Inflammatory bowel disease / Irritable bowel disease Flashcards
What is the definition of Crohn’s disease?
a disease of unknown aetiology that is characterised by transmural inflammation of the GI tract and can affect any part from mouth to anus
Crohn’s disease is found as skip lesions
Which parts of the bowel are usually affected by Crohn’s disease?
- terminal ileum (close to the ileocaecal valve)
- peri-anal region
What is transmural inflammation?
inflammation that affects the whole thickness of the bowel wall
What does the inflammation associated with Crohn’s disease eventually lead to?
inflammation results in ulceration
as all layers of the GI tract are affected, the result is non-caseating granuloma formation
What are the risk factors for Crohn’s disease?
- family history
- smoking
- oral contraceptive pill
- diet high in refined sugars
- ? NSAIDs
- ? not being breast fed
it is a combination of genetic & environmental factors
What is the epidemiology of Crohn’s disease?
- seen in Ashkenazi Jews
- it has a bimodal peak seen in 15-40s and 60-80s
What is the typical presentation of Crohn’s disease?
abdominal pain:
* can be crampy or constant but is SEVERE
* affects the RLQ + peri umbilical region (terminal ileum)
diarrhoea:
* severe diarrhoea (10+ times daily) that can be nocturnal
* can contain mucus, pus or blood occasionally
peri anal lesions:
* skin tags, fistulae, abscesses
other symptoms include:
* weight loss (due to malnourishment)
* painful oral lesions
* fatigue
What are the 2 extra-intestinal skin lesions associated with Crohn’s disease?
pyoderma gangrenosum:
* small red/purple bumps or blisters that eventually erode into painful ulcers
* rapid progression
* affects the legs
erythema nodosum:
* swollen fat under the skin causes dark red patches on the shins
What are the other extra-intestinal manifestations associated with Crohn’s disease?
- arthropathy (joint pain)
- uveitis
- episcleritis
affects 20-40% patients
EI manifestations are more common when Crohn’s colitis / perianal disease are present
What is often a consequence of inflammation affecting all layers of the bowel wall down to the serosa?
patients with Crohn’s are more prone to strictures, fistulas and adhesions
What features may be seen on examination of a Crohn’s disease patient?
abdominal tenderness:
* this is usually in the right iliac region (lower right)
* there may be a mass if inflammation causes everything to “stick together”
oral examination:
* presence of painful apthous ulcers
peri-anal lesions:
* skin tags, fistulae, abscesses
Why is Crohn’s disease associated with malabsorption?
- decreased absorption of bile acids results in secretory diarrhoea
- depletion of the bile salt pool leads to malabsorption of fat, steatorrhoea + increased risk of gallstones
- malabsorption results in depletion of fat-soluble vitamins (A, D, E & K)
- severe ileal disease can result in vitamin B12 malabsorption
What blood tests are performed in a Crohn’s patient and what might they show?
- FBC / iron studies show anaemia of chronic disease
- raised inflammatory markers (CRP + ESR)
- low vitamin B12 and vitamin D
- faecal calprotectin may be raised
Inflammatory markers are NOT diagnostic but they can be used for monitoring disease progression
What might be seen on a plain AXR in Crohn’s disease?
bowel dilation
- small bowel - dilation > 3cm is abnormal
- large bowel - dilation > 6cm is abnormal
- caecum - dilation > 9cm is abnormal
this is remembered by the 3, 6, 9 rule
What might be seen on a CT scan in Crohn’s disease?
bowel wall thickening + skip lesions
What is meant by a “bowel series”?
What might this show in Crohn’s disease?
bowel series = XR + barium enema
rose thorn ulcers:
* deep ulcers seen in a stenosed ileum with a thickened wall
string sign of Kantor:
* this is indicative of fibrosis + strictures
What is the gold-standard + diagnostic test for Crohn’s disease?
colonoscopy + biopsy
colonoscopy:
* shows a “cobblestone” appearance, ulcers and skip lesions
histology:
* shows transmural involvement with non-caseating granulomas
histology is confirmative of the diagnosis
What is the first line drug to induce remission in Crohn’s disease?
steroids (glucocorticoids) IV, topical or oral
typically prednisolone is used
budenoside is an alternative in a small subgroup of patients
this is an inflammatory disease - steroids will dampen down the immune response
What other medications (other than steroids) may be used to induce remission in Crohn’s disease?
immunomodulators:
* oral or IV
* this includes azathioprine, mercaptopurine or methotrexate
* these are used as an add-on therapy / not in isolation
biological therapy:
* IV
* includes infliximab and adalimumab
* used as an add-on therapy in refractory disease / fistulating Crohn’s
What is the difference in inducing remission if a Crohn’s patient has an acute presentation?
steroids + immunomodulator are given IV opposed to oral
What are the adjuncts added on to therapy to induce remission in Crohn’s?
- smoking cessation
- perianal disease mx (usually metronidazole)
- nutritional support
If a patient has steroids + immunomodulator + biologic and still has not entered Crohn’s remission, what is done?
surgery
- this is for severe remission / presentation, refractory disease + obstruction
- usually involves colectomy or Hartmann’s procedure
if obstruction results from severe stricturing, this is a SURGICAL EMERGENCY
What is the problem with providing surgery for Crohn’s disease?
it is NOT curative, and only works for symptom managment
- can remove the severely affected part / obstruction
- the disease can re-grow at the site of anastomosis
After the symptoms have been controlled, what is the treatment for maintaining remission in Crohn’s disease?
Immunomodulators:
* this is azathioprine, mercaptopurine and methotrexate
+/- Biologics:
* this is infliximab and adalimumab
the regime depends on individualised disease + progress
systemic corticosteroids are NOT effective in retaining remission and have many side effects from long-term use
What adjuncts may be given to maintain remission in Crohn’s disease?
- anti-spasmotics for cramp relief
- anti-diarrhoeals
What is the definition of UC?
diffuse inflammation of the colonic mucosa affecting the colon + rectum only
How is the inflammation in UC different to Crohn’s?
- inflammation affects the mucosa only
- inflammation is continuous (not patchy) but only present in the colon + rectum
What are the presenting symptoms of UC?
- BLOODY DIARRHOEA is the main symptom
- rectal bleeding + mucus
- abdominal pains + cramps
- tenesmus
- weight loss
in Crohn’s, the diarrhoea is profuse but not necessarily bloody
What might be seen on a plain XR in UC?
- dilated bowel (> 6cm)
- thumbprinting (sign of bowel wall thickening due to oedema or inflammation)
What might be seen on a double contrast barium enema in UC?
lead pipe colon
- complete loss of haustral markings throughout the colon
- colon appears smooth-walled / cylindrical like a lead pipe
this sign can be seen on plain XRs and XRs using barium contrast
What is the first line and diagnostic investigation for UC?
colonoscopy:
* shows continuous erythema, bleeding + ulcers
biopsy / histology:
* shows crypt abscesses + deletion of goblet cell mucin
What is the normal diameter / features of the small and large bowel on AXR?
What is the treatment to induce remission in mild-moderate UC?
Mesalazine (5-ASA):
* topical aminosalicylate is given at first
- if remission is not acheived in 4 weeks, an oral aminosalicylate is given in addition
Corticosteroids:
* if remission is not acheived within 4 weeks of oral mesalazine, oral beclamethasone is given
What other steps can be taken to maintain remission in UC?
following severe relapse / 2+ exacerbations/yr:
* immunosuppressives such as azathioprine / mercaptopurine are given
- biologics such as infliximab / adalimumab can be added on top
methotrexate is NOT recommended in UC
What surgery may be performed in UC?
Why is this a better alternative than in Crohn’s disease?
- total colectomy can cure the disease as it is confined to the colon / rectum
- the small bowel is joined to the rectum to create a “J-pouch”
What are the consequences of coeliac disease on the intestine?
- villous atrophy
- hypertrophy of intestinal crypts
these features will be seen on histology and result from repeated exposure to gluten
What are the extra-intestinal manifestations of coeliac disease?
dermatitis herpetiformis:
* this involves bilateral itchy vesicles / plaques on the elbows
others:
* prolonged fatigue
* weight loss
* symptoms of B12 / iron / folate deficiency
What is the diagnostic investigation for coeliac disease?
endoscopy + biopsy showing villous atrophy and crypt hyperplasia
typically done in the duodenum, but can also be done in the jejunum
How can IBD be classifed?
