Infective Endocarditis

Question 1

Bacteraemia

Answer 1

Presence of bacteria in the bloodstream

Question 2

Skin organisms associated with cardiac implantable electronic devices

Answer 2

Staphylococcus aureus, staphylococcus epidermis, corynebacterium sp., propionibacterium acnes

Question 3

Risk factors for infection after cardiac implantable electronic devices

Answer 3

• Pre procedure prophylaxis
• Complexity of procedure
• Temporary pacer use
• Type of device
• Number of revisions/reinterventions
• Fever within 24 hours
• Heart failure, renal failure
• Haematoma post procedure

Question 4

Implantable cardiac electronic devices:

- Generator pocket infection

Answer 4

Localised cellulitis, pain, swelling, discharge, wound breakdown

Question 5

Non-specific signs and symptoms of systemic infection

Answer 5

Fevers, chills, night sweats, malaise, anorexia

Question 6

When should blood cultures be taken?

Answer 6

Prior to starting antimicrobial therapy for cardiac infections, on clinical suspicion on implantable cardiac electronic devices infection with chronic or subacute presentation

Question 7

Blood cultures:

• How many taken?
• How far apart?

Answer 7

• 3 sets from peripheral sites

- >6 hours between them

Question 8

Infective endocarditis

Answer 8

Infection of the endothelium of the heart valves

Question 9

Predisposing factors for infective endocarditis

Answer 9

Heart valve abnormality (calcification/sclerosis in elderly, congenital heart disease, post rheumatic fever), prosthetic heart valve, PWID, IV lines, previous dental treatment

Question 10

Pathogenesis of infective endocarditis

Answer 10

• Heart valve damaged
• Turbulent blood flow over roughened endothelium
• Platelets/fibrin deposited
• Bacteraemia
• Organisms settle in fibrin/platelet thrombi becoming a microbial vegetation
• Infected vegetations are friable (susceptible to break off) and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage

Question 11

What side of the heart is usually affected by endocarditis

Answer 11

Left side

Question 12

Usual organisms causing infective endocarditis

Answer 12

Staph aureus, viridian’s group streptococci, enterococcus sp. (elderly), staph epidermis (think metal or plastic)

Question 13

Unusual organisms causing infective endocarditis

Answer 13

Atypical organisms, gram negatives, fungi

Question 14

Atypical organisms causing infective endocarditis

Answer 14

Bartonella, coxiella burnetii (Q fever), chlamydia, legionella, mycoplasma

Question 15

Gram negative organisms causing infective endocarditis

Answer 15

HACEK organisms

Question 16

HACEK organisms

Answer 16

H = haemophilia spp.
A = aggregatibacter spp.
C = cardiobacterium
E = eikenella sp.
K = kingella sp.

Question 17

What test do you do instead of blood culture for unusual organisms causing infective endocarditis?

Answer 17

Antibody test

Question 18

Duke criteria

Answer 18

2 separate positive blood cultures with microorganism(s) typical for infective endocarditis
Echocardiographic evidence of endocardial involvement
New valvular regurgitation

Question 19

Blood cultures for infective endocarditis

Answer 19

• Detection of endocarditis-specific pathogens in 2 blood cultures
  Or
• Microorganisms compatible with an IE in persistently positive blood cultures: at least 2 positive blood cultures from blood withdrawals at least 12 hours apart
  Or
  -A single positive blood culture with Coxiella burnetiid or a phase I IgG antibody titre >1:800

Question 20

Subacute symptoms of infective endocarditis

Answer 20

Fever, malaise, weight loss, tiredness, breathlessness

Question 21

Subacute signs of infective endocarditis

Answer 21

Fever, new or changing heart murmur, finger clubbing, splinter haemorrhages, splenomegaly, Roth spots, janeway lesions, Osler nodes, microscopic haematuria

Question 22

First investigation for infective endocarditis

Answer 22

Transthoracic echo, then transoesophageal

Question 23

Prosthetic valve endocarditis - early and late

Answer 23

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 later after valve insertion – due to co-incidental bacteraemia. Wide range of possible organisms

Question 24

Endocarditis in PWID:

• What side is usually affected?
• Which organism is usually responsible?

Answer 24

• Right side (tricuspid valve)

- Staph aureus

Question 25

Treatment for native valve endocarditis (viridian’s strep)

Answer 25

Amoxicillin and gentamicin IV

Question 26

Treatment for prosthetic valve endocarditis

Answer 26

Vancomycin and gentamicin IV, add in day 3-5 rifampicin orally and often valve replacement required

Question 27

Treatment for drug user endocarditis

Answer 27

Flucloxacillin IV

Question 28

Treatment for infective endocarditis caused by staph aureus

Answer 28

Flucloxacillin IV

Question 29

Treatment for infective endocarditis caused by viridans streptococci

Answer 29

Benzylpenicillin and gentamicin IV

Question 30

Treatment for infective endocarditis caused by enterococcus sp

Answer 30

Amoxicillin/vancomycin and gentamicin IV

Question 31

Treatment for infective endocarditis caused by staph epidermis

Answer 31

Vancomycin and gentamicin IV and rifampicin orally

Question 32

How long are antibiotics usually given for in infective endocarditis?

Answer 32

4-6 weeks

Question 33

Clinical complications of infective endocarditis

Answer 33

Heart failure, renal failure, brain haemorrhage, septic shock

Question 34

Echocardiographic findings in infective endocarditis

Answer 34

Periannular complications, severe left-sided valve regurgitation, low left ventricular ejection fraction, pulmonary hypertension, large vegetations, severe prosthetic valve dysfunction

Question 35

Signs and symptoms of myocarditis

Answer 35

Symptoms - fever, chest pain, SOB, palpitations

Signs - arrhythmia, cardiac failure

Question 36

Main causes of myocarditis

Answer 36

Enteroviruses - coxackie A and B, echovirus etc

Question 37

Diagnosis of myocarditis

Answer 37

Viral PCR, throat swab and stool for enteroviruses, throat swab for influenza