Crohn's Disease

Question 1

What is Crohn’s disease?

Answer 1

Chronic transmural granulomatous inflammatory disease that can affect any part of the GI tract

Question 2

Give 3 epidemiological facts about Crohn’s

Answer 2

Affects any age but peaks in 15-30
Prevalence increasing
M:F

Question 3

Describe the aetiology of Crohn’s

Answer 3

UNKNOWN
FH increases risk of IBD
Smoking increases risk

Question 4

Which area of the GI tract is most commonly affected in Crohn’s?

Answer 4

80% have small bowel involvement (usually in ileum)

Question 5

List 3 symptoms of Crohn’s

Answer 5

Diarrhoea: unexplained + persistent. May be bloody or steatorrhoea
Crampy abdominal pain
Non specific Sx: Fatigue, fever, malaise + WL

Question 6

List 7 signs of Crohn’s on examination

Answer 6

Pallor, clubbing, apthous mouth ulcers
Abdominal tenderness/ mass
Perianal skin tags, fistulae + abscesses
Signs of malnutrition: serial WL/ faltering growth
Extra-intestinal manifestations

Question 7

What is the most common presenting complaint in adults and children with Crohn’s?

Answer 7

Adults: Diarrhoea
Children: Abdo pain

Question 8

Where is the most commonly affected area in Crohn’s?

Answer 8

Terminal ileum

Question 9

List 6 extra intestinal features of Crohn’s

Answer 9

Erythema nodosum, pyoderma gangrenosum
Clubbing
Enteropathic arthritis
Uveitis, Episcleritis
Gallstones
Kidney stones

Question 10

Describe bloods taken/ results for Crohn’s

Answer 10

FBC: low Hb, high platelets
U+Es: ?dehydration
LFTs: low albumin
High ESR: chronic inflammation
CRP: correlates with disease activity
Ferritin, B12, Folate + Vit D: ?deficiency

Question 11

Why is a stool sample used in suspected Crohn’s?

Answer 11

Microscopy + culture
To exclude infective gastroenteritis/ pseudomembranous colitis

Question 12

Which investigation differentiates IBD from IBS?

Answer 12

Faecal calprotectin
If raised, suggests active inflammation in IBD
(normal in IBS)

Question 13

What imaging can be performed in Crohn’s and why?

Answer 13

CT enterography or MR enterography: localises disease, identifies fistulae + abscesses

Question 14

What is the investigation of choice in Crohn’s? Name 3 hallmark features

Answer 14

Colonoscopy
Skip lesions
Deep mucosal ulcers (rose thorn)
Cobblestone appearance

Question 15

What may show on a small bowel enema in Crohn’s?

Answer 15

Strictures (string sign of Kantor - part of intestine looks like a piece of string= incomplete filling of intestinal lumen)
Proximal bowel dilation
Fistulae

Question 16

What may be seen on histology in Crohn’s?

Answer 16

Inflammation in all layers from mucosa to serosa
Goblet cells
Non- Caseating Granulomas with epithelioid giant cells
Creeping fat

Question 17

What general advice is given to patients with Crohn’s?

Answer 17

Smoking cessation

Question 18

Describe induction of remission in acute Crohn’s

Answer 18

Glucocorticoids (first line): Prednisolone PO, IV Methylprednisolone
5-ASA drugs (second line): Mesalazine

Question 19

Which steroid is used preferentially in limited terminal ileal/ ascending colonic CD?

Answer 19

Budesonide PO

Question 20

List 3 immunomodulators that can be used as add on therapy to induce remission of Crohn’s

Answer 20

Azathioprine
Mercaptourine
Methotrexate

Question 21

When are immunomodulators added to glucocorticoids to induce remission of Crohn’s?

Answer 21

If >,2 inflammatory exacerbations in a 12-month period
OR
if steroid dose can’t be tapered as planned

Question 22

Why should immunomodulators not be used as monotherapy to induce remission in Crohn’s?

Answer 22

Onset of clinical effect is too slow.

Question 23

What can be used to induce remission of isolated peri-anal crohns?

Answer 23

Metronidazole

Question 24

Which drug can be used in refractory/ fistulating Crohn’s ?

Answer 24

Infliximab (+ typically continue on Azathioprine or Methotrexate)

Question 25

Describe maintenance therapy for Crohn's disease

Answer 25

Azathioprine or Mercaptopurine (Methotrexate second line)

Question 26

What must be assessed prior to offering azathioprine or mercaptopurine?

Answer 26

Thiopurine methyltransferase (TPMT) activity

Question 27

Describe pharmacological therapy in Crohn's

Answer 27

CS can be used to induce remission but should be discontinued once the acute flare has been managed. Immunomodulators + biologics are the mainstays of maintenance therapy but can ALSO be used to induce remission

Question 28

What drugs can be used in supportive management of Crohn's?

Answer 28

Anti-motility: Loperamide Anti-spasmodics: Mebeverine Bulk-forming laxatives: Ispaghula husk

Question 29

List 3 indications for surgical management of Crohn's

Answer 29

Severe complications (e.g., bowel obstruction, intra-abdominal abscess, perianal abscess) Unsuccessful medical therapy Sx control in disease localised to a short segment of bowel

Question 30

List 3 procedures that may be performed in management of Crohn's

Answer 30

Surgical drainage of abscess Laparoscopic/ open resection of the diseased bowel segment (small bowel resection, segmental colectomy) Stricturoplasty (bowel-sparing technique)

Question 31

List 6 GI complications of Crohn's

Answer 31

Perianal fistulae + abscesses Small bowel cancer Colorectal cancer Strictures Perforation + peritotnitis Short bowel syndrome

Question 32

What is the investigation of choice for perianal fistula?

Answer 32

MRI: determines if there is an abscess + if the fistula is simple (low) or complex (high- passes through/ above muscle layers)

Question 33

Describe management of perianal fistulae

Answer 33

Metronidazole PO +/- Infliximab (aids in closure + maintaining closure) If complex: Draining seton

Question 34

What is a seton?

Answer 34

A piece of surgical thread that is run through the fistula to allow continuous drainage while the fistula is healing. Useful because persisting fistula tracks after premature skin closure predispose to abscess formation This ensures the fistula doesn't heal containing pus within, which would result in further abscess formation.

Question 35

What is the prognosis in Crohn's?

Answer 35

Chronic relapsing condition 2/3 require surgery at some stage 2/3 of these patients require > 1 operation

Question 36

What bowel pathogen must be excluded from differentials when suspecting crohns?

Answer 36

Yersinia enterocolitica

Question 37

List 4 systemic complications of Crohn's

Answer 37

Failure to thrive in kids Iron Deficiency Anaemia Osteoporosis: malabsorption of calcium + vit D Amyloidosis: chronic inflammation leads to increased production of serum amyloid A