COLORECTAL

Question 1

Give 2 genetic mutation types that are known to predispose to CRC, including their inheritance pattern:

Answer 1

Both AD

HNPCC (Lynch syndrome) - MSH2 and MLH1 are MMR genes with mutations causing defects in DNA repair

APC is a tumour suppressor gene = FAP syndrome. 100% with get CRC

Question 2

75% of CRC is sporadic, developing in people with no specific risk factors. However, some risk factors are recognised. Give some:

Answer 2

IBD
Low fibre, high processed meat diet
Increased age
Male
FHx
Smoking
Alcohol

Question 3

Amsterdam criteria for diagnosing Lynch syndrome:

Answer 3

3 or more family members with colon cancer

Cases spanning at least 2 generations

At least one member dx before 50

Question 4

Give a variant of FAP that has extra-colonic features:

Answer 4

Gardner syndrome - also osteosarcoma of the skull and mandible, retinal pigmentation,, thyroid carcinoma and epidermoid cysts

Question 5

Which operation do most patients with FAP undergo in their twenties?

Answer 5

Total proctocolectomy and ileo-anal ouch anastomosis

Question 6

What does the FIT test look for specifically?

Answer 6

Human haemoglobin in stool

Question 7

How often is bowel cancer screening offered?

Answer 7

Every 2 years

Question 8

FIT testing should be used to guide referral for suspected CRC in adults, with >10 indicating referral. Who should be considered for a FIT test and referral?

Answer 8

Abdominal mass
Change in bowel habit
>40 with weight loss + abdominal pain
<50 with rectal bleeding + [abdo pain OR weight loss]
>50 with rectal bleeding OR weight los s/ abdo pain
>60 with anaemia even without iron deficiency

Question 9

Which tumour marker should NOT be used for diagnosis of CRC but can monitor disease progression ?

Answer 9

CEA

An elevated CEA at abseline may indicate a worse prognosis

Question 10

Gold standard for diagnosis of CRC:

Answer 10

Colonoscopy with biopsy

?sigmoidoscopy if only rectal bleeding symptom?

Question 11

3 further imaging techniques for staging a CRC, and when they might be indicated:

Answer 11

CT CAP for distal mets and local invasion

MRI rectum for rectal cancer only , depth and need for pre-op chemo

Endoanal US for early rectal cancers

Question 12

CRC is mostly staged using TNM but Duke’s is still sometimes used. Describe it:

Answer 12

1 confined to mucosa and muscle

2 extends through muscle of bowel wall

3 lymph node involvement

4 metastatic

Question 13

What is removed in a right hemicolectomy?

Answer 13

caecum, ascending and prox transverse

Question 14

What is removed in a left hemicolectomy?

Answer 14

diatl transverse + desc

Question 15

What is removed in a high anterior resection?

Answer 15

sigmoid

Question 16

What is removed in a low anterior resection?

Answer 16

sigmoid + upper rectum

Question 17

What is removed in an abdomino-perineal resection?

Answer 17

Rectum + anus, sutures over anus.

Question 18

What is removed in a Hartmann’s procedure?

Answer 18

Rectosigmoid colon + colostomy formation

Most commonly done in emergency setting of sigmoid perforaton or sigmoid malignancy causing obstruction.

Question 19

What does low anterior resection syndrome refer to?

Answer 19

Urgency and frequency of bowel movements, faecal incontinence, flatulence, due to removal of part of the rectum

Question 20

Mechanical bowel obstruction pathophysiology/ features:

Answer 20

Gross dilation of bowel proximal to the blockage, increased peristalsis of the bowel, secretions of large volumes of fluid with lots of electrolytes, causing third spacing.

Urgent fluid resus is needed.

Abdo pain, vomiting, distension, constipation, cramp due to peristalsis.

Question 21

DDx for patients presenting with a bowel obstruction:

Answer 21

Paralytic ileus
Pseudoobstruction (adynamic bowel due to disruption of autonomic nervous system)
Toxic megacolon
Constipation

Question 22

Investigations inc labs and imaging for bowel obstruction:

Answer 22

FBC, UEs, Renal fucniton closely due ot dehydration rik, Gand Save,

VBG for lactate and metabolic derangment

CT Contrast AP, will also allow underlying cause but AXR would not

AXR
Small dilated >3cm, central valvulae conniventes
Large = >6 or >9 if caecum, haustra

Question 23

AXR findings in small vs large bowel obstruction:

Answer 23

AXR
Small dilated >3cm, central valvulae conniventes
Large = >6 or >9 if caecum, haustra

Question 24

A patient has been treated conservatively for a bowel obstruction with NG insertion, fluid therapy, catheterisation and analgesia. What further study can you do if it is not resolving / you’re not sure?

Answer 24

Contrast study / XR
If contrast goes past blockage = good sign

Gastrograffin dye?

Question 25

When is surgical management for bowel obstruction indicated?

Answer 25

>48 hours no improvement Ischaemia or closed loop bowel obstruction Cause requiring surgical correction e.g. strangulated hernia, obstructing tumour

Question 26

Causes of small vs large bowel obstruction:

Answer 26

Small = adhesions and hernias Large = malignancy, diverticular disease, volvulus

Question 27

4 anal glands are located in the intersphincteric space; name these 4 glands, which have the potential to cause anorectal abscesses:

Answer 27

Perianal Ischiorectal Intersphincteric Supralevator

Question 28

Patients with an anorectal abscess without any known risk factors such as fistula-in-ano or other rectal pathology should have what test done?

Answer 28

HbA1c for DM

Question 29

3 common causative organisms in ano-rectal abscess:

Answer 29

E.coli Enterococcus Bacterioides

Question 30

What is the cancer risk % in FAP?

Answer 30

100%

Question 31

Common presenting complaint in Peutz-Jeghers syndrome:

Answer 31

SBO due to intussusception - hamartomatous polyps in the GI tract + pigmented lesions on lips, face, palms, soles

Question 32

Mechanism of orlistat, including NICE criteria:

Answer 32

Pancreatic lipase inhibitor For obesity >BMI28 + risk factors >=30

Question 33

Mechanism of liraglutide, including NICE criteria

Answer 33

GLP-1 analogue Prediabetic hyperglcaemia 42-47 BMI >=35

Question 34

Positions of normal haemorrhoidal cushions:

Answer 34

3 oclock 7 oclock 11 oclock

Question 35

4 symptoms of haemorrhoids:

Answer 35

Painless rectal bleeding Pruritis ?pain if thrombosed Soiling Incomplete emptying dragging sensation

Question 36

A haemorrhoid can be manually reduced. What grade is it?

Answer 36

III

Question 37

A haemorrhoid prolapses on defecation but reduces spontaneously. What grade is it?

Answer 37

II

Question 38

First line managements of haemorrhoids:

Answer 38

increase dietary fibre and fluid intake topical local anaesthetics and steroids may help symptoms

Question 39

What window of time do patients need to present in for referral to be considered for surgical excision of an acutely thrombosed external haemorrhoid?

Answer 39

72 hours

Question 40

Which line indicates whether a haemorrhoid is internal or external?

Answer 40

dentate / pectinate