Gastroenteritis

Question 1

What are common causes of diarrhoea?

Answer 1

• Bacterial: samlonella, E.Coli, campylobacter, C.Diff, staph aureus
• Non infective
• Viral: Noro/rotavirus
• Parasitic: cryptosporidium, Giardia lamblia, Entamoeba

Question 2

Describe viral gastroenteritis

Answer 2

• Norovirus
• Diarrhoea & projectile vomiting
• 24-48hrs
• Aerosol transmission= low infective dose

Question 3

What parasites can cause parasitic gastroenteritis?

Answer 3

• Cryptosporidium
• Giardia
• Entamoeba

Question 4

Describe cryptosporidium infection

Answer 4

• Cryptospordiosis mainly waterborne disease (contaminated water)
• Oocyst resistant to chlorine based disinfectant
• Watery diarrhoea
• Mild to severe mainly children affected
• 2nd half of the year though to be caused by C.hominis

Question 5

In bacterial gastroenteritis what pathogens produce enterotoxins?

Answer 5

• Vibrio cholerae
• E.Coli
• Clostridium perfringens
• Staph aureus
• Bacillus cereus
• C.Diff

Question 6

In bacterial gastroenteritis what pathogens produce adherence?

Answer 6

• Shigella sonnei/flexneri
• E.Coli
• Salmonella
• Campylobacter jejuni

Question 7

What is E.Coli’s mechanism of action?

Answer 7

• Similar to cholera
• Toxin activates G protein leading to inc levels of cAMP
• Activates ion channels- overexcretes ions
• Water follows out of cell into bowel
• Efflux of K or Cl ions meaning water loss by osmosis

Question 8

How is gastroenteritis treated?

Answer 8

-Supportive
-No antibiotics
Except: V. young/old, campylobacter-prolonged/severe symptoms, invasion

Question 9

What antibiotics are associated with a high & medium risk of C.Diff infection?

Answer 9

• High: Cephalosporins, Clindamycin

- Medium: Macrolides, fluoroquinolones, co-trimoxazole, ampicillin/amoxicillin