2: Infections of GI tract Flashcards
Define gastroenteritis
Diarrhoea cause by infection of GI tract with bacteria, virus or parasite
Define diarrhoea
More than 3 episodes of partially formed watery stool for <14d
Define dystentry
Infective gastroenteritis with blood
What is persistent diarrhoea
Diarrhoea >14d
What 6 infections are know to cause dysentry
SECCSY (Sexy)
Salmonella E.Coli Campylobacter jejuni Clostridium difficile Shigella Yersinia
What bacteria have an incubation period of 1-6h
Staph.A
Bacilleus Cereus
What bacteria have an incubation period 12-48h
E.Coli
Salmonella
What bacteria have an incubation period of 48-72h
Campylobacter.J
Shigella
What two organisms have an incubation period for more than 7 days
Giardiasis
Amoebiasis
What are two risk factors for Norovirus
- Contact with infected food, person or surface
2. Outbreaks in hospitals
What is the incubation period of norovirus
12-48h
How will norovirus present clinically
Acute-onset vomiting and watery diarrhoea
When is norovirus infection common
Winter outbreaks at hospitals and nursing homes
What type of organism is norovirus
ssRNA
how is norovirus diagnosed
Clinically
rt-PCR
how is norovirus infection managed
Oral rehydration solution
In which population is rotavirus infection more common
Most common cause of gastroenteritis in children
How will rotavirus present clinically
Vomiting and diarrhoea
What is the incubation period of rotavirus
1-3d
How is rotavirus investigated for
Clinical
ELISA Stool toxin
What is used to manage rotavirus
Oral rehydration solution
How can rotavirus be prevented
Oral live-attenuated vaccine given at 2,3m as part of immunisation schedule in the UK
What food substance can cause clostridium pefringens infection
- Undercooked meat
- Refrigerated meet
- Legumes
What is the incubation of clostridium pefringens
6-24h
How does clostridium pefringens present clinically
Crampy abdominal pain and watery diarrhoea
What organism is clostridium pefringens
Gram positive anaerobe
What is a complication of clostridium pefringens
B toxin - can cause necrotising fulminant enterocolitis. Presents as abdominal pain, bloody diarrhoea and sepsis.
Where is bacillus cereus obtained from
re-heated rice
What are two sources of cholera
- Contaminated water
- Undercooked sea-food
How will cholera present clinically
Rice-water stools
Vomiting
Low-grade fever
What type of organism is cholera
Gram negative
How can cholera be diagnosed
Rapid stool test
MC+S
What is first-line to manage cholera
Oral rehydration solution. If severe, IV fluids
If severe, what antibiotics may be given in cholera
Doxycycline
Tetracycline
What is given to children with cholera and why
Zinc - as this shortens disease duration
What is a major complication of cholera
Major dehydration.
Anyone with watery diarrhoea >5 who died in an known epidemic is diagnosed as having cholera
What is the incubation period of Giardiasis
> 7d
How can Giardiasis infection be differentiated from Amoebiasis infection
Giardiasis has diarrhoea without blood. Whereas, amoebiasis has dysentry
How does shigella present clinically
Dystentry
Tenesmus
Fever
What type of organism is shigella
Grame negative
How can shigella be investigated
Stool Culture
What is shigella managed
Oral rehydration solution
Green bananas or zinc if under 6-years
What is given to children under 6 with shigella
Zinc
What are three complications of shigella infection
Haemolytic Uraemic Syndrome
Reactive arthritis
Bacteraemia
Where is enterohaemorrhagic E.coli obtained from
Undercooked meat
How will EHEC present
Diarrhoea
Haemorrhagic colitis
How is EHEC diagnosed
Stool MC+S
Why should antibiotics not be given for EHEC
Increases risk of HUS
What is the most common cause of haemolytic uraemia syndrome
Shiga toxin produced by EHEC:O157: H7
What are two sources of campylobacter jejuni
Unpasteruised milk
Undercooked meat
How does campylobacter jejuni infection present
Dysentry
Headache
Low grade fever
What type of organism is campylobacter
Gram negative
how is campylobacter investigated
Stool MC+S
what is a major complication of campylobacter infection
Gullian Barre Syndrome
What are three sources of salmonella
Poultry
Raw eggs
Milk
What is the incubation period of salmonella
12-48h
How does salmonella present
Headache
Dysentry
Vomiting
What is used to investigate salmonella
Stool MC+S
What is a complication of salmonella
Bacteraemia can lead to osteomyelitis
What are two sources of yersinia
- Pork
- Milk
How can yersinia present
Pseudo-appendicitis
What are two complications of yersinia
Erythema nodosum
Reactive arthritis
How does amoebiasis present
Gradual onset bloody diarrhoea + abdominal pain that can last weeks
What is the most common hospital acquired infection
C.difficle
What is a risk factor for C.difficle infection
Broad-spectrum antibiotics suppress gut flora leading to overgrowth of C.diff
What antibiotics are the main cause of C.difficle infections
Second and third generation cephalosporins
What other antibiotic is associated with causing C.difficle
Clindamycin
What is a risk factor for C.difficle
Antibiotic-use
PPIs
How will C.difficle present clinically
Crampy abdominal pain
Foul-smelling diarrhoea
What test is used to diagnose C.difficle
Two-phase test
Explain the two-phase test
- ELISA for glutamate dehydrogenase
2. ELISA for toxin A and toxin B
Why is glutamate dehydrogenase tested for
Presence of GDH indicates clostridium
Why is toxin A and B tested for
If present, indicates infection opposed to colonisation
What is first-line management of C.difficle
Oral vancomycin (14d)
If C.difficle toxic megacolon is suspected what should be done
Contact colorectal surgeons urgently
If unable to take oral food/medication what should be given to treat C.difficle
IV metronidazole
What is the mnemonic to remember infection control with C.difficle
S I G H T
What is SIGHT
Suspect infection
Isolate + contact Infection control
Gloves and apron
Hand washing
Two-phase test
Once lab has confirmed C.difficle what antibiotic should vancomycin be switched to
Oral fidoxamicin (10d)
Which 3 areas is it common to obtain traveller’s diarrhoea from
Asia
Africa
South America
What causes traveller’s diarrhoea
Enterotoxigenic E.coli (ETEC)
What are 3 presentations of traveller’s diarrhoea
- Watery diarrhoea
- Abdominal cramps
- Nausea
How can traveller’s diarrheoa be prevented
Wash hands Peel fruit and veg Boil water Avoid: ice, salads, shellfish Drink through straw
How is traveller’s diarrhoea managed
Oral rehydration solution. Ciprofloxacin (3d) can be given to individuals if need diarrhoea to stop asap