Gastroenteritis Flashcards
What are some GI infection risk factors?
- malnutrion
- closed communities
- exposure to contaminated food/water
- <5 years , not breastfeeding
- older age
What is the bacterial effect of gastroenteritis?
- cellular invasion
- production of exotoxins
- changes in epithelial cell physiology
- loss of brush borders
What defines diarrhoea?
- > 3 unformed stools/day
- stools hold shape of container
What scoring system is used for diahorrea?
- bristol stool chart
Explain dysentery
- inflammation of the intestine
- causing diarrhoea
- with blood and mucus
What is important when taking a history with someone with diarrhoea?
- other symtoms
- description of stools
- travel
- food history
What is the cause of traveler’s diarrhoea?
- eneterotoxgenic E.coli
What bacteria is the cause of gastroenteritis after a course of antibiotics?
- c.difficile
What may be the bacteria/virus that causes gastroenteritis in children or someone working in day care?
- rotavirus
What is the most common bacteria involved in gastroenteritis?
- campylobacter jejuni
What is the shiga toxin?
- inhibits protein synthesis
- causes cell death
- e.coli can produce the toxin
Which toxin of shiga is most potent?
- toxin 2
Should antibiotics be given to a patient with E.coli 0157?
- no
What antigens are present on salmonella?
- O antigens
What are the 2 most common viruses that cause gastroenteritis?
- norovirus
- rotavirus
Explain rotavirus in terms of gastroenteritis?
- commonest cause in children
- person-faceal oral spread
- NOT BLOODY STOOLS
Describe the rotavirus vaccine
- oral
- live attenuated
Explain the norovirus in terms of gastroenteritis?
- winter vomiting bug
- person-person spread
- highly infectious
When examinating a returned traveller what should you be looking for?
- fever
- rash
- hepatospenomegaly
- lymphadenopath
- insect bites
Purfuse watery diarrhoea may be a sign of what?
- cholera
What is enteric fever also called?
- typhoid fever
What causes enteric fever?
- returning from India or SE Asia
- salmonella typhi
What investigations should be done for amoebiasis?
- stool microscopy
- AXR (toxic megacolon)
- endoscopy
Explain campylobacter
- gram negative
- s shaped
- motile
Explain salmonella
- gram negative
- enterobacteiaceae
- bacilli
Explain e.coli 0157
- E.coli –> gram neg rod shaped
- shiga toxin production
low infectious doses makes spread_____
- easier
Explain gastroenteritis?
- illness caused by eating contaminated food, with micororganiss toxins and posinos
Large volume of diarrhoea more likely to be from the ____ bowel
- small
Bacillus cereus found?
- starchy food
- reheated rice
What is staphylococcus aures found in?
- milk/meat and fish
What does the shigella toxin bind to and what affect does it have?
- the shigella toxin binds to receptors on renal cells and RBC, inhibiting protein synthesis and causing cell death
What does E.coli bind to?
- binds to the absorptive enterocytes, causing cell death can also enter the blood stream
Explain ETEC
- Enterotoxigenic E.coli
- heat stable toxin
Explain EPEC
- Enteropathogenic E.coli
- no toxin, not invasive
- non-breastfed children
Explain EIEC
- Enteroinvasive E.coli
- watery diarrhoea
Explain EAIC
- Enteroaggreative E.coli
- traveller’s diarrhoea
Explain listeria monocytogenes
- 9-48hrs
- unpasturised milk products, deli counter
- gram +ve rod
