Diarrhoea Flashcards
What are the 3 types of diarrhoea?
Inflammatory, secretory and osmotic (malabsorptive).
Describe causes of the 3 types of diarrhoea.
Inflammatory - IBD, shigella, salmonella, irritable colon.
Secretory - Laxatives, Zollinger-Ellison syndrome, Carcinoid syndrome, acute infection (E. Coli), failure of bile salt absorption, malabsorption of fats.
Osmotic - IBD, short bowel syndrome, pancreatic insufficiency, medications (orlistat, a-carbose, laxatives), pancreatic enzyme deficiencies.
Describe characteristics of each type of diarrhoea with regards to the volume of diarrhoea produced.
Inflammatory - increased secretion and increased propulsion with a low volume.
Secretion - increased secretion and decreased absorption with a high volume.
Osmotic - decreased absorption with a low volume.
What are the pathogenic mechanisms of diarrhoea?
Toxin mediated (produced before or after consumption).
Damage to intestinal epithelial surface.
Invasion across intestinal epithelial barrier.
What is the pathogenesis of bacterial gastroenteritis?
Release toxins and invasion.
What is the pathogenesis of viral gastroenteritis?
Local invasion, cytopathic effects and cell destruction.
What is the pathogenesis of protozoal gastroenteritis?
Invasion and secretory products.
Give 2 examples of neurotoxins.
S. aureus and B aureus.
Give 3 examples of secretory enterotoxins.
E. Coli, salmonella, vibrio cholerae.
Give 3 examples of cytotoxins.
C. Diff, E. Coli and shigella.
How can diarrhoea be classified?
Acute, watery
Acute, bloody
Dysentery (blood and mucous)
Persistant (14 days+)
Is n&v common in gastroenteritis? What does vomiting suggest?
Nausea is, however vomiting isn’t.
Vomiting suggests pre-formed toxin - S. aureus or B. aureus - if there is a sudden onset within 6-12 hours.
Also may be norovirus.
What late complications can occur in campylobacter?
Reactive arthritis and Gullain-Barre.
What serotype of salmonella is most common in the UK?
Non-typhoidal.
How does campylobacter infect?
Invasion of epithelial cells.
