Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GI - Y2 > L9 - GI Infections 1 : Bacterial Gastroenteritis > Flashcards

L9 - GI Infections 1 : Bacterial Gastroenteritis Flashcards

1
Q

Describe norovirus

  • incubation periods
  • symptoms
  • diagnosis
A

Incubation period: 24-48hrs
Prominent vomitting.
Diagnosis
- electron microscopy, antigen or DNA detection (PCR) in stool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Astrovirus

- symptoms

A

Symptoms

- diarrhoea in small children and immuno-compromised individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Rotavirus

  • incubation period
  • symptoms
  • where does it infect
A

Infects enterocytes, major cause of diarrhoea in kids.
48hr incubation period.
Watery diarrhoea, vomitting, fever, abdominal pain and dehydration.
Diagnosis: enzyme immunoassay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Cholera

- organism

A

Vibrio cholerae - comma shaped, gram negative.

Contaminated drinking water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pathogenesis of cholera and how it will eventually cause diarrhoea

A

Cholera - 5 beta subunit, 1 alpha subunit

  • 5 beta subunit binds to GM1 ganglioside on surface of interstitial cell
  • Enters via endocytosis , retrorgrade transport
  • RER: ASU reduced by disulfide isomerase
  • ASU fragment unfolded and released into cytosol
  • Transported via host cell machinery. Normally hcm would move and sipose of misfolded proteins via proteasome.
  • ASU refolds to avoid degradation
  • ASU interacts with cytosolic ADP ribosylation factors to ribosylate and activate stimulatory G-proteins
  • adenyl cyclase
  • increases intracellular cAMP
  • cAMP inhibits Cl-, Na+ absorption
  • Opens CFTR channels
  • Release Cl-
  • Cl-, Na+, HCO3- accumulate in lumen, cause osmotic pull of water into lumen
  • DIARRHOEA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Clinical features of cholera

A 
Voluminous stools. 
Fishy odour. 
Dehydration. 
Hypotension. 
Muscular cramping. 
Anuria.
Shock.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What might be given to relieve symptoms of cholera

A

CFTR inhibitor blocking Cl- secretion.

Prevents diarrhoea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe campylobacter entercolitis?

A

Food poisoning.

Motility, adherence, toxin production and invasion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe shigella

A

Gram negative, Bloody diarrhoea. Causes Shigellosis.
Resistant to acidic pH of stomach.
Travels to intestine and is taken up by M-cells.
Shigella proliferate and escape into laminar propia.
Phagocytosis by macrophages.
Induce apoptosis
- inflammatory response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are M cells

A

Intestinal epithelial cells specialised for antigen sampling.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Salmonella

A

Salmonella typhi causes typhoid fever.
Non typhoid salmonella.
Capable of transferring bacterial proteins into M-cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Ribosylation

A

Addition of ribose to a protein

ADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe typhoid fever?

A

Salmonella enterica.
Able to survive in gastric acid.
Taken up by M-cells once in small intestine.
Bacteria engulfed by mononuclear cells in the underlying lymphoid tissue.

symptoms:

  • anorexia
  • abdominal pain
  • bloating
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the different toxins that E-Coli produce?

A

Heat labile toxins LT

Heat stable toxins ST

Both induce chloride and water secretion while inhibiting intestinal fluid absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the LT toxin produced by E-coli

A

Activates adenylate cyclase.
Increases cAMP.
Stimulates Cl- secretion.
Simultaneously inhibits absorption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the ST toxin produced by E-coli

A

Binds to guanylate cyclase.

increases cGMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe psuedomembrane colitis?

A
  • Generally caused by C-Diff
  • toxins cause ribosylation of small GTPases, RHO family of GTPases
  • leads to disruption of epithelial cytoskeleton, tight junction barrier loss, cytokine release and apoptosis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Norovirus will cause..

A

Norovirus: single stranded, RNA genome

Mild villous shortening.
Loss of microvilli brush border.
Crypt hypertrophy.
Lamina propia infiltration by lymphocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe damage caused by rotavirus

A

Rotavirus: segmented double stranded RNA genome.

Enterocyte damage can induce epithelial apoptosis.

Antibodies in breast milk provide protection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Damage caused by adenoviruses

A

Non-specific villous atrophy.

Compensatory crypt hyperplasia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Summarise the three main ways that bacteria can cause diarrhoea?

A
  1. Secretory toxins
  2. Cytotoxins
  3. Direct invasion
    - tends to be intracellular bugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Presentation of Campylobacter jejuni

A

Abdo pain

Diarrhoea +/- dysentry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Complications of campylobacter jejuni

A

Guillain-Barre syndrome
- ascending weakness and sensory loss starting in toes to fingers.

Reactive arthritis
- joint pain and swelling triggered by an infection in another part of the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Presentation of salmonella spp. (non-typhoidal)

A

Diarrhoea
Vomiting
Fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Complications of salmonella spp. (non-typhoidal)

A 
Bacteraemia +/- metastatic infection 
Septic arthritis (sickle cell)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Incubation period of Campylobacter jejuni

A

Days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Incubation period of Salmonella spp. (non typhoidal)

A

Hours - Days

28
Q

Presentation of Shigella spp.

A

Diarrhoea +/- dysentery

29
Q

Complications of Shigella

A

Haemolytic-uraemic syndrome (VTEC)

  • destruction of blood platelets (clotthing)
  • low red blood cell count (anaemia)
  • kidney failure due to damage of very small blood vessels of the kidneys
30
Q

Incubation of Shigella

A

Days

31
Q

Source of Shigella

A

Human GI tract

32
Q

Source of E-Coli

A

Human GI tract

33
Q

Incubation of E-coli

A

Hours to days

34
Q

Presentation of E-coli infection

A

Traveller’s diarrhoea

UK diarrhoea outbreaks

35
Q

Complications of E-coli

A

Haemolytic-uraemic syndrome

36
Q

Reservoir of Bacillus cereus

A

Found in food / environment

37
Q

Incubation of Bacillus cereus

A

Hours

38
Q

Presentation of Bacillus cereus

A

Diarrhoea (enterotoxin-producing strain)

Vomiting (emetic toxin-producing strain)

39
Q

Reservoir of Staph aureus

A

Human skin

Nasopharynx

40
Q

Incubation of S.aureus

A

Hours

41
Q

Presentation of staph aureus

A

Abdo pain
vomiting

not usually associated with diarrhoea

42
Q

Reservoir of clostridium perfringens

A

Animals / environment

43
Q

Incubation of Clostridium perfringens

A

hours

44
Q

Presentation of clostridium perfringens

A

abdo pain

diarrhoea

45
Q

Complications of clostridium perfringens

A 
Enteritis necroticans (group c)
- segmental necrotizing infection of jejunum and ileum
46
Q

Reservoir of Yersinia enterocolitica

A

Animals (mainly pigs)

47
Q

Incubation of Yersinia enterocolitica

A

days

48
Q

Presentation of Yersinia entercolitica

A

Abdo pain
Diarrahoea
Fever
Appendicitis mimic in children

49
Q

Reservoir of vibrio cholerae

A

Water

50
Q

Incubation of vibrio cholerae

A

Days

51
Q

Presentation of vibrio cholerae

A

Profuse ‘rice water’ diarrhoea

52
Q

Source of listeria monocytogenes

A

animals, environment

53
Q

Incubation of listeria monocytogenes

A

days - months

54
Q

Presentation of Listeria monocytogenes

A

Diarrhoea, fever

55
Q

Complications of listeria monocytogenes

A

Bacteraemia
Meningitis
Septic abortion

56
Q

Guarding

A

Tensing up when you touch a particular area e.g. patients hand

57
Q

Why is it important to wash hands with soap and water and not just alcohol?

A

Clostridium perfringens is a gram positive bacterium producing spores.
These spores are not killed by alcohol.

58
Q

Case study

28 y/o sales assistant.
Progressive ascending weakness and sensory loss in hands and feet.
1 month ago, had episode of bloody diarrhoea and abdominal pain 2 days following barbecue

A

Campylobacter (bbq bug)

Ascending weakness: indicative of Guillain Barre syndrome

No mention of vomiting, vomiting unusual for C.bacter

Blood in diarrhoea

59
Q

Case study

45 y/o , vomiting, diarrhoea and fever. Returned from spain 24hrs ago. Had egg salad sandwich at airport

A

Travel history: Salmonella

Eggs abroad might not meet safety standards set by UK.

60
Q

Case study

31 y/o nursery assistant. 2 day history of bloody diarrhoea.

A

Shigella

Haemolytic-uraemic syndrome

  • massive activation of clotting platelet aggregation factor.
  • bleeding damage to kidneys
61
Q

Case study

6/o fever, nosebleeds, severe hypotension. Platelet count low, prothrombin time up, creatinine very high. 1 week ago she had an episode of diarrhoea and vomiting following visit to petting zoo.

A

Severe acute kidney injury.

Caused by E-coli

Associated with cows and goats.

62
Q

Case study

19 y/o , severe vomiting and abdominal pain 4hrs after eating egg fried rice from local take away

A

Bugs associated with reheated rice - Bacillus Cereus

Extremely severe vomiting.

Even though bacillus might be dead the heat stable toxin left in rice.

63
Q

Case study

24 y/o presents with vomiting 45 mins after eating pre-prepared sandwiches at conference. Illness resolves within 24hrs

A

Staph aureus

- not usually associated with diarrhoea

64
Q

Case study

45 y/o nurse, abdominal pain and diarrhoea 24hrs after eating at buffet

A

Clostridrium perfringens

Tends to be associated with food that hasnt been kept warm properlly

65
Q

Case study

24 y/o sever abdo pain and diarrhoea. Undergoes a laparotomy and her appendix is removed

A

Yersinia entercolitica

- severe abdominal pain

66
Q

Case study

31 y/o health care worker providing hurricane relief has severe mucoid diarrhoea and is visibly dehydrated and hypotensive

A

Vibrio cholerae

profuse ‘rice water’ diarrhoea

contamination of water supply

67
Q

Case study

29 y/o pregnant woman presenting with diarrhoea, fever and confusion after recent trip to France

A

Unpasteurised cheese.
Listeria associated with meningitis , tropism for CNS tissue.

Can replicate at very low temperatures.

GI - Y2 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions