Define Infective Endocarditis. Describe its clinical features, diagnosis and management.

Definition

• Infective endocarditis (IE) is a microbial infection of the endocardium — usually the heart valves — leading to the formation of vegetations (masses of platelets, fibrin and organisms).
• It usually occurs on a previously abnormal heart.

Predisposing Factors & Organisms

• Underlying congenital heart disease (VSD, PDA, TOF) or rheumatic valve disease; prosthetic valves; indwelling catheters.
• Commonest organisms — Streptococcus viridans (subacute, after dental procedures) and Staphylococcus aureus (acute, virulent).

Clinical Features

• Persistent fever with malaise, weight loss, and a changing / new heart murmur.
• Splenomegaly; peripheral stigmata — petechiae, splinter haemorrhages, Osler nodes (tender), Janeway lesions (painless), and Roth spots (retina).
• Embolic and immune-complex phenomena (haematuria, arthralgia).

Diagnosis (modified Duke Criteria)

• Major: positive blood cultures (typical organisms) and echocardiographic evidence of vegetations.
• Minor: predisposing heart condition, fever, vascular/immunologic phenomena, and suggestive microbiology.
• Blood cultures (3 sets) and echocardiography are the key investigations.

Management & Prevention

• Prolonged IV bactericidal antibiotics (4–6 weeks), guided by culture and sensitivity; surgery for heart failure, large vegetations or failed therapy.
• Prophylactic antibiotics before dental/surgical procedures in high-risk children (prosthetic valves, previous IE, certain CHD), plus good oral hygiene.

Key Peripheral Signs (mnemonic)

• Osler nodes — tender nodules on finger pulps (immune).
• Janeway lesions — painless macules on palms/soles (embolic).
• Roth spots — retinal haemorrhages with pale centres; splinter haemorrhages.