Value of white cell count in predicting serious bacterial infection in febrile children under 5 years of age

摘要

Febrile illnesses are common in young children1 and account for 20% to 30% of all visits to paedi-atric emergency departments.2 Although most febrile episodes are self-limiting viral infections, a significant proportion (7% to 27% depending upon the setting) are due to serious bacterial infections,where a delayed diagnosis may lead to prolongation of illness, untoward complications or death.In one study, 95% of cases of bacteraemia, over half of all cases of pneumonia and all urinary tract infections were missed on history and examination, highlighting the challenging nature of the clinical evaluation of the febrile child.11 During the initial assessment of febrile children, clinicians therefore frequently rely on rapid laboratory tests, most commonly the total white blood cell and the absolute neutrophil counts to assess the likelihood of underlying serious bacterial infections.International guidelines and clinical decision rules for the evaluation of febrile children provide specific white blood cell count thresholds to guide further investigations and antibiotic therapy