Fever in infants less than two months of age: spectrum of disease and predictors of outcome.

Four hundred thirty-four febrile infants two months of age or younger were evaluated in the emergency departments of five major teaching hospitals over a one-year period. A culture-proven bacterial infection was present in 3.5% of the infants; bacteremia was detected in 3.3%. Bacterial meningitis was present in 2.4%, and aseptic meningitis was noted in 13.4%. Twenty-one percent had clinically apparent serious disease including pneumonia, otitis media, and gastroenteritis with dehydration. Six variables (age less than 1 month, lethargy, no contact with an ill individual, breast-feeding, total polymorphonuclear greater than or equal to 10,000/mm3 and band count greater than or equal to 500/mm3) were correlated with bacterial infection by step-wise discriminant analysis. However, these findings were neither sensitive nor specific enough to be clinically useful. Management varied, and 62% of the infants were hospitalized. Fifty-four percent, some of whom were managed as outpatients, received antibiotics. Febrile infants two months of age or younger require a comprehensive emergency department assessment, including appropriate laboratory studies (CBC, differential, urinalysis and culture, lumbar puncture, and blood culture), since 3.5% have bacterial infection that may be life-threatening. Hospitalization is warranted if the infant appears ill, laboratory studies indicate serious infection, or follow-up care is uncertain.