Week 6- Inflammatory bowel disease aetiology+pathogenesis+symptoms and complications Flashcards
what is inflammatory bowel disease? types
its 2 inflammatory disorders of the gastro-intestinal tract
– Crohn’s Disease (CD)
– Ulcerative Colitis (UC)
both chronic diseases follows an unpredicatble relapsing and remitting
what is crohns disease?
- Affects any part of the G.I. tract from mouth to rectum
- Inflammation extends through all layers of the gut wall
- inflammation is patchy in distribution
what is ulcerative colitis?
- Affects the colon and rectum only
- Only affects the mucosa (and submucosa)
- inflammation is diffuse in distribution
what is the epideiology for for IBD?
- more common in industrialised countries and affects races and both sexes
- can occur at any age, peak incidences occur between 10-40yrs
what is the incidences for IBD?
ulcerative colitis is twice as common as crohn’s disease
what is the aetiology of IBD?
- causative agent is unknown
- number of factors that play a role if environmental i.e. diet, smoking,infection, drugs and genetic
how does diet affect IBD?
-high dairy, fat and low fruit and veg (westernised) and high fibre
how does smoking affect IBD?
smoking may help to prevent the onset of UC as the chemicals affect colon smooth muscle, alters gut motility and transit time
how does infections affect IBD?
-exposure to Mycobacterium
paratuberculosis can cause CD
-UC can occur after episode of infective diarrhoea
-association with measles and mumps infection
how does enteric microflora affect IBD?
– IBD patients loss of immunological tolerance to intestinal microflora
-Can be manipulated by antibiotics, probiotics and prebiotics to balance favourably
how does drugs affect IBD?
- NSAIDs can exacerbate IBD
- antibiotics can change enertic microflora cause relapse
- oral contraceptive pill, increase risk of developing CD
- isotretinoin risk
how does having an appendectomy (removal of appendices) affect IBD?
-has a protective effect for UC and CD
how does stress affect IBD?
-can trigger a relapse
-Activates inflammatory mediators at enteric nerve
endings in gut wall, leading to inflammation in the bowel
how does genetic factors influence the risk of IBD?
- DISRUPTION IN EPITHEIAL BARRIER INTEGRITY
- deficits in autophagy (cell death)
- deficiencies in innate pattern receptors
- problems with lymphocytes differentiation especially CD
what is the gene that is mutated in CD ?
NOD2 it is a inflammatory receptor
which ethical group is more prone to IBD?
- jews
- is lower in non-white races
what is the pathophysiology?
IBD is a servere, prolonged and inappropriate inflammatory response to trigger factors. Alter the normal structure of the GI tract.
Could be due to:
– Increased activity of effector lymphocytes & proinflammatory cytokines that override normal control mechanisms
– Primary failure of regulatory lymphocytes &
cytokines
– In CD, T cells are resistant to apoptosis after
inactivation
what is the pathophysiology of CD?
- affects any part of the gut usually the terminal ileum and ascending colon and its discontinous
- affects areas are thickened, oedematous, and narrow. deep ulcers can appear, deeps fissuring ulcers, fibrosis
- Th1 associated
what is the pathophysiology of UC?
- only affects mucosa and submucosa
- can affect just retum or left side colitis or whole colon
- starts in rectum
- mucosal ulceration
- mucosa looks red, inflammed and bleeds
- Th2 associated
where does UC occur?
-lower bowel
what are some clinical features, symptoms for both diseases?
– Diarrhoea – Fever – Abdominal pain – Nausea and vomiting (more common in CD) – Malaise – Lethargy – Weight loss (more common in CD) – Malabsorption – Growth retardation in children
what are some clinical features, symptoms present for CD?
- pain in lower right quadrant
- anaemia
- palpable masses (feeling a lump due to swelling
- small bowel obstructions
- fistulas
- gut perforation (formation of hole)
what are some clinical features, symptoms present for UC?
- mainly diarrhoea possibly with blood/mucus
- abdominal pain
- constipation
what are some distinguising features of CD vs UC?
-patchy= common in CD never in UC
-rectal sparing= common in CD never in UC
-
how do complications occur of IBD?
-due to inflammation spilling over into other tissues
where do complications with IBD occur?
- joint and bones= cause arhropathies and loss of bone
- skin= erthema nodosum which is tender, hot, red nodules which subside but leave discolouration or pustles develop ulcers
- eyes= burning red eyes, blurred vision
- liver= narrowing of the bile duct
what is the morbidity for IBD?
- quality of life is generally lower in CD vs UC due to recurrences after surgery
- increased risk of cancer due to inflammation risk factor
- malnutrition and chronic anaemia common in long standing CD
what kind of tests can be done for IBD diagnosed?
- biochemical
- endoscopic
- radiological
- histological-nuclear medicine based
how can history of disease help IBD be diagnosed?
- recent travel
- medication
- smoking
- family history
- details of sympotoms like stool frequency, urgency, rectal bleeding, abdominal pain, fever
what is the essential initial assessment that can be done?
- abdominal radiography
- tell you if there is any mass in the right iluem for CD
- helps assess disease extent in UC
what other investigations can be done?
- sigmoidscopy= internal examination of the colon
- rectal biopsy
- colonscopy
- small bowel radiology
- ultrasound
- barium enema
