Gastroenteritis Flashcards by Alison Gourlay

What is the most common bacteria to cause Gastroenteritis?

Campylobacter

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What is the most common bacteria to cause outbreaks of Gastroenteritis?

Salmonella

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What is a rare cause of outbreaks of Gastroenteritis but one that can cause high morbitity?

E coli 0157

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What is the most common management of Gastroenteritis?

supportive

no antibiotics

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How is Gastroenteritis spread?

Faecal-oral transmission

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What are the global causes of Gastroenteritis?

Poor sanitation &amp; 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

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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

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What bacteria are people with acid supression more likely to contract?

C.diff

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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

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What defines diarrhoea?

> 3 unformed stools/day

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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)

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How long does acute gastroenteritis last for?

under 2 weeks

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What kitchen related things can cause gastroenteritis?

cross contamination of raw &amp; cooked food
preparation food too far in advance
inadequate heating &amp; cooling
contaminated environment &amp; equipment
poor personal hygiene

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What does cholera cause?

large volume diarrhoea

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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)

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What is the incubation period for E.coli?

3 - 8 days

uncooked beef, water, person to person contact, raw milk

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Where is shigella bacteria often found?

Refugees
institutionalisation
military

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What does shigella produce?

Shiga toxin

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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 jejuni subspecies jejuni

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