Infectious Diarrhoea Flashcards
What are stools like in diarrhoea?
Increase in fluidity and frequency of stool
What are stools like in gastroenteritis?
Three or more loose stools / day with accompanying features
What are stools like in dysentery?
Bloody stools
->type of large bowel inflammation btw
Which chart is used to differentiate between types of stool?
Bristol stool chart
What are some of the causes of gastro-enteritis?
Food poisoning
Travel related infections
Person-to-person spread
A lot of chicken which is intensely farmed can be contaminated with what bacteria which can cause gastro-enteritis?
Campylobacter
Which type of microorganism most commonly causes gastroenteritis?
Viruses
Despite viruses being the main cause of gastroenteritis, which would be the most common bacteria pathogen causing it?
Campylobacter
What are some of the defence against enteric* infections?
*intestine related
Hygiene
Stomach acidity
Normal gut flora
Immunity
Patients on which type of drug may be more likely to develop gastroenteritis?
Those on antacids
Give an example of a non-inflammatory gastroenteritis.
Cholera
->not seen much clinically
Give an example of an inflammatory gastroenteritis.
Shigella dysentery
Give an example of a non-inflammatory/inflammatory mixed gastroenteritis.
C,difficle diarrhoea
Features of non-inflammatory gastroenteritis?
Frequent watery stools with little abdominal pain
What is the mechanism driving diarrhoea in cholera?
Increased cAMP results in loss of Cl from cells along with Na and K
Osmotic effects lead to massive loss of water from the gut
What are the features of inflammatory gastroenteritis?
Pain and fever and diarrhoea
What is the treatment for diarrhoeal illnesses like gastroenteritis?
Rehydration
->sometimes antibiotics also required
What are some of the features of inflammation?
Fever
Raised WCC
How can hydration be assessed?
Postural BP, skin turgor, pulse
In diarrhoea, not only water is lost but also electrolytes.
Which electrolytes?
Sodium, potassium and chloride
Which investigations would be carried out in investigating a patient with diarrhoea?
Stool culture
Blood culture
Renal function
Blood count
Abdominal x-ray or CT is abdomen is distended or tender
Rectal carcinomas lead to the presence of what in stool?
Blood and mucus
Oral rehydration involves a solution with what?
Salt and sugar
What is the most common type of bacterial gastroenteritis?
Campylobacter gastroenteritis
What is important to note about culturing of stool in patients with campylobacter gastroenterirs?
Stool culture will be negative for the first 6 weeks
Campylobacter gastroenteritis can be harder to link to food poisoning, why?
There is up to 7 day incubation period so dietary history may be unreliable
What is a feature of campylobacter gastroenteritis?
Severe abdominal pain
Which conditions can occur after campylobacter gastroenteritis?
Guillain-Barre syndrome
Reactive arthritis
How long does it take for the symptoms of Salmonella gastroenteritis to present after exposure?
<48hrs after exposure
How long does the diarrhoea typically last in patients with salmonella gastroenteritis?
<10 days
What is a common complication of salmonella gastroenteritis?
Post-infectious irritable bowel
What is E.coli O157 spread from?
Infection from contaminated meat or person-person spread
What is the typical characteristic of E.coli O157 infection?
Frequent bloody stools
Which toxin does E.coli O157 produce?
Shiga toxin
->important to note that E.coli O157 stays in the gut but the toxin gets into the blood
What can the shiga toxin cause to happen?
HUS syndrome
->haemolytic anaemia and renal failure
What is the treatment for HUS syndrome?
Supportive treatment, antibiotics NOT indicated
When would gastroenteritis patients be given antibiotics?
Immunocompromised
Severe sepsis or invasive infection
Chronic illness e.g. malignancy
What is the commonest cause of bacterial food poisoning in the UK?
Campylobacter
What are some of the more common sources of campylobacter?
Chicken, contaminated milk. puppy faeces
Why do we in the UK usually avoid infection of Campylobacter from milk?
Our milk is pasteurised so any bacteria is destroyed
What are the two species of salmonella?
Salmonella enterira
Salmonella bongori
Which bacteria causes ‘traveller’s diarrhoea’?
Enterotoxic E.Coli
What is the difference between infection and intoxication?
Infection- inject bacteria which then colonises the gut
Intoxication- eating food which is already infected
In patients with C.diff diarrhoea, what do they usually have history of?
Previous antibiotic treatment
Which two toxins does C.diff produce?
Enterotoxin and cytotoxin
Which treatments can be used to treat C.diffocile?
Metronidazole
Oral vancomycin
Fidaxomicin
Stool transplants
How can C.diff infection be prevented?
Reducing broad spectrum antibiotic prescribing
What are the 4C’s which can cause C.difficile infection?
Cephalosporins
Co-amoxiclav
Clindamycin
Ciprofloxacin
What is the treatment for C.diff infection?
Stop the precipitating antibiotic if possible
Follow published treatment algorithm
Oral vancomycin if 2 or more severity markers
->severity markers include raised temperature, raised WCC, acute rising creatinine, suspicion of toxic megacolon
What is giardiasis?
Infection caused by giardia, a type of protozoa
What are the symptoms of giardiasis?
Abdominal cramps, bloating, nausea and bouts of watery diarrhoea, malabsorption and failure to thrive
What is the transmission of giardiasis?
Contaminated water
What are the two forms of giaedia?
Cysts
Trophozoites
Which type of the giardia would be picked up on tool microscopy?
Cysts
What is the treatment for gliadiasis?
Metronidazole
Another important UK
parasite is cryptosporidium. What are the two forms?
Oocysts
Trophazoites
What are the symptoms of Cryptosporidiosis?
Watery diarrhoea, nausea, vomiting, abdominal cramps, low grade fever
What is the mode of transmission for cryptosporidium?
Ingestion of oocysts in faecal contaminated water
What is the treatment for cryptosporidium?
Rehydration
What is one of the long term problems of Entamoeba histolytica infection, a type of imported parasity?
Liver abscess
How is Entamoeba histolytica infection treated?
Metronidazole
Diloanide furoate
What is one of the most common causes of viral diarrhoea in children under 5?
Rotavirus
How is a diagnosis of rotavirus or adenovirus made?
Rapid antigen detection
Which disease is known as the winter vomiting disease and can cause diarrhoea and vomiting?
Norovirus
How does norovirus spread?
Highly infectious, often hear of hospital or cruise outbreaks
How is a diagnosis of norovirus made?
PCR
Name three organisms which cause localised illness in the intestine.
Rotavirus
Noravirus
Cholera
Name three organisms which are toxin-mediated.
E.Coli O157
C.diff
Staph Aureus
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