Crohn's Disease

Question 1

Location

Answer 1

Mouth to Anus but inflammation is not continuous - skips areas

Rectal involvement not as common as UC

Perianal disease is common

Question 2

Epidemiology

Answer 2

Two peaks in incidence
1st - 15-30 years
2nd - >60 years

Question 3

Where is the inflammation?

Answer 3

Transmural - all layers

Mucosa is dominated by th1 cells which produce IFN-gamma and IL-2

Question 4

Presentation

Answer 4

If in upper GI:
Nausea, vomiting 
Dyspepsia 
Small bowel Obstruction 
Anorexia, Weight loss 
Loose stools 

Colonic disease:
Diarrhoea
Passage of obvious blood - heamatochezia - less common than with UC

Question 5

Why would Crohn’s Disease present with anaemia

Answer 5

Involvement of terminal ileum -> anaemia due to poor vit B12 absorption (vit b12 needed to make RBCs)

Question 6

What can genetically predispose you to Crohn’s?

Answer 6

risk allele (HETEROZYGOUS confers 2-4 fold risk, two heterozygous parents confers 20-40 fold risk), IBD1, NOD2, CARDI5

Question 7

What environmental factors contribute to development of Crohn’s?

Answer 7

NSAIDs (IBD generally due to alteration to intestinal barriers)
Smoking

Question 8

Microscopic changes (4)

Answer 8

1. Transmural inflammation through all layers of the intestinal wall
2. Increase in number of chronic inflammatory cells
3. Lymphoid hyperplasia
4. Granulomas are common - due to TH1 response

Question 9

Macroscopic changes (3)

Answer 9

1. Thickened and narrowed bowel
2. cobblestone appearance - deep ulcers and fissures in mucosa
3. penetrating disease -> fistulae (common) and abscesses

Question 10

Serological abnormality

Answer 10

ASCA

Question 11

Investigation

Answer 11

1. Colonoscopy - cobblestone
2. Upper GI endoscopy - exlcudes oesophageal and gastroduodenal disease in patients with relevant symptoms
3. Small bowel imaging (shows string sign of Kantur)- MANDATORY IN SUSPECTED CROHN’S - barium follow through, USS, MRI - asymmetrical alteration in the mucosal pattern with deep ulceration and areas of narrowing
4. capsule endoscopy - to follow up abnormal X-ray

Question 12

Management - inducing remission

Answer 12

Oral or IV glucocorticosteroids
Enteral nutrition
Infliximab

Question 13

Management - maintenance of remission

Answer 13

Methotrexate
Azathioprine - immunosuppressive drug
Infliximab

Question 14

Management - perianal disease

Answer 14

Ciprofloxacin (quinolone - X DNA gyrase)
Metronidazole
Azathioprine - immunosuppressive drug
Infliximab

Question 15

Management - surgery - how does this differ from UC?

Answer 15

Colectomy and ileorectal anastomosis may be performed.

UC- colectomy and end-ileostomy

Question 16

In which patients which you choose surgery as a means of management?

Answer 16

1. Failure to treat acute or chronic symptoms
2. Complications - dilation, obstruction, perforation, abscesses
3. Children with Crohn’s who fail to grow despite treatment

Question 17

Cancer risk

Answer 17

Small bowel cancer
Colorectal cancer

Location dependent