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Gastrointestinal > Bowel pathology > Flashcards

Flashcards in Bowel pathology Deck (28):
1

Which part of the colon is affected most by cancer?

Rectum and sigmoid colon

2

How do colorectal cancers arise?

Adenoma-carcinoma sequence:

Adenomatous polyp forms and eventually becomes an adenocarcinoma.

As the polyp becomes larger it accumulates more gene mutations leading to unregulated cell growth, invasive potential and cancer development

3

What is dysplasia?

A microscopic diagnosis synonymous with intraepithelial neoplasia.
It is a combination of:
1) cytological atypia
2) architectural disorder

4

What are the two morphological types of Adenoma in the colon?

Villous
Tubular

5

Name 2 familial polyposis syndromes

Familial adenomatous polyposis (FAP)
Hereditary non polyposis colon cancer (HNPCC)

6

What % of people with FAP develop adenocarcinoma before age of 45?

100%!

7

Which gene is mutated in FAP?

APC

8

How do we screen for colorectal cancer?

FOB- faecal occult blood

9

What blood tests should be done to investigate malabsorption?

Bone profile
Albumin
Hb
Fe, folate, B12
Prothrombin time
LFTs

Special tests:
Faecal fat
Breath tests- e.g. For bacterial overgrowth measure 14CO2 in breath

10

How can we test small intestine function?

Xylose absorption test

Xylose is absorbed in the jejunum and excreted unchanged in the urine.
This test is limited by renal function.

11

What are the 2 subtypes of IBD?

Crohn's disease
Ulcerative colitis

12

Which inflammatory bowel disease is granulomatous in nature?

Crohn's disease

13

What are the main differences between Crohn's disease and UC?

CROHN'S DISEASE
Mouth to anus
Skip lesions
Thickened bowel wall
Transmural inflammation
Granulomas
Deep fissuring ulcers
Fistula formation
Cancer rare
Non surveillance

ULCERATIVE COLITIS
Colon only
Continuous lesion
Normal bowel wall thickness
Mucosal inflammation
No granulomas
Pseudopolyp formation
No fistula formation
Cancer common
Surveillance

14

What are the possible complications of diverticula disease?

Diverticulitis- leading to perforation and abscess formation
Fistulae
Intestinal obstruction due to inflammatory mass
Haemorrhage

15

Which two viruses are the commonest causes of childhood viral enterocolitis?

Rotavirus (commonest)
Norwalk virus

These can kill!

16

Which organism is responsible for pseudomembranous colitis?

Clostridium difficile (antibiotic-associated colitis)

17

What is hirschprungs disease?

Congenital aganglionosis- area of the bowel with no ganglion cells so it immotile. Need to resect as it causes constipation and can lead to megacolon.

18

What is intusussception?

A medical condition in which a part of the intestine invaginates into another section of intestine, similar to the way the parts of a collapsible telescope slide into one another.

19

What are the systemic causes of constipation?

Hypothyroidism
Hypercalcemia/hypokalaemia
Drugs
Dehydration
Depression
Pregnancy
Neurological (Parkinsonism, autonomic neuropathy)

20

What is the most common cause of diarrhoea?

Gastroenteritis

21

What are the systemic causes of diarrhoea?

Hyperthyroidism
Drugs
Anxiety
Autonomic neuropathy

22

What bacterium might you get from reheated rice, causing diarrhoea?

Staphylococcus aureus

23

What are the symptoms of irritable bowel syndrome?

Abdominal pain
Bloating
Change in bowel habit

WITHOUT:
Weight loss
PR blood loss
Abdominal masses
Anaemia (suggests cancer)
Raised inflammatory markers

24

What can cause small bowel obstruction in Crohn's?

Stricturing or inflammation of a section of bowel

Patients who have had a bowel resection as a result of their inflammatory bowel disease can also get adhesions causing obstruction.

25

What can cause small bowel obstruction in UC?

Caecal inflammation, causing SBO at the ileocaecal valve

26

Where are the three locations for haemorrhoids?

Internal, interoexternal and external

27

How would you treat interoexternal haemorrhoids that get trapped externally and thrombose?

Painkillers and ice packs for symptomatic treatment.
Phenol 5% injection to cause ulceration and decrease vasculature.

Alternative: Barron's band to pull mucosa up.

28

What are the 3 main complications of haemorrhoidectomy?

1) Pain with acute urinary retention.
2) Secondary haemorrhage (1 week to 10 days post-operatively)
3) Anal stenosis (healing too tight if patient not taking bulk laxative)