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Flashcards in Histopath - Lower GI Deck (48)
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1
Q

What is Hirschprung’s disease caused by?

A

Absence of ganglion cells of the myenteric plexus

  • distal colon fails to dilate
2
Q

What presentation is Hirschsprung disease associated with?

A

Failure to pass meconium within 48h

3
Q

Which genetic syndrome is Hirschsprung associated with?

A

Down’s syndrome (2%)

4
Q

Two types of acute cholitis

A

Pseudomembranous colitis and ischaemic colitis

5
Q

*What cause is pseudomembranous colitis associated with?

A

Clostridium difficile

caused by 3C antibx: Cephalosporins, ciprofloxacin & clindamycin

6
Q

*Histology for pseudomembranous colitis

A

Pseudomembrane (membrane like material) formation

7
Q

Ix for diagnosing pseudomembranous colitis

A

Toxin stool assay (for exotoxins)

8
Q

Mx for pseudomembranous colitis

A

Side room, metronidazole

9
Q

*What is ischaemic colitis?

A

Bowel is hypoperfused

oedematous thickening bowel wall, areas necrotic ulceration confined to mucosal layers

10
Q

Where does ischaemic colitis usually occur?

A

Watershed zones -

splenic flexure and rectosigmoid

11
Q

*Causes of ischaemic colitis

A

Occlusive

  • Arterial/venous occlusion
  • Small vessel disease: DM, vasculitides
  • Obstruction: hernia, volvulus

Hypoperfusion

  • CHF
  • Haemorrhage
  • Shock
12
Q

Two types of Inflammatory bowel diseases

A

Crohn’s disease and ulcerative colitis

13
Q

What part of GI tract is affected in Crohn’s?

A

Entire GI tract: mouth to anus

(skip lesions)

14
Q

Inflammation depth for Crohn’s disease

A

Transmural inflammation

15
Q

Bowel wall thickness in Crohn’s

A

Thick bowel wall, narrow lumen

16
Q

*What feature is pathognomonic of Crohn’s disease?

A

Non-caseating granulomas

17
Q

What part of GI tract is affected in Ulcerative colitis?

A

Rectum and colon

(continuous)

18
Q

*Inflammation depth for UC?

A

Inflammation confined to mucosa (superficial)

19
Q

Bowel wall thickness in UC?

A

Normal thickness

20
Q

*Complication of UC

A

Toxic megacolon

+ (20-30x) increased risk colonic adenocarcinoma

21
Q

Extra-intestinal manifestations of UC

A
  • Uveitis
  • Erythema nodosum
  • Pyoderma gangrenosum (shallow, weeping, angry break in skin)
  • Arthritis
  • Stomatitis
22
Q

What are GI polyps?

A

Benign dysplastic lesions

(precursor to adenocarcinomas)

23
Q

What 3 polyp types have increased risk of becoming malignant?

A
  • Tubular
  • Tubulovillous
  • Villous
24
Q

Histopathology of tubular polyps

A

>75% has tubular appearance

25
Q

Histopathology of tubovillous polyps

A

25-75% villous

26
Q

Histopathology of villous polyps

A

>75% villous

27
Q

Which polyp type has highest risk of malignancy?

A

Villous

28
Q

How does polyp progress to adenocarcinoma?

A

Normal -(APC)-> Early adenoma -> late adenoma -(KRAS + p53)-> adenocarcinoma

29
Q

What type of ca is majority of colorectal ca?

A

Adenocarcinoma

30
Q

RFs of colorectal ca

A
  • Low fibre
  • High fat diet
  • No exercise
  • Obesity
  • Chronic IBD
31
Q

Staging used for colorectal ca

A

Duke’s staging

32
Q

Duke’s staging

A

A - confined to mucosa

B1 - extending into muscularis propria

B2 - transmural invasion

C1 - extending to muscularis propria with LN involvement

C2 - transmural invasion with LN involvement

D - distant metastasis

33
Q

*Colonic carcinoma presentation

A
  • Rectal bleeding
  • New onset constipation
  • Recent weight loss
  • Previous dx polyps in colon
34
Q

3 inherited lower GI conditions

A

Familial adenomatous polyposis, Gardner’s syndrome, Hereditary non-polyposis colorectal cancer/Lynch syndrome

35
Q

Hereditary pattern for FAP

A

AD

36
Q

What is FAP?

A

Lots of polyps! (~1000)

37
Q

What is the mutation for FAP?

A

Adenomatous polyposis coli (APC) tumour suppressor gene mutation on Cr 5q21

38
Q

Hereditary pattern for Gardner’s syndrome

A

AD

39
Q

What is Gardner’s syndrome?

A

Subtype of FAP with extra-intestinal manifestations

40
Q

What are extra-intestinal manifestations of Garnder’s syndrome?

A
  • Osteomas of skull and mandible
  • Epidermoid cyst
  • Dental caries
41
Q

What is hereditary non-polyposis colorectal ca/ lynch syndrome caused by?

A

Defective DNA mismatch repair

42
Q

What is a presenting feature of hereditary non-polyposis colorectal ca/lynch syndrome?

A

Other extra-colonic ca at the same time

43
Q

Hereditary pattern for hereditary non-polyposis colorectal ca/lynch syndrome

A

AD

44
Q

Lower GI inherited conditions Mx

A

Monitoring + total coelctomy (and stoma)

45
Q

*Histopathology of Diverticular disease

A

pouches of mucosa extruding through the muscle layer

46
Q

What is the name given to areas of regenerating mucosa which project into the lumen of the bowel, which may be visualised during a colonoscopy of a patient with ulcerative colitis?

A

Pseudopolyp

47
Q

*3 cancers associated w coeliac

A
  • enteropathy-associated T-cell lymphoma (EATL)
  • non-Hodgkin’s lymphoma
  • adenocarcinoma of the small intestine
48
Q

Non caseating granulomas

A

Crohn’s

(And Sarcoidosis!)