Infective endocarditis in children without underlying heart disease.

BACKGROUND/PURPOSE: Although pre-existing heart disease is the main predisposing factor for pediatric infective endocarditis (IE), cases of IE in children without underlying heart disease have been increasingly reported. This study reviews the clinical and laboratory characteristics of pediatric IE patients with and without underlying heart disease, and presents the unique features of patients with no apparent pre-existing heart disease.

METHODS: Children who were admitted to our hospital from January 1991 to April 2011 and met the Modified Duke criteria for definite or possible IE were retrospectively analyzed. Clinical characteristics and laboratory data were collected by chart review.

RESULTS: Forty-seven patients with a total of 48 episodes of IE were enrolled. Of these patients, 31 children (64.6%) had congenital heart disease (CHD), six (12.5%) had non-CHD chronic disease, and eleven (22.9%) were previously healthy adolescents. Five patients with non-CHD chronic conditions acquired infection from central catheter: two methicillin-resistant Staphylococcus aureus (MRSA), two Candida albicans and one coagulase-negative Staphylococcus (CoNS). The microbial pathogens in 11 previously healthy individuals were Streptococcus viridans (n = 3), methicillin-sensitive S. aureus (MSSA, n = 2), Haemophilus parainfluenzae (n = 2), Staphylococcus lugdunensis (n = 1), Enterococcus (n = 1), and Diphtheroid (n = 1). In total, five of 17 non-CHD patients were infected with S. aureus (two MRSA and three MSSA) and the vegetations in these five patients were detected in the right side of the heart (tricuspid valve or right atrium). The average interval between onset of symptoms and diagnosis of IE in the CHD and previously healthy groups was 18 and 31 days, respectively. Patients in the previously healthy group were older and more often required surgical interventions for removal of vegetation.

CONCLUSION: Over one-third (35.4%) of cases of IE in children occurred in patients without pre-existing cardiac disease. Early identification of these patients is critical and requires a high index of suspicion. The pathogenesis of IE in previously healthy individuals is still uncertain, but previous skin infection or dental problems may contribute to potential risk.