Week 101 Diarrhoea Flashcards
Name the Microbial Causes of acute Diarrhoea
Viruses, Bacteria, Parasites
What is the leading cause of gastroenteritis worldwide, and infects most children throughout the world in early childhood?
ROTOVIRUS
What is the second most common cause of AD in children in developed countries? It typically presents in winter months in closed communities.
NOROVIRUS
During a history from a middle aged woman with AD, you note that she owns several birds. Which pathogen is present in the GI tract of wild and domesticated birds?
Campylobacter
A patient presents with AD. A young child, that went with the family to a chicken house the previous evening, which is located next to a pet shop. What is the likely pathogen?
Salmonella. Transmission is mainly via contaminated food stuffs, and the pathogen is present in the GI tract of animals.
What is EHEC?
Enteroheamorrhagic Escheria. Coli. This is the most common cause of Diarrhoea in the US. Shed in cattle Faeces.
Can be life threatening when associated with haemolytic uraemic syndrome.
What is ETEC?
Enterotoxigenic E. Coli. Most common cause of “Travellers Diarrhoea” when in poor countries with poor sanitation. Causes tens of thousands of deaths every year in developing countries.
A photographer visiting a slum in southern India returns home with Acute Diarrhoea. They didn’t have access to good sanitation when there. What is the likely cause?
ETEC
A UN convoy is forced to stay overnight in a remote African village. They find a local well, and draw water from it. The next day all persons that drank the water have severe diarrhoea, some of them malaenic. What is the likely cause?
Cholera. Endemic in many countries with poor sanitation. Occurs in outbreaks, especially following the contamination of a water supply.
A gap year student returns home from their travels in remote Malaysian villages, and a few days later develops severe dysentry. What is the likely cause?
Though ETEC is a possibility, the severeity of symptoms suggests that this may be Shigellosis.
A 78 yr old man has been readmitted with severe ando pain and bloody diarrhoea after being discharged only 7 days ago, after you cleared up his chest infection with metronidazole. What is the likely pathogen in this instance?
Clostridium Difficile. It’s best to get these patients OUT of the ward and into isolation, as they may infect other compromised patients.
Name TWO parasites that cause AD in developed countries.
Giardiasis
Cryptosporidium
A patient arrives at your surgery describing some abdo pain and a foul smelling, pale, floating stool for the last few days. What do you suspect?
Parasitic infection with Giardia. Metronidazole is the drug of choice for treatment.
The news reports that the local village of gwynerthtrrerkjfhkdjks recently had a slurry contamination of its water supply (about a week ago). A patient now arrives at your surgery from the area, complaining of general fever and gastroenteritis. You suspect a parasite - but what is it?
Cryptosporidium. Most commonly outbreak when sewage/animal waste and water supplies get mixed up.
What is a cause of Dysentry in developing countries, other than cholera and giardiasis?
Entamoeba HIstolytica
Which bacteria causes diarrhoea with Toxin A and Toxin B?
C. Difficile.
Why is a patient that takes omeprazole more at risk of c. difficile than someone that is not taking it?
Omeprazole is a proton pump inhibitor, and it neutralises stomach acid. This compromises the gastric acid barrier to infection, increasing the risk of C. difficile infection.
What is E.Coli 0157?
An EHEC!
What is the HUS bacteria?
E.coli 0157!
What is meant by the term secretory Diarrhoea?
This means that diarrhoea is caused by either an increase in the active secretion, or the inhibition of absorbtion of water from the small intestine. There is little to no structural damage, and is usually caused by a pathogen that alters ion transfer into the lumen of the gut. Fasting does NOT help.
What is osmotic Diarrhoea?
Too much water drawn into the bowell from hyperosmolar fluid in the lumen. May be due to high consumption of sugary food, or maldigestion (due to pancreatic or coeliac disease). This is also how osmotic laxatives work. Fasting usually corrects non serious cases.
Define Virulence
A Multifactorial variable made up of virulence factors that denotes capacity to cause disease, and can be expressed as the number of cells required to elicit a specific immune response.
Give an example of a virulence factor.
Adhesion factor/Invasion Factor