Pathology of Colon Flashcards

1
Q

what is the role of the small bowel

A

absorptive role

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2
Q

what is the role of the large bowel

A

absorptive and secretory role

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3
Q

what is the small intestine divided into?

A

duodenum, jejunum and ileum

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4
Q

what is the large intestine divided into?

A
Caecum
Ascending colon-retroperitoneal
Transverse colon
Descending colon-retroperitoneal
Sigmoid –originates pelvic brim
Rectum-15cm, distal 7cm
    extraperitoneal
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5
Q

small intestine histology

A
Mucosa: innumerable villi
3 cell types
Goblet cells
Columnar absorptive cells
Endocrine cells
Crypts: stem, goblet, endocrine and Paneth
Lamina propria, muscularis mucosa, submucosa,
Muscularis propria and subserosa
Renewed every 4-6 days
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6
Q

large intestine histology

A

Flat –no villi
Tubular crypts
Surface-columnar absorptive cells
Crypts-goblet cells, endocrine cells, stem cells turnover 3-8 days

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7
Q

what does dysfunction of the intestinal immune system cause?

A

chronic disease

life threatening acute conditions

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8
Q

what is the small and large bowel peristalsis mediated by?

A

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

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9
Q

where is the meisseners plexus located?

A

base of the submucosa

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10
Q

where is the auerbach plexus located?

A

between the inner circular and outer longitudinal layers of the muscuularis propria

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11
Q

what causes inflammatory bowel disease?

A
Ulcerative colitis
Crohn’s disease
Ischaemic colitis
Radiation colitis
Appendicitis
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12
Q

what is idiopathic inflammatory bowel disease?

A

Chronic inflammatory conditions resulting from inappropriate and persistent activation of the mucosal immune system driven by the presence of normal intraluminal flora

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13
Q

what are the two main diseases of idiopathic inflammatory bowel disease?

A

crohns disease

ulcerative colitis

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14
Q

where does crohns disease effect you

A

any part of the GIT from the mouth to the anus

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15
Q

where does ulcerative colitis effect you?

A

limited to the colon

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16
Q

what is aetiology of inflammatory bowel disease?

A

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

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17
Q

what antibody to people with IBD posses?

A

pANCA

18
Q

who is more liley to get ulcerative colitis

A

male, 20-30 and 70-80 years

19
Q

UC pathology

A
Large bowel only
Continuous pattern of inflammation.
Rectum to proximal
Pseudopolyps
Ulceration
Serosal surface minimal or no inflammation
20
Q

complications of UC?

A

Haemorrhage
Perforation
Toxic dilatation

21
Q

who is more likely to get crohns disease?

A

females, 20-30 and 60-70

22
Q

CD pathology

A

Granular serosa / dull grey
Wrapping mesenteric fat
Mesentry- thickened, oedematous and fibrotic
Wall thick, oedematous
Narrowing of lumen
Sharp demarcation of disease segments from adjacent normal tissue “skip lesions”
Ulceration- “cobblestone”

23
Q

UC histology

A

no granulomas

24
Q

CD histology

A

non-caseating granulomas

25
Q

long term features of CD

A
SI – malabsorption 
Strictures
Fistulas and abscesses
Perforation
Increased risk of cancer -  5x increased risk over the same age matched population.
26
Q

where does ischaemic lesions effect?

A

either SI or LI or they can affect both dependeing on vessel affected

27
Q

predsiposing conditions for ischaemia?

A

Arterial thrombosis

severe atherosclerosis

systemic vasculitis eg PAN,HSP,WG

dissecting aneurysm

hypercoagulable states

oral contraceptives

Arterial embolism

cardiac vegetations

acute atheroembolism

cholesterol embolism

Non-occlusive ischaemia

cardiac failure

shock /dehydration

vasoconstricive drugs eg propanolol

28
Q

acute ischaemia histology

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

29
Q

chronic ischaemia histology

A
Mucosal inflammation
Ulceration
Submucosal inflammation
Fibrosis 
Stricture
30
Q

abdominal irradiation can impair what?

A

normal proliferate activity of the small and large bowel epithelium

31
Q

symptoms of radiation colitis?

A

anorexia, abdominal cramps, diarrhoea and malabsorption

32
Q

radiation colitis histology

A
Bizarre cellular changes
Inflammation-crypt abscesses and eosinophils
Later-arterial stenosis
Ulceration
Necrosis
Haemorrhage
perforation
33
Q

what is appendicitis

A

Acute inflammation
Cause-obstruction e.g. feocolith or Enterobius vermicularis
Increased intraluminal pressure- ischaemia

34
Q

appendicitis histology

A

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

35
Q

what are the types of large bowel neoplasia?

A

Dysplasia
Low grade
High grade

Malignancy
Colorectal carcinoma

36
Q

what are the types of adenoma (polyps)

A

Tubular (90% occur in colon)
Villous
Tubulovillous

37
Q

what is low grade dysplasia?

A

Increased nuclear nos.
Increased nuclear size
Reduced mucin

38
Q

what is high grade dysplasia?

A

Carcinoma in situ
Crowded
Very irregular
Not yet invasive

39
Q

what are the risk factors for colorectal carcinoma?

A

Lifestyle
Family history
IBD
UC & Crohn’s disease

Genetics
FAP
HNPCC
Peutz-Jeghers

40
Q

what are signs of right sided colorectal adenocarcinoma?

A
Exophytic/Polypoid
Anaemia
Altered blood PR
Vague pain
Weakness
Obstruction
41
Q

what are signs of left sided colorectal adenocarcinoma?

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