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Week 5 - Cardiology > Endocarditis > Flashcards

Endocarditis Flashcards

1
Q

Define endocarditis [1]

A

Infection of endocardium (lining of heart) leading to the formation of a vegetation which results in damage to cusp of valves

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2
Q

What is a vegetation? [1]

A

An abnormal outgrowth from a membrane found on the membrane lining the heart valves

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3
Q

What is the vegetation composed of? [5]

A
  1. fibrin mesh
  2. platelets (which adhere to fibrin mesh)
  3. white blood cells
  4. RBC debris
  5. infective organisms (which are trapped within the glue-like substance)
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4
Q

Which valves are commonly affected by infective endocarditis? [3]

A
  1. mitral valve → most commonly affected
  2. aortic valve → 2nd most common site
  3. tricuspid valve → 3rd most common site
    • most common site in IV drug users (IVDU)
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5
Q

Define quorum sensing [1]

A

Cell communication that is widely used by bacterial pathogens to coordinate the expression of several collective traits, including the production of multiple virulence factors, biofilm formation, and swarming motility once a population threshold is reached.

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6
Q

What are the 3 types of infective endocarditis? [3]

A
  1. native valve endocarditis (NVE)
  2. endocarditis in IVDUs (IVDU IE)
  3. prosthetic valve endocarditis (PVE)
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7
Q

What are the most common microbiological causes of native valve endocarditis? [1]

A

streptococcus viridians

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8
Q

What are the most common microbiological causes of IVDU infective endocarditis? [3]

A
  1. staphylococcus aureus
  2. gram negative organisms
  3. fungi
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9
Q

What are the most common microbiological causes of prostatic valve endocarditis? [3]

A
  1. coagulase-negative staphylococci (CoNS)
  2. gram negative organisms
  3. fungi
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10
Q

Who is more susceptible to infective endocarditis? Males or females? [1]

A

males

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11
Q

What are the risk factors of native valve endocarditis? [4]

A
  • underlying valve abnormalities
    • aortic stenosis
    • mitral valve prolapse (MVP)
  • IVDU
  • no risk factors in 30% of cases
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12
Q

Why are IV drug users (IVDU) more susceptible to right-sided endocarditis (i.e. IE in tricuspid valve)? [4]

A

due to a combination of factors:

  1. particulate-induced endothelial damage to right-sided valves
  2. increased bacterial loads in these patients
  3. direct physiologic effects of the injected drugs
  4. deficient immune response caused by IVDU
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13
Q

What are the general clinical features of acute infective endocarditis? [3]

A
  1. toxic presentation (patient presents very unwell)
  2. progressive valve destruction & metastatic infection developing in days to weeks (rapidly)
    • i.e. septic emboli fly off from the vegetation to other parts of the body
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14
Q

What is the most common cause of acute IE? [1]

A

S. aureus

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15
Q

What are the general clinical features of subacute infective endocarditis? [3]

A
  1. mild toxicity
  2. presents indolently over weeks to months in an insidious manner
  3. rarely leads to metastatic infection
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16
Q

What are the common causes of subacute IE? [2]

A
  1. Strep. viridans (most commonly)
  2. enterococcus species
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17
Q

How long can IE take to present? [3]

A
  1. typically around 2 weeks
  2. PVE can take longer to present
  3. some organisms (e.g. strep. viridian) can present more slowly over months
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18
Q

What are the 2 typical presenting symptoms of IE in the early stages and in what occasions can these symptoms be absent? [4]

A
  1. fever
    • may be absent in elderly
  2. murmur
    • often absent in tricuspid endocarditis
19
Q

What are the 2 hallmarks of embolic disease in IE? [2]

A
  1. splinter haemorrhages
  2. conjunctival petechiae
20
Q

What are conjunctival petechiae? [1]

A

red or purple spots on the skin or conjunctiva caused by a minor bleed from broken capillary blood vessels

21
Q

What are the complications of small emboli caused by IE? [3]

A
  1. petechiae
  2. splinter haemorrhages
  3. haematuria
22
Q

What are the complications of large emboli caused by IE? [2]

A
  1. stroke (CVA)
  2. renal infarction
23
Q

How does right sided endocarditis typically present? [3]

A
  1. septic pulmonary emboli, which results in…
    • pleuritic chest pain
    • classical CXR appearance (see image)
24
Q

Define pleuritic chest pain [1]

A

sudden and intense sharp, stabbing, or burning pain in the chest when inhaling and exhaling

25
Q

What is this? [3]

A
  • osler’s nodes
    • painful palpable lesions
    • found on hands and feet
26
Q

What are the long-term effects of infective endocarditis? [6]

A
  1. immunological reaction
    • splenomegaly
    • nephritis
    • vasculitis lesions of skin & eye
    • clubbing
  2. tissue damage
    • valve destruction
    • valve abscess
27
Q

When should you consider diagnosing IE? [3]

A
  1. all patients with S. aureus bacteraemia (SAB)
  2. IVDU with any positive blood cultures
  3. all patients with prosthetic valves and positive blood cultures
28
Q

How should you take blood cultures for IE? [3]

A
  1. 3 sets of blood cultures should be taken from different sites
  2. do not wait for fever before taking blood cultures as there is a constant bacteraemia in IE
  3. should be taken before antibiotics are given
29
Q

What are the 2 types of echocardiograph? [2]

A
  1. transthoracic (TTE)
  2. transoesophageal (TOE)
30
Q

What are the features of transthoracic echo (TTE)? [5]

A
  1. non-invasive
  2. transducer is placed at front of chest
  3. easy to perform
  4. 50% sensitivity
  5. performed first
    • if negative but still a high clinical suspicion remains, a TOE is indicated
31
Q

What are the features of a transoesophageal echo (TOE)? [5]

A
  1. invasive
  2. transducer placed in oesophagus
  3. may require sedation
  4. 85-100% sensitivity
  5. better in detecting smaller vegetations
32
Q

What is the Duke Criteria for diagnosing IE? [3]

A
  • 2 major (or)
  • 1 major + 3 minor (or)
  • 5 minor criteria fulfilled
33
Q

What are the major criteria for diagnosing IE according to the Duke Criteria? [2]

A
  1. typical organism detected in 2 separate blood cultures
  2. positive echocardiogram or new valve regurgitation
34
Q

What are the minor criteria for diagnosing IE according to Duke Criteria? [5]

A
  1. predisposition (heart condition or IVDU)
  2. fever >38°C
  3. vascular phenomena (e.g. septic emboli)
  4. immunological phenomena (e.g. olser’s nodes)
  5. 1 positive blood culture
35
Q

Bactericidal antibiotics are usually used in high doses for curing IE. What is the difference between a bactericidal antibiotic and a bacteriostatic antibotic? [2]

A
  1. bactericidal agents = actively kill organisms
  2. bacteriostatic agents = inhibit growth of organisms, allowing the immune system to mount a lethal response
36
Q

How long is antimicrobial therapy typically given for native valve endocarditis (NVE)? [1]

A

4 weeks

37
Q

How long is antimicrobial therapy typically given for prostatic valve endocarditis (PVE)? [1]

A

6 weeks

38
Q

The antimicrobial treatment given is typically tailed to organism’s susceptibility. What therapies are typically given for the Streptococcus species? [2]

A

benzylpenicillin +/- gentamicin

39
Q

The antimicrobial treatment given is typically tailed to organism’s susceptibility. What therapies are typically given for the Enterococcus species? [3]

A

amoxicillin or vancomycin

+/- gentamicin

40
Q

The antimicrobial treatment given is typically tailed to organism’s susceptibility. What therapies are typically given for the S. aureus (MSSA)? [2]

A

flucloxacillin +/- gentamicin

41
Q

The antimicrobial treatment given is typically tailed to organism’s susceptibility. What therapies are typically given for the S. aureus (MRSA)? [2]

A

vancomycin +/- gentamicin

42
Q

The antimicrobial treatment given is typically tailed to organism’s susceptibility. What therapies are typically given for CoNS? [3]

A

vancomycin +/- gentamicin +/- rifampicin

43
Q

What are the indications for surgical intervention? [3]

A
  1. heart failure
  2. uncontrollable infection
  3. prevention of embolism
44
Q

What are the signs & symptoms of an uncontrollable infection requiring surgical intervention? [6]

A
  1. abscess
  2. false aneurysm
  3. enlarging vegetation
  4. persisting fever + positive blood cultures >7 to 10 days
  5. infection caused by multi-drug resistant organisms

Week 5 - Cardiology (12 decks)

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