Gastroenteritis Flashcards
(62 cards)
what are 3 crucially important pathogens?
1) campylobacter
2) salmonella
3) E. coli 0157
what are 6 GI infection risk factors?
1) malnutrition (micro-nutrient) deficiency
2) closed/semi-closed communities
3) exposure to contaminated food/water/travel
4) winter congregating/summer floods
5) age<5, not breastfeeding
6) older age
what are 4 other risk factors?
1) acid suppression
- yersinia enterocolitica, helicobacter pylori tolerant of acid
- C. difficile more common with acid suppression
- Vibrio cholera, non typical salmonella, campylobacter, E. coli
2) immuno-suppression
- salmonella, campylobacter, shigella shed for longer
- other organisms that are uncommon in immune competent
3) micro-biome
4) genetics
- IL8 promoter variant & servere C. difficile
- O blood group& vibrio cholera
what are 6 bacterial factors involved in GI infections?
1) adherence/attached to GI mucosa
2) cellular invasion
3) production of exotoxins
4) changes in epithelial cell physiology
5) loss of brush border digestive enzymes, and/or cell death
6) increased intestinal motility, next fluid secretion, influx of inflammatory cells, and/or intestinal haemorrhage
describe innocuous size that makes picking up GI infections likely.
- low infectious doses make spread easier
- pH affects required dose
what is diarrhoea?
= >3 unformed stools/day
= no the cause
- exclude laxative use/abuse & use of drugs/stimulants
- departure from normal bowel habits
- use Bristol stool char
what is gastro-enteritis?
= inflammation of intestines, particularly colon, causing diarrhoea, associated with blood and mucosa
what are 2 examples of bacteria that could cause gastro-enteritis?
- shigella
- campylobacter
what systemic things is gastro-enteritis associated with?
- fever
- abdominal pain
- rectal tenesmus (sense of incomplete defaeceation)
describe the duration of gastro-enteritis?
acute duration < 2 weeks
if gastroenteritis affects the large bowel describe the volume affected?
smaller volume
what can mimic appendicitis and why?
= yersinia enterocolitica
- as it may invade mesenteric nodes
what 4 things does bacteria need to multiply?
- Time
- temperature
- food source
- moisture
what can survive adverse conditions?
= spores
what happens in the kitchen that promotes bacteria growth?
- cross contamination of raw & cooked food
- preparation food too far in advance
- inadequate heating & cooling
- contaminated environment & equipment
- poor personal hygiene
what is gastroenteritis caused by?
= eating food contaminated with micro-organisms, toxins, poisons
e. g. bacteria, viruses, parasites
- invasion of tissue +/- toxin production
what effect does cholera have on volume of diarrhoea?
= large volume of diarrhoea
describe the history most commonly associated with gastroenteritis?
- diarrhoea, blood, mucus, time course
- other GI symptoms
- travel, contacts = human and animal
- food history = storage, re-heating, washing
- age of patients
- co-morbitidites
describe what infections would be common with foreign travel, recent camping, recent antibiotics, daycare exposure, exposure to raw seafood, anal sex, HIV positive status and outbreaks.
Foreign travel
- travellers diarrhoea = enterotoxigenic E. coli
- Southeast Asia = vibrio species
- South America, Africa, Asia = rotavirus
Recent camping
= giardia
= aeromonas
= cryptosporidium
Recent antibiotics
= C. difficile
Daycare exposure
= rotavirus
Exposure to raw seafood
= non-cholera vibrio
Anal sex
= shigella
= campylobacter
= salmonella
HIV positive statua
= mycobacterium avium-intracellular complex, mixrosporidia, cytomegalovirus, giarida
Outbreaks
- cruise ships = noro
- contaminated water, food = salmonella, E. coli, campylobacter
what 2 bacterias have a short incubation time of 1-6hours?
1) bacillus cereus (gram + bacillus)
- starchy foods
- heat resistance spores
- profuse vomiting
- reheating rice
2) staphylococcus aureus (Gram + coccus)
- performed toxin in food, rapid absorption
- acts on vomiting centre in bran
- foods left in room tempt
- milk/meat/fish
what do all stooges get tested for?
= salmonella = shigella = campylobacter = E. coli 0157 = cryptosporidium
All > 4years stools get;
= C. difficile
what are the 4 groups associated with Shigella sp?
group A
= S. dysenteriae
group B
= S. flexneri
group C
= S. boydii
group D
= S. sonnei
what does shiga toxins do?
- binds to receptors on renal cells, RBC and others
- inhibiting proteins synthesis
- causes cell death
what toxin can produce E. coli?
= shiga-toxin producing E. coli
