Infectious diarrhoea (I) Flashcards
How can we define diarrhoea?
The passage of:
- 3+ loose or liquid stools per 24h, and/or
- stools that are more frequent than what is normal for the individual lasting <14d, and/or
- stool weight >200g/day
How can we classify diarrhoea based on duration? (3)
- acute (</=14 days)
- persistent (>14 days)
- chronic (>4 weeks)
Why does diarrhoea occur?
Decreased absorption or increased secretion of fluid and electrolytes, or increase in bowel motility
What viral causes of diarrhoea are there? (3)
- Norovirus
- Rotavirus
- Adenovirus
What bacterial causes of diarrhoea are there? (6)
- Campylobacter jejuni (gram -ve curved rod best incubated at 42C) - after exposure to poultry
- E. coli (gram -ve rod) - traveller’s diarrhoea
- C. diff (anaerobic gram +ve rod) - Abx and PPI-associated diarrhoea
- Shigella (gram -ve rod)
- Salmonella (gram -ve rod)
- Bacillus cereus - incubation period 6h until vomiting and diarrhoea
What parasitic causes of diarrhoea are there? (3)
- Giardiasis - can cause lactose intolerance
- Enterobiasis
- Amebiasis
What are some risk factors for infectious diarrhoea? (4)
- recent travel (traveller’s diarrhoea - E. coli)
- exposure to outbreak
- recent hospitalisation (C. diff)
- medication use
What condition is infectious diarrhoea associated with?
Gastroenteritis - may be accompanied by abdominal pain and N/V
What are the main clinical features of infectious diarrhoea? (4)
- sudden onset watery/fatty/bloody stool
- fever
- abdominal pain and cramping
- nausea and vomiting
What is the most common cause of food poisoning from raw meat?
Campylobacter jejuni –> bloody diarrhoea
What type of disease can Salmonella cause, and what are the features of this?
Typhoid fever:
- non-bloody, yellow-green ‘pea soup’ diarrhoea
- fever
- abdominal pain
- rose spots over abdomen
How is Salmonella spread? (3)
- eggs
- poultry
- contaminated food
How is Bacillus cereus spread? (2)
- rice
- pasta
When does S. aureus infection cause its symptoms and what are they?
- starts 1-6h after exposure
- profuse vomiting (only mild diarrhoea)
What is the incubation period and main symptom of norovirus?
- highly infective - incubation period 12-24h
- projectile vomiting
What is the incubation period and main symptoms of Campylobacter? (4)
- incubation period of 1-6 days
- prodrome - headache, malaise
- bloody diarrhoea
- abdominal pain - may mimic appendicitis
What is the incubation period and main symptom of E. coli?
- incubation period: 3-4 days
- commonly after air travel (traveller’s diarrhoea)
- bloody diarrhoea lasting up to 1 week
What is the incubation period for Bacillus cereus?
6h –> vomiting and diarrhoea
How is Entamoeba histolytica spread?
Contaminated water
What are the symptoms of Giardiasis? (4)
After ongoing diarrhoea and recent travel:
- abdominal pain
- bloating/flatulence - can develop lactose intolerance after Giardiasis
- steatorrhoea
- lethargy
How do we diagnose bacterial infections (infectious diarrhoea)?
Stool culture
When is a stool culture recommended in a primary care setting for infectious diarrhoea? (6)
- patient systemically unwell and needs hospital admission +/- Abx
- blood or pus in stool
- immunocompromised
- recently received Abx, PPI or been in hospital
- recent foreign travel
- public health indication - diarrhoea in high-risk, suspected food poisoning
How do we diagnose viral infections (infectious diarrhoea)?
PCR
What other investigations can be done for infectious diarrhoea? (2)
- U&Es - if severe may show AKI, hypokalaemia and hyponatraemia
- CRP and ESR for inflammation
What supportive treatment do we give for infectious diarrhoea with no systemic signs? (3)
- bed rest
- fluids
- electrolyte replacement - oral rehydration therapy (ORT)
How do we manage infectious diarrhoea with systemic signs? (3)
- admit
- IV fluids
- stool culture
What medication can we give for infectious diarrhoea symptoms?
Anti-diarrhoeal agents e.g. loperamide
What antibiotics can we give for C. diff infectious diarrhoea?
Oral vancomycin (+ IV metronidazole if severe)
What antibiotics can we give for Campylobacter infectious diarrhoea?
Clarithromycin if severe
What antibiotics can we give for E. coli infectious diarrhoea?
Ciprofloxacin
