Infectious Diarrhoea Flashcards
Vomiting is a more common symptom than nausea in patients with gastroenteritis. T/F?
False - the opposite is true
What are some of the non-intestinal manifestations of gastroenteritis?
Botulism
Gullain-Barre syndrome
If vomiting is the predominant symptom of gastroenteritis then what aetiologies does this suggest?
S.aureus
B.cereus
Norovirus
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
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
What is tenesmus?
Urgent desire to defecate and a feeling of incomplete defecation
Which bacteria commonly cause gastroenteritis?
Campylobacter Salmonella Shigella E.coli 0157 Clostridium difficile
Which viruses commonly cause gastroenteritis?
Norovirus
Sapovirus
Rota virus
Adenoviruses
Which parasites commonly cause gastroenteritis?
Cryptosporidium Giardia Entamoeba histolytica Cyclospora Isospora
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
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
Diarrhoeal disease is self-limiting. T/F?
True
What technique is used to look for ova and cysts if parasitic causes of gastroenteritis are suspected?
Microscopy
How might viruses be identified when investigating gastroenteritis?
PCR
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
How is the dehydration which accompanies diarrhoea treated?
Oral rehydration salts or (if severe diarrhoea) IV fluids
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
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
What types of antibiotics are most commonly used in the treatment of gastroenteritis?
Quiolones
Symptomatic treatment is used in gastroenteritis. T/F?
False
What kind of food is campylobacter most commonly found?
Uncooked poultry
Campylobacter has a high infectious dose of around…?
9000 organisms
Campylobacter is sensitive to stomach acidity. T/F?
True
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
