GI infection and Gastroenteritis Flashcards
What is the commonest bacterial cause of food poisoning?
Campylobacter
What food poisoning pathogens have a short incubation period and why is this?
Staph aureus, bacterius cerus
They are pre formed toxins
What is a short incubation time?
1 - 6 hours
Describe the presentation of bacillus cerus infection
- Common after eating rice/pasta
- Initially vomitting
- Diarrheoa within 1 - 6 hours
(usually not bloody)
Describe how a campylobactor infection would present?
Long incubation time (2 - 14 days following exposure)
Blood diarrhoea
Usually due to eating raw poultry
What antibiotics would you use to treat campylobactor?
Ciproflaxin
Erythromycin
(but only in some circumstances - very old/very young)
What is the incubation period of salmonella enteritidis?
12 - 48 hours
How do you determine the type of infecting salmonella?
- Antigen on body, 0 antigen/ serotype (B, C and D most common) allows to follow outbreak
- Antigen on tail (serotype) allows you to decide the most likely origin
How do you test for the body antigen in salmonella?
Slide agglutination test
Give two serotypes of salmonella
Salmonella enteritidis
Salmonella Typhimurium
What are the key features of E Coli 0157?
Bloody diarrhea, most often in children under 16 (especially those under 5. Recent contact with farm animals/raw milk.
What is the increased risk with E Coli infection?
Release of verotoxins with can then cause Haemolytic uraemia syndrome.
What is HUS?
Verotoxins act to cause apoptosis in RBC’s and kidney causing the patient pain fever and bloody diarrhoea
What is a marker for cell damage that will be raised in HUS?
lactate dehydrogenase
What tests would you perform on a patient you suspect has HUS?
Stool culture U & E FBC Clotting Lactate dehydrogenase Urine dipstick
How do you treat HUS?
Monitioring/ rehydration NO antibiotics NO anti motility NO NSAIDS Inform Health protection unit
How does rotavirus present?
Watery diarrhoea (no blood) Children under 5
How is rota virus spread?
Faecal oral
How do you test for rotavirus?
PCR on faeces
How do you treat rotavirus?
Hydration
How is the rotavirus vaccine given?
Orally given live attenuated vaccine given at 2 and 3 months old
How is noro virus spread?
faecal oral/droplet
How is noro virus tested for?
PCR of faeces
How do you treat norovirus?
Rehydration
What toxins does C Diificile produce?
Entero/cytotoxins
What does C Difficile produce that makes the infection so difficult to contain?
Spores
What kind of colitis is found in C Difficile infection?
Pseudomembranous colitis
How do you test for C Difficile?
- Sensitive screening test (detects antigen and toxin)
- More specific test (done when screening is positive to test for further toxins)
- Stool culture
What do you do if the screening test in positive but the toxin is negative?
Re assess and repeat tests
What tests do all stools get tested for?
Salmonella, Shigella, Campylobactor, E Coli 0157 and cryptomagalovirus
Anyone over 15 years gets C Diff test also
What is acute enteritis?
Fever, D &V, abdominal pain
What is acute colitis?
Fever, pain, bloody diarrhoea
What is enters fever like illness?
fever, rigors, pain, little diarrhoea
What are the most common infectious causes of bloody diarrhoea?
Campylobactor, shigella, e coli, amoebiasis
Give some non infectious causes for bloody diarrhoea?
IBD
Malignancy
Ischaemia
What is a further disease that could develop as a result of campylobactor infection?
Guillain barre syndrome
What tests would you need to diagnose typhoid?
Blood cultures (most important) Stool and urine cultures
How does typhoid present?
Traveller (e.g. india)
Mile bacteraemia, enterocolitis
How effective is the typhoid vaccine?
70% against typhoid but not effective against parathyroid
When would you order a stool microscopy?
Suspicion of parasites
When would you do a stool culture?
Salmonella, campylobacter, shigella
When would you do a stool toxin?
C Difficiile
When would you do blood cultures?
Salmonella, Typhoid
Why would you do a FBC?
Asses severity of C Diff infection
Why would you do U & E tests?
Assess renal function (e.g. from dehydration)
When would you want to give antibiotics?
Typhoid Shigella E coli (sometimes) Cholera C Diff Giardiasis Amoediasis Invasive Salmonella
WHat antibiotic would you give to patients with gastroenteritis
Ciprofloxacin for 3 - 5 days
What is the gram stain of c diff?
Gram positive, spore forming, bacillis
What antibiotics precipitate C diff?
fluoroquinolones, cephalosporins, clindamycins, broad spectrum penicillins
(most begin with C)
What other medication can precipitate C diff?
PP1
Histamine 2 antagonist
Chemotherapy
What are the four C antibiotics?
ANTIBITOICS- CEPHALOSPROINS, CLINDAMYCIN, CIPROFLOXACIN [QUINOLONES] , CLARITHROMYCIN [ MACROLIDES]
How do you treat pseudomembranous colitis?
Discontinue current antibiotics, PPIs Avoid opiates and anti peristaltic drugs Non severe: Metronidazole (10 - 14 dyas) Severe: Vancomycin (orally)
What is a future drug that could be used to treat C Diff?
Fidaxamicin
When will fidaxomicin be used?
For first relapse within 12 weeks of initial infection
What is amoebiasis?
Protozoal infection spread by faecal oral route seen in areas of poor sanitation
How do you diagnose amoebiasis?
Hot stool microscopy
Also serology
How do treat amoebiasis?
Metronidazole
Removal from lumen using diloxanide furoate or paromomycin
What are the symptoms of giardiasis?
Foul smelling diarrhoea
mal absorption
How is giardiasis spread?
By cysts in normal drinking water
How is the diagnosis of giardiasis made?
Hot stool microscopy
Duodenal aspiration
How do you treat giardiasis?
Metronidazole
What is cryptosporidiosis?
A parasite that is one of the main causes of travel related diarrhoea infection. Usually self limiting
How do you treat cryptosporidosis?
Supportive
Nitizoxamide?
How do you diagnose cryptosporidosis?
Duodenal aspirate
Stool microscopy
