Inflammatory Bowel Disease Flashcards
What are some IBD conditions?
Ulcerative colitis Crohn's disease Diversion colitis Diverticular colitis Radiation, drug, infectious, ischaemic colitis
What is IBD?
A group of conditions characterised by idiopathic inflammation of the GI tract
What is colitis?
Inflammation of the lining of the colon
Pathophysiology of IBD?
Unknown
Most likely to be immune dysfunction which is genetically mediated, causes inappropriate immune activation in response to luminal microorganisms
Where does ulcerative colitis affect?
Rectum
Extends proximally IN CONTINUITY to affect a variable extent of the colon
Inflammation confined to mucosa
Who does ulcerative colitis affect?
High incidence in UK, US and Northern Europe
Young adults, more commonly females
What is UC a result of?
Environmental trigger in a genetically susceptible person
Pathology of UC?
Bacterial/dietary antigens taken up by M cells in Peyer’s patches and pass into lamina propria
Antigens picked up by antigen-presenting cells in lamina propria
APCs release inflammatory cytokines - IL-12 and 18, α-ΤΝF
This and presentation of antigens to CD4+ T cells -> activation of TH1 cells
Secrete more cytokines and attract more T cells -> inflammatory response
What is the result of the pathology of UC?
Ulceration and stricture formation
There may be an accompanying fever, malaise, anorexia
What does UC present with?
Rectal bleeding Diarrhoea Abdominal pain Fever Malaise Anorexia
What is Crohn’s disease and where does it affect?
A condition of chronic inflammation
Can involve any part of GI tract, from mouth to anus
Not continuous
Symptoms of Crohn’s disease?
Diarrhoea Abdominal pain Weight loss Fever Malaise Anorexia Nausea Vomiting Constipation if in terminal ileum/causing a blockage Anaemia if terminal ileum is involved due to B12 nor absorbed
What gene is affected in Crohn’s disease?
IBD1
Environmental factors for development of UBD?
NSAIDs - can alter intestinal barrier Low residue, high refined sugar diet Antibiotics because they can get rid of normal flora Diet Acute infections Smoking Stress (Crohn's)
How does smoking affect UC and CD?
Smoking can protect against UC
Can increase chance of Crohn’s
What investigations would you do for IBD?
Colonoscopy - take biopsy of mucosa and look at ulceration
Stool analysis - look at parasites, C. Diff toxin, culture to exclude infectious cause
Barium radiograph
CT scan - acute attacks
Capsule endoscopy - examine small intestine
Plain X-ray if vowel obstruction/perforation is suspected
What can a barium radiograph show?
Macroscopic extent of the disease
Ulceration
Loss of Haustra
Shortened colon as a result of scarring/fibrosis
What macroscopic changes are seen in Crohn’s?
Bowel is thickened and narrowed
Deep ulcers and fissures five cobblestone appearance
Fistulae
Abscesses
Macroscopic appearance of ulcerative colitis?
Reddened mucosa
Inflamed
Bleeds easily
If severe
- extensive ulceration
- adjacent mucosa appears as inflammatory pseudopolyps
Microscopic features of Crohn’s disease?
Inflammation through all layers of the bowel (transmural)
Increase in chronic inflammatory cells
Lymphoid hyperplasia
Granulomas from T helper cell response
Microscopic features of UC?
Superficial inflammation
Chronic inflammatory cells in lamina propria
Crypt abscesses
Goblet cell depletion
If you cannot distinguish between UC and CD in a patient, what is the patient said to have?
Colitis of Undetermined Type and aEtiology (CUTE)
What can be used to help in differentiating between UC and CD?
Serological testing
UC - anti-neutrophil cytoplasmic antibodies (ANCA)
CD - anti-Saccharomyces cervisiae (ASCA)
What endoscopic abnormalities are seen in CD?
Colonoscopy - cobblestoning
What is seen in imaging of the small bowel in Crohn’s disease?
String sign of Kantor
Asymmetrical alteration in mucosal pattern with deep ulceration
Areas of narrowing/strictures
What methods can be used for imaging of the small bowel?
Barium follow through
CT scan with oral contract
Small bowel ultrasound
MRI
What is gold standard for the diagnosis of ulcerative colitis?
A colonoscopy to take a biopsy
Allows you to assess disease activity and extent
What is seen in an abdominal X ray for UC?
Excludes colonic dilation
Collar button ulcers (ulcers through the bowel mucosa into the muscle, then up and down like a T)
In the treatment of CD, how is remission induced and maintained?
Induced: corticosteroids (oral/IV), enteral nutrition, anti-TNF antibodies (Infliximab), methotrexate (modifies and suppresses immune system)
Maintained: methotrexate, azathioprine (same as methotrexate), infliximab
How does infliximab work?
Binds to membrane-bound TNF-α to induce immune cell apoptosis
When and how is CD surgically managed?
If there is failure of therapy, still acute and chronic symptoms
If there are complicatins eg dilation, obstruction, perforation, abscesses
Failure to grow in children despite treatment
Colectomy or ileorectal anastamosis is done
How is ulcerative colitis treated?
Distal disease - topical/suppository corticosteroids
Left-sided colitis - topical corticosteroid enema
Extensive colitis - oral corticosteroids, infliximab
When and what surgery is done for UC?
Patients with complications/corticosteroid dependence.
In acute disease, subtotal collecting with end ileostomy preservation of rectum.
What is the cancer risk of UC and CD?
UC: colorectal
CD : colorectal, small bowel (depends on location)
In which one is perianal disease more common in?
CD
In which one are you more likely to find granulomas?
Crohn’s
In which one do you get straightening of the colon?
Ulcerative colitis after a long time
When are the two peaks in incidence for IBD?
15-30
60
What is the mucosa of CD patients dominated by?
TH2 (T-helper) cells
They release interferon γ and IL-2
Presentation of Crohn’s if there is upper GI involvement?
Nausea and vomiting Dyspepsia Small bowel obstruction Anorexia and weight loss Loose stools
Presentation of Crohn’s if there is lower GI involvement?
Diarrhoea
Passage of obvious blood
What is the mucosa of UC patients dominated by?
TH2 cells which produce transforming growth factor (TGF) and IL-5
