Crohn's Disease Flashcards
Definition
Chronic granulomatous inflammatory disease that can affect any part of the gastrointestinal tract. Grouped with ulcerative colitis and known, together, as inflammatory bowel disease.
Aetiology/Risk factors
· 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
Epidemiology
· UK annual incidence: 5-8/100,000
· UK prevalence: 50-80/100,000
· Affects any age but peaks in teens, 20s and 40s
Presenting symptoms
· Crampy abdominal pain (due to inflammation, fibrosis or bowel obstruction)
· Diarrhoea (may be bloody or steatorrhoea)
· Fever, malaise, weight loss
· Symptoms of complications
· Sometimes right iliac fossa pain due to inflammation of terminal ileum
Signs on physical examination
· Weight loss
· Clubbing
· Signs of anaemia
· Aphthous ulcers in mouth
· Perianal skin tags, fistulae and abscesses
· Uveitis, erythema nodosum, pyoderma gangrenosum
Investigations (bloods)
o FBC - low Hb, high platelets, high WCC o U&Es o LFTs - low albumin o High ESR (suggests chronic inflammation) o CRP may be high or normal
Investigations (endoscopy)
· Endoscopy (OGD, colonoscopy) and biopsy may show:
o Could help differentiate UC and CD
o Useful for monitoring malignancy and disease progression
o Can show mucosal oedema and ulceration with ‘rose thorn fissures’ (occurs when there is a cobblestone mucosa)
o Fistulae and abscesses
o Transmural chronic inflammation with infiltration of macrophages, lymphocytes and plasma cells
o Granulomas with epithelioid giant cells may be seen in blood vessels and lymphatics
Investigations (other)
· Stool microscopy and culture: exclude infective colitis
· AXR: could show evidence of toxic megacolon
· Erect CXR: if there is a risk of perforation
· Small bowel barium follow-through could show:
o Fibrosis/strictures (string sign of Kantor - part of the intestine looks like a piece of string, showing incomplete filling of the intestinal lumen)
o Deep ulceration (rose thorn ulcers)
o Cobblestone mucosa
· Radionucide-labelled neutrophil scan: can localise the inflammation (when other investigations are contraindicated)
Management plan (acute)
Acute Exacerbation
o Fluid resuscitation
o IV/oral corticosteroids
o 5-ASA analogues (e.g. mesalazine and olsalazine)
o Analgesia
o Parenteral nutrition may be necessary
o Monitor markers of disease activity e.g. fluid balance, ESR, CRP, platelets, Hb
Management plan (chronic)
Long-Term
o Steroids - for acute exacerbations
o 5-ASA analogues - decreases the frequency of relapses (useful for mild to moderate disease)
· NOTE: more commonly used in UC
o Immunosuppression: using steroid-sparing agents (e.g. azathioprine, 6-mercaptopurine, methotrexate) reduces the frequency of relapses
o Anti-TNF agents: (e.g. infliximab and adalimumab) - very effective at inducing and maintaining remission. Usually reserved for refractory Crohn’s.
Management plan (advice)
General Advice:
o Stop smoking
o Dietician referral (low fibre diet necessary if there are stricture present)
Management plan (surgery)
Surgery indicated it:
o Medical treatment fails
o Failure to thrive in children in the presence of complications
o Involves resection of affected bowel and stoma formation - NOTE: there is a risk of disease recurrence
Possible complications (GI)
o Haemorrhage o Strictures o Perforation o Fistulae (between bowel, bladder, vagina) o Perianal fistulae and abscesses o GI cancer o Malabsorption
Possible complications (extra-intestinal features)
o Uveitis o Episcleritis o Gallstones o Kidney stones o Arthropathy o Sacroiliitis o Ankylosing spondylitis o Erythema nodosum o Pyoderma gangrenosum o Amyloidosis
Prognosis
· 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
