Gastroenteritis Flashcards
What pathogens can cause gastroenteritis that I should know about?
Campylobacter Salmonella E coli 0157 C diff Listeria Shingella Norovirus Rotavirus
What are the general risk factors for GI infection?
Malnutrition (micro nutrient) deficiency Closed/semi closed communities (preschools, cruise ships) Exposure to contaminated food, water Winter congregating (more time spent indoors) Age <5 Not breastfed Older age Travel
If a patient is on acid supression, which organisms are more likely?
Yersinia H pylori (tolerant of acid) C diff Cholera Salmonella Campylobacter Listeria
What are the most common organisms in immunosuppressed patients?
Salmonella, campylobacter
Shingella
(all shed in faeces for longer)
Other uncommon organisms, MAK (micobacterium avian complex), CMV (cytomegalovirus))
Gut microbiome and genetics play a role in predisposing to infection. WHat are 2 genetic associations with GI infection?
IL8 promoter variants and severe C diff
O blood group and cholera
What does the pathogenic bacteria do to cause an infection?
Adherence/attachment to the mucosa
Cellular invasion
Production of exotoxins
Changes epithilial cell physiology
Loss of brush boarder, digestive enzymes and cell death
Increased intestinal motility, net fluid secretion, influx of inflammatory cells +/- intestinal haemorrhage
What is the inoculum size?
Median infecting dose required to cause disease in 50% of individuals
What does a low inoculum dose imply?
More infectious spread
What can affect the inoculum dose?
pH and gastric motility
What is diarrhoea?
> 3 unformed stools per day with no other cause (laxatives, excess stimulants (coffee))
Stool holds the shape of container
Departure from normal bowel habit
Which ‘types’ on the bristol stool chart are classified as diarrhoea?
types 5, 6, 7
What is dysentery?
Type of gastroenteritis.
Inflammation of the intestine, esp colon, causing diarrhoea associated with blood and mucus. Associated with fever, abdo pain, recal tenesmus
What is recal tenesmus?
Feeling of incomplete defication
Which type of gastroenteritis can mimic appendicitis and why?
Yersinia enterocolitica
It can invase mesenteric nodes
What organisms can cause dysentery?
Shingella and campylobacter
What does acute gastroenteritis imply?
Diarrhoea for less than 2 weeks
Problems in the large bowel produces a larger or smaller volume of diarrhoea compared to the small bowel?
Smaller volume
What are common problems in the kitchen which lead to gastroenteritis?
Cross contamination of raw and cooked foods Preparation to far in advance Inadequate heating/cooling Contaminated environment Poor personal hygiene
Spores are resistant to most of our cooking methods. T or F?
True
Symptoms of gastroenteritis?
Abdo pain
Vomiting
Diarrhoea.
Caused by invasion of tissue +/- toxin production
Large volume diarrhoea tends to come from the small bowel
What are the mos common organisms in travelers?
Enterotoxigenic E coli
Vibro species
Rota virus
What is the most common organism if the patient has been camping?
Giardia, Aeromonas, Cryptosporidium
What is the most common organism if the patient has had recent antibiotics?
Increased risk of C diff
What is the most common organism if the patient has exposure to see food?
Non cholera Vibro