Exam 4: Infective Endocarditis Flashcards
What is infective endocarditis?
Syndrome resulting in colonization or invasion of the endocardium by various types of microorganisms
What is the most common organism causing endocarditis?
Staphylococci (staph aureus)
Who is most likely to have fungi causing infective endocarditis?
Narcotic addicts
Patients after reconstructive cardiovascular surgery
Patients after prolonged IV and/or antibiotic therapy
What laboratory test is used to diagnose endocarditis?
Blood cultures
-Bacteremia is continuous and low grade (<100 CFU/ml blood)
*Draw at least 3 sets from different sites initially, then 2 sets q2-3 days
-Do culture and susceptibility testing
What are the requirements for blood cultures to be considered positive for endocarditis?
Microorganisms that commonly cause endocarditis are seen on 2 or more separate blood culture sets
Microorganisms that occasionally or rarely cause endocarditis are seen on 3 or more separate blood culture results
What kind of imaging is done for endocarditis?
Echocardiography
Most diagnoses are made with TTE or TEE
CT scans
Can also be diagnosed through surgery
(look for vegetation, perforations, aneurysms, abscesses, or fistulas)
To diagnose someone with endocarditis using the Duke criteria, they must be exhibiting what?
2 major criteria
or
1 major and 3 minor criteria
or
5 minor criteria
What are the major criteria used in the Duke criteria for diagnosing endocarditis?
Positive blood cultures
(if commonly causing organism, then 2 culture sets must be positive; if not common, then 3 culture sets must be positive)
Positive Laboratory Test
(Positive for Coxiella burnetii, Bartonella species, or Tropheryma whipplei)
Positive Imaging
(CT, Nuclear)
Evidence of endocarditis found in surgery
What are the minor criteria predispositions used in the Duke criteria for endocarditis?
Previous history of endocarditis
Prosthetic valve
Previous valve repair
Congenital heart disease
More than mild regurgitation or stenosis
Endovascular intracardiac implantable electronic device
Hypertrophic obstructive cardiomyopathy
Injection drug use
What are the minor criteria based on symptoms used in the Duke criteria?
Fever (>100.4F, 38C)
Vascular Phenomena (emboli, infarcts, abscess, aneurysm, hemorrhage, lesions)
Immunologic Phenomena (+ rheumatoid factor, Osler’s nodes, Roth spots, immune complex-mediated glomerulonephritis)
Microbiological evidence not meeting major criteria (ex: + blood culture not meeting major criteria)
Imaging Criteria (abnormal metabolic activity detected within 3 mo of implantation of heart device)
Physical Exam Criteria (new valvular regurgitation)
What factors contribute to complete eradication of organisms in endocarditis taking weeks to achieve?
-Infection is in an area with impaired host defenses
-Large number of bacteria in vegetation and cells that may exist in a reduced metabolic activity state and not divide as much
-Potential for resistance
What considerations must be made when choosing endocarditis therapy?
Need high dose empiric therapy based on the most likely pathogens
Bactericidal activity is required (may need synergistic combinations for some pathogens)
Need to determine MICs
What is the normal duration of endocarditis therapy?
Shortest: 2 weeks
Normal: 4-6 weeks
note: begin counting treatment duration on the first day of negative blood cultures
How does the duration of therapy differ based on if we are treating native valves or prosthetic valves?
Native valves are treated for shorter periods of time
Prosthetic valves are treated for longer periods of time
What is the most common reason why someone would have surgical intervention for endocarditis?
Vegetation > 10mm
What MIC indicates that the microorganism is high penicillin-susceptible?
MIC </= 0.12 ug/mL
What are the treatment options for Highly Penicillin Susceptible Native Valve Endocarditis (Viridians Group Streptococci and S. gallolyticus)?
Penicillin G -4 weeks
Ceftriaxone -4 weeks
Penicillin G + Gentamicin -2 weeks
Ceftriaxone + Gentamicin - 2 weeks
Vancomycin -4 weeks
What patients should not receive Penicillin + Gentamicin for native valve endocarditis?
Those with known cardiac or extracardiac abcesses
CrCl <20
What MIC indicates that the microorganism is “Relatively” resistant to Penicillin? (native valves only)
MIC > 0.12 </= 0.5
What are the treatment options for Relatively Penicillin Resistant Native Valve Endocarditis (Viridians Group Streptococci and S. gallolyticus)?
Penicillin G (4 wks) + Gentamicin (2 wks)
note: ampicillin is an option
Ceftriaxone (4 wks) + Gentamicin (2 wks)
Vancomycin (4 weeks) (only if B-lactam intolerant)
What are the treatment options for Penicillin Susceptible Prosthetic Valve Endocarditis (Viridians Group Streptococci and S. gallolyticus)?
Penicillin G (6 wks) +/- Gentamicin (2 wks)
Ceftriaxone (6 wks) +/- Gentamicin (2 wks)
Vancomycin (6 wks) (only if B-lactam intolerant)
Who should not receive gentamicin for prosthetic valve endocarditis?
CrCl < 30
What is a reasonable alternative for ceftriaxone in prosthetic valve endocarditis therapy?
Ampicillin
What MIC indicates “Penicillin Relatively or Fully Resistant” in Prosthetic Valve endocarditis?
MIC > 0.12
What are the treatment options for Penicillin Relatively or Fully Resistant Prosthetic Valve Endocarditis (Viridians Group Streptococci and S. gallolyticus)?
Penicillin G (6 wks) + Gentamicin (6 wks)
(ampicillin is alternative)
Ceftriaxone (6 wks) + Gentamicin (6 wks)
Vancomycin (6 wks) (only in B-lactam allergy)
What is the treatment for Oxacillin-Susceptible Native Valve Endocarditis caused by Staphylococci (MSSA)?
Nafcillin or Oxacillin (6 wks)
(note that uncomplicated, right-sided is 2 wks)
Pen-allergy: Cefazolin (6 wks)
What is the treatment for Oxacillin-Resistant Native Valve Endocarditis caused by Staphylococci (MRSA)?
Vancomycin (6 wks)
Daptomycin (6 wks) (*right IE sided only)
True or False: We do not care about MIC in endocarditis caused by staphylococci
True
-Only care if it is MSSA or MRSA
-Also if it is native or prosthetic
What is the target trough for Vancomycin used in Native Valve Endocarditis caused by Staphylococci?
10-20 ug/mL
What is the approved dose for daptomycin use in staphylococcal endocarditis?
6 mg/kg/day
What are the MRSA alternatives that can be used in endocarditis?
Ceftaroline (salvage therapy)
Linezolid (not really used, serotonin syndrome)
Tedizolid (No clinical evidence)
What are the treatment options for Oxacillin-Susceptible Prosthetic Valve Endocarditis caused by staphylococci (MSSA)?
Nafcillin or Oxacillin (>6 wks)
+
Rifampin (>6 wks)
+
Gentamicin (2 wks)
note: can use Vancomycin if severe B-lactam allergy, can use Cefazolin if mild B-lactam allergy
What are the treatment options for Oxacillin Resistant Prosthetic Valve Endocarditis caused by Staphylococci (MRSA)?
Vancomycin (>/= 6 weeks)
+
Rifampin (>/= 6 weeks)
+
Gentamicin (2 weeks)
Generally, what is true regarding native and prosthetic valve therapy duration?
Native = 4 weeks
Prosthetic = 6 weeks
For endocarditis caused by enterococci, what are the possible treatments for either native or prosthetic valve infections that are Penicillin and Gentamicin susceptible, and able to tolerate B-lactam therapy?
Ampicillin + Gentamicin (4-6 wks)
Penicillin + Gentamicin (4-6 wks)
Ampicillin + Ceftriaxone (6 wks)
*note: 4 weeks if symptoms are present < 3months, 6 weeks if > 3 months
Prosthetic valve = 6 wks
*use ampicillin + ceftriaxone if CrCl < 50
For endocarditis caused by enterococci, what are the possible treatments for both native and prosthetic valve infections that are Penicillin-susceptible, Aminoglycoside resistant?
Ampicillin + Ceftriaxone (6 wks)
What are the treatment options for enterococci (Native or Prosthetic valve) endocarditis that is: Penicillin-Susceptible, Streptomycin-Susceptible, and Gentamicin-Resistant?
Ampicillin + Streptomycin (4-6wks)
Penicillin + Streptomycin (4-6 wks)
