Gastroentertitis Flashcards
What is normal flora also known as?
Commensal flora/ coliforms
Describe the flora in the GI tract
Many anaerobic bacteria
some facultatively anaerobic coliform - both aerobic and anaerobic
altered by diet and upbringing e.g. bottle fed v breast fed babies
What is the most common type of microorganism that causes gastroenteritis?
Bacteria e.g. salmonella, shigella, e.coli
Where does E.Coli 0157 colonise?
water
lakes
swimming pools
farms
What are the presenting complaints of gastroenteritis?
acute onset vomiting diarrhoea - frequently, mucosal, blood abdominal pain fever
What investigations are done to diagnose gastroenteritis?
Bloods - FBC, U&E, CRP, blood cultures
Abdominal X Ray (severe)
stool - look for toxins, oocytes, parasites, viral PCR
What are the symptoms of norovirus?
diarrhoea
projectile vomiting
How is norovirus managed?
no specific treatment
let illness take its course
stay hydrated
How do you prevent norovirus spreading?
practice good hygeine
stay away from others to prevent spreading
What are 3 examples of parasitic organisms that cause gastroenteritis?
Cryptosporidium
Giardia
Entamoeba
Where does cryptosporidium colonise?
Waterborn: drinking water, swimming pools
Why is cryptosporidium problematic at being killed? What are the oocytes resistant to?
Chlorine
What two categories do bacterial gastroenteritis fall into according to how they infect the host?
Enterotoxin production - produces toxins that cause symptoms
Adherence - caused by the bacteria itself
What is a complication of E.Coli O157?
haemolytic uraemic syndrome - e.coli acts on epithieal cells and RBC → debris → clogging of kidneys/anaemia
How does E.coli cause diarrhoea?
toxi produced by cells internalises → causes cells to pump out ions → osmosis → fluid fills illius → diarrhoea
What causes antibiotic associated diarrhoea?
antibiotics changes metabolism and growth of pathogenic organisms
What are the symptoms of antibiotic associated diarrhoea?
range from mild diarrhoea to pseudomembranous colitis (caused by c.diff)
What are the complications of antibiotic associated diarrhoea?
toxic megacolon
perforation
shock
plaques of intestinal wall
What are the 2 high risk antibiotics for C.Diff infection?
cephalosporins
clindamycin
Broader spectrum = greater risk of c diff
What is the relationship between e.coli O157 and floroquinolones?
particularly resistant to e.coli O157 therefore can drive this infection
What is the therapy for C.Diff?
oral metronizadole
oral vancomycin
Faecal transplant
What is the problem with using antibiotics to treat C.diff?
they effect gut flora (which is the cause of C.Diff)
risk factor for vancomycin-resistant enterococci
potential for resistance
