Infective Endocarditis

Question 1

what are the predisposing factors to infective endocarditis?

Answer 1

o	Heart valve abnormality
o	Prosthetic heart valve
o	IV drug user
o	IV lines
o	Recent Dental treatment

Question 2

what are the common causative organisms of infective endocarditis?

Answer 2

o Staphylococcus aureus (38%)
o Viridans group streptococci (31%)
o Enterococcus sp (8%)
o Staphylococcus epidermidis

Question 3

what are the atypical organisms associated with infective endocarditis?

Answer 3

• Bartonella, Coxiella burnetii (Q-fever), Chlamydia, Legionella, Mycoplasma, Brucella

Question 4

what are the gram negative organisms associated with infective endocarditis?

Answer 4

HACEK organisms - Haemophilus spp. , Aggregatibacter spp, ( was Actinobacillus) , Cardiobacterium, Eikenella sp., Kingella sp.
Non HACEK gram negatives

Question 5

what is the pathophysiology of infective endocarditis?

Answer 5

Heart valve damaged, turbulent blood flow leads to platelets/fibrin thrombus, bacteraemia results in organisms settling in thrombi, infective vegetations are friable and break off lodging in capillaries

Question 6

what are the two ways in which infective endocarditis presents?

Answer 6

subacute or sepsis/HF

Question 7

what are the clinical features of infective endocarditis?

Answer 7

Fever, malaise, Weight loss, Tiredness, Breathlessness, New or changing heart murmur, finger clubbing, splinter haemorrhages, splenomegaly, Roth spots, Janeway lesions, Osler nodes, microscopic haematuria

Question 8

what criteria is used in infective endocarditis?

Answer 8

Dukes

Question 9

what are major criteria of Dukes criteria?

Answer 9

Two separate posistive blood cultures with microorganism(s) typical for infective endocarditis: Viridans streptococci, Streptococcus bocis, HACEK group, Staphylococcus aureus, community acquired enterococci
Echocardiographic evidence of endocardial involvement - Typical valvular lesions: vegetation, abscess, or new partial dehiscence of a prosthetic valve
New valvular regurgitation

Question 10

what are the minor criteria of Dukes criteria?

Answer 10

Predisposition: predisposing heart condition or IV drug use
Temperature greater than 38C
Vascular phenomena - Major areterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial haemorrhage, conjunctival haemorrhage, Janeway lesions
Immunological phenomena - Glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor
Microbiological Evidence - Positive blood culture but not meeting major criterion, or serological evidence of active infection with organisms consistent with infective endocarditis

Question 11

What Dukes criteria is required for definitive IE?

Answer 11

2 main criteria
1 main and 3 secondary
5 minor criteria

Question 12

What Dukes criteria is needed for possible IE?

Answer 12

1 main and 1 secondary

3 minor criteria

Question 13

which main investigation is needed for IE?

Answer 13

blood cultures - 3 sets

Question 14

what is the diagnostic criteria for blood cultures in IE?

Answer 14

o Detection of endocarditis-specific pathogens in 2 independent blood cultures
o Microorganisms compatible with an IE in persistently posistive blood cultures: at least 2 posistive blood cultures from blood withdrawals at least 12 hours apart pr each of 2 or a pluraility of > 4 separate blood cultures (first and last sample taken at least 1hr apart)
o A single positive blood culture with Coxiella Burnetii or a Phase 1 IgG antibody titer> 1:800

Question 15

What will the features of an echo show in IE?

Answer 15

o Posistive echocardiography for an IE: vegtation, abscess, pseudoaneurysm, intracardiac fistula, valve perforation, new partial dehiscence of a valve prosthesis
o Abnormal heart valve prosthetic activity detected with F-FDG-PET/ CT (only > 3months after valve implantation) or SPECT / CT with radiolabelled leukocytes
o Paravalvular lesions in cardiac CT

Question 16

what other investigations should be done in IE?

Answer 16

blood tests, urinalysis, CXR, ECG, Echo

Question 17

what is the management of Native valve indolent (Subacute) IE?

Answer 17

Amoxicillin IV 2g 4 hourly + Gentamicin 1mg/kg bd (use actual body weight - max 120mg/dose)

Question 18

what is the management of Native valve Sepsis (Acute) IE?

Answer 18

Flucloxacillin IV 2g 6 hourly (4 hourly if >85kg)

Question 19

what is the management of Prosthetic valve or Suspected MRSA IE?

Answer 19

Vancomycin IV + Gentamicin IV 1mg/kg bd (use actual body weight - max 120mg/dose + when therapeutic vancomycin levels reached add Rifampicin PO 600mg bd (always check for interactions)

Question 20

what is the management of drug user endocarditis (MSSA) IE?

Answer 20

Flucloxacillin IV

Question 21

what is the management of Staphylococcus aureus (not MSSA) IE?

Answer 21

Flucloxacillin IV

Question 22

what is the management of Viridans IE?

Answer 22

Benzylpenicillin iv & gentamicin iv (synergistic)

Question 23

what is the management of Enterococcus sp. IE?

Answer 23

Amoxicillin/ vancomycin & gentamicin IV

Question 24

what is the management of Staphylococcus epidermis IE?

Answer 24

Vancomycin & gentamicin IV & rifampicin PO

Question 25

what is the management of MRSA IE?

Answer 25

as per prosthetic valve

Question 26

how should management be monitored in IE?

Answer 26

o IV antibiotics usually given for 4 - 6 weeks
o Monitor cardiac function, temperature and serum C-reactive protein (CRP)
o If failing on antibiotic therapy, consider referral for surgery early