Occult bacteremia in toxic-appearing, febrile infants. A prospective clinical study in an office setting.

The prevalence of occult bacteremia was evaluated prospectively in two groups of infants: those with a toxic appearance and temperature greater than 38.8 C and a comparison group with similar fever but without a toxic appearance. All patients were diagnosed by one physician employed in a suburban, middle-class, private ambulatory pediatric practice. Toxicity scores were assigned based on the results of history and physical examination. Peripheral white blood cell (WBC) counts and blood cultures were obtained for every child. Of 52 toxic infants involved in the study, an infectious source, commonly otitis media, was found in 26 (50%). Eighteen patients (35%) had WBC counts above 15,000. Bacteremia was documented in six patients (12%), due to Streptococcus pneumoniae in five and to group C Streptococcus in one. Five bacteremic infants had toxic, febrile illnesses for which no overt focus could be identified. None of 31 febrile infants without a toxic appearance had bacteremia. We conclude that highly febrile, toxic-appearing infants are at risk for occult bacteremia even when they are seen in the pediatrician's office. Toxicity diagnosed on the basis of clinical findings in a febrile infant warrants obtaining a white blood cell count and a blood culture.