title: Does extreme leukocytosis predict serious bacterial infections in infants in the post-pneumococcal vaccine era? The experience of a large, tertiary care pediatric hospital.
abstract: BACKGROUND
  Extreme leukocytosis, defined as a peripheral white blood cell count greater than 25,000/mm, may alarm clinicians and prompt extensive evaluation in infants with fever, especially in the pediatric emergency department.
  
  
  METHODS
  We reviewed data from children aged 3 to 36 months with extreme leukocytosis, fever and the risk of serious bacterial infections (SBI) at our institution from July 2010 to December 2012, a period after the universal introduction of pneumococcal vaccine.
  
  
  RESULTS
  Serious bacterial infection was recorded in 57 (39%) of the 147 infants. The most common SBI were segmental or lobar pneumonia, in 28 (19%) patients, and urinary tract infection in 16 (10.9%) patients. Three patients had positive blood cultures, corresponding to a bacteremia rate of 2%. C-reactive protein was significantly higher in the SBI group than in the non-SBI group.
  
  
  CONCLUSIONS
  All well-looking febrile infants with white blood cell greater than 25,000/mm should undergo a chest radiograph unless there are clear physical findings that indicate a different etiology. Urine culture should be considered in women. C-reactive protein can have an added value in the differential diagnosis.
authors.affiliation: From the *Division of Pediatric Emergency Medicine, Department of Pediatrics, Dana-Dwek Children Hospital, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; †Divisions of Pediatric Emergency Medicine and Clinical Pharmacology and Toxicology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; ‡Division of Infectious Disease, Department of Pediatrics, and §Division of Clinical Pharmacology and Toxicology, Dana-Dwek Children's Hospital, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Dana
authors.initials: D
authors.lastname: Danino
authors.forename: Ayelet
authors.initials: A
authors.lastname: Rimon
authors.forename: Dennis
authors.initials: D
authors.lastname: Scolnik
authors.forename: Galia
authors.initials: G
authors.lastname: Grisaru-Soen
authors.forename: Miguel
authors.initials: M
authors.lastname: Glatstein
mesh_terms: D016470:Bacteremia / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D001424:Bacterial Infections / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D002097:C-Reactive Protein / Q000032:analysis; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D005334:Fever / Q000209:etiology; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007557:Israel / Q000453:epidemiology; D007958:Leukocyte Count; D007964:Leukocytosis / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D022242:Pneumococcal Vaccines; D018410:Pneumonia, Bacterial / Q000097:blood / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D011859:Radiography; D062606:Tertiary Care Centers / Q000706:statistics & numerical data; D014552:Urinary Tract Infections / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology
chemical_list: D022242:Pneumococcal Vaccines; D002097:C-Reactive Protein