Gastroenteritis Flashcards
What is the most common bacteria to cause Gastroenteritis?
Campylobacter
What is the most common bacteria to cause outbreaks of Gastroenteritis?
Salmonella
What is a rare cause of outbreaks of Gastroenteritis but one that can cause high morbitity?
E coli 0157
What is the most common management of Gastroenteritis?
supportive
no antibiotics
How is Gastroenteritis spread?
Faecal-oral transmission
What are the global causes of Gastroenteritis?
Poor sanitation & hygiene Commercialisation of food production Import of food from other countries Increase in day care/care home International Travel Acid suppression Healthcare associated infections of GI tract
What can make a patient more susceptible to Gastroenteritis?
Malnutrition (micronutrient) deficiency
Closed/ semi-closed communities – cruises etc
Exposure to contaminated food/water /travel
Winter congregating/ summer floods
Age <5, not breastfeeding
Older age
What bacteria are people with acid supression more likely to contract?
C.diff
Describe how the bacteria acts in gastroenteritis?
adherence/attachment to the gastrointestinal mucosa
cellular invasion
production of exotoxins
changes in epithelial cell physiology
loss of brush border digestive enzymes, and/or cell death
increased intestinal motility, net fluid secretion, influx of inflammatory cells, and/or intestinal hemorrhage
What defines diarrhoea?
> 3 unformed stools/day
What is Dysentry gastroenteritis?
inflammation of the intestine, particularly the colon, causing diarrhea associated with blood and mucus
Caused by: Shigella, Campylobacter
generally associated with fever, abdominal pain, and rectal tenesmus (sense of incomplete defaecation)
How long does acute gastroenteritis last for?
under 2 weeks
What kitchen related things can cause gastroenteritis?
cross contamination of raw & cooked food preparation food too far in advance inadequate heating & cooling contaminated environment & equipment poor personal hygiene
What does cholera cause?
large volume diarrhoea
What bacteria require short incubation times? (1-6hrs)
Staphylococcus aureus - preformed toxin in food Gram positive coccus - Foods left at room temperature Bacillus cereus - Starchy foods - Heat resistant spores (reheated rice)
What is the incubation period for E.coli?
3 - 8 days
uncooked beef, water, person to person contact, raw milk
Where is shigella bacteria often found?
Refugees
institutionalisation
military
What does shigella produce?
Shiga toxin
What does the shiga toxin do?
Binds to receptors found on renal cells, RBC & others
Inhibit protein synthesis
Causes cell death
Which type of shiga toxin is more potent?
Type 2
What is the development of Hematuria and renal failure (HUS) associated with?
primarily with serotypes that produce Shiga toxin 2
What can shiga toxin produce?
E. coli O157
What is the signs of E. coli O157 and what can cause it?
bloody diarrhoea (90%) /blood per rectum
very low infectious dose
food: beef (raw milk/water) but wide range
also person to person direct/indirect (11% of cases)
animal contact – petting zoos
What can E. coli O157 also be called?
EHEC
Describe EHEC?
incubation 1-14 days (7)
produces verotoxin (VTEC)
mild - severe (death)
bloody diarrhoea
haemorrhagic colitis
Describe HUS?
Abdo pain, fever, pallor, petechiae, oliguria (low urine output) bloody diarrhoea in 90% of cases 85% of HUS cases are under 16 years old High white cells Low platelets Low HB Red cell fragments LDH>1.5 x normal May develop after diarrhoea stopped
What are the investigations for HUS?
Send stool culture samples: all patients with bloody faeces
Send U&E, FBC, film, LFT, clotting, urine, (dipstick/micro), lactate dehydrogenase
What should be avoided in a pateint with suspected HUS?
NO antibiotics: may precipitate HUS
NO anti-motility agents
NO NSAIDS
Name 4 other E. coli pathotypes?
enteroToxigenic(ETEC)
enteroPathogenic (EPEC)
enteroInvasive (EIEC)
enteroAggregative (EAIC)
Describe enteroToxigenic(ETEC)?
Produces heat labile and heat stable toxin
Heat stable toxin similar to cholera and Yersinia toxins
Travel related
Describe enteroPathogenic (EPEC)?
Attaching and effacing lesions. No toxin, not invasive
Synthesises, secretes and inserts its own receptor into cell membranes
Non breastfed children
Can be asymptomatic
Describe enteroInvasive (EIEC)?
Watery diarrhoea, rare dysentery
Demonstrates invasion
Sereny test
Describe enteroAggregative (EAIC)?
Travellers diarrhoea
New kid on the block
Cytogenic, secretogenic, proinflammatory
What is the incubation time for Campylobactor?
16- 48 hrs incubation
What is a possible treatment for Campylobactor?
macrolide - clarithromycin
What is the most common Campylobactor pathogenic strain?
C jejunisubspeciesjejuni
Why should HIV patients not keep reptiles?
they are full of salmonella – can end up with a bacteriemia
Describe the incubation time, clinical signs and source of Salmonella?
12-48 hr incubation D&V, blood, fever Food: poultry, meat, raw egg animal gut, multiplies in food toxin and invasion
Where can Listeria monocytogenes come from?
delicatessens
Unpasteurised milk products
What is the danger with Listeria monocytogenes?
Can cause child mortality if passed on from mother to child in utero
What are the clinical signs of Listeria monocytogenes?
Fever
muscle aches
diarrhoea
What is the treatment for Rotavirus and Norovirus?
supportive treatment
What is the investigation done to diagnose Rotavirus and Norovirus?
PCR
Rota - on feaces
Noro - on vomit
What are the features of Rotavirus?
Commonest cause in kids <3 yrs ~ all kids get it before 5 person-person Faecal oral Direct & indirect usually in the winter Subclinical or mild in adults Immunocompromised? can be severe May have moderate fever first, vomiting then diarrhoea Lasts a week
What does the rotavirus affect?
absorption & secretion in bowel
What are the features of Norovirus?
‘Winter Vomiting Disease’- lately all year round!
affect all ages: HIGHLY infectious
5 billion viruses per gram of faeces
faecal-oral/droplet routes of spread
person to person (or on contaminated food/water)
What is the key management for Noro and Rota viruses?
hydration
