Infective Endocarditis
Jane W. Newburger MD1
Alexander S. Nadas MD2
1 Associate in Cardiology, Children's Hospital Medical Center; Instructor in Pediatrics Harvard Medical School, Boston
2 Chief, Department of Cardiology, Children's Hospital Medical Center; Professor of Pediatrics, Harvard Medical School, Boston
Infective endocarditis is one of the most serious complications of structural heart disease. It occurs primarily in children and adolescents with preexisting anatomic abnormalities of the heart, with an incidence that varies with the specific cardiac lesion. An identifiable potential source of bacteremia precedes infective endocarditis in approximately one fifth of cases in children. The high mortality (19% to 25%), morbidity, and prolonged treatment course of infective endocarditis make its diagnosis, management, and prevention a matter of great importance to pediatricians.
PREDISPOSING FACTORS
Structural Heart Disease
Cardiac malformations are the major predisposing factor to infective endocarditis. Although rheumatic heart disease has gradually declined as a substrate for endocarditis, the increased survival of children with congenital heart disease in the past two decades has increased the number and age of children susceptible to infective endocarditis. In general, lesions leading to a high velocity of blood flow through a heart valve, septal defect, or blood vessel are associated with increased susceptibility to endocarditis (Table 1). Children at highest risk are those with cyanotic congenital heart disease (eg, tetralogy of Fallot), ventricular septal defect with aortic regurgitation, left-sided valvar regurgitation or obstruction, prosthetic valves, and recent cardiac surgery. Endocarditis is exceedingly uncommon in individuals with isolated atrial septal defect secundum and with mild pulmonic valve stenosis.
