21 Lower GI pathology Flashcards Preview

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Flashcards in 21 Lower GI pathology Deck (26):
1

Describe diverticulosis of the colon.
Location?

Protrusions of mucosa and submucosa through the bowel wall.
Commonly in sigmoid colon.
Located between mesenteric + anti-mesenteric taenia coli.

2

What is the epidemiology of diverticulosis of the colon? (4)

Western, urban areas.
Related to fibre content in diet.
Increases with age.
Male = female.

3

What is the pathogenesis of diverticulosis of the colon?

Increased intra-luminal kPa (irregular peristalsis due to overlapping arcs in bowel wall).
Points of weakness in wall (penetration by arteries + age related connective tissue changes).

4

What is the pathology of diverticulosis? (4)

Thickening of muscular propria.
Elastosis of taeniae coli (shortening the colon).
Redundant mucosal folds.
Sacculation and diverticula.

5

What are the symptoms of diverticulosis?
Complications? (7)

Asymptomatic.
Diverticulitis, perforation, haemorrhage.
Obstruction, fistula, colitis, polypod prolapsing mucosal folds.

6

What are the acute classifications of colitis? (6)

Infective: campylobacter, salmonella, CMV.
Antibiotic associated.
Drug induced.
Acute ischaemic and radiation.
Neutropenic.
Phlegmonous (diffuse inflammation).

7

What are the chronic classifications of colitis? (8)

Chronic idiopathic IBD.
Microscopic.
Ischaemic.
Diverticular.
Chronic infective: amoebic + TB.
Diversion
Eosinophilic.
Chronic radiation.

8

What is the epidemiology of IBD?
age, sex, living, RFs (2)

20-40 years.
CD= 1.3F : 1M UC Male=Female.
More UC in urban areas.
Oral contraceptive increases both.
Smoking: UC:0.5x CD:2x

9

How does IBD present? (8)

Diarrhoea - urgency/tenesmus.
Constipation, bleeding.
Abdo pain.
Anorexia.
Weight loss
Anaemia.
Palpable mass.
Oral ulcers if CD.

10

What are the complications of IBD? (5)

Toxic megacolon and perforation.
Haemorrhage.
Carcinoma.
Stricture (rare in UC, common in CD).
Short bowel syndrome in CD.

11

Where is Crohns disease commonly distributed? (3)

Ileocolic.
Small bowel.
Colonic.

12

What is the pathology of ulcerative colitis? (8)
Site. Appearance. Histology.

Affects colon, appendix, terminal ileum.
Continuous.
Rectum always involved.
Granular and red. Normal serosa.
Strictures rare.
Mucosal.
Crypt abscesses present with severe crypt distortion.
Polyps common.

13

What is the pathology of Crohns disease? (10)
Site. Appearance. Histology.

Affects all of GI tract.
Terminal ileum involved more than in UC.
Anal fissures very common.
Skip lesions.
Cobblestone.
Serositis.
Strictures common.
Spontaneous fistulae.
Transmural.
Sarcoid like granulomas are present.

14

What are the extra-intestinal manifestations of IBD? (6)

Hepatic: fatty change, carcinoma.
Skeletal: polyarthritis, ankylosing spondylitis.
Oral ulcers, pyoderma gangrenosum, erythema nodosum.
Renal stones.
Anaemia, thrombo/leukocytosis.
Amyloid, vasculitis.

15

What are the risk factors for colorectal cancer in ulcerative colitis? (7)

Early age of onset.
Duration >10 years.
Total colitis.
Primary sclerosing cholangitis.
Family history.
Severe inflammation.
Dysplasia presence.

16

Name the non-neoplastic polyps of the colo-rectum. (6)

Hyperplastic.
Hamartomatous (Peutz-jeghers, juvenile).
Mucosal prolapse related.
Post inflammatory.
Inflammatory fibroid.
Benign lymphoid.

17

Describe the pathology of hyper plastic polyps.
Size, location, ca risk.

1-5mm. Common. Often multiple.
In rectum and sigmoid colon.
Small and distal: NO Ca potential.
Large right sided may give rise to miscrosatellite unstable carcinoma.

18

Describe the pathology of juvenile polyps.
Shape, size, who, ca potential.

Often pedunculate. 10-30mm.
Common in children.
Sporadic: NO Ca potential.
Juvenile polyposis increased colorectal + gastric Ca risk.

19

What is peutz-jeghers syndrome?
Gene, symptoms (3), external feature

Autosomal dominant - STK11 gene. Increased Ca risk.
Teens - abdo pain, GI bleeds + anaemia. Multiple GI polyps - mostly small bowl.
Also muco-cutaneous pigmentation.

20

What are adenomas in the colon?
Risks, distribution.

Benign epithelial tumours.
Polypoid.
Precursor to 80% of CRC. Adenocarcinoma sequence over 10-15 years.
Evenly distributed, larger in recto-sigmoid + caecum.

21

What are the risk factors for colonic adenomas becoming malignant? (5)

Flat.
Size >10mm.
Villous + Tubule-Villous.
Severe displasia.
HNPCC associated adenomas.

22

What are the risk factors for colorectal cancer? (9)

Diet. Obesity. Alcohol.
NSAIDs, HRT, OC.
Schistosomiasis.
Radiation.
IBD.

23

Describe the genetics of Familial adenomatous polyposis (FAP).
Inheritance, risk, mutation.

Autosomal dominant.
100% risk of large bowel cancer.
Mutation in APC tumour supressor gene.

24

Describe the genetics of HNPCC.
Inheritance, risk, mutation.

Autosomal dominant.
50-70% risk large bowel cancer, increased risk of others.
Mutation in DNA mismatch repair genes.

25

How does colorectal cancer spread? (5)

Direct invasion.
Lymph metastasis.
Haematogenous mets (liver + lung).
Transcoelemic mets.
Iatrogenic.

26

What is the Dukes staging used for and what are the stages?
5 year survival?

Colorectal cancer.
A: confined to bowel wall >90%.
B: invades bowel wall 70%.
C: regional lymph node mets. 40%
D: distant mets

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