A 14-year-old girl with a history of mitral regurgitation that complicated rheumatic heart disease was brought in by her parents after two weeks of intermittent low-grade fevers, fatigue, weakness, arthralgias, and myalgias. On examination, she appeared ill, was febrile, and had a heart murmur. Her funduscopic examination revealed Roth spots (Figures 44-1 and 44-2). Her blood cultures grew Streptococcus mitis. An echocardiogram demonstrated a vegetation on the mitral valve. She was hospitalized and treated for bacterial endocarditis.

Bacterial endocarditis is a serious infection that in the pediatric population is seen most commonly in patients with congenital heart disease, prosthetic valves, injection drug users, and patients with indwelling central venous catheters. The diagnosis is made based on the Duke Criteria. The rate of cure with appropriate antibiotics and surgical management, when indicated, is high, and facilitated by prompt diagnosis and vigilance in recognizing complications.

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  0.34 to 0.64 cases per 100,000 patient-years.¹

  
  
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  1 case per 1000 pediatric hospital admissions.

  
  
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  46 percent of cases in ages 0 to 1, followed by 23 percent, 20 percent, and 12 percent in ages 12 to 18, 5 to 12, and 1 to 5 years, respectively.²

  
  
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  58 percent of cases in male patients.²

  
  
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  68 percent of patients hospitalized with infective endocarditis (IE) had some type of congenital heart disease.²

  
  
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  2007 AHA guidelines for IE prophylaxis have not changed IE admissions.²

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  Flow through an abnormal valve or abnormal communication between systemic and pulmonary circulation (as in various congenital heart diseases) damages endothelium.

  
  
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  Platelets and fibrin adhere to damaged endothelium initiating a sterile thrombus.

  
  
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  Microbes adhere to compromised endothelium during transient bacteremia.

  
  
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  Common organisms include viridans Streptococci (such as Streptococcus mitis and Streptococcus oralis) Staphylococcus aureus, coagulase-negative Staphylococci, Enterococci, Candida spp, and rarely Streptococcus pneumoniae.

  
  
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  Viridans streptococci are more commonly associated with rheumatic fever, unrepaired congenital heart disease, and late postoperative endocarditis.

  
  
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  Staphylococcal species, including methicillin-resistant S aureus (MRSA) and coagulase-negative Staphylococci, are commonly associated with endocarditis after cardiac surgery and with prosthetic valves; S aureus is also common as a cause of endocarditis in individuals who have normal hearts and in intravenous drug users.

  
  
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  Fungal causes of endocarditis, such as Candida spp., are especially common in those who have hospital-acquired endocarditis, those with central venous catheters, those with prosthetic valves, and in neonates.

  
  
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  Fastidious agents, known as the HACEK group, are rare causes of endocarditis in the pediatric population and include Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella (neonates and immunocompromised).

  
  
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  Blood contacts subendothelial factors, which promotes coagulation.

  
  
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  Pathogens bind and activate monocyte, cytokine, and tissue factor production, enlarging the vegetations on the heart valves.

  
  
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  The vegetations enlarge and damage the heart valves (Figure 44-3). This process can lead to death if not treated adequately in time.

  
  
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  Septic emboli can occur, most commonly in the brain, spleen, or kidney.³

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  Congenital heart disease.

  
  
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  Prosthetic valve.

  
  
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  Injection drug use.

  
  
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  Rheumatic fever.

  
  
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  Prior episode of bacterial endocarditis.

  
  
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  Central venous catheters (neonates).

  
  
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  Prior heart surgery with resultant valvulopathy or systemic to pulmonary shunt.

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  The Duke criteria use a combination of history, physical examination, laboratory, and echocardiogram findings, and across several studies, have a sensitivity of approximately 80 percent.⁵

  
  
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  The diagnosis is considered definite when patients have two major, one major and three minor, or five minor criteria.⁵

  
  
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  The diagnosis is considered possible when one major and one minor or three minor criteria are present.⁵

  
  
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  Major criteria include:⁵

  
  
  
  
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    Two separate blood cultures positive with:

    
    
    
    
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      viridans Streptococci, S aureus, HACEK group, or enterococci.

      
      
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      Persistently positive blood cultures.

      
      
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      Single positive culture or high IgG titer for Coxiella burnetti (Q fever).

    
    
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    Echocardiogram evidence of vegetation, abscess, or new partial dehiscence of a prosthetic valve.

    
    
    
    
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      New valvular regurgitation.

  
  
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  Minor criteria include:⁵

  
  
  
  
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    Predisposition (e.g., heart condition such as a congenital or acquired valvular defect, injection drug use, prior history of endocarditis).

    
    
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    Temperature >38°C (100.4°F).

    
    
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    Clinical signs: arterial emboli, septic pulmonary infarcts, mycotic aneurysms, intracranial hemorrhages, splinter hemorrhages, Osler nodes, Roth spots, or Janeway lesions (Figures 44-1,44-2, and 44-4 to 44-7).

    
    
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    Glomerulonephritis.

    
    
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    Positive rheumatoid factor.

    
    
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    Positive blood culture not meeting major criteria.

    
    
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    Echocardiographic findings consistent with infective endocarditis that do not meet major criteria.