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• Infective Endocarditis


  Microbial infection of the endocardium (endothelial) surface of the heart
• Infective Endocarditis


  • Valves are the most frequently involved sites
  • Can also involve septal defects, the mural endocardium, intracardiac devices or arterial lines (endarteritis)
• Types of Infective Endocarditis


  • Native valve endocarditis (NVE)
  • Acute
  • Subacute
  • Prosthetic valve endocarditis (PVE)
  • Early -- <1 yr after valve surgery
  • Late -- >1 yr after valve surgery
  • Nosocomial IE (NIE) -- in a patient hospitalized >48 hrs prior to the onset of signs and symptoms
• Epidemiology


  Incidence of IE -- 3.6 to 7.0/ 100,000/years<|>Rheumatic heart disease was a major underlying cardiac condition in developing countries
• Risk stratification - High Risk


  • Prosthetic valves
  • Previous IE
  • Complex cyanotic CHD (TGA,TOF...)
  • Surgically constructed systemic artery-to-pulmonary artery shunts
  • Injection drug use
  • Indwelling central venous catheters
• Risk stratification - Moderate Risk

  • Uncorrected PDA, VSD, ASD
  • Bicuspid aortic valve
  • Mitral valve prolapse with regurgitation
  • Rheumatic mitral or aortic valve disease
  • Hypertrophic cardiomyopathy
• Risk stratification - Low/no risk


  • MVP without murmur
  • Trivial valvular regurgitation
  • Isolated ASD
  • Implanted device (pacer, ICD)
• Special risk groups


  • Intravenous drug users
  • Survivors of cardiac surgery, especially those with mechanical prosthesis
  • Patients taking immunosuppressant medications
  • Patients who require chronic intravascular catheters
• Etiology - Causative agents

  • Viridans-type streptococci (α-hemolytic streptococci)
  • Staphylococcus aureus
  • Enterococci
  • HACEK group
  • Fungal organisms (after open heart surgery)
  • Coagulase-negative staphylococci (in the presence of an indwelling central venous catheter)
• Culture negative endocarditis


  Occurs in about 6% of patients

  Causes:

  Poor microbiologic techniques

  Prior administration of antibiotics

  Highly fastidious microorganisms

  Non-culturable organisms (like mycoplasma, Chlamydia, C.burnetti, bartonella, fungi)
• Pathogenesis of Infective Endocarditis

  1. Risk

  2. Damage to the endothelium

  3. Formation of NBTE

  4. Transient bacteremia

  5. Adherence and proliferation
• Clinical features - History

  • Prior congenital or rheumatic heart disease
  • Preceding dental, urinary tract, or intestinal procedure
  • Intravenous drug use
  • Central venous catheter
  • Prosthetic heart valve
• Clinical features - Symptoms

  • Fever
  • Weight loss
  • Hematuria
  • Arthralgia, myalgia
  • Dyspnea
  • CNS manifestations (stroke, seizures, headache)
• Clinical features - Signs

  • Fever
  • Tachycardia
  • New or changing murmur
  • Splenomegaly
  • Arthritis
  • Heart failure
  • Arrhythmias
  • Metastatic infection (arthritis, meningitis, mycotic arterial aneurysm, pericarditis, abscesses, septic pulmonary emboli)
  • Clubbing
• Janeway Lesions


  Painless, small erythematous or hemorrhagic lesions on the palms and soles
• Splinter Hemorrhages


  Nonspecific, nonblanching, linear reddish-brown lesions found under the nail bed, usually do not extend the entire length of the nail
• Osler's Nodes


  Tender, pea-sized intradermal nodules in the pads of the fingers and toes
• Petechiae


  Nonspecific, often located on extremities or mucous membranes
• Investigations


  • Blood culture
  • Echo
  • TTE
  • TOE
  • FBC/ESR/CRP
  • Rheumatoid Factor
  • OFT
  • U/A
  • CBC
• Blood culture


  1. Three to five blood collections each from a separate venipuncture over a 24-hour period

  2. 3 separate cultures of blood (with first and last sample drawn ≥1 h apart)

  3. Avoid Contamination

  4. Timing of collections is not important

  5. 1 to 3 mL in infants and young children and 5 to 7 mL in older children are adequate

  6. Inoculating blood into bottles designed for aerobic incubation

  7. In 90% of cases of endocarditis, the causative agent is recovered from the 1st two blood cultures
• Lab findings


  Acute-phase reactants are commonly elevated<|>Anemia is common (hemolytic or chronic disease)<|>Hematuria represents either renal embolization or immune complex related nephritis
• Echocardiography


  Sensitivities in children reported to be >80%

  Neither sensitivity nor specificity of echo is 100%

  A negative echocardiogram does not always rule out endocarditis

  TEE is superior to TTE for identification of vegetations, but similar information in children is not available
• Echocardiographic findings suggestive of Infective Endocarditis

  • Oscillating intracardiac mass
  • Abscess
  • New partial dehiscence of prosthetic valve
  • New valvular regurgitation (worsening or changing or pre-existing murmur not sufficient)
• Duke Criteria - Major criteria

  • Positive blood cultures (two separate cultures for a usual pathogen, two or more for less typical pathogens)
  • Evidence of endocarditis on echocardiography (intracardiac mass on a valve or other site, regurgitant flow near a prosthesis, abscess, partial dehiscence of prosthetic valves, or new valve regurgitant flow murmur)
• Duke Criteria - Minor criteria

  • Predisposing conditions
  • Fever
  • Embolic-vascular signs
  • Immune complex phenomena (glomerulonephritis, arthritis, rheumatoid factor, Osler nodes, Roth spots)
  • A single positive blood culture or serologic evidence of infection
  • Echocardiographic signs not meeting the major criteria
  • Newly diagnosed clubbing
  • Splenomegaly
  • Splinter hemorrhages and petechiae
  • High ESR or a high C-reactive protein level
  • Presence of central nonfeeding lines, peripheral lines
  • Microscopic hematuria
• Clinical Criteria for Diagnosis

  • Definite endocarditis: 2 major criteria or 1 major plus 3 minor criteria or 5 minor criteria
  • Possible endocarditis: 1 major and 1 minor criteria or 3 minor criteria
  • Rejected IE: Firm alternative diagnosis explaining evidence of IE; or Resolution of IE syndrome with antibiotic therapy of 4 days; or No pathological evidence at surgery or autopsy after 4 days of antibiotic; Does not meet criteria for possible IE
• Management Principles


  • Eradication of causative organism
  • Treatment of heart failure
  • Surgical management
  • Management of complications
  • Prevention
• Antibiotic therapy


  High dose with high serum concentration<|>In combination of bactericidal antibiotics<|>Prolonged period of treatment<|>Parenteral administration
• Empiric Management


  Ampicillin and Gentamicin are the choice of antibiotics

  Duration of therapy - 4-6 weeks (except gentamicin for 2 weeks)

  Adjustment of drugs can be done depending on blood culture results
• Complications of Infective Endocarditis

  • Cardiac: Myocardial abscesses and toxic myocarditis, heart failure

  Acute glomerulonephritis - renal failure

  Life-threatening arrhythmias & aneurism

  Systemic emboli: CNS & renal manifestations

  Pulmonary emboli (rare, but may occur in children with VSD or TOF)

  Meningitis, osteomyelitis, arthritis
• Prognosis


  Despite antibiotic use, mortality is 20-25%

  Poor prognostic factors: PVE, presence of complications, S.aureus, fungal infection
• Prevention


  • Prophylaxis

  Repairing the underlying cardiac defect

  Reducing the likelihood of bacteremia

  Vigorous treatment of sepsis and local infections
• Prophylaxis


  Administration of antibiotics before certain procedures to prevent infective endocarditis
• Maintaining oral hygiene and continuing education regarding oral hygiene is important