superficial ulceration

Question 10

what is ischaemic enteritis the result of?

Answer 10

occlusion of one of the 3 major vessels supplying the small and large intestine (coeliac, SM and IM)

Question 11

why does gradual occlusion of major vessels to the small and large intestine has little effect?

Answer 11

because of the anastomotic circulation

Question 12

what are some of the predisposing conditions for ischaemia?

Answer 12

arterial thrombosis;
- atherosclerosis 
- systemic vasculitis 
- dissecting aneurysm
- hypercoagubility
- oral contraceptive 
arterial embolism;
- cardiac vegetations
- acute atheroembolism
- cholesterol embolism
non-occlusive ischaemia;
- cardiac failure
- shock/dehydration
- vasoconstriction drugs i.e. propanolol

Question 13

how does appendicitis cause ischaemia?

Answer 13

inflammation causes an increase in intraluminal pressure = ischaemia