Infective Endocarditis Flashcards

1
Q

What is infective endocarditis overall, what are the subtypes and what is its mortality and why?

A
  • Infection of the endothelium of the heart valves
  • Acute or Subacute
  • Up to 25% mortality as often diagnosed late
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2
Q

What are the predisposing factors of infective endocarditis?

A
  • Heart valve abnormality
    • Calcification/sclerosis in the elderly
    • Congenital heart disease
    • Post rheumatic fever
  • Prosthetic heart valve
  • IV drug users
  • Intravascular lines
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3
Q

What are the 6 stages in the pathogenesis of infective endocarditis?

A
  1. Heart valve damages
  2. Turbulent blood flow over roughened endothelium
  3. Platelets/fibrin deposited
  4. Bacteriaemia (may be very transient) e.g. from dental treatment
  5. Organisms settle in fibrin/platelet thrombi becoming a microbial vegetation
  6. Infected vegetations are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage (may be fatal)
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4
Q

What valves are normally affected?

A

Left sided valves - mitral and aortic

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5
Q

What are the causative organisms of infective endocarditis (from most common to least)

A
  • Staphylococcus aureus (38%)
  • Viridans streptococci (31%)
  • Enterococcus sp (8%)
  • Staph epidermidis (6%)
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6
Q

What are the unusual organisms that can cause IE?

A
  • Gram negatives - HACEK and non-HACEK
  • Fungi
  • other atypical organisms
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7
Q

What is the pathway of investigations if there is a clinical suspicion of IE?

A
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8
Q

What are the major dukes criteria for IE?

A
  • Two separate positive blood cultures with typical IE microorganism(s)
  • Echo evidence of valvular involvement
  • New valvular regurgitation
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9
Q

What are the minor dukes criteria for IE?

A
  • Predisposing heart condition / IV drug use
  • Temperature >38oC
  • Vascular phenomena
  • Immunological phenomena
  • Microbiological evidence (not major)
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10
Q

What infection appears as gram positive cocci in clusters when cultured?

A

Staphylococcus

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11
Q

Why do you take multiple blood cultures?

A
  • Staph. epidermis is a skin/prosthetic material contaminant so can cause false results
  • Take multiple to minimise chance of this
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12
Q

What is the process of identifying a species of microorganism?

A
  1. Select colony or process blood culture bottle
  2. Prepare target plate
  3. Generate MALDI-TOF profile spectrum
  4. Interpret data and identify species
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13
Q

What antimicrobial guidelines do you follow after identifying the causative organism?

A

Local guideline e.g. Antibiotic Man

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14
Q

What are the presenting features of acute endocarditis? Why?

A
  • Patients present with overwhelming sepsis and cardiac failure
  • Usually due to aggressive (virulent) organisms such as staph. aureus
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15
Q

What are the presenting symptoms of subacute IE?

A
  • Fever
  • Malaise
  • Weight loss
  • Tiredness
  • Breathlessness
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16
Q

What are the presenting signs of subacute IE?

A
  • Fever
  • New or changing heart murmur
  • Clubbing
  • Splinter haemorrhages
  • Splenomegaly
  • Roth spots, Janeway lesions, Osler nodes
  • Microscopic haematuria
17
Q

What class are viridans group streptococci?

A

Alpha, haemolytic strep

18
Q

Where are janeway lesions, roth spots and osler nodes found and how are they different?

A
  • Janeway = palms/soles
  • Roth = back of eye
  • Osler = palms/soles (raised)
19
Q

What are the subclasses of prosthetic valve endocarditis and what are the causes?

A
  • Early (within 60 days) - usually infected at time of valve insertion and usually due to staph. epidermis or staph. aureus
  • Late - up to many years after valve insertion, due to coincidental bactaraemi (wind range of possible organisms)
20
Q

What antibiotics are given in Tayside whilst waiting on culture results if IE suspected and the patient has a prosthetic valve or suspected MRSA?

A
  • Vancomycin & Gentamicin IV
  • Rifampicin at day 3-5
21
Q

What is the most common sites of IE in people who inject drugs (PWID) and what is the normal causative organism?

A
  • Right sided endocarditis
  • Tricuspid most commonly
  • Usually staph aureus
22
Q

What is the bacteriacidal regime for native valve IE?

A

Amoxicillin and gentamicin IV

23
Q

What is the bactericidal regime for drug user IE?

A

Flucloxacillin IV

24
Q

What is the specific treatment of staph. aureus?

A

Flucloxacillin IV

25
Q

What is the specific treatment of viridians streptococci?

A

Benzylpenicillin and gentamicin IV

26
Q

What is the specific treatment of enterococcus sp.?

A

Amoxicillin/vancomycin and gentamicin IV

27
Q

What is the specific treatment of staph. epidermis?

A

Vancomycin and gentamycin IV and rifampicin PO

28
Q

What is the antibiotic time length and monitoring therapy for IE?

A
  • IV antibiotics usually for 4-6 weeks
  • Monitor cardiac function, temperature and serum CRP
  • If antibiotics are failing, consider surgery early
29
Q

What is myocarditis, what can it cause and what is the at risk group?

A
  • Inflammation of the heart muscle
  • Cause of sudden death
  • More common in young people
30
Q

What are the symptoms and signs of myocarditis?

A
  • Fever
  • Chest pain
  • Dyspnoea
  • Palpitations
  • Arrhythmia
  • Cardiac Failure
31
Q

What are the main causes of myocarditis and how is it diagnosed?

A
  • Enteroviruses e.g. coxsackie A&B, echovirus
  • Diagnosed by viral PCR (throat swab and stool)
32
Q

What is pericarditis, what does it often occur with and what is its main feature?

A
  • Inflamed pericardium
  • Often occurs with myocardituis
  • Chest pain main feature
33
Q

What is the normal cause of pericarditis?

A
  • Mainly viral
  • Can be bacterial