Gastroenteritis Flashcards
what is the perfect environment for organisms to grow in- dry or moist sites
moist
what are the main beneficial effects of commensal flora of the gut.
metabolism, colonisation resistance, antibody induction
examples of 2 obligate anaerobes
clostridia, bifidobacteria
what pathogens are vitamins B12 and k secreted by
commensal eneteric bacteria
examples of 2 facultative anaerobes
enterobacteriacea and enterococci.
what are the most common bacterial causes of diahorrhea
salmonela, shinglla, E coli, Campylobacter, vibrio cholera, clostridium difficile, staph auerus, bacillus cerues
what are the most common parasitic causes of diarrhoea
Parasitic- Entamoeba hist, Giardia lamblia, cyrptospodium
what are the most common viral causes of diarrhoea
Viral- norovirus- rotavirus
what are the presenting complaint symptoms of gastroenetriritis
- Acute onset
- Vomiting AND/OR diarrhoea (frequency, mucous, blood).
- Abdominal pain
- Systemic-fever
complications of gastroenteritis
dehydration, renal failure, Haemolytic urea syndrome, toxic mega colon, salmonella, GBS (Guillain-Barre Syndrome)
common investigations in gastroenteritis
• Bloods – FBC, U&E, CRP, blood cultures- what is causing the infection
• AXR (abdominal X-ray) – if severe
• Stool
– Ova, parasites and cysts ‘OCP’
– Microscopy, culture and sensitivity ‘MC&S’
– Clostridium difficile toxin ‘CDT’
– Viral PCR- difficult to interpret due to 100’s of normal gut flora(coliforms)
what is the most common cause of viral gastroenteritis
norovirus
what are the symptoms of viral gastroenteritis
diahorrhea and projectile vomitting.
treatment of viral gastroenteritis
drinks water to avoid dehydration, stay away from work and good hygiene.
how to prevent viral gastroenetitis
rotovirus vaccine
how is cryptospordium transferred to humans
water bourne/ food bourne
symptoms of cryptospordium parasitic gastroenteritis
watery diahorrhea.
what chemical are the oocytes of cryptosporidium resistant to
chlorine
2 ways in which bacteria can cause gastroenteritis
produce toxin (eneterotoxin bacteria itself (adherence)
enterotoxin (bacteria producing toxin) organism which causes gastroenteritis
– Vibrio cholerae – Escherichia coil (entertoxigenic – ETEC, verotoxigenic - VTEC) – Clostridium perfringens – Staphylococcus aureus – Bacillus cereus – Clostridium difficile
bacterial which causes gastroenerteritis itself. (adherence)
– Shigella sonnei / flexneri
– Escherichia coil (entertoadherent – EAEC)
– Campylobacter jejuni
– Salmonellae
what is the name of the toxin produced by E.coli
shiga toxin
what is the source of E coli
cattle
symptoms associated with E coli infection
HUS (haemolytic uraemic syndrome)
pathogenesis of E coli
toxin activates G protein leading to increased cAMP, activates ion channels, chloride ions leave and water follows.
killing bacteria can result in release of more toxin and making the disease worse
where is salmonella transmitted from
abroad from food or drink.
4 types of salmonella causing organisms
S. typhi, S. paratyphi, S. enteritidis, S. typhimurium
what is the difference between typhoid and paratyphoid salmonella
typhoid- affects cells outside the GI tract
Parathyphoid- stays within the Gl tract
supporative management of gastroenteritis
avoid antibiotics- salmonella and E. coli
antibiotics- prolonged camplyobacter and very young/old.
how much time after antibiotic treatment does antibiotic associated diahorrhea occur
months after treatment
what causes antibiotic associated diahorrehea.
disruption to gut flora
- Change in metabolism (carbohydrates / bile acids), leads to osmotic change and diarrhoea.
- Overgrowth of pathogenic organisms
most common cause of antibiotic associated diahorrehea.
C.diff
severe symptoms of antibiotic associated diahorrehea.
pseudomembranous colitis
- Toxic mega colon, perforation, shock
high risk antibiotics for antibiotic associated diahorrehea form C. diff
cephlosporin and clindamycin
medium risk antibiotics for antibiotic associated diahorrehea C. diff.
ampicillin, amoxicillin, co-triazole, macrolides, fluroquinolones
low risk antibiotics for ntibiotic associated diahorrehea C. diff.
aminoglycosides, metronidazole, anti pseudomonal penicillin, B lactamase inhibitor, tetracycline, rifampicin, vancomycin.
control mechanism for C diff
early warning system
reduce risk of transmission
early isolation/cohorting of patients with diarrhoea
• Environmental cleaning, chlorine
• Hand hygiene soap & water
• Examine/optimise/reduce overall antibiotic use
• Limit high risk agents in high risk patients
• Feedback CDI & antibiotic data on a regular basis
tretament for C diff antibiotic associated diarrhoea
oral metronidazole / oral vancomycin
new drug- oral fidaxomicin
potential risk of antibiotic treatment for C diff antibiotic associated diarrhoea
increased risk of vancomycin resistant enterococci selection
• Potential for emergence of resistance to vancomycin / metronidazole in C. difficile.
do patients relapse with antibiotic treatment for C diff antibiotic associated diarrhoea
yes
so patients relapse with Faecal transplant for antibiotic treatment for C diff antibiotic associated diarrhoea
no
define faecal transplant
• Family faeces used orally or rectally- increases gut flora diversity similar to donor.
