Pathology of Colon

Question 1

What does the portal venous system transmit?

Answer 1

Deoxygenated blood from most of the GI tract and GI organs to the liver

Question 2

Hepatocytes receive oxygenated blood from the

Answer 2

hepatic artery

Question 3

The mixture of oxygenated and deoxygenated blood received by the liver filters through the

Answer 3

sinusoids

Question 4

The portal vein is formed from

Answer 4

the superior mesenteric and splenic veins

Question 5

Where does the portal vein lie in relation to the hepatic artery and bile duct?

Answer 5

Posterior

Question 6

The portal vein penetrates the right border of the

Answer 6

lesser omentum

Question 7

The porto-systemic/porto-caval anastamosis is the

Answer 7

collateral communication between the portal and systemic venous systems

Question 8

What are the types of ano-rectal conditions?

Answer 8

Congenital/acquired
Local/systemic
Benign/malignant
Early/late

Question 9

What are the most common presentations of ano-rectal conditions?

Answer 9

Pain
Haemorrhage
Dysfunction

Question 10

Ano-rectal conditions can be caused by;

Answer 10

Inflammation
Infection
Malignancy
Trauma

Question 11

Give an example of A congenital an-rectal condition

Answer 11

Imperforate anus
Uro-genital fistulae
Hirschprung’s Myenteric Plexus Deficiency

Question 12

Give 5 examples of acquired ano-rectal conditions

Answer 12

Haemorrhoids 
Fissure 
Abscess 
Fistula-in-ano 
Ulceration 
Cancer 
Incontinence

Question 13

What is the typical presentation of haemorrhoids?

Answer 13

Itching/irritation/pain around the anus
Painful bowel movements
Bleeding from anus after defaecation

Question 14

What is the typical surgical treatment for haemorrhoids?

Answer 14

Stapled anopexy

Ultrasound guided ligation of haemorrhoids

Question 15

What are the stagings of anal fissures?

Answer 15

Acute or chronic

Question 16

At what point is an anal fissure classed as chronic

Answer 16

If it has been [resent for more than 6 weeks

Question 17

How is an anal fissure treated?

Answer 17

By relaxing internal anal sphincter;
medically - topical nitric oxide, glyceryl trinitrate paste or diltiazem calcium blocker
surgically - internal lateral sphincterotomy

Question 18

What is the treatment for a peri-anal abscess?

Answer 18

Incision and drainage

Question 19

At what locations can a peri-anal abscess occur?

Answer 19

Submucosal
Intersphincteric
Ischiorectal
Perianal

Question 20

What is the typical presentation of fistula-in-ano?

Answer 20

Pain and swelling around the anus and pain during bowel movements

Question 21

How is a superficial fistula-in-ano treated?

Answer 21

Fistulotomy

Question 22

How is a trans-sphincteric fistula-in-ano treated?

Answer 22

Seton suture, fistula plug or permacol paste

Question 23

What are the causes of anal ulceration?

Answer 23

Crohn’s disease
Malignancy
Syphilis chancre
Nicorandil

Question 24

What is the treatment for anal squamous cell carcinoma?

Answer 24

Radiotherapy and surgery

Question 25

What is the treatment for rectal adenocarcinoma?

Answer 25

Neo-adjuvant chemo and radiotherapy and laparoscopic resection

Question 26

Give 6 causes of constipation

Answer 26

``` Lack of fibre in diet Change in eating habits Ignoring urge to defaecate Immobility/lack of exercise Low fluid intake Anxiety/depression Antacids Antidepressants Anti-epileptics Calcium supplements Opiate painkillers Diuretics Iron supplements ```

Question 27

What do the majority of colorectal cancers arise from?

Answer 27

Pre-existing polyps

Question 28

What fraction of colorectal cancers are colonic and what fraction are rectal?

Answer 28

Two thirds colonic, one third rectal

Question 29

The majority of polyps are

Answer 29

adenomas

Question 30

What are the main histological types of polyps?

Answer 30

Tubular (75%) Villous (10%) Tubulovillous (15%)

Question 31

What appearances can polyps have?

Answer 31

Pedunculated | Sessile

Question 32

What is the basic pathogenesis of colorectal cancer from polyps?

Answer 32

Normal epithelium - > small adenoma (polyp) - > large adenoma - > invasive adenocarcinoma

Question 33

What is the typical presentation of colorectal cancer?

Answer 33

Persistent rectal bleeding Altered bowel opening (particularly diarrhoea) Iron deficiency anaemia Palpable rectal or lower right abdominal mass Acute colon obstruction (if stenosing tumour) Systemic symptoms

Question 34

What are the sites of colorectal cancers?

Answer 34

``` Ascending colon Transverse colon Descending colon Rectum Anus ```

Question 35

What is the most common histological type of colorectal carcinoma?

Answer 35

Adenocarcinoma

Question 36

What are the risk factors for developing colorectal carcinoma?

Answer 36

Lifestyle factors Family history IBD Genetics

Question 37

What is the typical presentation of right sided colorectal carcinoma?

Answer 37

Anaemia Vague pain Weakness Obstruction

Question 38

What is the typical presentation of left sided colorectal carcinoma?

Answer 38

Bleeding Altered bowel habit Obstruction

Question 39

What investigations would be done to diagnose colorectal cancer?

Answer 39

Colonoscopy Barium enema CT colongraphy CT abdomen/pelvis

Question 40

What is the benefit of a colonoscopy?

Answer 40

Any polyps found can be removed and biopsies can be taken

Question 41

What staging investigations would be doe after a diagnosis of colorectal cancer had been reached?

Answer 41

CT chest, abdomen and pelvis MRI scan for rectal tumours PET/rectal endoscopic ultrasound in selected cases

Question 42

What are the treatment options for colorectal cancer?

Answer 42

Surgery - endoscopic if caught early enough Stoma formation may be required Removal of lymph nodes for histological analysis Partial hepatectomy Chemotherapy Radiotherapy