Pathology of Colon

Question 1

name the three cell types in the small bowel

Answer 1

> goblet cells
columnar absorptive cells
endocrine cells

Question 2

what cells are at the surface of the large bowel?

Answer 2

columnar absorptive cells

Question 3

what cells are present in the crypts of the large bowel?

Answer 3

> goblet cells
endocrine cells
stem cells

Question 4

what is large and small bowel peristalsis mediated by?

Answer 4

> intrinsic - enteric nervous system

> extrinsic - autonomic innervation

Question 5

what makes up the enteric nervous system?

Answer 5

> meissener’s plexus: base of the submucosa (submucosal plexus)
auerbach plexus: between the inner circular and outer longitudinal layers of the muscularis propria (myenteric plexus)

Question 6

what conditions are included within inflammatory bowel disease?

Answer 6

> ulcerative colitis
> crohn's disease
> ischaemic colitis
> radiation colitis
> appendicitis

Question 7

define idiopathic inflammatory bowel disease?

Answer 7

chronic inflammatory conditions resulting from inappropriate and persistent activation of the mucosal immune system driven by the presence of normal intraluminal flora

Question 8

what do you require to diagnose IBD?

Answer 8

> clinical history
radiographic examination
pathological correlation

Question 9

what does ulcerative colitis effect?

Answer 9

the large bowel

Question 10

what would you expect to see in histology of ulcerative colitis?

Answer 10

> inflammation of mucosa
> cryptitis
> crypt abscesses
> architectural disarray of crypts
> ulceration into submucosa (psuedopolyps)
> submucosal fibrosis

Question 11

what are the possible complications from ulcerative colitis?

Answer 11

> dysplasia
haemorrhage
perforation
toxic dilatation

Question 12

describe the pathology of crohns disease

Answer 12

> granular serosa
mesentery is thickened, oedematous and fibrotic
lumen is narrowed
‘skip lesions’ demarcated areas of disease, adjacent to normal tissue
ulceration - cobblestone appearance

Question 13

what would you expect to see in a histological slide of crohns disease?

Answer 13

> non-caseating granulomas
> cryptitis and crypt abscesses
> atrophy - crypt destruction
> deep ulceration
> transmural inflammation
> fibrosis
> lymphangiectasia
> hypertrophy of mural nerves
> paneth cell metaplasia

Question 14

what are the long term features of crohns disease?

Answer 14

> malabsorption
> strictures
> fistulas and abscesses
> perforation
> increased cancer risk (5*)

Question 15

in ischaemic enteritis what can lead to infarction?

Answer 15

acute occlusion of 1 of the 3 major supply vessels

Question 16

why may gradual occlusion have little effect in ischaemic enteritis?

Answer 16

anastomotic circulation

Question 17

what conditions can predispose for ischaemia?

Answer 17

> arterial thrombosis (atherosclerosis, OCP, dissecting aneurysm)
arterial embolism (cardiac vegetations, cholesterol embolism)
non-occlusive ischaemia (cardiac failure, shock, vasoconstrictive drugs)

Question 18

describe the histology of acute ischaemia

Answer 18

> oedema
> interstitial haemorrhage
> sloughing necrosis of mucosa
> nuclei indistinct
> vascular dilatation
> 1-4 days bacteria gangrene

Question 19

what can abdominal irradiation impair?

Answer 19

the normal proliferative activity of the small and large bowel epithelium

Question 20

what are the symptoms of radiation colitis?

Answer 20

> anorexia
> abdominal cramps
> diarrhoea
> malabsorption
> chronic mimics IBD

Question 21

describe histological changes that can be seen in radiation colitis

Answer 21

> inflammation - crypt abscesses and eosinophils
> arterial stenosis
> ulceration
> necrosis
> haemorrhage
> perforation

Question 22

how does appendicitis lead to ischaemia?

Answer 22

there is increased intraluminal pressure

Question 23

describe the histological changes that may be seen in appendicitis

Answer 23

> acute supprative inflammation in the wall
pus in the lumen
acute gangrenous fill thickness necrosis (perforation)

Question 24

describe the histological appearance of low grade adenoma dysplasia

Answer 24

> increased nuclear nos.
increased nuclear size
reduced mucin

Question 25

describe the histological appearance of high grade adenoma dysplasia

Answer 25

> carcinoma in situ
crowded
very irregular

Question 26

what are the risk factors for colorectal carcinomas?

Answer 26

> lifestyle
family history
genetics
IBD