Infectious Diarrhoea Flashcards by Lauren Horsburgh

Vomiting is a more common symptom than nausea in patients with gastroenteritis. T/F?

False - the opposite is true

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What are some of the non-intestinal manifestations of gastroenteritis?

Botulism

Gullain-Barre syndrome

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If vomiting is the predominant symptom of gastroenteritis then what aetiologies does this suggest?

S.aureus
B.cereus
Norovirus

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What diarrhoeal symptoms are particularly associated with infection of the small intestine?

Large volume of watery stool
Not usually blood in the stool
Cramps
Bloating
Wind
Weight loss
Rarely there is fever

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What diarrhoeal symptoms are particularly associated with infection of the large intestine?

Small volume of stool
frequent stool passage which is often painful
associated with fever and blood in the stool

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What is tenesmus?

Urgent desire to defecate and a feeling of incomplete defecation

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Which bacteria commonly cause gastroenteritis?

Campylobacter
Salmonella
Shigella
E.coli 0157
Clostridium difficile

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Which viruses commonly cause gastroenteritis?

Norovirus
Sapovirus
Rota virus
Adenoviruses

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Which parasites commonly cause gastroenteritis?

Cryptosporidium
Giardia
Entamoeba histolytica
Cyclospora
Isospora

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What factors in a patients history are particularly important in cases of gastroenteritis?

Food history
Onset and nature of symptoms
Residence and travel
Occupation
Pets
Hobbies
Recent hospitalisation
Recent antibiotic use
Comorbidities

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Stool cultures can be used to investigate gastroenteritis but have a low rate of positive results. Why is this?

Many causes of diarrhoea are actually viral

Many bacteria which cause gastroenteritis can only survive in very specific environments

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Diarrhoeal disease is self-limiting. T/F?

True

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What technique is used to look for ova and cysts if parasitic causes of gastroenteritis are suspected?

Microscopy

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How might viruses be identified when investigating gastroenteritis?

PCR

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Why might endoscopy and biopsy be used in investigation of gastroenteritis?

To look for alternative non-infective causes of diarrhoea if other tests are negative

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How is the dehydration which accompanies diarrhoea treated?

Oral rehydration salts or (if severe diarrhoea) IV fluids

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Why do oral rehydration salts contain glucose and salt?

Because, despite the diarrhoea the sodium/glucose transporters are often still functioning and so using glucose and sodium in the oral rehydration salts helps to increase the absorption of water

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Antibiotics should only be used in specific incidences when a patient has gastroenteritis. What are these?

Sepsis
Significant co-morbidities
Causal agents such as c.difficile

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What types of antibiotics are most commonly used in the treatment of gastroenteritis?

Quiolones

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Symptomatic treatment is used in gastroenteritis. T/F?

False

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What kind of food is campylobacter most commonly found?

Uncooked poultry

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Campylobacter has a high infectious dose of around…?

9000 organisms

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Campylobacter is sensitive to stomach acidity. T/F?

True

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Campylobacter has a short incubation period of around…?

3 days

What are the symptoms of campylobacter symptoms?

``` Frequent, high volume and bloody diarrhoea Abdominal pain Nausea Fever (Vomiting is not common) ```

Campylobacter infections are self-limiting and usually disappear within how many days?

7 days

Campylobacter has a high rate of resistance to antibiotics. T/F?

True

What are the potential late complications of campylobacter infection?

Reactive arthritis | Gullain-barre syndrome

How does salmonella spread?

Commonly found in poultry | Spreads person to person

What kind of pets put people at a higher risk of salmonella infection?

Reptiles such as snakes

Salmonella has a high infectious dose of around...?

10,000 organisms

Salmonella is sensitive to stomach acidity. T/F?

True

Within how many hours of ingestion of salmonella do patients become unwell?

72 hours

What symptoms does salmonella infection usually cause?

Diarrhoea Nausea Abdominal Cramps Fever

Because salmonella is invasive it can, in rare cases, cause bacteraemia. This can cause secondary infectious such as...?

Endocarditis Osteomyelitis Mycotic aneurysms

Salmonella infection is a self-limiting disease and lasts around how many days...?

10 days

There can be asymptomatic shedding of salmonella for up to how many weeks?

5 Weeks

In what foodstuffs is E.coli 0157 present?

Mince Spinach Bean sprouts

E.coli 0157 can be spread person to person. T/F?

True

E.coli 0157 produces shiva toxin. What are its effects?

Eneterocyte death | Enters the systemic circulation

What is the incubation period of E.coli 0157?

3-4 days

What symptoms result from E.coli 0157 infection?

Bloody diarrhoea and abdominal tenderness

Haemolytic uraemia syndrome is a very serious complication of the effects of the shiva toxin. What does this involve?

Microangiopathic haemolytic anaemia Acute renal failure Thrombocytopaenia

What percentage of patients with haemolytic uraemia syndrome will require dialysis?

50%

If a person infected with E.coli 0157 develops haemolytic uraemia syndrome how many days after the onset of diarrhoea will the syndrome present?

5-10 days

There is an associated between haemolytic uraemia syndrome and antibiotic use. T/F?

True

Describe the pathogenesis of C.difficile infection?

Normally when c.difficile is ingested the healthy bowel will provide resistance to it. But when there is a reduction in colon resistance (normally due to age or antibiotic use) this causes colonisation and toxin production

What symptoms result for c.difficile infection?

Loose stool and colic Fever Leukocytosis Protein losing enteropathy

Infection by which bacterium causes pseudomembranous colitis?

C.difficile

How has the incidence of c.difficle in Scotland been reduced?

More careful use of antibiotics

What techniques are used to identify c.difficile infection?

ELISA assays and then tests for toxin presence if these are positive

How is c.difficile infection treated?

Stopping causative antibiotics Using metronidazole or vancomycin Facial transplant to recolonise with normal flora

What is the most common viral cause of gastroenteritis?

Norovirus

What is the route of transmission for norovirus?

Facael oral route

What is the infectious dose of norovirus?

10-100 viruses

What is the infectious dose of E.coli 0157?

10 organisms

Norovirus is very stable in the environment - it can survive alcohol gel, bleach and temperatures of up to...?

60 degrees Celsius

How long does norovirus diarrhoea last?

24-28 hours

There is long lasting immunity to norovirus. T/F?

False