infective%20endocarditis%20(pediatric)
INFECTIVE ENDOCARDITIS (PEDIATRIC)
Infective endocarditis is an infection of the endocardial surface of the heart including infections of the large thoracic vessels and intracardiac foreign bodies characterized by the presence of vegetation which is a nidus for microorganism invasion.
Native valve endocarditis is an endovascular microbial infection of native heart valves that may be local including valvular and perivalvular destruction or distal due to detachment of septic vegetations with embolism, metastatic infection and septicemia.
Prosthetic valve endocarditis is an endovascular microbial infection of prosthetic heart valves and may be classified as an infection likely to have been acquired perioperatively and thus being nosocomial or likely to have been community-acquired.

Definition

  • Infective endocarditis (IE): An infection of the endocardial surface of the heart including infections of the large thoracic vessels & intracardiac foreign bodies characterized by the presence of vegetation which is a nidus for microorganism invasion
  • Native valve endocarditis (NVE): An endovascular microbial infection of native heart valves that may be local (cardiac) including valvular & perivalvular destruction or distal (noncardiac) due to detachment of septic vegetations with embolism,metastatic infection & septicemia. May also be broken down as acute & subacute; the only difference is that subacute endocarditis has a more indolent course than the acute form
  • Prosthetic valve endocarditis (PVE): An endovascular microbial infection of prosthetic heart valves (intracardiac foreign body) & may be classified as an infection likely to have been acquired perioperatively & thus being nosocomial (early prosthetic valve endocarditis) or likely to have been community-acquired (late prosthetic valve endocarditis). Early prosthetic valve endocarditis occurs within 60 days of valve implantation & late prosthetic valve endocarditis occurs ≥60 days after valve implantation

Etiology

Bacterial

  • Staphylococcus sp: Causes approximately 8-10% of native valve endocarditis
    • S aureus (coagulase-positive staphylococci): Commonly cause prosthetic valve endocarditis, infective endocarditis in IV drug abusers (IVDA) & in patients with previously normal cardiac valves
    • IV drug abusers often present with right-sided cardiac involvement
    • Non-IVDA usually present with left-sided cardiac involvement & have skin & soft tissue infections with underlying congenital abnormalities
    • S epidermidis, S lugdunensis (coagulase-negative staphylococci): Most common cause of prosthetic valve endocarditis & has been known to cause native valve endocarditis
    • Methicillin susceptible S aureus (MSSA): May cause right-sided endocarditis in IV drug users
    • Methicillin resistant S aureus (MRSA): Occurs particularly in prosthetic valve endocarditis, right-sided endocarditis in IV drug users & nosocomial endocarditis
  • Streptococcus sp (viridans group of streptococci; S pneumoniae; S pyogenes; Lancefield group B, C, G streptococci; S bovis, S mitis, S mutans, S sanguis & Abiotrophia sp): Most common cause of native valve endocarditis
    • Group B streptococci: Most common β-hemolytic streptococci & cause the most virulent infective endocarditis among streptococci which is characterized by a fulminant disease with large crumbling vegetations with the frequency of embolization related to size
    • Group G streptococci: Both native & prosthetic valves can be affected with left-sided involvement being more common
    • Viridans streptococci: Most common cause of native valve endocarditis in patients with congenital heart disease or defects & in patients who are not IV drug users
    • S bovis: Also causes bacterial endocarditis
  • Enterococci
  • Culture negative organisms: Common causative organisms of endocarditis producing negative blood cultures
    • HACEK (Haemophilus parainfluenzae, aphrophilus, & paraphrophilus; Actinobacillus actinomycetemcomitans; Cardiobacterium hominis, Eikenella corrodens; & Kingella sp): Can cause native valve endocarditis & prosthetic valve endocarditis
    • Bartonella henselae: Exposure to infected cats may predispose patient to infective endocarditis
    • Brucella
    • Chlamydia psittaci: Exposure to infected birds may predispose patient to infective endocarditis
    • Coxiella burnetii: Exposure to infected sheep, cattle & wild rabbits may predispose patient to infective endocarditis
    • Legionella
      • Characterized by a febrile course that extends up to a month with cardiac signs of newly developed murmurs & extremely high anti-Legionella titers
    • Mycobacterium
    • Pseudomonas aeruginosa: Most commonly occur in IV drug abusers & is an important pathogen in early prosthetic valve endocarditis
      • Commonly involves the tricuspid valve & may present as subacute infection with septic pulmonary emboli & right-sided heart failure

Fungal

  • An increasing cause of prosthetic valve endocarditis: Candida sp, Aspergillus sp, Nocardia sp

Signs and Symptoms

  • Neonates: Signs & symptoms are nonspecific; may include fever, thrombocytopenia, peripheral stigmata of blood-borne infection (ie peripheral abscesses-septic arthritis, petechiae, hepatosplenomegaly)
  • Children: Fever, night sweats, malaise, anorexia, signs & symptoms of heart failure, changing or new cardiac murmur, cutaneous findings (eg Osler’s nodes, Janeway lesions), splinter hemorrhages, Roth spots, embolic complications (eg cerebrovascular infarcts or hemorrhages, peripheral arterial embolism, pulmonary infarcts & abscess)
  • Moderate & remitting fever is the most common symptom
  • Anorexia, wt loss, malaise & night sweats, fatigue, diaphoresis, chills, nausea, vomiting, arthralgia, myalgia
  • Feeding difficulties, tachycardia, respiratory distress, & low blood pressure in neonates

Risk Factors

Cardiac Risk Factors for Infective Endocarditis

  • Use of central venous line
  • Congenital heart disease (CHD)
    • High risk: Aortic regurgitation, aortic stenosis, coarctation of aorta, cyanotic congenital heart disease, patent ductus arteriosus, ventricular septal defect, mitral regurgitation, mitral stenosis with regurgitation
    • Intermediate risk: Asymmetrical septal hypertrophy, bicuspid aortic valve, mitral stenosis, tricuspid valve disease, pulmonary stenosis
  • Previous cardiac surgery with or without grafts, patches, or prosthesis
  • Transcatheter treatment of heart defects
  • Post-radiofrequency ablation for arrhythmias
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