🩺 Chapter 486: Infective Endocarditis
Nelson's Textbook of Pediatrics 22e | Duke criteria · Blood cultures · Echocardiography · Antibiotic therapy · Prophylaxis · AHA guidelines · Transition
📚 Reference: www.paeds.online — Paediatric Resource Hub
📌 Modified Duke Criteria – Major Criteria1. Blood culture positive for typical organism (viridans streptococci, S. aureus, HACEK, enterococci). 2. Echocardiogram positive for vegetation, abscess, new valvular regurgitation. 3. Single positive culture for Coxiella burnetii or IgG phase I >1:800.
📌 Modified Duke Criteria – Minor CriteriaPredisposing heart condition, fever (>38°C), vascular phenomena (septic emboli, Janeway lesions), immunologic phenomena (Osler nodes, Roth spots, glomerulonephritis), microbiologic evidence (positive culture not meeting major).
📌 High-risk conditions for IE prophylaxis (AHA 2007/2023)Prosthetic valves, previous IE, unrepaired cyanotic CHD, repaired CHD with prosthetic material (first 6 months), repaired CHD with residual defect adjacent to prosthetic patch, cardiac transplant valvulopathy.
📌 Common organisms – Pediatric IEViridans group streptococci (dental), Staphylococcus aureus (acute, central lines, IVDU), Enterococcus (GI/GU), Coagulase-negative staphylococci (prosthetic valves, catheters). Culture-negative: HACEK, Bartonella, Coxiella, fungi.
📌 Clinical presentation – IEFever (most common), new or changing murmur, splenomegaly, petechiae, embolic phenomena (stroke, pulmonary infarcts), Osler nodes (tender), Janeway lesions (non-tender), Roth spots (retinal), clubbing late.
📌 Echocardiography in IETransthoracic (TTE) first-line in children. Transesophageal (TEE) for prosthetic valves, perivalvular abscess, poor windows. Vegetation size >10 mm higher embolic risk.
📌 Empiric antibiotic therapy (native valve)Vancomycin + gentamicin. After culture/sensitivities tailor. Viridans streptococci: penicillin G or ceftriaxone 4 weeks. S. aureus: nafcillin/oxacillin (or vancomycin if MRSA) 4-6 weeks.
📌 Surgical indications for IEHeart failure (valvular regurgitation), uncontrolled infection (persistent bacteremia >7-10 days), perivalvular abscess, fungal endocarditis, recurrent emboli, large vegetation (>10 mm with emboli).
📌 Antibiotic prophylaxis for dental procedures – 2023 ESC guidelinesProsthetic valves, previous IE, untreated cyanotic CHD, postoperative palliated CHD, transcatheter valve prostheses, within 6 months of repair with prosthetic material.
📌 Transition & IE in ACHDPatients with repaired CHD and residual valve lesions (prosthetic valves, conduits) remain at risk for IE lifelong. Oral hygiene, avoid body piercing, tattoo risk. Antibiotic prophylaxis for at-risk procedures.
🔍 Step 1: Recognize risk factors
Congenital heart disease (VSD, TOF, bicuspid aortic valve), prosthetic valve, previous IE, indwelling central line, IV drug use, poor dental hygiene.
📈 Step 2: Identify clinical features
Prolonged fever (>1 week) without source, night sweats, malaise, weight loss, myalgia. New or changing heart murmur – especially regurgitant lesions (aortic, mitral).
🩺 Step 3: Look for peripheral stigmata
Petechiae, splinter hemorrhages, Osler nodes (fingertips/toes), Janeway lesions (palms/soles), Roth spots (retinal hemorrhages), splenomegaly, clubbing (late).
🔄 Step 4: Embolic complications
Neurologic: stroke, mycotic aneurysm, brain abscess. Pulmonary: septic emboli (right-sided IE). Renal: glomerulonephritis (immune complex).
🚨 Step 5: Diagnostic confirmation (Duke criteria)
Blood cultures (3 sets). Echocardiogram (TTE/TEE). Apply modified Duke criteria (2 major, 1 major+3 minor, 5 minor = definite IE).
1️⃣ Obtain blood cultures (3 separate draws) before antibiotics
▪ Optimal volume: 10-20 mL (adolescent), 4-10 mL (child), 2-4 mL (infant).
▪ Notify lab for prolonged incubation if culture-negative suspected.
2️⃣ Start empiric antibiotics
▪ Native valve: vancomycin + gentamicin.
▪ Prosthetic valve: vancomycin + gentamicin + rifampin.
▪ MRSA risk: vancomycin. MSSA: nafcillin or oxacillin.
3️⃣ Tailor therapy based on culture/sensitivities
▪ Penicillin-susceptible viridans streptococci: penicillin G or ceftriaxone ×4 weeks.
▪ S. aureus: nafcillin/oxacillin (MSSA) or vancomycin (MRSA) ×4-6 weeks.
▪ HACEK: ceftriaxone ×4 weeks.
▪ Enterococcus: ampicillin + gentamicin ×4-6 weeks.
4️⃣ Echocardiographic surveillance
▪ TTE at baseline. TEE if prosthetic valve, abscess suspicion, or poor windows.
▪ Repeat echo for new complications (valve dysfunction, abscess).
5️⃣ Surgical consultation if indications present
▪ Heart failure (severe aortic/mitral regurgitation).
▪ Uncontrolled infection (persistent fever/bacteremia >7-10 days).
▪ Perivalvular abscess, fungal endocarditis, recurrent emboli.
6️⃣ Transition & long-term follow-up
▪ Complete course of IV antibiotics.
▪ Oral hygiene, dental follow-up.
▪ Prophylaxis for future procedures per AHA/ESC guidelines.
▪ Transition to adult cardiology for high-risk lesions.
❓ Reflex prompt 1: A 10-year-old with bicuspid aortic valve presents with fever and new diastolic murmur. What is the most likely diagnosis and next step?
✅ Answer: Infective endocarditis with aortic regurgitation. Obtain 3 sets of blood cultures, start empiric antibiotics, order TTE.
❓ Reflex prompt 2: A 6-year-old with repaired VSD (patch) presents with fever, splinter hemorrhages, splenomegaly. Which Duke major criteria are fulfilled?
✅ Answer: 1) Predisposing heart condition (minor), fever (minor), vascular phenomena (minor). Need positive blood culture or echo vegetation for major.
❓ Reflex prompt 3: A 16-year-old with prosthetic mitral valve and fever. Blood cultures grow coagulase-negative staphylococcus. Likely source?
✅ Answer: Prosthetic valve endocarditis. Coagulase-negative staphylococci (S. epidermidis) common after surgery or catheter-related. Requires vancomycin + gentamicin + rifampin.
❓ Reflex prompt 4: A child with IE and vegetation on mitral valve (15 mm) develops sudden hemiparesis. Mechanism?
✅ Answer: Embolic stroke. Vegetation >10 mm has higher embolic risk. Urgent neurology evaluation, continue antibiotics, consider surgery if recurrent emboli.
❓ Reflex prompt 5: A 12-year-old with repaired tetralogy of Fallot requires dental extraction. Does he need antibiotic prophylaxis?
✅ Answer: If residual prosthetic material (patch, conduit) or within 6 months of surgery → prophylaxis (amoxicillin 50 mg/kg). If native repair without residual → no prophylaxis per AHA 2007, but ESC 2023 recommends first 6 months.
❓ Reflex prompt 6: A 15-year-old with IE and persistent bacteremia (S. aureus) despite 7 days of vancomycin. Next step?
✅ Answer: Surgical evaluation for abscess, vegetation debridement, or valve replacement. Uncontrolled infection is a Class I surgical indication.
📌 Infective Endocarditis – Core Concepts (Nelson 22e, Chapter 486)

1. Definition: Infection of endocardial surface (valves, mural endocardium, prosthetic material). Associated with bacteremia + predisposing cardiac lesion (high-velocity jets, prosthetic material).
2. Microbiology:
- Viridans group streptococci (dental origin) – subacute.
- Staphylococcus aureus – acute, aggressive, central lines, IVDU.
- Enterococci – GI/GU procedures.
- Coagulase-negative staph – prosthetic devices.
- HACEK group, Bartonella, Coxiella – culture-negative.
3. Diagnosis – Modified Duke Criteria (Definite: 2 major, or 1 major+3 minor, or 5 minor):
- Major: typical organism blood cultures, echocardiographic vegetation/abscess.
- Minor: predisposition, fever, vascular/immunologic phenomena, microbiologic.
4. Evaluation: Blood cultures (3 sets), TTE/TEE, CBC, inflammatory markers (ESR, CRP), ECG (heart block → abscess).
5. Treatment:
- Empiric: vancomycin + gentamicin.
- Tailored: penicillin/ceftriaxone for viridans; nafcillin/oxacillin for MSSA; vancomycin for MRSA; ampicillin+gentamicin for enterococcus.
- Duration: 4-6 weeks.
6. Surgical indications (Class I):
- Heart failure (valvular regurgitation).
- Uncontrolled infection (bacteremia >7-10 days).
- Perivalvular abscess, fungal IE, recurrent emboli.
7. Prophylaxis (AHA 2007, ESC 2023):
- High-risk patients only: prosthetic valves, previous IE, unrepaired cyanotic CHD, repaired CHD with prosthetic material (first 6 months), cardiac transplant valvulopathy.
- Dental procedures only (manipulation of gingiva/periapical region).
- Amoxicillin 50 mg/kg PO (max 2g) 30-60 min prior.
8. Transition & ACHD: Lifelong follow-up for valvular/ prosthetic lesions. Oral hygiene paramount. Avoid body piercing/tattoos. Pregnancy with prosthetic valve requires anticoagulation and IE prophylaxis.
💡 Clinical pearls:
➤ Fever + known heart murmur = IE until proven otherwise.
➤ Negative blood cultures: consider HACEK, Bartonella, Coxiella (Q fever), fungi; request extended incubation or serology.
➤ Vegetation size >10 mm → higher embolic risk.
➤ New heart block → perivalvular abscess, emergency surgery.
➤ All patients with IE need dental evaluation after treatment.