Pathology of Colon

Question 1

What is the small and large bowel peristalsis mediated by?

Answer 1

Intrinsically - Myenteric plexus

Extrinsic neural control - Autonomic innervation

Question 2

Where is the Meissner’s plexus (Part of the myenteric plexus) found?

Answer 2

Base of the submucosa

Question 3

Where is Auerbach’s plexus found?

Answer 3

Between the inner circular and out longitudinal layers of the muscularis propria

Question 4

Is the duodenum intraperitoneal or retroperitoneal?

Answer 4

Retroperitoneal

Question 5

Histologically, in the small intestine, what are the three cell types present and what are the three levels of the bowel wall?

Answer 5

Goblet, Columnar absorptive & Endocrine

Lamina propria, Muscularis mucosa & Submucosa

Question 6

How long is the rectum and how much of it is extraperitoneal?

Answer 6

15cm

Distal 7cm

Question 7

Histologically, what is the large bowel like?

Answer 7

No villi present

Flat with tubular crypts and the surface is made of columnar absorptive cells

Question 8

What three types of cell may the crypts in the large bowel contain?

Answer 8

Goblet
Endocrine
Stem

Question 9

What IBD of the lower GI Tract are there? (5)

Answer 9

UC
CD
Appendicitis
Ischaemic colitis
Radiation colitis

Question 10

What drives the mucosal immune system to be activated?

Answer 10

The presence of normal intraluminal flora e.g. H. pylori

Question 11

When diagnosing a patient what is it best to do?

Answer 11

Have a conversation - It could be? What it might be? No definitive answers

Question 12

Where must UC originate from and where is it limited to?

Answer 12

Rectum

Colon

Question 13

Where can UC never just present?

Answer 13

Caecum

Question 14

What organ can be involved with UC and its systemic manifestations?

Answer 14

Appendix

Question 15

In UC, what does the ulceration erode and what might the UC have?

Answer 15

Mucosa

Pseudopolyps

Question 16

In UC, does the serosal surface have any inflammation?

Answer 16

Minimal or none at all

Question 17

What kind of fibrosis occurs in UC?

Answer 17

Submucosal fibrosis

Question 18

How is dysplasia categorised in UC?

Answer 18

High or Low grade

Question 19

What complications of UC are there?

Answer 19

Haemorrhage
Perforation
Toxic dilatation

Question 20

How does the mesentery thicken and fibrose in CD?

Answer 20

Granular serosa/dull grey wraps around the mesenteric fat

Question 21

Histologically, how does CD appear? (4)

Answer 21

Cryptitis and crypt abscesses with atrophy leading to crypt destruction
Deep ulceration
Fibrosis is present
Contains non-caseating granulomas

Question 22

What are the long term features of CD? (5)

Answer 22

Small Intestine has malabsorption
Strictures
Fistulas & Abscesses
Perforation
Increased risk of cancer

Question 23

Where does Ischaemic Enteritis affect?

Answer 23

Small Intestine
or
Large Intestine
or
Both at the same time

Question 24

What happens if one of the Coeliac, Inferior and Superior mesenteric arteries become occluded?

Answer 24

Infarction

Gradual occlusion will have little effect

Question 25

What type of occlusion is less common?

Answer 25

Mesenteric venous

Question 26

Histologically, how does acute ischaemia appear?

Answer 26

Oedema with interstitial haemorrhages Initial absence of inflammation Within 1-4 days bacteria gangrene and perforation has occured

Question 27

Why is splenic flexure vulnerable?

Answer 27

It has an arterial sharp demarcation as the venous fades gradually

Question 28

What is indicative of chronic ischaemia?

Answer 28

``` Mucosal inflammation Ulceration Submucosal inflammation Fibrosis Stricture ```

Question 29

Radiation colitis - What does abdominal irradiation impair?

Answer 29

The normal proliferative activity of the small and large bowel's epithelium

Question 30

What are the symptoms of radiation colitis?

Answer 30

Anorexia Abdominal cramps Diarrhoea Malabsorption

Question 31

Histologically, how does radiation colitis appear?

Answer 31

``` Inflammation of crypt abscesses and eosinophils Necrosis Ulceration Haemorrhage Perforation ```

Question 32

What is appendicitis?

Answer 32

Inflammation of the appendix causing tissue to regress with age and it has fibrous obliteration

Question 33

Histologically, how does appendicitis appear?

Answer 33

Exudate Perforation Abscess Acute gangrene leads to full thickness necrosis

Question 34

In dysplasia, how does the adenoma present?

Answer 34

``` Tubular or Villous or Tubulovillous *90% of tubular occur in the colon* ```

Question 35

What is the main type of tumour in colorectal carcinoma?

Answer 35

Adenocarcinoma (98%)

Question 36

What are the risk factors for colorectal carcinoma?

Answer 36

Lifestyle Family history IBD Genetics e.g. FAP & HNPCC

Question 37

What are the two most common sites of metastases for colorectal carcinoma?

Answer 37

Liver | Lung

Question 38

What are the signs of right sided (Ascending colon) adenocarcinoma?

Answer 38

``` Exophytic/polypoid Anaemia Vague pain Weakness Obstruction ```

Question 39

What are the signs of left sided (Descending colon) adenocarcinoma?

Answer 39

Annular - Napkin ring lesion Bleeding - Fresh/altered blood PR Altered bowel habit Obstruction