PE22.5 | Infective Endocarditis — Summary & Reflection

KEY TAKEAWAYS

Infective endocarditis is a microbial infection of the cardiac endocardium, most commonly affecting valves. In children, the most common predisposing factors are structural CHD (risk of turbulent-flow-related endothelial injury) and indwelling venous catheters. Common organisms: Streptococcus viridans (subacute IE after dental procedure in CHD), Staphylococcus aureus (acute IE with IV catheters, post-surgery). Pathogenesis: endothelial damage → platelet-fibrin nidus → bacteraemia → vegetation → valve destruction and embolic complications. Clinical features: fever, new or changing murmur, peripheral stigmata (Osler nodes: painful, immune complex; Janeway lesions: painless, septic emboli), splenomegaly, embolic phenomena (stroke, renal infarction). Diagnosis by modified Duke Criteria (definite = 2 major, or 1 major + 3 minor, or 5 minor). Mandatory: 3 blood culture sets from 3 separate sites BEFORE antibiotics. Treatment: IV antibiotics 4–6 weeks (empirical penicillin + gentamicin; targeted to culture); surgical indications include haemodynamic failure, uncontrolled infection, large vegetations. Prophylaxis (amoxicillin 50 mg/kg oral 30–60 min before dental procedure) for highest-risk CHD only: unrepaired cyanotic CHD, previous IE, prosthetic valve, repaired CHD within 6 months, residual defects at prosthetic material.

REFLECT

Reflect on the child from the hook — a straightforward dental extraction, no prophylaxis given, now hospitalised with 6 weeks of IV antibiotics ahead of him. Consider: what would you have done differently if you had been the doctor at the dentist's reception desk reviewing his cardiac history? What does it feel like to recognise, in retrospect, that a complication was preventable? Now think about the positive side — you were the doctor who got the blood cultures right (3 sets, 3 venesections, before antibiotics), identified the organism, and chose the correct antibiotic. What was the knowledge that made that difference? Identify one concrete piece of knowledge from this module — a dose, a criterion, a diagnostic step — that you did not know before and that you will carry into clinical practice.