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Snapshot
  • A 50-year-old man presents to the emergency room for a fever that has persisted for several days. He denies any history of intravenous drug use or any congenital heart disease. Physical exam reveals nailbed splinter hemorrhages, Osler nodes on his fingers, and Janeway lesions on his palms and soles. Heart auscultation reveals a new murmur. An echocardiogram shows vegetations on the mitral valve, and blood cultures that were drawn 12 hours apart were positive for Streptococcus bovis. Antibiotic therapy is started and he is scheduled for a colonoscopy. 
Introduction
  • Clinical definition
    • inflammation of the heart valve, typically secondary to infection
  • Epidemiology
    • location
      • mitral valve > tricuspid valve
      • tricuspid valve disease is associated with intravenous (IV) drug use
        • Staphylococcus aureus, Pseudomonas, Candida
    • risk factors
      • rheumatic heart disease
      • IV drug use
      • immunosuppression
      • prosthetic heart valve
      • congenital heart disease
  • Etiology
    • acute endocarditis
      • Streptococcus pneumoniae
      • Streptococcus pyogenes
      • Neisseria gonorrhea
      • Staphylococcus aureus
        • IV drug users
        • large vegetations seen on valves
    • subacute bacterial endocarditis is characterized by slower onset and less severe symptoms
      • Streptococcus bovis (gallolyticus) 
        • in the setting of colon cancer
      • Enterococcus
        • in the setting of gastrointestinal/genitourinary procedures
      • Streptococcus viridans
        • often a complication of dental procedures
          • makes dextrans, which binds to fibrin-platelet aggregates on the heart valves
      • Staphylococcus epidermidis
        • often in the setting of prosthetic valves
      • Candida albicans
        • IV drug users
    • non-infectious endocarditis
      • Libman-Sacks endocarditis
        • from systemic lupus erythematosus
        • mitral or aortic valve involvement
      • marantic endocarditis
        • from metastatic cancer seeding to the valves
        • very poor prognosis
  • Pathogenesis
    • endothelial damage on the surface of the cardiac valve can cause a thrombus to form
      • factors include turbulent blood flow that can damage endothelium, or deposition of fibrin-platelet aggregate on damaged endothelium
      • bacteria can then adhere to thrombus
    • vegetations are caused by further depositions of fibrin and platelets
  • Prognosis
    • often presents as fever of unknown origin
    • endocarditis prophylaxis may be required before dental procedures
Presentation
  • Symptoms
    • persistent fevers (most common symptoms)
    • shortness of breath
    • systemic symptoms
      • weakness
      • fever
      • malaise
  • Physical exam
    • new murmur on auscultation
    • from emboli
      • Roth spots
        • retinal hemorrhages on funduscopy
      • Janeway lesions
        • erythematous and nontender macules on palms or soles
      • nail bed splinter hemorrhages
    • from immune complex deposition
      • Osler nodes
        • tender nodules on fingers or toes
      • glomerulonephritis
Imaging
  • Echocardiography
    • indication
      • for all patients
    • findings
      • vegetations on valves
Evaluation
  • Labs 
    • positive blood cultures drawn at least 12 hours apart or multiple positive cultures (at least 3 of 4) with the first and last drawn at least 1 hour apart
    • complete blood count
      • anemia
    • serum creatinine
      • to evaluate renal function (glomerulonephritis)
  • Making the diagnosis
    • based on clinical presentation and Duke criteria 
      • pathologic criteria
        • culture of organism
        • histologic evidence of endocarditis from vegetation or intracardiac abscess
      • clinical criteria: 1 of the following
        • 2 major criteria
        • 1 major and 3 minor criteria
        • 5 minor criteria
    • if blood cultures are negative but echocardiography shows endocarditis, consider 1 of the causes of Culture-Negative Endocardidtis (CNE)
      • Coxiella burnetii
      • Bartonella spp
      • HACEK organisms
        • Haemophilus
        • Aggregatibacter
        • Cardiobacterium
        • Eikenella
        • Kingella
Duke Criteria
Major Minor
  • Positive blood cultures from 2 separate blood cultures drawn > 12 hours apart, or 3 out of 4 blood cultures that are positive, with first and last samples drawn 1 hour apart
  • Abnormal echocardiogram with vegetation, abscess ,or partial dehiscence of prosthetic valve
  • Fever
  • Presence of risk factors, including intravenous drug use, structural heart disease, prosthetic heart valve, dental procedures, or history of endocarditis
  • Vascular phenomena, including Janeway lesions, emboli, mycotic aneurysm, and conjunctival hemorrhage
  • Immunologic phenomena, including glomerulonephritis, Osler nodes, and Roth spots
  • Positive blood cultures not meeting major criterion
  • Echocardiographic findings consistent with endocarditis but not meeting major criterion
 
Differential
  • Osteomyelitis
    • distinguishing factor
      • although this can present as fever of unknown origin, it typically lacks other findings of endocarditis and will not have vegetations on echocardiography
Treatment
  • Management approach
    • choice of antibiotics ultimately depend on causative agent and susceptibility as well as the presence of prosthetic material in the heart
    • all antibiotics should be given intravenously
  • Medical
    • vancomycin plus ceftriaxone or gentamicin
      • indications
        • for patients with no prosthetic valve
        • empiric antibiotic therapy
    • vancomycin plus gentamicin and rifampin
      • indications
        • for patients with prosthetic valve
        • empiric antibiotic therapy
  • Operative
    • surgical valve replacement
      • indications
        • heart failure
        • patients who are refractory to medical therapy
        • abscess formation
        • conduction disturbance
Complications
  • Cardiac complications
    • perivalvular abscess
    • arrhythmias
    • heart failure
  • Neurologic complications
    • stroke
 

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