Crohn's Disease Flashcards
What is Crohn’s disease?
Chronic transmural granulomatous inflammatory disease that can affect any part of the GI tract
Give 3 epidemiological facts about Crohn’s
Affects any age but peaks in 15-30
Prevalence increasing
M:F
Describe the aetiology of Crohn’s
UNKNOWN
FH increases risk of IBD
Smoking increases risk
Which area of the GI tract is most commonly affected in Crohn’s?
80% have small bowel involvement (usually in ileum)
List 3 symptoms of Crohn’s
Diarrhoea: unexplained + persistent. May be bloody or steatorrhoea
Crampy abdominal pain
Non specific Sx: Fatigue, fever, malaise + WL
List 7 signs of Crohn’s on examination
Pallor, clubbing, apthous mouth ulcers
Abdominal tenderness/ mass
Perianal skin tags, fistulae + abscesses
Signs of malnutrition: serial WL/ faltering growth
Extra-intestinal manifestations
What is the most common presenting complaint in adults and children with Crohn’s?
Adults: Diarrhoea
Children: Abdo pain
Where is the most commonly affected area in Crohn’s?
Terminal ileum
List 6 extra intestinal features of Crohn’s
Erythema nodosum, pyoderma gangrenosum
Clubbing
Enteropathic arthritis
Uveitis, Episcleritis
Gallstones
Kidney stones
Describe bloods taken/ results for Crohn’s
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
Why is a stool sample used in suspected Crohn’s?
Microscopy + culture
To exclude infective gastroenteritis/ pseudomembranous colitis
Which investigation differentiates IBD from IBS?
Faecal calprotectin
If raised, suggests active inflammation in IBD
(normal in IBS)
What imaging can be performed in Crohn’s and why?
CT enterography or MR enterography: localises disease, identifies fistulae + abscesses
What is the investigation of choice in Crohn’s? Name 3 hallmark features
Colonoscopy
Skip lesions
Deep mucosal ulcers (rose thorn)
Cobblestone appearance
What may show on a small bowel enema in Crohn’s?
Strictures (string sign of Kantor - part of intestine looks like a piece of string= incomplete filling of intestinal lumen)
Proximal bowel dilation
Fistulae
What may be seen on histology in Crohn’s?
Inflammation in all layers from mucosa to serosa
Goblet cells
Non- Caseating Granulomas with epithelioid giant cells
Creeping fat
What general advice is given to patients with Crohn’s?
Smoking cessation
Describe induction of remission in acute Crohn’s
Glucocorticoids (first line): Prednisolone PO, IV Methylprednisolone
5-ASA drugs (second line): Mesalazine
Which steroid is used preferentially in limited terminal ileal/ ascending colonic CD?
Budesonide PO
List 3 immunomodulators that can be used as add on therapy to induce remission of Crohn’s
Azathioprine
Mercaptourine
Methotrexate
When are immunomodulators added to glucocorticoids to induce remission of Crohn’s?
If >,2 inflammatory exacerbations in a 12-month period
OR
if steroid dose can’t be tapered as planned
Why should immunomodulators not be used as monotherapy to induce remission in Crohn’s?
Onset of clinical effect is too slow.
What can be used to induce remission of isolated peri-anal crohns?
Metronidazole
Which drug can be used in refractory/ fistulating Crohn’s ?
Infliximab (+ typically continue on Azathioprine or Methotrexate)
Describe maintenance therapy for Crohn’s disease
Azathioprine or Mercaptopurine
(Methotrexate second line)
What must be assessed prior to offering azathioprine or mercaptopurine?
Thiopurine methyltransferase (TPMT) activity
Describe pharmacological therapy in Crohn’s
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
What drugs can be used in supportive management of Crohn’s?
Anti-motility: Loperamide
Anti-spasmodics: Mebeverine
Bulk-forming laxatives: Ispaghula husk
List 3 indications for surgical management of Crohn’s
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
List 3 procedures that may be performed in management of Crohn’s
Surgical drainage of abscess
Laparoscopic/ open resection of the diseased bowel segment (small bowel resection, segmental colectomy)
Stricturoplasty (bowel-sparing technique)
List 6 GI complications of Crohn’s
Perianal fistulae + abscesses
Small bowel cancer
Colorectal cancer
Strictures
Perforation + peritotnitis
Short bowel syndrome
What is the investigation of choice for perianal fistula?
MRI: determines if there is an abscess + if the fistula is simple (low) or complex (high- passes through/ above muscle layers)
Describe management of perianal fistulae
Metronidazole PO
+/- Infliximab (aids in closure + maintaining closure)
If complex: Draining seton
What is a seton?
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.
What is the prognosis in Crohn’s?
Chronic relapsing condition
2/3 require surgery at some stage
2/3 of these patients require > 1 operation
What bowel pathogen must be excluded from differentials when suspecting crohns?
Yersinia enterocolitica
List 4 systemic complications of Crohn’s
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
