endocarditis

Question 1

cardiac physiology

Answer 1

tricuspid valve - between right atrium and right ventricle - goes to lungs
mitral valve - between left atrium and ventricle - goes to body

Question 2

infective endocarditis

Answer 2

syndrome resulting in colonization or invasion of the endocardium by various types of organisms
classification - valve location (tricuspid, mitral, pulmonic, aortic), native vs prostethic, organism

Question 3

highest risk of endocaritis

Answer 3

presence of a prosthetic valve, previous endocarditis

Question 4

staph in infective endocarditis

Answer 4

30-70% of cases**
usually S.aureus**
myocardial abscesses, purulent pericarditis and valve ring abscesses are more common
S. aureus - most common pathogen in IV drug users
no previous heart condition required for this

Question 5

strep virdans in infective endocarditis

Answer 5

more common in patients with underlying cardiac abnormalities

Question 6

enterococci in infective endocarditis

Answer 6

primarily infects abnormal heart valves

Question 7

fastidious gram negative coccobacilli in infective endocarditis

Answer 7

HACEK - H. influ, H, parainflu, Aggregatibacter, cardiobacterium, eikenella, kingella

Question 8

most adherent organism

Answer 8

P. aeruginosa

Question 9

inoculum

Answer 9

may reach 10^10 GRU/gram of tissue - inoculum effect - problem in B-lactams

Question 10

clinical presentation

Answer 10

variable and non-specific
heart murmur - may be 1st sign
embolic phenomena - vegetation dislodges and clots

Question 11

lab findings

Answer 11

blood cultures - single most important lab test

draw at least 3 sets from different sites initially, then 2 sets q2-3 days

Question 12

treatment - general considerations

Answer 12

primary goal: eradicate infection/sterilize vegitation
begin high dose, empiric antibiotics based on the most likely pathogens
bactericidal activity is required
determine MICs - MBCs if concerned about tolerance (MBC is 32xMIC)
duration of therapy: shortest is 2 weeks, but 4-6 weeks or longer needed depending on organism, susceptibilty, native vs prosthetic
optimize dosing based on PK/PD parameter

Question 13

viridans group strep native valve endocarditis pen MIC less than 0.12***

Answer 13

Pen G 12-18 million units/day IV cont or in 4-6 doses x 4 weeks (may use ampicillin) OR ceftriaxone 2 g IV q24h x 4 weeks - Patients over 65 or with renal dynfxn or hearing impairment
Pen G 12-18 million units/day IV cont or in 6 doses x 2 weeks PLUS gentamicin 3 mg/kg/day IV x 2 weeks - not intended for patients with known cardiac or extracardiac abscessess of CrCl under 20; peak 3-4 and trough less than 1
Ceftriaxone 2 g IV q24 x 2 weeks PLUS gent 3 mg/kg/d IV x 2 weeks - peak 3-4 and trough less than 1
vancomycin 15 mg/kg IV q12h x 4 weeks - ONLY for patient unable to tolerate B-lactams; target trough 10-15

Question 14

Viridans group strep - native valve endocarditis; pen MIC over 0.12, less than 0.5***

Answer 14

Penicillin G 24 million units/day IV cont or in 4-6 divided doses x 4 weeks PLUS gentamicin 3 mg/kg/day IV x 2 weeks - ampicillin 2g IV q4h is a reasonable option
Ceftriaxone 2 g IV q24h x 4 weeks PLUS gentamicin 3 mg/kg/d IV x 2 weeks
vancomycin 15 mg/kg IV q12h x 4 weeks - ONLY in patients unable to tolerate B-lactam therapy

Question 15

Virdans group strep - prostetic valve endocarditic pen MIC less than 0.12***

Answer 15

Pen G 24 million units/day IV cont or in 4-6 divided doses x 6 weeks WITH or WITHOUT gentamicin 3 mg/kg/d IV x 2 weeks - combination therapy not superior* to monotherapy for highly susceptible strains, avoid gent if CrCl under 30, ampicillin 2 g IV q4h is a reasonable alternative
ceftriaxone 2 g IV q24h x 6 weeks WITH or WITHOUT gent 3 mg/kg/d IV x 2 weeks - combination therapy not superior* to monotherapy for highly susceptible strains, avoid gent if CrCl under 30, ampicillin 2 g IV q4h is a reasonable alternative
vancomycin 15 mg/kg q12h x 6 weeks - ONLY in patients unable to tolerate B-lactam therapy

Question 16

viridans group strep - prosthetic valve endocarditis pen MIC over 0.12***

Answer 16

Pen G 24 millin units/day IV cont or in 4-6 divided doses x 6 weeks PLUS gent 3mg/kg/day IV x 6 weeks - ampicillin 2 g IV q24h is an alternative
ceftriaxone 2 g IV q24h x 6 weeks PLUS gent 3 mg/kg/d IV x 6 weeks
Vanc 15 mg/kg q12h x 6 weeks - ONLY in patients unable to tolerate B-lactam therapy

Question 17

staphylococci - native valve endocarditis - oxacillin susceptible***

Answer 17

nafcillin or oxacillin 12 g/24 h in 4-6 divided doses x 6 weeks - for complicated right-sided IE; 2 weeks for uncomplicated right-sided IE
for pen-allergic: cefazolin 2 g IV q8h x 6 weeks - consider skin testing, avoid in patients with anaphylactoid reactions

Question 18

staphylococci - native valve endocarditis - oxacillin resistant***

Answer 18

vancomycin 15 mg/kg q12h x 6 weeks - target trough 10-20

daptomycin 8+ mg/kg/dose q24h x 6 weeks - limited data regarding efficacy, FDA-approved for right-sided IE only

Question 19

staphylococci - prosthetic valve endocarditis - oxacillin-susceptible ***

Answer 19

Nafcillin or oxacillin 12 g/24h in 6 divided doses x 6+ weeks PLUS rifampin 300 mg IV/PO q8h x 6+ weeks PLUS gent 3 mg/kg/day IV in 2-3 doses x 2 weeks - vanc in patients with immediate-type hypersensitivity reactions to B-lactams; cefazolin may be used in patients with non-immediate type hypersensitivity reactions

Question 20

staphylococci - prosthetic valve endocarditis oxacillin resistant strains***

Answer 20

Vanc 15 mg/kg q12h x 6+ weeks PLUS rifampin 300 mg IV/PO q8h x 6+ weeks PLUS gent 3 mg/kg/day IV in 2-3 doses x 2 weeks - target trough 10-20

Question 21

enterococci - native or prosthetic valve endocarditis - pen and gent susc, able to tolerate B-lactams ***

Answer 21

Ampicillin 2 g IV q4h x 4-6 weeks PLUS gentamicin 3 mg/kg/d in 2-3 divided doses x 4-6 weeks - NVE: 4 weeks if sxs of illness less than 3 months, 6 weeks if symptoms over 3 months, prosthetic valve: 6 weeks, recommended in patients with CrCl over 50, target peaks 3-4 and troughs under 1
Penicillin 18-30 million units/24 h IV cont or in 6 doses x 4-6 weeks PLUS gent 3mg/kg/d in 2-3 doses x 4-6 weeks - NVE: 4 weeks if sxs of illness less than 3 months, 6 weeks if symptoms over 3 months, prosthetic valve: 6 weeks, recommended in patients with CrCl over 50, target peaks 3-4 and troughs under 1
Ampicillin 2 g q4h x 6 weeks PLUS ceftriaxone 2 g q12h x 6 weeks - for patients with CrCl under 50 or who develop CrCl under 50 on gent

Question 22

enterococci - native or prosthetic endocarditis - pen susc and AG resistant ***

Answer 22

ampicillin 2 g IV q4h x 6 weeks PLUS ceftriaxone 2 g IV q12h x 6 weeks - normal or impaired renal function, when lab is unable to provide rapid results of streptomycin serum conc

Question 23

Enterococci - native or prosthetic valve endocarditis - pen susc, streptomycin susc, gent-resistant ***

Answer 23

ampicillin 2 g IV q4h x 4-6 weeks PLUS streptomycin 15 mg/kg/d IV in 2 divided doses x 4-6 weeks - only for patients if rapid measurement of streptomycin conc is available, adjust streptomcycin dose to obtain peaks of 20-35 and troughs less than 10
penicillin 18-30 million unites/24 h either cont or in 6 doses x 4-6 weeks PLUS streptomycin 15 mg/kg/d IV in 2 divided doses x 4-6 weeks - only for patients if rapid measurement of streptomycin conc is available, adjust streptomcycin dose to obtain peaks of 20-35 and troughs less than 10

Question 24

Enterococci - native or prosthetic valve endocarditis - vanc regimens in patients unable to tolerate B-lactam therapy; vanc and AG susc ***

Answer 24

vanc 15 mg/kg IV q12h x 6 weeks PLUS gent 3 mg/kg/d IV in 3 divided doses x 6 weeks - vanc target troughs 10-20 and gent target peaks 3-4 and troughs under 1

Question 25

Enterococci - native or prosthetic valve endocarditis - intrinsic resistant to pen or B-lactamase producer ***

Answer 25

vanc 15 mg/kg IV q12h x 6 weeks PLUS gent 3 mg/kg/d IV in 3 divided doses x 6 weeks - if B-lactamase producing straing and able to tolerate B-lactam, Amp-sulbactam 3 g IV q6h plus gent may be used

Question 26

Enterococci - native or prosthetic valve endocarditis -penicillin, AG, and vanc resistant strains

Answer 26

daptomycin 10-12 mg/kg q24h x over 6 weeks - monitor CPK
linezolid 600 mg IV or PO q12h x over 6 weeks - concern for severe bone marrow suppression (thrombocytopenia (over 2 weeks)), neuropathy and drug interactions