Inflammatory Bowel Disease Flashcards
Where does Crohn’s Disease affect, ,what causes it and how does it fluctuate?
- Anywhere on the GI tract
- Cause is unknown
- Exacerbations and remission
How does the inflammation in Crohn’s differ from UC and how is it caused?
- Crohn’s:
Transmural inflammation (throughout wall of GI tract)
Caused by dense infiltration of lymphocytes and macrophages - Ulcerative Colitis:
Inflammation of mucosal layer ONLY
Caused by an infiltration of inflammatory cells into mucosa
What are the differences in consequences of inflammation in Crohn’s vs. UC?
Crohn’s:
- Fissuring ulceration (eating away at wall of tract leads to fistulae)
- Submucosal fibrosis (scar tissue formation between epithelial + smooth muscle leading to strictures)
UC:
- Loss of goblet cells (inflammation affects mucosal layer)
- Presence of ulcerations
What are the symptoms of Crohn’s?
- Diarrhoea
- Pain
- Narrowing of the gut lumen leading to strictures (narrowed lumen) and bowel obstruction
- Abscess formation
- Fistulization to skin and internal organs
How do strictures form and how do they affect you?
- Inflammation (from infiltration of lymphocytes/macrophages) leads to scar tissue formation
- This leads to narrowing of the lumen and then obstruction
- Risk of rupture as pressure builds at narrow lumen/obstruction
- Resulting in pain/cramp/bloating
- Scar tissue = poor absorption of food/drug
How do fistulae form and where are they found?
- Via ulcers; inflammation leads to ulcers
- These develop into tunnelst = fistulae
- Go between areas of GIT, between organs (to bladder etc) or to skin (anal fistula)
What are the consequences of Crohn’s?
- Weight loss
- Macronutrient/micronutrient deficiency (when inflamed/exacerbated)
- Fatigue
What are the differences in how nutrition is affected between Crohn’s and UC?
Crohn’s:
- Protein-energy malnutrition in 20-80% of patients
- Weight loss from macro/micronutrient deficiency
UC:
- Less severe nutritional consequences (inflammation of the colon only : none observed aside from in severe diarrhoea with electrolyte/fluid loss, and GI pain can affect appetite)
What are the symptoms of ulcerative colitis?
- Severe diarrhoea (electrolyte/fluid loss)
- Blood loss (via ulcers; lowers blood pressure)
- Loss of peristaltic function leading to rigid colonic tube > potentially leading to toxic megacolon in severe cases
What is toxic megacolon?
Distension of the colon resulting in perforation and systemic toxicity in the form of sepsis; colonic bacteria enter bloodstream
How does taking loperamide affect UC?
Patients unwittingly take loperamide to stop severe diarrhoea but ends up contributing to the loss of peristaltic function (and potentially leading to toxic megacolon)
Where can extra-intestinal inflammation occur and for which IBD?
- In joints/eyes/skin/mouth/liver
- In Crohn’s and IBD
(systemic disease)
What is the mode of action of 5-aminosalicylate (mesalazine) and what does it treat?
- It inhibits leukotriene & prostanoid synthesis, scavenges free radicals and decreases neutrophil chemotaxis (movement/activity from chemical stimulus - changes in gene transcription of PPAR(gamma) receptor)
- Sulfasalazine is metabolised to mesalazine (requires colonic bacteria)
- Effects observed in UC/questionable use in Crohn’s
What issues with absorption could arise from sulfasalazine to treat UC?
Sulfasalazine is a pro-drug; required to be metabolised by colonic bacteria in to the active drug mesalazine; may have insufficient time for metabolism w/severe diarrhoea
How are steroids used in IBD?
For their anti-inflammatory and immunosuppressive effect:
- Corticosteroids
E.g. budesonide; poorly absorbed thus far fewer systemic side effects
-Used to induce remission (particularly in severe disease)
-Enemas used for more distal or rectal inflammation e.g. Predfoam
