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Flashcards in GI Infectious Diseases Deck (97):
1

What percentage of children under 5 dying is caused by diarrhoea? Pneumonia?

diarrhoea: 11%
pneumonia: 18%

2

why does diarrhoea kill
1. immediately
2. delayed?

1. fluid and electrolyte loss
2. malnutrition

3

Which bugs have a 20x higher death rate post infection?

ecoli, shigella, parasites

4

33% of all children deaths are caused by?

malnutrition

5

2 ways diarrhoea causes malnutrition?

1. increased energy loss
2. reduced energy intake

6

2 reasons for reduced energy intake in diarrhoea?

malabsorption post gut damage
withholding of food (moms think breast milk caused it)

7

how is Gut damage in kids different than adults?

kids guts repair slower

8

out of 10 litres of liquid consumed in 24 hours, how much is absorbed?

9.9 litres

9

what is the reserve capacity of the GIT for fluids?

4-5 litres

10

what happens if you surpass the reserve capacity of the GIT for fluid?

diarrhoea

11

3 aetiological agents of diarrhoea?

bacteria
viruses
protozoa

12

What is the predominant cause of diarrhoea in developed countries?

Viral 40%

13

What is the predominant cause of diarrhoea in developing countries?

bacterial (35%)

14

Gastroenteritis generally just means?

vomiting and diarrhoea

15

dysentery needs to have?

blood, pus, mucous in the feces

16

enteroinvasive ecoli AKA:

shigella

17

shigella causes what kind of diarrhoea?

dysentery

18

what does entamoeba histolytica cause? what is it?

protozoal cause of dysentery

19

Which foods do you find staph and salmonella poisoning in?

Mayonnaise (raw eggs)

20

Listeria outbreaks recently in which foods?

soft cheeses

21

clostridium perfringes, bacillus, vibrio are from what kind of syndrome?

food poisoning

22

ciguatoxin si dangerous why?

can kill

23

Traveller's diarrhoea mainly caused by?

ETEC, bac, viruses, protozoa

24

What causes atibiotic-associated colitis?

Clostridium difficile

25

What the difference between dysentery and haemorrhagic colitis?

No pus in the faeces

26

main bug that causes haemorrhagic colitis?

EHEC (entero-hemorrhagic e.coli)

27

What causes cholera-like symptoms?

vibrio cholerae, ETEC

28

enteric fevers are local or systemic?

systemic

29

Which 2 bugs cause enteric fever?

salmonella typhi
salmonella paratyphi

30

What is ETEC?

enterooxigenic E. coli

31

What is EPEC?

Enteropathogenic E. coli

32

What is EHEC?

enterohaemorrhagic E. coli

33

what is EIEC?

enteroinvasive E. coli

34

what is EAEC?

enteroaggregative E. coli

35

What are the adhesins for ETEC?

CFAs

36

What are the adhesins for EPEC?

intimin, Bfp

37

What are the adhesins for EHEC

intimin and Efa

38

EHEC evolved from?

EPEC

39

What are the adhesins for EAEC?

AAF

40

Which ecoli can secrete shiga toxin?

EHEC?

41

shiga toxin is AKA?

verotoxin

42

which two ecoli cause watery diarrhoea?

ETEC
EAEC

43

which ecoli causes bloody diarrhoea?

EHEC

44

what does EIEC cause?

dysentery

45

EPEC causes?

non-specific gastro

46

5 levels of invasion of mucosa?

1. adhesive enterotoxigenic
2. adhesive with bush border damage
3. invasion restricted to muscosa
4. invasion of submucosa
5. systemic invasion

47

Bugs that are adhesive enterotoxigenic?

cholera, ETEC

48

Bugs that are adhesive enterotoxigenic adhesive with bush border damage?

EPEC

49

Bugs that are invasion restricted to muscosa

shigella

50

Bugs that are invasion of submucosa

salmonella
capylobacter

51

Bugs that are systemic invasion?

salmonella

52

What happens if immunocompromised patient has invasion of submucosa bugs like: salmonella
capylobacter?

could turn systemic

53

EPEC has two stages of adherence they are?

1. plasmid mediated
2. chromosomal (attachment)

54

where do you find bundle forming pili?

stage one plasmid mediated adherence of EPEC only

55

Do mammals use Type III secretion systems?

Nope. ONLY pathogens

56

Why is Type III secretion system for pathogens special?

gets a protein DIRECTLY from bacterial cytoplasm to host cytoplasm via small 'syringe'

57

the Tir and Intimin combo is unique in nature for the following reason?

TIR = translocated intimin receptor
essentially e.coli secretes it's own receptor onto our cells so that their intimin can adhere to our cells

58

Which shigella is the worst and the only one that produces shiga toxin?

shigella dysenteriae

59

do ALL shigella dysenteriae produce shiga toxin?

Nope.

60

Do ALL EHEC produce shiga toxin?

yes by definition

61

what does HUS stand for?

Haemolytic urea syndrome

62

Haemolytic urea syndrome caused by which toxin?

NEED shiga toxin

63

4 Virulence Determinants?

adhesins
invasive ability
exotoxins
ability to resist killing

64

3 pathogens that are invasive?

shigella
salmonella
yersinia

65

2 kinds o adhesins?

fimbriae
non-fimbriate

66

2 kinds of exotoxins?

cytotonic: cholera
cytotoxic: shiga

67

2 ways to resist killing?

resist serum
resist phagocytes (eg. salmonella, macrophages)

68

are there microvilli on immature enterocytes?

Nope

69

after damage by rotavirus, what happens to intestinal architecture?

flattening of microvilli/improper absorption

70

do labs culture viruses?

only for the more common ones

71

5 things the lab does to diagnose pathogens?

macroscopic appearance
microscopy
culture
antigen detection
detection of nucleic acid

72

Would you see bacteria with amoeboid infection? Why?

Nope, because amoebas eat bacteria!

73

Trophozoites of Giarbia lamblia are found where usually?

proximal small intestine, then let go an move down the gut making cysts along the way

74

In active trophozooite of Entamoeba histolytica, what the smoking gun in the diagnosis?

RBCs ingested by the amoeba on light microscope

75

Entamoeba histolytica can live as two things

commensal and pathogen

76

3 ways to culture faeces

enrichment (salmonella)
direct plating on selective/indicator media
confirm suspicious colonies

77

3 ways to confirm suspicious colonies?

biochem tests (virulence typing)
serotyping (EHEC0157, salm.typhi)
pathotyping (PCR)

78

What the last resort for viral infection diagnosis?

electron microscopy

79

3 ways to diagnose viral infections

antigen detection
detection of nucleic acid
electron microscopy

80

Eg. of when you would use capture assay for antigen?

rotavirus from a faeces sample

81

Viral nucleic acids by PCR revealed by?

electrophoreses

82

2 best treatments for diarrhoea?

1. fluid and electrolyte replacement
2. reduce fluid loss

83

Why give electrolytes with fluid?

electrolytes help the body uptake water as water and other ions follow Na+

84

3 kinds of anti-diarrhoeals? (do they work?)

antimotility (still diarrhoea-ing on inside)
anti-secretory agents (doesn't work)
binding agents (does stop it, just looks better)

85

Is shiga toxin dangerous to non-humans?

Not as dangerous as they have the shiga toxin receptor and only destroys a few gut cells

86

Why is shiga toxin dangerous to humans?

we don't have a shiga toxin receptor so it can pass straight through and cause havoc on brain/heart etc.

87

Antibiotics for diarrhoea, what does it do for cholera?

shortens illness a smidge

88

which systemic infection MUST you treat with Antibiotics for diarrhoea?

typhoid fever

89

Antibiotics for diarrhoea for immunocompromised patients?

yes

90

treat shigella dystenteriae with antibiotics?

yes indeed

91

Would you treat someone with a protozoal infection even if they feel fine?

Yes. Always treat

92

Why is pseudomembranous colitis treatment paradoxical?

treatment is antibiotic (metronidazole)
caused by: antibiotics

93

WHO two best ways to reduce incidence of diarrhoea?

1. education: hygiene, breast-feeding
2. immunisation

94

3 ways to prevent traveller's diarrhoea?

reduce exposure
antimicrobials (maybe)
immunisation (active/passive)

95

what's the function of bundle forming pili?

prevent washing away of pathogen due to peristalsis

96

LEE pathogenicity island stands for?

Locus of Enterocyte Effacement

97

EPEC and EHEC both made which two adherins?

intimin and LEE