Viral diarrhoea and C diff infection Flashcards
What is the commonest cause of diarrhoea in kids under 3 years old?
Rotavirus
How is rotavirus spread?
Person to person
faecal-oral
Direct and indirect
When are most cases of Rotavirus contracted?
The winter
What effects does Rotavirus have in adults?
Subclinical or mild cases in adults
Which group of patients can be severely affected by Rotavirus?
The immunocomprimised
What are the features of Rotavirus infection?
Range of symptoms- Mild watery diarrhoea to profuse, and the patient can go into shock
Patient may have moderate fever first, then vomiting then diarrhoea.
The diarrhoea is not bloody
It is self limiting and lasts for about a week.
Does rotavirus have a low or a high infectious dose?
Low
Can rota virus survive outside of a host?
Yes, it can survive in the environment
What functions of the bowel are affected by rotavirus?
Absorption and secretion
What complication may children get post rotavirus infection?
What is the effect of this?
Malabsorption.
This leads to more diarrhoea.
There can be repeat infections which get milder each time.
There can be outbreaks.
How is rotavirus diagnosed?
PCR on faeces
How is rotavirus infection managed?
It is self limiting
Management is rehydration therapy
This is done orally where possible i.e. in mild/moderate disease
Antibiotics should not be prescribed
How can rotavirus be prevented?
Vaccination
An oral, live attenuated vaccine
There are 2 doses at 2 and 3 months
Who is the rotavirus vaccine not given to?
A first dose is not given to babies over 15 weeks old
No dose is give to babies over 24 weeks old
What is norovirus known as?
The winter vomiting disease
However, lately it has been causing illness all year round
Which ages are affected by norovirus?
All ages
It is highly infectious
How is norovirus spread?
Faecal-oral
Droplet
It can be spread person to person or from contaminated food or water
How long can norovirus survive in the environment for?
It can survive on fomites for days-weeks
What is the reservoir for norovirus?
Community circulation
What symptoms does norovirus cause?
Abrupt and unpredictable onset of symptoms
Explosive and sudden vomiting and diarrhoea
Vomiting can lead to widespread environmental contamination and onward transmission
What is the incubation and duration period of norovirus?
It has a short incubation period of <24 hours
it lasts 2-4 days
How is norovirus diagnosed?
PCR on stool or vomit
How is norovirus managed?
It is self limiting but very unpleasant
Rehydration therapy
Early ward closure, isolation and cohorting required.
Which patients can die partly due to norovirus?
The frail and elderly
What percentage of healthy adults have C difficile in their faeces?
2-5%
What percentage of hospital patients are colonised with C difficile?
10%
What age group has high levels of C diff in their faeces but are not infected?
Babies
What is C diff infection a side effect of?
Antibiotic treatment, as a result of disruption of the normal bowel flora
What does C diff produce?
It produces two toxins:
Toxin A is an enterotoxin
Toxin B is cytotoxic and causes bloody diarrhoea
What are the clinical features of C diff infection?
C diff associated diarrhoea an begin 2 days to some months after taking the antibiotics
Elderly hospitalised patients are most frequently affected
Symptoms can range from mild diarrhoea to profuse, water, haemorrhagic colitis, along with lower abdominal pain.
There is pseudomembranous colitis
Relapses/reinfections are common (30%)
How is C diff diagnosed?
Stool testing- microbiology
1. Sensitive screening test detects both C diff antigen and toxin
2. More specific test applied to screen positives: toxins by ELISA (enzyme-linked immunosorbant assay)
3. Culture: ribotyping
Screening tests positive and toxin positive = positive
Screening positive and toxin negative = indeterminate- re-assess and repeat.
Sigmoidoscopy - membranous lesions
CT scan
What antibiotics can cause C diff infection?
Any, but especially those beginning with C
What percentage of C diff infection is acquired in the community?
40%
What are risk factors for C diff infection?
Recent antibiotics
Surgery
Hospital
Use of stomach acid suppressants like PPI
How is a patient with an indeterminate test result managed?
Singe room
Contact precautions
Close assessment
How is CDI incidence controlled?
Good infection control (cleaning and bleach)
Strict control on antibiotic use
Surveillance at local level
Handwashing - not gels
When are more cases of C diff infection seen?
Winter
Name some non-gut infections which are spread by the faecal-oral route
Hep A
Typhoid
Vancomycin resistant enterococci
Which patients with a gut infection are the most infectious?
Those with diarrhoea
What are contact precautions for?
To prevent spread via contact with contaminated hands
To prevent indirect spread via contaminated equipment/environment
What are the contact precautions for infectious diarrhoea?
Single room Cohort bay Hand washing- not gel Glove use Apron if anticipate contamination Sometimes ward closure Limit movement Single use items Cleaning/disinfection of items Report all exposures to infective material
Is all diarrhoea infection?
No
