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A. Block E Microbiology > Infective Endocarditis > Flashcards

Infective Endocarditis Flashcards

1
Q

Endocarditis is the when there is an infection of the inner layer of cardiac tissue that causes it to become inflamed. What is the annual incidence of IE in the UK?

1 - 6–7/100 000
2 - 60–70/100 000
3 - 600–700/100 000
4 - 6000–7000/100 000

A

1 - 6–7/100 000
- rare can but can carry high mortality
- more common in elderly patients

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2
Q

Endocarditis is the when there is an infection of the inner layer of cardiac tissue that causes it to become inflamed. Is infective endocarditis more common in men or women?

A
  • men
  • 3 times more common
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3
Q

Endocarditis is the when there is an infection of the inner layer of cardiac tissue that causes it to become inflamed. However, which of the following patients are at risk of infective endocarditis?

1 - mitral valve stenosis
2 - ventricular septal defect
3 - aortic stenosis
4 - all of the above

A

4 - all of the above

  • infection typically occurs where turbulent blood flow is present
  • all have turbulent blood flow due to narrow or valves or defects
  • valves are commonly affected as this is generally where turbulent blood flow occurs
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4
Q

Which valves are typically affected in infective endocarditis?

1 - aortic and pulmonary
2 - mitral and aortic
3 - mitral and tricuspid
4 - aortic and tricuspid

A

2 - mitral and aortic
- can affected any valve, but these are most common
- left side of heart is more commonly affected

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5
Q

Patients with pathology that causes turbulent blood flow in the heart are at an increased risk of infective endocarditis (IE). Even prior to a patient becoming infected what can happen to the endocardium that predisposes the patient to IE?

1 - valves can rupture leading to fibrosis
2 - endocardial damage
3 - ventricular hypertrophy
4 - increased pulmonary pressure

A

2 - endocardial damage
- collagen and tissue factor are exposed
- platelets/fibrin lead to thrombosis (clot)

  • THIS ALL OCCURS EVEN WITHOUT THE PRESENCE OF A MICROBE
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6
Q

Patients with pathology that causes turbulent blood flow in the heart are at an increased risk of infective endocarditis (IE). The turbulent blood flow damages the endocardial lining and a small thrombosis (clot) can form. How would a microbe then infect this exposed/damaged endocardial lining?

1 - abscess
2 - dental procedure
3 - surgery
4 - open wound (cellulitis)
5 - all of the above

A

5 - all of the above
- anything that increases the patients risk of infection
- always ask questions that relate to these in the history

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7
Q

Patients with pathology that causes turbulent blood flow in the heart are at an increased risk of infective endocarditis (IE). The turbulent blood flow damages the endocardial lining and a small thrombosis (clot) can form, this is called a non-bacterial thrombotic endocarditis (NBTE). If a patient does become infected, bacteraemia can follow. The microbes can then bind to the NBTE, which is called what?

1 - microfilms
2 - biofilms
3 - vegetations
4 - infective NBTE

A

3 - vegetations
- lots of microbes secrete a matrix which forms a biofilm and behave like a colony

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8
Q

There is an acute and subacute form of infective endocarditis (IE). All of the following are common risk factors for acute IE, EXCEPT which one?

1 - dermatitis (skin breach)
2 - renal failure
3 - aortic/mitral valve disease
4 - immunocompromised
5 - diabetes mellitus

A

3 - aortic/mitral valve disease
- acute IE is typically associated with normal valves

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9
Q

In patients with acute infective endocarditis, what is the most common organism involved?

1 - Staphylococcus aureus
2 - Viridans streptococci
3 - Streptococcus gallolyticus
4 - HACEK group

A

1 - Staphylococcus aureus
- used to be Viridans streptococci

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10
Q

In patients with acute infective endocarditis, what is the most destructive organism involved?

1 - Staphylococcus aureus
2 - Viridans streptococci
3 - Streptococcus gallolyticus
4 - HACEK group

A

1 - Staphylococcus aureus

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11
Q

There is an acute and subacute form of infective endocarditis (IE). Acute IE typically occurs in patients with normal valves. What is the mortality in acute IE?

1 - 0.5-1%
2 - 10-20%
3 - 40-50%
4 - 5-50%

A

4 - 5-50%

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12
Q

There is an acute and subacute form of infective endocarditis (IE). All of the following are common risk factors for sub-acute IE, EXCEPT which one?

1 - IV drug use
2 - renal failure
3 - aortic/mitral valve disease
4 - ventricular septal defect
5 - patent ductus arteriosum
6 - prosthetic valves

A

2 - renal failure

  • IV drug use = risk of infection
  • aortic/mitral valve disease, ventricular septal defect, patent ductus arteriosum and prosthetic valves = all cause turbulent flow
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13
Q

What is the mortality rate of patients with infective endocarditis who do not receive treatment?

1 - 20%
2 - 40%
3 - 60%
4 - 100%

A

4 - 100%

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14
Q

Which of the following is NOT a common symptom patients with infective endocarditis present with?

1 - fever with night sweats
2 - rigors and malaise (not feeling great)
3 - pulmonary oedema
4 - weight loss
5 - arthralgia
6 - dyspnoea

A

3 - pulmonary oedema

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15
Q

Which of the following is NOT a common clinical sign in patients with infective endocarditis ?

1 - new/change in murmur
2 - splinter hemorrhages
3 - Osler nodes / Janeway macules
4 - roth spots
5 - Tendon xanthomas or xantholasmata
6 - clubbing
7 - splenomegaly
8 - haematuria

A

5 - Tendon xanthomas or xantholasmata
- these do not typically occur in a patient with infective endocarditis

  • new/change in murmur = turbulent blood flow
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16
Q

Infective endocarditis (IE) can cause splinter hemorrhages and osler nodes. How does IE cause these?

1 - high levels of bacteria damage tissues around the body
2 - immune response causing antigen-antibody complexes that collect in tissues
3 - bacteria occlude small blood vessels
4 - bacteria form septic emboli

A

4 - bacteria form septic emboli
- septic emboli = vegetations that are dislodged from valves and travel in blood
- they can get trapped under finger nails
- trapped in palms of hands of feet

17
Q

Infective endocarditis (IE) can cause osler nodes and roth spots in the eyes and glomerulonephritis. How does IE cause these?

1 - high levels of bacteria damage tissues around the body
2 - immune response causing antigen-antibody complexes that collect in tissues
3 - bacteria occlude small blood vessels
4 - bacteria form septic emboli

A

2 - immune response causing antigen-antibody complexes that collect in tissues

  • antigen-antibody complexes deposit in tissues, leading to inflammation and tissue damage
18
Q

Why can infective endocarditis cause haematuria?

1 - kidney becomes infected and goes into AKI
2 - septic emboli elicit immune response causing antigen-antibody complex formation
3 - reduced perfusion of kidneys
4 - all of the above

A

2 - septic emboli elicit immune response causing antigen-antibody complex formation

  • it would be microcytic haematuria
  • sign of nephritis
19
Q

When trying to diagnose a patient with infective endocarditis blood samples are typically taken for culture to identify the microbe. How many blood samples from different sites of the body need to be taken?

1 - just 1
2 - 2
3 - 3
4 - 5

A

3 - 3
- 3 separate samples at 3 separate times from 3 separate body sites
- try to do this at the peak of the fever

20
Q

When doing a blood test in a patient with suspected infective endocarditis, we may see all of the following, EXCEPT which one?

1 - raised ESR/CRP
2 - normochromic normocytic anaemia
3 - proteinuria
4 - neutrophilia (excessive neutrophils)
5 - positive rheumatoid factor

A

3 - proteinuria
- not a common finding, found in nephrotic syndrome
- U&Es and LFTs should also be measured

21
Q

What might we see on an ECG in a patient with infective endocarditis?

1 - inverted T waves
2 - prolonged QRS complex
3 - absent P waves
4 - prolonger PR interval

A

4 - prolonger PR interval

22
Q

What is typically the gold standard for diagnosing a patient with infective endocarditis using imaging modalities?

1 - ultrasound
2 - chest X-ray
3 - MRI
4 - echocardiography

A

4 - echocardiography
- thoracic = 70% sensitivity for vegetations
- transoesophageal = >90% sensitivity for vegetations

  • sensitivity = confirm a diagnosis in patient who has condition
  • specificity = confirm a patient doesn’t have a disease
23
Q

To diagnose a patient with infective endocarditis we can use the modified Dukes criteria. In this there are 2 major and 5 minor criteria. Which 2 of the following are the major criteria?

1 - temperature >38 degrees
2 - immunologic phenomena (glomerulonephritis, Osler’s nodes, Roth’s spots, or rheumatoid factor)
3 - 2 positive blood cultures <12 hours
4 - evidence of endocardium involvement on echocardiogram
5 - microbiology evidence (not sufficient for major criteria)
6 - embolic phenomonom (splinter haemorrhage and janeway lesion)
7 - risk factors (congenital heart disease or IV drug use)

A

3 - 2 positive blood cultures <12 hours
4 - evidence of endocardium involvement on echocardiogram

  • mnemonic BE TIMER
  • BE = major, blood and echocardiogram
24
Q

To diagnose a patient with infective endocarditis we can use the modified Dukes criteria. In this there are 2 major and 5 minor criteria. All of the following are the minor criteria, EXCEPT which one?

1 - temperature >38 degrees
2 - immunologic phenomena (glomerulonephritis, Osler’s nodes, Roth’s spots, or rheumatoid factor)
3 - proteinuria >3 to 3.5 g in 24h
4 - microbiology evidence (not sufficient for major criteria)
5 - embolic phenomonom (splinter haemorrhage and janeway lesion)
6 - risk factors (congenital heart disease or IV drug use)

A

3 - proteinuria >3 to 3.5 g in 24h

mnemonic BE TIMER
- BE = major, blood and echocardiogram
- TIMER = minor, Temperature, Immunological phenomena, M = Microbiology, Embolic phenomena and Risk Factors

25
Q

To diagnose a patient with infective endocarditis we can use the modified Dukes criteria. In this there are 2 major and 5 minor criteria. Using the Dukes criteria, what provides a definitive diagnosis of infective endocarditis?

1 - all 5 minor criteria
2 - 2 major criteria
3 - 1 major and 3 minor criteria
4 - all of the above

A

4 - all of the above

Anyone of these in isolation is diagnostic of infective endocarditis:

  • all 5 minor criteria
  • 2 major criteria
  • 1 major and 3 minor criteria
26
Q

To diagnose a patient with infective endocarditis we can use the modified Dukes criteria. In this there are 2 major and 5 minor criteria. Using the Dukes criteria, which 2 of the following provides a probable diagnosis of infective endocarditis?

1 - all 5 minor criteria
2 - 3 minor criteria
3 - 1 major and 1 minor criteria
4 - 1 major and 2 minor

A

2 - 3 minor criteria
3 - 1 major and 1 minor criteria

27
Q

To treat a patient with infective endocarditis (IE), we should be guided by microbiology and local guidelines. Typically if a patient has IE due to the most common microbe viridans streptococcus, which 2 antibiotics should they be given via IV for 2 weeks?

1 - amoxicillin
2 - vancomycin
3 - metronidazole
4 - gentamicin

A

1 - amoxicillin
4 - gentamicin

28
Q

To treat a patient with infective endocarditis (IE), we should be guided by microbiology and local guidelines. Typically if a patient has IE due to the most common microbe viridans streptococcus, they would be administered with amoxicillin and gentamicin for 2 weeks via IV. What will they then take orally for 4 weeks?

1 - amoxicillin
2 - vancomycin
3 - metronidazole
4 - gentamicin

A

1 - amoxicillin

29
Q

To treat a patient with infective endocarditis (IE), we should be guided by microbiology and local guidelines. Typically if a patient has IE due to the most aggresive microbe Staphylococcus aureus, which 2 of the following would they be administered via IV for 6 weeks?

1 - amoxicillin
2 - vancomycin
3 - flucloxacillin
4 - gentamicin

A

3 - flucloxacillin
4 - gentamicin

30
Q

To treat a patient with infective endocarditis (IE), we should be guided by microbiology and local guidelines. If a patient has a prosthetic valve which 2 of the following will they be treated with for 6 weeks via IV?

1 - amoxicillin
2 - vancomycin
3 - flucloxacillin
4 - gentamicin

A

2 - vancomycin
4 - gentamicin

31
Q

Are patients given antibiotics if they are having an invasive procedure according to NICE guidelines?

A
  • no
  • BUT if given antibiotics they should cover common causes of infective endocarditis
32
Q

If a patient is at risk of infective endocarditis (IE), which of the following are recommended to reduce the risk of IE?

1 - Regular dental checks
2 - Antibiotics for bacterial infections BUT no self medication
3 - No piercings/tattoos
4 - Change IV cannulae every 3-4 days
5 - all of the above

A

5 - all of the above

A. Block E Microbiology (38 decks)

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