title: Extreme thrombocytosis predicts Kawasaki disease in infants.
abstract: Infants with Kawasaki disease are at high risk of developing life-threatening coronary complications, yet may elude timely diagnosis because they often lack the full complement of classic clinical features. We retrospectively studied 26,540 children 1 year of age or less who were evaluated at a tertiary care pediatric emergency department in whom a platelet count was performed. Among those infants with fever without a source identified, 8.5% with platelet counts of 800,000 cells/mm(3) or greater had Kawasaki disease compared to 0.4% with platelet counts of less than 800,000 cells/mm(3) (likelihood ratio for Kawasaki disease was 17 [95% confidence interval, 8-34]). Because many infants present atypically, Kawasaki disease should be considered in all children of 1 year or less with prolonged fever, extreme elevation of the platelet count, and no compelling alternative diagnosis.
authors.affiliation: Division of Emergency Medicine, Children's Hospital Boston, Boston, MA 02115, USA.
authors.forename: Lise E
authors.initials: LE
authors.lastname: Nigrovic
authors.forename: Peter A
authors.initials: PA
authors.lastname: Nigrovic
authors.forename: Marvin B
authors.initials: MB
authors.lastname: Harper
authors.forename: Vincent W
authors.initials: VW
authors.lastname: Chiang
mesh_terms: D000367:Age Factors; D018798:Anemia, Iron-Deficiency / Q000097:blood*; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016013:Likelihood Functions; D008297:Male; D009080:Mucocutaneous Lymph Node Syndrome / Q000097:blood / Q000175:diagnosis*; D010976:Platelet Count; D012189:Retrospective Studies; D013922:Thrombocytosis / Q000097:blood*; D014463:Ultrasonography