Incidence and clinical characteristics of "culture-negative" infective endocarditis in a pediatric population.

Sixty episodes of infective endocarditis were analyzed in 56 pediatric patients over a 10-year period from 1974 to 1984. Culture-negative infective endocarditis was noted on five occasions or 8.3% of all episodes. In addition to the physical findings, a combination of laboratory parameters including anemia, erythrocyte sedimentation rate, elevated rheumatoid factor, C1q activation and microhematuria supported the diagnosis. The clinical characteristics of these patients are described in detail. Pretreatment with an antimicrobial agent was only one factor associated with the failure to isolate an organism. Empiric treatment with penicillin and gentamicin and in one case nafcillin/ampicillin and gentamicin was satisfactory.