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Snapshot
  • A 25-year-old woman presents to the emergency room for fever of unknown origin. She has a history of intravenous drug use, and had previously been treated for osteomyelitis. On physical exam, she is febrile, and heart auscultation reveals a new systolic murmur at the tricuspid area. Funduscopy also revealed retinal hemorrhages. An echocardiogram reveals tricuspid valve vegetations. She is started on antibiotics.
Introduction
  • Clinical definition
    • inflammation of the heart valve, typically secondary to infection, most commonly by Staphylococci or Streptococci
  • 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
        • can also occur with upper respiratory infections
        • 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 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: one 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 one 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 or abscess or partial dehiscence of prosthetic valve
  • Fever
  • Presence of risk factors, including intravenous drug use, structural heart disease, prosthetic heart valve, dentla 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 presence of prosthetic material in the heart
    • all anitbiotics should given intravenously
  • Medical
    • vancomycin plus ceftriaxone or gentamicin
      • indications
        • for patients with no prosthetic valve
        • empiric antibiotic therapy
        • often for 4-6 weeks
    • vancomycin plus gentamicin and rifampin
      • indications
        • for patients with prosthetic vlave
        • empiric antibiotic therapy
        • often for 4-6 weeks
  • 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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