Infective Endocarditis

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IE Basics & Etiology - Heart's Unwanted Guests

  • Infection of endocardium, valves, or devices.
  • Etiology:
    • Mainly bacterial; fungi rare.

    Staphylococcus aureus is the most common causative organism of infective endocarditis in children, particularly with intravascular catheters or post-cardiac surgery.

    • S. viridans (post-dental).
    • HACEK group (📌 Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella).
    • CoNS (prosthetic valves/devices).
  • Risk Factors (Pediatrics):
    • CHD (most common).
    • RHD.
    • Central venous catheters.
    • Previous cardiac surgery.
    • Immunocompromised state_

IE Pathophysiology - Attack on the Valves

⭐ The formation of vegetations in infective endocarditis typically begins with endothelial damage, leading to a non-bacterial thrombotic endocarditis (NBTE) nidus, which is then colonized by bacteria during transient bacteremia.

IE Clinical Features - Signs of Siege

  • Systemic: Persistent fever (often > 38°C), chills, malaise, weight loss, arthralgia.
  • Cardiac:
    • New or changing heart murmur (most specific sign).
    • Signs of heart failure (tachycardia, tachypnea, hepatomegaly).
  • Peripheral Stigmata (📌 FROM JANE):
    • Fever
    • Roth spots (retinal hemorrhages)
    • Osler nodes (painful, tender nodules on digits)
    • Murmur (new/changed)
    • Janeway lesions (painless, erythematous macules on palms/soles)
    • Anemia
    • Nail-bed (splinter) hemorrhages
    • Emboli (septic; to brain, spleen, kidney, etc.)
  • Other: Splenomegaly, clubbing (late finding). Clinical signs of infective endocarditis

⭐ A new or changing heart murmur is a hallmark clinical finding in pediatric infective endocarditis and should prompt further investigation.

IE Diagnosis - The Evidence Trail

  • Blood Cultures: 3 sets, different sites, 1hr apart, pre-antibiotics.
  • Echo: TTE → TEE. Shows vegetations, abscess, new regurgitation.
  • Modified Duke Criteria: IE = 2M / 1M+3m / 5m.
  • Other: CBC (anemia), ↑ESR/CRP.
Major CriteriaMinor Criteria
1. +Blood cultures (typical orgs)1. Predisposition (cardiac/IVDU)
2. Echo evidence (vegetation etc)2. Fever ≥38°C
3. Vascular (emboli, Janeway)
4. Immunologic (Osler, Roth, GN)
5. +Micro evidence (not major)

⭐ The Modified Duke Criteria are essential for diagnosing infective endocarditis, with positive blood cultures for typical organisms and echocardiographic evidence of endocardial involvement being the two major criteria.

IE Management & Prophylaxis - Shielding the Heart

  • Management:

    • Goals: Eradicate infection, manage complications.
    • Antibiotics:
      • Empirical: Vancomycin + Gentamicin.
      • Culture-directed: 4-6 weeks (Native Valve Endocarditis - NVE), ≥6 weeks (Prosthetic Valve Endocarditis - PVE).
    • Surgery Indications: Heart Failure (HF), fungal IE, persistent sepsis, large vegetations (>10mm) + emboli, perivalvular abscess.
  • Prophylaxis:

    • High-Risk Patients Only: Prosthetic valves, prior IE, specific Congenital Heart Diseases (CHDs) (unrepaired cyanotic; repaired <6 months with prosthetic material or device; repaired with residual defect), cardiac transplant recipients with valvulopathy.
    • High-Risk Procedures:
      • Dental: Gingival/periapical manipulation, oral mucosa perforation.
      • Respiratory Tract: Incision/biopsy of mucosa (e.g., tonsillectomy, adenoidectomy).
    • Regimen: Amoxicillin 50 mg/kg (max 2g) orally 30-60 minutes before procedure.
      • Penicillin allergy: Clindamycin 20 mg/kg (max 600mg) or Azithromycin/Clarithromycin 15 mg/kg (max 500mg).

⭐ Antibiotic prophylaxis for infective endocarditis is recommended only for the highest-risk pediatric patients (e.g., those with prosthetic cardiac valves or previous IE) undergoing specific dental procedures involving gingival manipulation or respiratory tract incisions.

High‑Yield Points - ⚡ Biggest Takeaways

  • Most common organisms: Staphylococcus aureus; Viridans streptococci with underlying CHD.
  • Congenital Heart Disease (CHD) is the major predisposing factor in pediatrics.
  • Diagnosis uses Modified Duke Criteria; echocardiography confirms vegetations.
  • Obtain multiple blood cultures (ideally 3 sets) before starting antibiotics.
  • Antibiotic prophylaxis is vital for high-risk CHD patients during certain procedures.
  • Empirical treatment: Typically Vancomycin plus Gentamicin.
  • Key complications include septic emboli and congestive heart failure.

Practice Questions: Infective Endocarditis

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What is the optimal timing for administering antibiotic prophylaxis before surgery?

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Flashcards: Infective Endocarditis

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The symptoms of _____ disease may be remembered with the mnemonic "CRASH and burn": C: ConjunctivitisR: Rash (polymorphous -> desquamating)A: Adenopathy (cervical lymph nodes)S: Strawberry tongue (oral mucositis)H: Hand-foot erythema and edema&Burn: Fever

TAP TO REVEAL ANSWER

The symptoms of _____ disease may be remembered with the mnemonic "CRASH and burn": C: ConjunctivitisR: Rash (polymorphous -> desquamating)A: Adenopathy (cervical lymph nodes)S: Strawberry tongue (oral mucositis)H: Hand-foot erythema and edema&Burn: Fever

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