Alimentary Tract Pathology Flashcards Preview

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Flashcards in Alimentary Tract Pathology Deck (26)
1

What are the three cell types in the small intestine?

Goblet Cells
Columnar absorptive cells
Endocrine cells

2

Where is Meissener's Plexus and Auerbach Plexus

Meissener's Plexus = base of the sub mucosa

Auerbach Plexus = between the inner circular and the outer longitudinal layers of the muscularis propria

3

What gene mutation is associated with CD?

NOD2

4

What gene mutation is associated with UC?

HLA

5

Whats the basic suspected cause of IBD?

Strong immune response against normal flora with defects in the epithelial barrier function in genetically susceptible individuals.

6

What antibody can you use in diagnosis of IBD?
What is its limitations?

perinuclear AntiNeutrophilic Cytoplasmic Antibody (pANCA)

Positive in 75% of UC patients
BUT only 11% of CD patients

NOT diagnostic

7

Can the appendix be involved in Ulcerative Colitis?

Yes

8

What is the definitive histological difference between UC and CD

UC = No granulomas
CD = granulomas

9

What are strictures in UC compared to Crohn's?

CD = Variable
UC = late/rare

10

How do pseudopolyps and ulcers in CD and UC compare?

Pseudopolyps are marked in both UC and CD

Ulcers in CD are deep and linear
Ulcers in UC are superficial

11

How does the fibrosis in CD compare to UC?

Moderate in CD
Mild in UC

12

Concerning ischaemic enteritis, how do acute and gradual occlusion compare?

Acute of 1 of the 3 major supply vessels leads to infarction.
Gradual occlusion can have little effect- anastomotic circulation

13

What areas are at risk from acute ischaemia?

Splenic flexure and sigmoid

Watershed areas

14

What is the histology of acute ischaemia?

Oedema
Interstitial haemorrhage
Sloughing necrosis of mucosa (ghost outlines)
Nuclei indistinct
Initial absence of inflammation
1-4 days = bacteria -> gangrene and perforation
Vascular dilatation

15

What are the features of Chronic ischaemia?

Mucosal inflammation
Ulceration
Submucosal inflammation
Fibrosis
Stricture

16

Explain radiation colitis

Abdominal irradiation can impair the normal proliferative activity of the small and large bowel epithelium
Usually rectum-pelvic radiotherapy
Damage depends on dose
Targets actively dividing cells (esp. blood vessels and crypt epithelium)

17

What are the symptoms of radiation colitis?

Anorexia, abdominal cramps, diarrhoea and malabsoption

Chronic disease will mimic IBD

18

What is the histology of radiation colitis?

Bizarre cellular changes
Inflammation = crypt abscesses and eosinophils
Later = Arterial stenosis
Ulceration
Necrosis
Haemorrhage
Perforation

19

What happens to the appendix as we age?

Prominent lymphoid tissue regresses with age
Fibrous obliteration

20

What organisms may obstruct the appendix and what can this cause?

Feocolith or Enterobius Vermicularis

Increased intraluminal pressure -> ischaemia

21

What is the macro and microscopic histology of appendicitis?

Macroscopically:
Fibrinopurulent exudate, perforation, abscess

Microscopically:
Active suppurative inflammation in the wall and puss in the lumen
Acute gangrenous full thickness necrosis +/- perforation

22

What structures does dysplasia in the colon usually form?

Adenoma's (polyps):
-Tubular (90% in colon)
-Villous
-Tubulovillous

50% are solitary
Prevelence = 30% at post mortem

23

Dysplasia in adenoma's are divided into two.
What are the histological features of each?

Low Grade Dysplasia:
-Increased nuclear number
-Increased nuclear size
-Reduced Mucin

High Grade Dysplasia:
-Carcinoma in situ
-Crowded
-Very irregular
-Not yet invasive

24

What are the risk factors of colorectal carcinoma?

Lifestyle
Family
IBD (UC and CD)
Genetics: FAP, HNPCC, Peutz-Jeghers

25

What are the features of right sided adenocarcinoma of the colon?

Exophytic/polypoid
Anaemia
Vague pain
weakness
Obstuction

26

What are the features of left sided adenocarcinoma of the colon?

Annular (napkin ring lesions)
Bleeding (fresh/altered blood PR)
Altered bowel habit
Obstruction