Crohn's Disease

Question 1

Define Crohn’s Disease?

Answer 1

Chronic granulomatous inflammatory disease that can affect any part of the GI tract
Grouped with UC and known together, as inflammatory bowel disease

Question 2

What is the aetiology of Crohn’s Disease?

Answer 2

Cause unknown but thought to be due to interplay between genetic and environmental factors
Though inflammation can occur anywhere from mouth to anus, 40% involves the terminal ileum

Question 3

What is the epidemiology of Crohn’s Disease?

Answer 3

UK annual incidence: 5-8/100,000
UK prevalence: 50-80/100,000
Affects any age but peaks in teens, 20s and 40s

Question 4

What are the presenting symptoms of Crohn’s Disease?

Answer 4

Crampy abdominal pain
Diarrhoea (may be bloody or steatorrhoea)
Fever, Malaise, weight loss
Symptoms of complications 
Right Iliac Fossa Pain sometimes

Question 5

Why is there crampy abdominal pain in Crohn’s Disease?

Answer 5

Due to inflammation, fibrosis or bowel obstruction

Question 6

Why is there sometimes right iliac fossa pain?

Answer 6

Due to inflammation of terminal ileum

Question 7

What are the signs of Crohn’s Disease on physical examination?

Answer 7

Weight Loss
Clubbing
Signs of Anaemia
Aphthous ulcers in mouth
Perianal skin tags, fistulae and abscesses
Uveitis, erythema nodusum, pyoderma gangrenosum

Question 8

What bloods do we do for Crohn’s Disease?

Answer 8

FBC
U&Es
LFTs
High ESR
CRP may be high or normal

Question 9

What do we look for specifically in the FBC for Crohn’s Disease?

Answer 9

Low Hb, high platelets, high WCC

Question 10

What do we look for specifically in the LFTs for Crohn’s Disease?

Answer 10

Low albumin

Question 11

Why do we do stool microscopy and culture for Crohn’s Disease?

Answer 11

Exclude Infective Colitis

Question 12

What might we see on an AXR for Crohn’s Disease?

Answer 12

Could show evidence of toxic megacolon

Question 13

When do we do an Erect CXR for Crohn’s Disease?

Answer 13

If there is a risk of perforation

Question 14

What might we see on a Small bowel barium follow-through for Crohn’s Disease?

Answer 14

Fibrosis/strictures (string sign of Kantor)
Deep ulceration (rose thorn ulcers)
Cobblestone mucosa

Question 15

What is the String sign of Kantor?

Answer 15

Part of the intestine looks like a piece of string, showing incomplete filling of the intestinal lumen

Question 16

What is the use of Endoscopy (OGD, colonoscopy) and biopsy in Crohn’s Disease?

Answer 16

Could help differentiate UC and CD

Useful for monitoring malignancy and disease progression

Question 17

What might you see on an Endoscopy (OGD, colonoscopy) and biopsy for Crohn’s Disease?

Answer 17

Can show mucosal oedema and ulceration with ‘rose thorn fissures’ (occurs when there is a cobblestone mucosa)
Fistulae and abscesses
Transmural chronic inflammation with infiltration of macrophages, lymphocytes and plasma cells
Granulomas with epithelioid giant cells may be seen in blood vessels

Question 18

How can we use a Radionucide-labelled neutrophil scan for Crohn’s Disease?

Answer 18

Can localise the inflammation (when other investigations are contraindicated)

Question 19

What is the management plan for an Acute Exacerbation of Crohn’s Disease?

Answer 19

Fluid Resuscitation
IV/oral corticosteroids
5-ASA analogues (e.g. mesalazine and olsalazine)
Analgesia
Parenteral nutrition may be necessary
Monitor markers of disease activity (e.g. fluid balance, ESR, CRP, platelets, Hb)

Question 20

What is the long-term management plan for Crohn’s Disease?

Answer 20

Steroids
5-ASA analogues
Immunosuppression
Anti-TNF agents (e.g. infliximab and adalimumab)

Question 21

Why do we use Steroids for Crohn’s Disease?

Answer 21

For acute exacerbations

Question 22

How do 5-ASA analogues work for Crohn’s Disease?

Answer 22

Decreases the frequency of relapses (useful for mild to moderate disease)
More commonly used in UC however

Question 23

What is the immunosuppression drugs used for Crohn’s Disease?

Answer 23

Using steroid-sparing agents (e.g. azathioprine, 6-mercaptopurine, methotrexate) reduces the frequency of relapses

Question 24

How can we use Anti-TNF agents for Crohn’s Disease?

Answer 24

Very effective at inducing and maintaining remission

Usually reserved for refractory Crohn’s

Question 25

What is the general advice for patients with Crohn’s Disease?

Answer 25

Stop smoking 
Dietician referral (low fibre diet necessary if there are stricture present)

Question 26

When is surgery indicated in Crohn’s Disease?

Answer 26

If:
Medical treatment fails
Failure to thrive in children in the presence of complications
Involves resection of affected bowel and stoma formation (there is a risk of disease recurrence)

Question 27

What are the possible GI complications of Crohn’s Disease?

Answer 27

Haemorrhage 
Strictures 
Perforation
Fistulae (between bowel, bladder, vagina)
Perianal fistulae and abscesses 
GI cancer 
Malabsorption

Question 28

What are the extraintestinal features of Crohn’s Disease?

Answer 28

Uveitis 
Episcleritis 
Gallstones 
Kidney Stones 
Arthropathy
Sacroilitis 
Ankylosing Spondylitis 
Erythema nodosum
Pyoderma gangrenosum
Amyloidosis

Question 29

What is the prognosis for patients with Crohn’s Disease?

Answer 29

It is a chronic relapsing condition
2/3 of patients will require surgery at some stage
2/3 of these patients require more than 1 operation