Endocarditis
Todd L. Kiefer
Fred A. Lopez
Randall Vagelos
NATIVE VALVE ENDOCARDITIS
Staphylococcus aureus: Increasing prevalence; Streptococcus viridans; Streptococcus species: S. mitis, S. mutans, S. bovis, S. sanguis; Coagulase-negative Staphylococcus species: Staphylococcus lugdunensis is quite virulent;Enterococcus species; Gram-negative bacilli; Fungi: Candida and Aspergillus species
Other less common organisms, which are often “culture negative”: HACEK organisms (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae), Abiotrophia species, Bartonella quintana, Bartonella henselae, Tropheryma whipplei, Legionella, Coxiella burnetii, Brucella species, Chlamydia psittaci, Mycoplasma, Neisseria gonorrhoeae
Clinical Presentation3
Fever, weight loss, fatigue, anorexia, arthritis/arthralgias, myalgias, skin manifestations, cough, mental status changes, headache
Risk Factors
Mitral valve prolapse (most common), other valvular abnormalities, hemodialysis, indwelling vascular catheters, intravenous drug use
Differential Diagnosis/Endocarditis Mimics4
Atrial myxoma, carcinoid valve disease, myxomatous valve degeneration, papillary fibroelastoma, Lambl excrescence, ruptured chordae, thrombus or stitch after valvular surgery, eosinophilic heart disease, acute rheumatic fever, pulmonary embolus, CVA.
PHYSICAL EXAM
Cardiac auscultation for evidence of new heart murmur (in particular, murmur of valvular regurgitation), Janeway’s lesions, Osler’s nodes (painful), splinter hemorrhages, Roth spots, skin petechiae, oral petechiae, conjunctival hemorrhage, splenomegaly, clubbing, S3 gallop, lung crackles.
Electrocardiogram (ECG)
Evaluate for prolonged P-R interval or high-grade A-V block suggestive of aortic perivalvular abscess, or evidence of other new conduction abnormalities
DIAGNOSIS5
Modified Duke Criteria for definite infective endocarditis: 2 major criteria or; 1 major and 3 minor criteria or; 5 minor criteria
Major criteria: blood culture positive for typical organism from two separate blood cultures or persistent culture positive from specimens greater than 12 hours apart or all of 3 or a majority of greater than 4 separate cultures with an organism consistent with endocarditis, new valvular regurgitation, echocardiogram positive for endocarditis (oscillating mass, abscess, or partial dehiscence of prosthetic valve), evidence of endocardial involvement, blood culture positive for Coxiella burnetti or IgG titer > 1:800.
Minor criteria: temperature > 38°C, vascular ( Janeway’s lesions, emboli, mycotic aneurysm), immunologic (Osler’s nodes, Roth’s spots, glomerulonephritis, positive rheumatoid factor), positive blood culture not meeting major criteria or serological data supporting infection with organism known to cause endocarditis, predisposing heart condition or intravenous drug use.
Laboratory evaluation:6 Blood cultures prior to antibiotics; if initial cultures are negative (approximately 10%) and diagnosis is still suspected, alert lab to hold for fastidious organisms (HACEK organisms); May also be associated with leukocytosis, anemia, and/or microscopic hematuria
Chest radiograph: May reveal septic pulmonary emboli from right-sided endocarditis
Echocardiography7, 8, and 9: Transsthoracic echo: Starting point for suspected native valve endocarditis: Sensitivity: 32% to 63%; Specificity: 98% to 100%; Transesophageal echo: Next step if transthoracic echocardiogram (TTE) nondiagnostic and endocarditis is still suspected; First step in evaluation of patient with prosthetic valve (see section below), high clinical suspicion, or anticipated difficulty imaging with TTE; Also perform pre-operatively if patient will undergo valve surgery: Sensitivity: 94% to 100%; Specificity: 98% to 100%; Additional considerations for transesophageal echocardiography (TEE): Enhanced ability to detect myocardial abscess, aneurysm, fistula
TREATMENT10
Early cardiothoracic surgery consultation and evaluation with coordination of care involving infectious diseases and cardiology consultants.
Antibiotic regimens: See reference 10 for dosing regimens.
Penicillin-sensitive Streptococcus viridans and S. bovis: Penicillin G or ceftriaxone for 4 weeks OR Vancomycin for 4 weeks with penicillin allergy
Penicillin-resistant Streptococcus viridans and S. bovis: Penicillin G or ceftriaxone for 4 weeks with the addition of gentamicin for 2 weeks OR Vancomycin for 4 weeks with penicillin allergy
Penicillin-sensitive Enterococcus: Ampicillin for 4-6 weeks with the addition of gentamicin for 4-6 weeks; penicillin G for 4-6 weeks with the addition of gentamicin for 4-6 weeks; vancomycin and gentamicin for 6 weeks with penicillin allergy
Oxacillin-sensitive Staphylococcus: Nafcillin or oxacillin for 6 weeks +/−3-5 days of gentamicin; cefazolin for 6 weeks with penicillin allergy (not ananphylaxis)
Oxacillin-resistant Staphylococcus: Vancomycin for 6 weeks
HACEK endocarditis: Ceftriaxone or ampicillin/sulbactam or ciprofloxacin (ampicillin/ceftriaxone allergy) for 6 weeks
Inpatient parenteral antibiotics first 2 weeks of treatment when risk of embolism and other complications is highest, then selection of lower-risk patients for outpatient parenteral therapy based on published guidelines8
High risk for outpatient therapy: congestive heart failure (CHF), arrhythmia, altered mental status, perivalvular abscess, aortic valve disease, prosthetic valve disease, infection with S. aureus, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitides or N. gonorrhoeae, betahemolytic Strep, gram-negative organisms, or fungal organism11
Indications for surgery:10 Class I: heart failure secondary to valve stenosis or insufficiency, aortic or mitral insufficiency with elevated left ventricular end-diastolic or left atrial pressures, aortic insufficiency with mitral valve preclosure, fungal endocarditis, infection with highly resistant organism, heart block, abscess, fistula formation, or mitral leaflet perforation. Class IIa: recurrent embolic events, persistent vegetation with appropriate antimicrobial therapy. Class IIb: mobile vegetation > 10 mm.
OUTCOMES
Overall mortality of 10% to 20% for hospitalized patients, 30% to 40% 1-year mortality12
Right-sided endocarditis: Mortality less than 10%13
Significant increase in 6-month survival with valve replacement surgery for left-sided endocarditis using current criteria for valve replacement (16% vs. 33%); most significant decrease in mortality seen in patients with evidence of moderate to severe CHF (14% vs. 51%)14
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