Lecture 20 Alimentary Tract Pathology Flashcards Preview

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Flashcards in Lecture 20 Alimentary Tract Pathology Deck (25)
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1
Q

Small bowel and large bowel peristalsis is mediated by what neural control

A

Intrinsic (myenteric plexus) and extrinsic (autonomic innervation) neural control

2
Q

Where is the Meissener’s plexus located

A

Base of submucosa

3
Q

Where is the Auerbach plexus located

A

Between the inner circular and outer longitudinal layers of the muscular propria

4
Q

Whats the main difference between ulcerative colitis and Crohn’s

A

Crohn’s can affect any part of the GIT from mouth the anus

UC is limited to colon

5
Q

What is the aetiology of IBD

A

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

6
Q

What gene mutation is seen in Crohn’s disease

A

NOD2

7
Q

What gene mutation is seen in Ulcerative colitis

A

HLA

8
Q

What is UC called when it is localised in the rectum

A

Proctitis

9
Q

Describe the pathology of UC

A
  • Large bowel only
  • Continuous pattern of inflammation.
  • Rectum to proximal
  • Pseudopolyps
  • Ulceration
  • Serosal surface minimal or no inflammation
10
Q

Histology of UC

A
Inflamed mucosa
Cryptitis
Crypt abscesses
Disarray of crypts
Mucosal atrophy
Ulceration into submucosa
No granulomas 
Submucosal fibrosis
Reactive atypic/dysplasia
11
Q

Complications of UC

A

 Haemorrhage
 Perforation
 Toxic dilatation

12
Q

Describe pathology of Crohn’s disease

A
Granular serosa
Mesentery thickened, oedema and fibrotic
Narrowing of lumen
Skip lesions
Ulceration- cobble stone
13
Q

Describe the histology of Crohn’s disease

A
  • Cryptitis and crypt abscesses
  • Architectural distortion
  • Atrophy –crypt destruction
  • Ulceration-deep
  • Transmural inflammation
  • Chain of pearls
  • Non-caseating granulomas
  • Fibrosis
  • Lymphangiectasia
  • Hypertrophy of mural nerves
  • Paneth cell metaplasia
14
Q

Long term features of CD

A
  • SI – malabsorption
  • Strictures
  • Fistulas and abscesses
  • Perforation
  • Increased risk of cancer
15
Q

What is Ischaemic Enteritis

A

Occlusion of SI or LI major soppy vessels

16
Q

Predisposing Conditions for Ischaemia

A

Arterial thrombosis
Arterial embolism
Non-occlusive ischaemia

17
Q

Histology of Acute Ischaemia

A
  • Oedema
  • Interstitial haemorrhages
  • Sloughing necrosis of mucosa-ghost outlines
  • Nuclei indistinct
  • Initial absence of inflammation
  • 1-4 days –bacteria-gangrene and perforation
  • Vascular dilatation
18
Q

Features of Chronic ischaemia

A
  • Mucosal inflammation
  • Ulceration
  • Submucosal inflammation
  • Fibrosis
  • Stricture
19
Q

Define Radiation Colitis

A

• Abdominal irradiation can impair the normal proliferative activity of the small and large bowel epithelium

20
Q

Symptoms of radiation colitis

A

Anorexia, abdominal cramps, diarrhoea and malabsorption

21
Q

Histology of radiation colitis

A
  • Bizarre cellular changes
  • Inflammation-crypt abscesses and eosinophils
  • Later-arterial stenosis
  • Ulceration
  • Necrosis
  • Haemorrhage
  • perforation
22
Q

Causes of appendicitis

A

Obstruction
Enterobius vermicularis
Intraluminal pressure leading to ischaemia

23
Q

Histology of appendicitis

A

Macro-fibrinopurulent exudate, perforation, abscess
• Acute suppurative inflammation in wall and pus in lumen
• Acute gangrenous-full thickness necrosis +/- perforation

24
Q

Colorectal adenocarcinoma right sided

A
exophytic/polypoid
Anaemia- altered blood pH
Vague pain
Weakness
Obstruction
25
Q

Colorectal adenocarcinoma left sided

A

Annular- napkin ring lesion
Bleeding- fresh altered blood PR
Altered bowel habit
Obstruction

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