Gastroenteritis Flashcards Preview

Year 2 Clinical Pathology > Gastroenteritis > Flashcards

Flashcards in Gastroenteritis Deck (50):
1

Is gastroenteritis only caused by infection?

No, can have many different causes, not just infective

2

The faecal flora is estimated to have a metabolic capacity equal to what organ?

The liver

3

What are the 3 main beneficial affects of the commensal flora of the gut?

1) Metabolism
2) Colonisation resistance
3) Antibody induction

4

What is thought to have a profound effect on the composition of gut flora?

Diet

5

Which 2 vitamins are secreted by enteric bacteria?

Vitamins K and B12

6

We are born sterile, what is the difference in the flora of bottle fed babies compared to breast fed babies?

Bottle fed - adult microflora
Breast fed - bifidobacteria

7

Are the bacteria in the gut mainly anaerobes or aerobes?

Obligate anaerobes (cant survive in presence of oxygen)

8

What are facultatively anaerobic bacteria?

Can survive in presence or absence of oxygen

9

What are the 4 most common commensal flora of the gut, what kind of bacteria are they?

1) Bacteroides (anaerobic GNB)
2) Clostridium perfringens (anaerobic GPB)
3) Escherichia coli (Facultative GNB)
4) Enterococcus faecalis (Facultative GPC)

10

Globally there are roughly how many cases of diarrhoeal disease every year?

1.7 billion

11

What is the leading cause of malnutrition in children under 5 years old?

Diarrhoea

12

What are the 8 common bacterial causes of gastroenteritis?

1) Salmonella
2) Shigella
3) E coli
4) Campylobacter
5) Vibrio cholera
6) Clostridium difficile
7) Staph aureus
8) Bacillus cereus

13

What are the 3 common parasitic causes of gastroenteritis?

1) Entamoeba hist.
2) Giardia lamblia
3) Cryptosporidium

14

Have outbreaks of foodbourne diseases in England and wales increased or decreased?

Decreased - mainly due to salmonella - more education and better food standards

15

Have outbreaks of non-foodborne diseases increased or decreased?

Increased - often related to recreational water or animal contact

16

What are the 5 main presenting complaints for gastroenteritis?

1) Acute onset
2) Vomiting
3) Diarrhoea - frequency, mucous, blood
4) Abdominal pain
5) Systemic effects - fever etc.

17

What are the 6 complications of gastroenteritis?

1) Dehydration
2) Renal failure
3) HUS - haemolytic urea syndrome
4) Toxic megacolon
5) Guillan barre syndrome
6) Dissemination of salmonella

18

What are the 3 main investigations in gastroenteritis?

1) Bloods - FBC, U&E, CRP, blood cultures
2) Abdo XR if severe
3) Stool analysis

19

What 4 tests may be used to analyse a stool in gastroenteritis?

1) Ova, parasites and cysts 'OCP'
2) Microscopy, culture and sensitivity 'MC&S'
3) Clostridium difficile toxin 'CDT'
4) Viral PCR

20

Name one common viral gastroenteritis?

Norovirus

21

Norovirus incidence is higher in which season?

Winter

22

What are the 2 main symptoms of norovirus?

1) Diarrhoea
2) Projectile vomiting

23

How long does norovirus tend to last, is it dangerous?

24-48 hours, not dangerous

24

How is norovirus spread?

Via aerosols which come off the vomit of infected people

25

How is norovirus managed?

Manage dehydration and let illness take its course, stay away from others and diligent hand washing to prevent transmission

26

What are the 3 main causes of parasitic gastroenteritis?

1) Cryptosporidium
2) Giardia
3) Entamoeba

27

Cryptosporidium is transmitted how?

Predominantly water borne disease which is spread via contaminated drinking water, swimming pools etc.

28

Why is cryptosporidium commonly spread via swimming pools?

Oocytes are resistant to chlorine based disinfectants

29

Is cryptosporidium infection more common in the first or second half of the year, why?

Second half - related to foreign travel and summer holidays

30

Via which 2 mechanisms can bacteria cause gastroenteritis?

1) Enterotoxin production - toxin produced by bacteria attacks host enterocytes
2) Adherence or invasion of enterocytes by bacteria itself

31

Other than gastroenteritis what other infection does E coli commonly cause?

UTI

32

Via what mechanism does E coli cause gastroenteritis?

Enterotoxin production

33

10-15% of patients with gastroenteritis caused by E coli also develop what complication and why?

Haemolytic urea syndrome
Toxin affects RBCs too

34

How does E coli infection lead to inflamed and fluid filled bowel?

1) Toxin produced which is internalised by epithelial cells
2) Toxin affects small proteins so that Cl- moves out of the cell followed by Na+
3) High electrolyte content in the lumen also pulls water out in the lumen by osmosis - leading to a fluid filled lumen and dehydration

35

What are the 4 main types of salmonella?

1) S. typhi
2) S. paratyphi
3) S. enteritidis
4) S. typhimurium

36

What 3 conditions does salmonella cause?

1) Food poisoning
2) Typhoid
3) Paratyphoid

37

What is the treatment for infective gastroenteritis?

Supportive management.
Generally avoid Abx as this may increase duration of salmonella carriage
Abx treatment may also worsen E coli HUS (Haemolytic urea syndrome)

38

What is the difference between tyhpoidal salmonella and non-typhoidal salmonella?

Typhoidal salmonella can disseminate to other cells outside of the GIT and cause typhoidal fever

39

Why does Abx associated diarrhoea occur?

Due to disruption of the gut microflora which leads to a change in metabolism (carbohydrates/bile acids) and overgrowth of pathogenic organisms

40

What are the symptoms of Abx associated diarrhoea?

Range from mild diarrhoea to pseudomembranous colitis and can lead to conditions such as toxic megacolon, perforation and shock

41

What is the most common cause of Abx associated diarrhoea?

C. diff - accounts for 10-25%

42

Other than C diff what 5 organisms can cause Abx associated diarrhoea commonly?

1) C perfringens
2) S aureus
3) Candida spp
4) Klebsiella spp
5) Salmonella spp

43

Risk of C diff infection increases massively with increasing...?

Age

44

What strain of C diff is associated with a 2.5-3.5 fold increased death rate and deaths in younger people?

CD 027

45

What 2 Abx are high risk for C diff infection?

1) Cephalosporins
2) Clindamycin

46

What 4 Abx are medium risk for C diff infection?

1) Ampicillin/amoxicillin
2) Co-trimoxazole
3) Macrolides
4) Fluoroquinolones

47

Which Abx is CD 027 resistant to and is therefore of particular importance?

Fluoroquinolones

48

What are the 8 CD infection control measures?

1) Early warning system to identify changes in epidemiology
2) Reduce risk of transmission
3) Early isolation/cohorting of patients with diarrhoea
4) Environmental cleaning, chlorine
5) Hand hygiene soap & water
6) Examine/optimise/reduce overall Abx use
7) Limit high risk agents in high risk patients
8) Feedback CDI and Abx data on a regular basis

49

What 2 Abx are the current therapy for CD infection and what is the new Abx?

Current: Oral metronidazole/ oral vancomycin
New: oral fidaxomicin

50

Other than Abx what is the other treatment for C diff?

Faecal transplant

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