Endocarditis

From Anvita Health Wiki

Contents 1 Etiology 2 Epidemiology 3 Pathology 4 Clinical-manifestations 5 Diagnostic-criteria 6 Laboratory 7 Diagnostic-procedures 8 Radiology 9 Complications 10 Management 11 More General Terms 12 Additional Terms 13 References

Etiology

• common microbiologic causes (see common organisms by study)

• native valve

• Streptococci
• Staphylococci ( S aureus most common cause)
• Gram-negative rods

• prosthetic valve & IV drug abuse

• Staphylococci
• Streptococci & Enterococci
• Gram-negative rods
• fungi

• uncommon microbiologic causes

• HACEK bacterial group (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)
• anaerobes
• Chlamydia
• Rickettsia
• Brucella
• Legionella
• Coxiella
• viruses

• echovirus
• coxsackie virus
• adenovirus

• culture negative infectious endocarditis (3-5%)

• prior antibiotics
• fastidious organisms
• viral or fungal etiology
• indolent tricuspid valve disease

• non infectious endocarditis

• systemic lupus erythematosus

• risk factors for endocarditis

• prosthetic heart valve*
• congenital heart disease: Tetralogy of Fallot
• rheumatic heart disease
• mitral valve prolapse with regurgitation
• prior endocarditis*
• Marfan's syndrome
• valvular stenosis
• valvular insufficiency
• hypertrophic cardiomyopathy
• intravenous drug abuse ( IVDA)
• central venous catheters
• hemodialysis catheters & shunts
• wires from pacemakers & implantable defibrillators
• recent dental work or surgery

• * high-risk of endocarditis

Epidemiology

• mean age of patients is > 50 years

Pathology

• cardiac

• valve-ring abscess
• valvular perforation
• valvular rupture
• myocardial abscess
• valvular stenosis secondary to large vegetations
• systemic embolization
• mycotic aneurysms

• kidney (common)

• renal abscess
• renal embolization & infarction
• glomerulonephritis

• CNS involvement

• ischemic stroke secondary to cardiac emboli
• cerebral vasculitis
• meningitis
• cerebral abscess
• subarachnoid hemorrhage due to ruptured mycotic aneurysm

• affected valves:

• single valve involvement

• mitral > aortic > tricuspid > pulmonic

• involvement of right & left heart valves (3-5%)
• involvement of both aortic & mitral valves (30-35%)
• heroin associated with right-sided endocarditis [6]

Clinical-manifestations

• protean manifestations due to:

• cardiac complications of valvular dysfunction
• bacteremia
• bland or septic emboli
• circulating immune complexes

• common manifestations

• fever/ chills (90-95%)
• bacteremia
• malaise
• heart murmur (> 80%)
• embolic phenomena - focal neurologic signs
• congestive heart failure
• cough, pleuritic chest pain & pneumonia more common in right-sided endocarditis ( IV drug abuse)

• uncommon manifestations

• splenomegaly
• retinal lesions ( Roth spots)
• meningitis
• cutaneous manifestations

• splinter hemorrhages
• Osler's nodes
• Janeway lesions
• petechiae

Diagnostic-criteria

• Duke criteria for diagnosis of infectious endocarditis

Laboratory

• complete blood count ( CBC)

• normocytic anemia
• leukocytosis
• monocytosis (< 25%)

• urinalysis (abnormal < 65%)

• proteinuria
• pyuria
• hematuria

• blood cultures (positive in > 93%)
• antibiotic sensitivities

• determination of the minimum inhibitory ( MIC) & minimum bactericidal concentration ( MBC)
• assess aminoglycoside synergy for penicillin-resistant streptococci & enterococci
• Schlicter test

• erythrocyte sedimentation rate (ESR) increased in > 90%

Diagnostic-procedures

• electrocardiogram ( ECG) - may show conduction abnormalities
• echocardiogram

• transthoracic echocardiogram ( TTE)

• all septic or bacteremic patients
• TTE with lower sensitivity than TEE, but better specificity

• transesophageal echocardiogram ( TEE)

• septic or bacteremic patients with negative TTE
• better sensitivity than transthoracic echo, but higher incidence of false positives
• patients with prosthetic valves
• perivalvular abscess

• role of echocardiography in assessing prognosis or need for surgery is controversial

• colonoscopy to assess colon cancer in patients with blood cultures positive for:

• Streptococcus bovis
• Clostridium septicum [4]

Radiology

• chest X-ray may show multiple bilateral small nodules
• multislice computed tomography ( CT) may be alternative to TEE [7]

Complications

• embolic strokes are common with left-sided endocarditis, but often clinically silent
• in- hospital or 14.7% & 1-year mortality of 23.2% when associated with cardiac device ( pacemaker, mechanical valve) [11]

Management

• antibiotic therapy

• general considerations

• 4-6 weeks duration of therapy*
• use of synergistic combinations of antibiotics
• selection of antibiotic(s) on the basis of an isolated organism (see laboratory)
• recognition of indications for surgical management

• empiric therapy (after obtaining blood cultures)

• community-acquired endocarditis

• vancomycin plus gentamicin, or
• ampicillin sulbactam ( Unasyn) plus gentamicin

• nosocomial endocarditis

• vancomycin, gentamicin + rifampin ( S epidermidis) + antipseudomonas penicillin or beta-lactam antibiotic (gram-negative baccilli)

• specific organisms

• Streptococcus

• penicillin-sensitive ( MIC < 0.2 ug/mL)

• penicillin G 10-20 million units IV QD for 4 weeks +/- 2 weeks of gentamicin 1 mg/kg IV every 8 hours
• vancomycin 15 mg/kg IV every 12 hours for 4 weeks

• penicillin-resistant ( MIC > 0.5 ug/mL)

• penicillin G 20 million units IV QD plus Gentamicin 1 mg/kg every 8 hours for 6 weeks
• ampicillin 2 g IV every 6 hours plus Gentamicin 1 mg/kg every 8 hours for 6 weeks
• vancomycin 15 mg/kg IV every 12 hours plus Gentamicin 1 mg/kg every 8 hours for 6 weeks

• Enterococcus - treat as penicillin-resistant Streptococcus
• Staphylococcus

• nafcillin 1.5-2.0 g IV every 4 hours for 4-6 weeks plus gentamicin 1 mg/kg IV every 8 hours for 5-7 days
• vancomycin 15 mg/kg IV every 12 hours plus rifampin 300 mg PO every 12 hours for 4-6 weeks plus gentamicin 1 mg/kg IV every 8 hours for 5-7 days
• cephalothin 2 gm IV every 6 hours for 4-6 weeks plus gentamicin 1 mg/kg IV every 8 hours for 5-7 days

• Enteric gram-negative bacilli ( E coli, Klebsiella, Proteus, Pseudomonas, Serratia)

• cephalosporin or broad-spectrum penicillin plus an aminoglycoside determined by antibiotic sensitivity for 6 weeks
• left-sided endocarditis due to Pseudomonas or Serratia may require combined medical & surgical intervention

• fungal

• prognosis poor
• antifungal agents with poor activity

• prosthetic valve

• Staphylococcus aureus & epidermidis, diphtheroids

• vancomycin + gentamicin + rifampin
• nafcillin + gentamicin

• Candida or aspergillus

• amphotericin B + 5-FC + surgery consult

• indications for surgery [9]

• hemodynamic instability

• surgery should not be delayed while active infection is treated

• progressive congestive heart failure [10]
• recurrent embolization
• antibiotic- refractory disease

• persistent bacteremia (> 3 days) on appropriate antibiotics

• extravalvular intracardiac abscess (ring abscess)
• mycotic aneurysm
• any treatment failure with prosthetic valve endocarditis
• prosthetic valve endocarditis caused by fungi, Pseudomonas aeruginosa or Staphylococcus aureus
• severe cardiac valvular dysfunction identified by echocardiography
  

• * special case of right-sided endocarditis caused by methicillin-sensitive S. aureus may be treated by 2 weeks of IV nafcillin + an aminoglycoside [4]
• see prophylaxis for bacterial endocarditis

More General Terms

• valvular heart disease
• inflammation

Additional Terms

• antibiotic prophylaxis for bacterial endocarditis
• Duke criteria for diagnosis of infectious endocarditis
• empiric antibiotic therapy
• etiology of bacterial endocarditis, common organism
• Janeway spot or lesion (smoke ring)
• Osler's node
• Slichter test

References

1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 265-67
2. Dajani AS et al Prevention of bacterial endocarditis. Recommendations by the American Heart Association. JAMA 1990, 264:2919 PMID: [1]
3. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 785-91
4. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, American College of Physicians, Philadelphia 1998, 2006
5. Snygg-Martin U et al, Cerebrovascular complications in patients with left-sided infective endocarditis are common: A prospective study using magnetic resonance imaging and neurochemical brain damage markers. Clin Infect Dis 2008, 47:23 PMID: [2]
   - Baddour LM and Bayer AS. Cerebrovascular complications in patients with left-sided infective endocarditis: Out of site, out of mind. Clin Infect Dis 2008, 47:31 PMID: [3]
6. Jain V et al. Infective endocarditis in an urban medical center: Association of individual drugs with valvular involvement. J Infect 2008 Aug; 57:132. PMID: [4]
7. Feuchtner GM et al. Multislice computed tomography in infective endocarditis: Comparison with transesophageal echocardiography and intraoperative findings. J Am Coll Cardiol 2009 Feb 3; 53:436. PMID: [5]
8. Fowler VG et al, Staphylococcus aureas Endocarditis: A Consequence of Medical Progress JAMA 2005, 293(24):3012 PMID: [6]
9. Lalani T et al. Analysis of the impact of early surgery on in-hospital mortality of native valve endocarditis: Use of propensity score and instrumental variable methods to adjust for treatment-selection bias. Circulation 2010 Mar 2; 121:1005. PMID: [7]
10. Kiefer T et al. Association between valvular surgery and mortality among patients with infective endocarditis complicated by heart failure. JAMA Nov 23/30; 306:2239. PMID: [8]
11. Athan E et al. Clinical characteristics and outcome of infective endocarditis involving implantable cardiac devices. JAMA 2012 Apr 25; 307:1727. PMID: [9]
12. National Guideline Clearinghouse Suspected infective endocarditis. (American College of Radiology) ngc-guideline: [10]
    - Prevention of infective endocarditis: guidelines from the American Heart Association. ngc-guideline: [11]
    - Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009) European Society of Cardiology ngc-guideline: [12]

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