Reevaluation of the ambulatory pediatric patient whose blood culture is positive for Haemophilus influenzae type b

We conducted a retrospective review of 60 patients with Haemophilus influenzae type b bacteremia initially treated as outpatients, to test the hypothesis that a subgroup of these patients is at low risk of continuing invasive infection and thus requires a less comprehensive reevaluation. These patients were 6% of the 975 patients with invasive H. influenzae type b infection identified by active surveillance in Dallas County, Texas, during a 6 1/2-year period. The clinical assessment of "ill" appearance and persistent fever (greater than or equal to 38.0 degrees C) on the return visit were the two most useful variables in identifying patients at risk of continuing infection. Among 25 (42%) patients who were considered "ill" (febrile or afebrile), 20 (80%) had continuing invasive infection and 14 (56%) had a subsequent culture that was positive for H. influenzae type b. Among 8 patients who were considered "well" but who remained febrile, 3 (38%) had continuing infection, including 1 (13%) patient with a second culture that was positive. By contrast, among 27 (45%) patients who were considered "well" and who were afebrile, continuing invasive infection was identified in only 2 (7%) patients, and all repeat cultures were negative. These results suggest that when patients return for reevaluation of H. influenzae type b bacteremia, clinical assessment by an experienced physician, together with the febrile status of the patient, can identify those at high versus low risk of continuing invasive infection and thus guide the extent of diagnostic reevaluation.