Endocarditis Flashcards
(49 cards)
What is infective endocarditis?
syndrome resulting in colonization
or invasion of the endocardium by various types of microorganisms
* Bacteria, fungi, others
What are risk factors predisposing for infective endocarditis?
- Presence of a prosthetic valve (highest risk)
- Previous endocarditis (highest risk)
- Acquired valvular dysfunction
- Mitral valve prolapse with regurgitation
- Intravenous drug use
- Congenital heart disease
- Cardiac implantable devices
- Surgically constructed systemic pulmonary shunts or conduits
- Hypertrophic cardiomyopathy
What are the causative pathogens in infective endocarditis?
- Staphylococci (30-70% of cases): S. aureus – most common, S. aureus – most common pathogen in persons who inject drugs (PWID)
- Streptococci of the viridans group (10-28% of cases): More common in patients with underlying cardiac abnormalities (e.g., mitral valve prolapse, rheumatic heart disease)
- Enterococci (5-18% of cases): E. faecalis, E. faecium
- Fastidious gram-negative coccobacilli (5-10% of cases): HACEK group – Haemophilus parainfluenzae, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae
- Fungi: Mostly seen in narcotic addicts, patients after reconstructive cardiovascular surgery, patients after prolonged IV and/or antibiotic therapy
What is the pathophysiology of infective endocarditis?
- Bacterial growth in vegetation is unimpeded due to lack of host defenses.
- Valvular tissue may be destroyed with vegetation formation: May lead to acute heart failure via perforation of valve leaflet or
rupture of the chordae tendinae or papillary muscle; May see valve dehiscence in PVE
What is the clinical presentation of infective endocarditis?
- Highly variable and non-specific – depends on chronicity of infection
- Signs and symptoms
- Fever (95%)
- Malaise
- Fatigue
- Chills
- Heart murmur
- Embolic phenomena
- Skin manifestations
- Weakness
- Dyspnea
- Night sweats
- Weight loss
What are the laboratory findings in infective endocarditis?
hematologic: Normochromic, normocytic anemia (70-90%); Leukocytosis (5-15%) – may be normal to slightly elevated
* Increased ESR and CRP
* Urinalysis: Proteinuria; Microscopic hematuria
* Blood cultures – single most important laboratory test!!: 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; Culture and susceptibility testing
What are the peripheral manifestations of endocarditis?
osler’s nodes, janeway lesions, splinter hemorrhages, petechiae, roth spots
What are osler’s nodes?
Purplish or erythematous subcutaneous papules or nodules that appear on the pads of the fingers and toes (painful and tender)
What are janeway lesions?
- Hemorrhagic, painless plaques on palms of hands or soles of feet
- Embolic in origin
What are splinter hemorrhages?
Thin, linear hemorrhages under the nail beds of fingers or toes
What is petechiae?
- Small, erythematous, painless hemorrhagic lesions on anterior trunk, conjunctivae, buccal mucosa, and palate
- Result from either local vasculitis or emboli
What are roth spots?
Oval, pale, retinal lesions surrounded by hemorrhage
What is included in the diagnosis of endocarditis? - major criteria
microbiological, imaging, surgical
What are microbiological criteria?
- Positive blood cultures: Microorganisms that commonly cause IE isolated from 2 or more separate blood culture sets; Microorganisms that occasionally or rarely cause IE isolated from 3 or more separate blood culture sets
- Positive laboratory test: Positive PCR for Coxiella burnetii, Bartonella species, or Tropheryma whipplei from blood; Single positive blood culture for Coxiella burnetii or antiphase IgG antibody titer ≥ 1:800; Indirect immunofluorescence assay (IFA) for detection of IgM and IgG antibodies to Bartonella henselae or Bartonella quintana with IgG titer ≥ 1:800
What is imaging criteria?
Echocardiography and cardiac computed
tomography (CT) imaging: Echocardiography or cardiac CT showing vegetation, valvular/leaflet perforation, valvular/leaflet aneurysm, abscess, intracardiac fistula
Positron emission computed tomography with 18F-fluorodeoxyglucose (18-F FDG PET/CT) imaging
What is the surgical criteria?
Evidence of IE documented by direct inspection during cardiac surgery
What are minor criteria for endocarditis? - predisposition
- Previous history of IE
- Prosthetic valve
- Previous valve repair
- Congenital heart disease
- More than mild regurgitation or stenosis of any etiology
- Endovascular intracardiac implantable electronic device
- Hypertrophic obstructive cardiomyopathy
- Injection drug use
What are minor criteria for endocarditis? - clinical symptoms
- Fever – documented temperature > 38°C (100.4°F)
- Vascular phenomena – clinical or radiologic evidence of arterial emboli, septic pulmonary infarcts, cerebral or splenic abscess, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions
- Immunologic phenomena – positive rheumatoid factor, Osler’s nodes, Roth spots, immune complex-mediated glomerulonephritis
- Microbiologic evidence not meeting major criteria: Positive blood culture for organism consistent with IE but not meeting major criteria
- Imaging criteria–abnormal metabolic activity detected by PET/CT within 3 months of implantation of prosthetic valve, aortic graft, intracardiac device leads, or other prosthetic material
- Physical exam criteria–new valvular regurgitation identified on auscultation (if echo not available)
What are general considerations for treatment for endocarditis?
- Primary goal: eradicate infection (sterilize vegetation)
- Complete eradication of organisms takes weeks to achieve
- Begin high dose, empiric antibiotics based on the most likely pathogen(s)
- Bactericidal activity is required; synergistic combinations needed for some pathogens
What is the duration of therapy for the treatment of endocarditis?
Prolonged therapy required to eradicate pathogen in the vegetation.
Shortest duration is 2 weeks, but 4-6 weeks (or longer) needed depending on organism, organism susceptibility, native valve vs. prosthetic valve
Begin counting days for treatment duration on first day of negative blood cultures
Surgical intervention in endocarditis
- Vegetation: Persistent vegetation after systemic embolization; Anterior mitral valve leaflet vegetation > 10 mm; ≥ 1 embolic event during first 2 weeks of antimicrobial therapy; Increased vegetation size despite appropriate antimicrobial therapy
- Valvular dysfunction: Acute aortic or mitral insufficiency with signs of ventricular failure; Heart failure unresponsive to medical therapy
- Valve perforation or rupture
- IE caused by resistant organism
- Large myocardial abscess or extension of abscess despite appropriate antimicrobial therapy
- Early PVE (< 1 year)
What is the treatment for Viridans Group Streptococci and S. gallolyticus - Native Valve Endocarditis? - highly penicillin-susceptible
penicillin OR ceftriaxone: Preferred in patients > 65 years or with renal dysfunction or hearing impairment
penicillin plus gentamicin: Not intended for patient with known cardiac or extracardiac abscesses or CLcr < 20 ml/min
ceftriaxone plus gentamicin
vancomycin: Only for patients unable to tolerate β- lactams
What is the treatment for Viridans Group Streptococci and S. gallolyticus - Native Valve Endocarditis? - penicillin relatively resistant
penicillin plus gentamicin
ceftriaxone plus gentamicin
vancomycin: Only in patients unable to tolerate β- lactam therapy
treat for 4 weeks
What is the treatment for Viridans Group Streptococci and S. gallolyticus - Prosthetic Valve Endocarditis? - penicillin susceptible
penicillin with or without gentamicin: Avoid gentamicin if CrCl < 30 min/mL
cefriaxone with or without gentamicin
vancomycin: Only in patients unable to tolerate β- lactam therapy
treat for 6 weeks
