Benign colorectal

Question 1

Define colonic diverticula

Answer 1

Acquired lesions associated with ageing
They are false diverticula
They are partial-thickness herniations of the mucosa and muscularis mucosa of the colon, at the point where the vasa recta enter the colonic wall

Some congenital colonic diverticula are true (ie outpouchings of all walls of the colon), most often found on the right side of the colon

Question 2

Aetiology of colonic diverticula

Answer 2

Unknown aetiology, many theories
Positive association between diverticula and smoking, obesity and NSAID use
Genetics
The dietary fibre hypothesis of Burkitt and Painter has little contemporary evidence to support it

Question 3

Modified Hinchey classification of diverticulitis

Name another classification

Answer 3

0: mild clinical diverticulitis
Ia: colonic wall thickening/confined pericolic inflammation
Ib: confined small pericolic abscess (<5cm)
II: pelvic, distant abdominal or retroperitoneal abscess
III: purulent peritonitis
IV: faeculent peritonitis

Question 4

% risk of subsequent diverticulitis after first attack
What makes risk higher
Risk of resection at each attack
What other factors increase risk of resection?

Answer 4

30-36% risk of any subsequent diverticulitis after first attack
Risk higher in long segment or family history
20% risk of resection at initial attack
5.5% risk of resection on subsequent attacks
Resection risk higher in renal disease, collagen vascular disease, immunosuppression

Question 5

Scoring system to evaluate risk of emergency surgery in severe divertculitis (4)

Answer 5

Abscess >4cm (2)
Pericolic free air (2)
Pericolic abscess (5)
Distant free air (7)

0-4: <25% risk of surgery
5-9: 50% risk of surgery
>9: >50% risk of surgery

Question 6

Goal of treatment of complicated diverticulitis

Answer 6

Optimise patient condition to avoid urgent or emergent procedure requiring faecal diversion, and convert to an elective, one-stage procedure with primary anastomosis

Question 7

PSC and UC together increases risk of

Answer 7

colonic neoplasia (5x)
33% risk of cancer at 20y and 40% risk of cancer at 30y following diagnosis of UC if PSC present

Question 8

Which extra-intestinal manifestations of UC do and don’t improve after colectomy?

Answer 8

Improve: peripheral arthropathy, erythema nodosum, iritis, episcleritis
Do not improve: axial arthropathy, PSC, uveitis

Question 9

What increases risk of pouchitis following restorative proctocolectomy for UC?

Answer 9

PSC (46 vs 79% 10y risk of pouchitis)

Question 10

Which opthalmological extra-intestinal manifestation of UC is urgent?

Answer 10

Uveitis (central redness, dissipates radially; does not coincide with UC flare)

Question 11

Define toxic megacolon

Answer 11

Partial or total colonic distension in the absence of obstruction that occurs in the presence of systemic toxicity

Question 12

Toxic megacolon diagnosis criteria

Answer 12

Definition: acute segmental or total colonic dilatation >6cm in the presence of systemic toxicity

Diagnosis:
- colon >6cm
plus at least 3 of
- fever
- tachycardia
- leucocytosis
- anaemia
plus at least one of
- dehydration
- reduced GCS
- electrolyte disturbance
- hypotension

Question 13

Endoscopic changes of UC (7)

Answer 13

erythema
friability
erosions
pseudopolyps
granular mucosa
ulcers
cobblestoning
no skip lesions, no granulomas

Question 14

Changes of UC seen on biopsy

Answer 14

Crypt atrophy
Crypt branching, shortening and disarray
Crypt abscesses

Question 15

Trulove and Witt score for UC (6)

Drawbacks

Answer 15

Stool frequency, number of bloody stool, anaemia, pulse, ESR, sigmoidoscopy findings
Interuser variability, no definition of ‘improving’

Question 16

Mayo score for severity of UC

Answer 16

Stool frequency, number of bloody bm, sigmoidoscopy findings, physician’s global assessment of severity
4-12, 11-12 = severe

Use for monitoring response to therapy

Question 17

Risk of colon cancer with UC

Answer 17

2% at 10y
8% at 20y
18% at 30y

Starting 10y following diagnosis, increase of CRC increases by 1% each year the patient has their colon

Question 18

Flat low-grade dysplasia in UC

Answer 18

9x increased risk of colorectal cancer
Can progress directly to cancer
Is as likely as HGD to be associated with an already established cancer
55% chance of progression to cancer at 5y
Proctocolectomy recommended

Question 19

Flat high-grade dysplasia in UC

Answer 19

45% rate of associated colorectal cancer

Proctocolectomy mandatory even if completely excised or found on random biopsies

Question 20

Surveillance in UC

Answer 20

colonoscopy every 1-2 years starting 8-10 years after diagnosis
Use chromendoscopy (methylene blue, indigo carmine) as well as white light

Question 21

Crohn’s disease: definition

Answer 21

A chronic relapsing-remitting transmural inflammatory disease that can affect anywhere in the gastrointestinal tract from mouth to anus, and which may be associated with extra-intestinal manifestations

Question 22

Aetiology of Crohn’s

Answer 22

Genetic predisposition to abnormal interaction between immune system and environmental factors
Linked to host-microbe pathways of recognition and clearance, and formation of mucosal barrier

The specific cause of the exaggerated inflammatory response at mucosal level is unclear

Question 23

Risk factors for Crohn’s

Answer 23

Smoking (x2)
Familial (2-22% patients have FDR with IBD)
NOD2 gene: early onset disease, ileal disease, increased ileocolic resections

Relatives of patients with Crohns have increased risk of UC

Question 24

Distribution of Crohn’s disease (5)

Answer 24

Small bowel alone: 30-35%
Colon alone: 25-35%
Small bowel and colon: 30-50%
Perianal: >50%
Stomach and duodenum: 5%
- subclinical mucosal abnormalities in 50%

Question 25

Hallmarks of Crohns (histology) (3)

Answer 25

Deep non-caseating granulomas (bowel wall, mesentery, nodes, liver, peritoneum)
Granulomatous vasculitis
Intralymphatic granulomas

Question 26

Differentiating Crohn’s from UC

Answer 26

Use cumulative clinical picture, endoscopic, histological and radiographic features

Rectal sparing: Crohn’s unless pt using enemas
Lymphoid aggregates at base of mucosa: Crohn’s
Mucin depletion: UC
Perianal disease: Crohn’s (UC can have cryptoglandular disease)

Question 27

Medical treatment for Crohn’s disease

Answer 27

Mild-moderate:
Oral prednisone
Budesonide for right sided disease
Oral and PR salicylates for colitis
Metronidazole or ciprofloxacin for perianal disease

Severe: IV steroids or biologics

Maintenance: azathioprine, 6-mercaptopurine, budesonide, methotrexate, infliximab, adalimumab

Question 28

Factors for normal anal continence (3)

Answer 28

A reservoir
An anorectal junction that opens and closes at will
A closed anal canal at rest

Question 29

Pathogenesis of Crohn’s disease

Answer 29

A chronic transmural inflammatory disease affecting anywhere in the GI tract

Results from a genetic predisposition between host immune system and environmental factors

Abnormal responses to microbes within the gut microbiome
Increased mucosal permeability

Both lead to T-cell mediated immune response and release of IL-1, IL-6 and TNFa

Question 30

What do you know about pouchitis?

Answer 30

Aetiology unknown, thought to be secondary to bacterial overgrowth or mucosal ischaemia
50% at 5y, 5% unremitting
Sx: increased stool frequency, fever, bleeding, cramps, dehydration
Rx: rehydration, metronidazole, ciprofloxacin
Significant recurrent pouchitis? Consider Crohn’s