Introduction to Infective Endocarditis

INTRODUCTION

Infective endocarditis includes acute and subacute bacterial endocarditis, as well as nonbacterial endocarditis caused by viruses, fungi, and other microbiologic agents. It is a significant cause of morbidity and mortality in children and adolescents despite advances in the management and prophylaxis of the disease with antimicrobial agents

ETIOLOGY.

Viridans-type streptococci (?-hemolytic streptococci) and Staphylococcus aureus are the leading causative agents for endocarditis in pediatric patients. Other organisms cause endocarditis less frequently and, in ?6% of cases, blood cultures are negative for any organisms

EPIDEMIOLOGY.

Infective endocarditis is often a complication of congenital or rheumatic heart disease but can also occur in children without any abnormal valves or cardiac malformations. In developed countries, congenital heart disease is the overwhelming predisposing factor

In ?30% of patients with infective endocarditis, a predisposing factor is recognized. A surgical or dental procedure can be implicated in ?65% of cases in which the potential source of bacteremia is identified. Poor dental hygiene in children with cyanotic heart disease results in a greater risk for endocarditis

CLINICAL MANIFESTATIONS

Early manifestations are usually mild, especially when viridans group streptococci are the infecting organisms.

Prolonged fever without other manifestations (except, occasionally, weight loss) that persists for as long as several months may be the only symptom. Alternatively, the onset may be acute and severe, with high, intermittent fever and prostration. Usually, the onset and course vary between these two extremes

New or changing heart murmurs are common, particularly with associated heart failure.

Splenomegaly and petechiae are relatively common.

Serious neurologic complications such as embolic strokes, cerebral abscesses, mycotic aneurysms, and hemorrhage are most often associated with staphylococcal disease and may be late manifestations.

Many of the classic skin findings develop late in the course of the disease; they are seldom seen in appropriately treated patients. Such manifestations include Osler nodes (tender, pea-sized intradermal nodules in the pads of the fingers and toes), Janeway lesions (painless small erythematous or hemorrhagic lesions on the palms and soles), and splinter hemorrhages (linear lesions beneath the nails).