Pathology of the colon

Question 1

What is the structure of the colon, from proximal to distal?

Answer 1

Caecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum

Question 2

What is the peritoneum of the colon?

Answer 2

Caecum- inta
A- retro
T- intra
D- retro
S- intra

Question 3

What is the histology of the colon?

Answer 3

Flat
Tubular crypts
-goblet and endocrine cells
Columnar absorptive epithelium

Question 4

What is idiopathic IBD?

Answer 4

Chronic inflammatory conditions resulting from inappropriate and persistent activation of mucosal immune system

Question 5

What are the 2 main inflammatory bowel diseases?

Answer 5

Crohn’s

Ulcerative colitis

Question 6

What is the main difference between Crohn’s and UC?

Answer 6

Crohn’s can affect anywhere from mouth to anus

UC can only affect colon

Question 7

What is the cause of IBD?

Answer 7

Strong immune response against normal flora with defects in epithelial barrier function in genetically suseptibel individuals

Question 8

How is IBD diagnosed?

Answer 8

History, x ray, pathological correlation

pANCA- good for differentiating UC and Crohn’s

Question 9

Who does UC most commonly affect?

Answer 9

Males

20-30 and 70-80 years

Question 10

How does UC spread?

Answer 10

Most commonly proximally

Question 11

What is the pathology of UC?

Answer 11

Large intestine only
Continuous pattern of inflammation
Often spreads from rectum proximally
Pseudopolyps
UlcerationSerosal surface has minimal or no inflammation

Question 12

What is the histology of UC?

Answer 12

Inflammation of mucosa
Crypitis
Crypt abscesses and disarray
Mucosal atrophy
Ulceration into submucosa creating pseudopolyps
Submucosal fibrosis
No granulomas

Question 13

What can submucosal fibrosis is UC cause?

Answer 13

Stricturing of bowel and obstruction

Question 14

What are the complications of UC?

Answer 14

Haemorrhage
Perforation
Toxic dilation

Question 15

Where does the majority of Crohn’s affect?

Answer 15

Small intestine

Question 16

What % of Crohn’s affects the small intestine and large intestine?

Answer 16

Small- 40%
Both- 30%
Large- 30%

Question 17

What is the pathology of Crohn’s?

Answer 17

Granular serosa
Wrapping mesenteric fat
Thickened, oedematous, fibrotic mesentery and wall
Narrowing of lumen
Ulceration
Patch disease

Question 18

What is the histology of Crohn’s disease?

Answer 18

Cryptitis and crypt abscesses
Architestural distortion
Atrophy
Deep ulceration
Transmural inflammation
Non caveating granulomas
Fibrosis
Lymphangiectasia
Hypertrophy of mural nerves
Paneth cell metaplasia

Question 19

What are the long term features of Crohn’s?

Answer 19

Malabsorption
Strictures
Fistulas and abscesses
Perforation
Increased risk of cancer

Question 20

What is ischaemic enteritis?

Answer 20

Occlusion of celiac, s mesenteric or i mesenteric vessels causing infarction

Question 21

What does major vessel occlusion in ischaemic enteritis cause?

Answer 21

Transmural injury

Question 22

What are the predisposing conditions for arterial thrombosis in ischaemic enteritis?

Answer 22

Severe atherosclerosis
Systemic vasculitis
Dissecting aneurysm
Hypercoagulate states
Oral contraceptive

Question 23

What are the predisposing conditions for arterial embolism in ischaemic enteritis?

Answer 23

Cardiac vegetations
Acute after-embolism
Cholesterol embolism

Question 24

What are the predisposing conditions for non occlusive ischaemic enteritis?

Answer 24

Cardiac failure
Shock/dehydration
Vasoconstrictive drugs

Question 25

What part of the gut is vulnerable to acute ischaemic enteritis?

Answer 25

Splenic flexure

Question 26

What is the histology of acute ischaemic enteritis?

Answer 26

``` Oedema Interstitial haemorrhages Sloughing necrosis of mucosa Nuclei indistinct Initial absence of inflammation Vascular dilatation ```

Question 27

What are the features of chronic ischaemic enteritis?

Answer 27

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

Question 28

Where does radiation colitis normally affect?

Answer 28

Rectum after pelvic radiotherapy

Question 29

What does radiation colitis normally target?

Answer 29

Actively dividing cells, esp blood vessels and crypt epithelium

Question 30

what are the symptoms of radiation colitis?

Answer 30

Anorexia Abdo cramps Diarrhoea Malabsorption

Question 31

What is the histology of radiation colitis?

Answer 31

``` Inflammation Arterial stenosis Ulceration Necrosis Haemorrhage Perforation ```

Question 32

What is the histology of appendicitis?

Answer 32

Fibrinopurulent exudate Perforation Abscess Acute inflammaation in wall, pus in lumen Acute gangrenous full thickness necrosis, w/ possible perforation

Question 33

What are the forms of colorectal dysplasia?

Answer 33

Tubular, villous or tubulovillous adenomas

Question 34

What are the features of low grade colorectal dysplasia?

Answer 34

Increased nuclear number and size | Reduced mucin

Question 35

What are the features of high grade colorectal dysplasia?

Answer 35

Carcinoma in situ Crowded Very irregular Not yet invasive

Question 36

What are the majority of colorectal cancers?

Answer 36

Adenocarcinomas

Question 37

What are the risk factors of colorectal cancer?

Answer 37

Lifestyle Family history IBD Genetics

Question 38

What are the signs and symptoms of right sided adenocarcinoma of the colon?

Answer 38

Anaemia Vague pain Weakness Obstruction

Question 39

What are the signs and symptoms of left sided adenocarcinoma of the colon?

Answer 39

Fresh blood PR Altered bowel habit Obstruction