Rethinking the boundaries of Kawasaki disease: toward a revised case definition

This paper describes the historical evolution of the Kawasaki disease (KD) case definition and its limitations for identification and treatment of children at risk for coronary artery aneurysms (CAA). The dominant view of pathogenesis is that an unknown agent infects infants and children, who then develop the signs of KD. Some of the infected infants and children then develop CAA, and a few die from myocardial infarction. Because the etiologic agent remains unknown, diagnosis of KD relies on observation and recognition of the clinical signs that comprise the KD case definition criteria. This approach has been successful in identifying and treating many children at risk for CAA. Unfortunately, however, it has delayed the effective treatment of children who fail to meet the KD case definition criteria but who, nevertheless, develop CAA. The original case definition was developed before the general acceptance of CAA as sequelae of KD, the availability of the echocardiogram, and effective treatment with intravenous immunoglobulin. Despite an evolution in awareness, detection, and treatment of possible CAA sequela, the case definition has not been altered so as to incorporate this knowledge. Our investigation explores the transformation of the case definition from an epidemiological instrument to a diagnostic tool. We urge the construction of a more sensitive KD case definition that includes signs and laboratory findings associated with CAA.