Week 5 - Inflammation Pt 1 (all IBD screencasts) Flashcards
IBD : aetiology pathogenesis symptoms and complications Symptoms + diagnosis ( from essential readfing)
Aetiology
What are the two (chronic) GI inflammatory diseases?
Crohn’s Disease (CD)
Ulcerative Colitis (UC)
Describe the differences between Crohns D and Ulcerative colitis
**1. Where it affects: **
CD - All parts of GI tract ( mouth to rectum)
UC- Only Colon and rectum
2. Inflammation sites:
CD - Inflammation extends through all 4 layers of the gut wall (Mucosa , submucosa , Muscularis externa & serosa)
UC- Inflammation extends as far as mucosa and submucosa
**3. Inflammation pattern: **
CD- Patchy distribution
UC- Diffuse in distribution
Epidemiology
What ages is IBD prevelant in ?
How prevelant is IBD in the UK?
Peak incidence - 10-40yrs
1/250 ppl in UK
Epidemiology
What is the prevelance of Crohn’s Disease and Ulcerative Colitis?
UC more common than CD
CD- ( typically at a younger age - slightly common F>M)
UC- ( Typically at an older age - slightly common M>F)
Aetiology
What are the possible contributing factors to IBD onset?
** Environmental :**
- Diet
- smoking
- infection
- Drugs
** - Genetic **
Aetiology
Describe how diet affects IBD onset?
- Typically a ‘western’ diet of high fat, milk and fibre content has been associated with exacerbating symptoms e.g gas
- particular foods may vary from person to person
Describe how smoking (environmental factors) affects IBD onset?
- worsens prognosis of the disease
- increases relapse risk and surgery requirement
- **HOWEVER ** smoking may help prevent UC onset as the chemical including tobacco which can lower cytokine levels ( and therefore inflammation )
Describe how Infection affects IBD onset?
– Exposure to Mycobacterium paratuberculosis can cause CD
– UC can occur after episode of infective diarrhoea,
* No definite association with a single infective agent*
– Association with measles & mumps infections
– Possibly immune system does not switch off after infection leading to autoimmunity
Aetiology
Describe Enteric Microflora affects IBD onset?
– IBD patients - loss of immunological tolerance to intestinal microflora
– Can be manipulated by antibiotics, probiotics and prebiotics to balance favourably
Describe Drugs affects IBD onset?
**NSAIDs can exacerbate IBD **
- Inhibit the synthesis of cytoprotective prostaglandins
– Antibiotics can change enteric microflora
* Precipitate a relapse
– Oral contraceptive pill
* Increase risk of developing CD
* Possibly caused by vascular changes
**– Isotretinoin **– for acne – possible risk factor`
Aetiology
Describe how genetic factors can contribute to IBD onset
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Genetic factors influence the risk of IBD by causing:
– Disruption of epithelial barrier integrity
genetics
– Deficiencies in innate pattern recognition receptors
– Problems with lymphocyte differentiation, especially CD
-Inappropriate response of the immune system in the mucosa of the
G.I tract to normal enteric flora
Describe the pathophysiology of CD and what parts it affects
- Affects ileum and ascending (start) colon
- Discontinuous inflammation
- Deep ulcers
- Cobblestone appearance
Describe the pathophysiology of UC
- Affects the the whole colon from the rectum
- bleeds easily
What are the symptoms of CD
- abdominal pain
- anaemia
- abcesses
- fistula
Name the distinguishing factors of CD ( exclusive to CD and not UC)
- Patchy inflammation
- cobblestone mucosa
- Transmural involvement
- not common in the rectum
- fistulas common