Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis.

OBJECTIVE: The goal of this study was to evaluate the effect of antibiotic administration before lumbar puncture on cerebrospinal fluid profiles in children with bacterial meningitis. METHODS: We reviewed the medical records of all children (1 month to 18 years of age) with bacterial meningitis who presented to 20 pediatric emergency departments between 2001 and 2004. Bacterial meningitis was defined by positive cerebrospinal fluid culture results for a bacterial pathogen or cerebrospinal fluid pleocytosis with positive blood culture and/or cerebrospinal fluid latex agglutination results. Probable bacterial meningitis was defined as positive cerebrospinal fluid Gram stain results with negative results of bacterial cultures of blood and cerebrospinal fluid. Antibiotic pretreatment was defined as any antibiotic administered within 72 hours before the lumbar puncture. RESULTS: We identified 231 patients with bacterial meningitis and another 14 with probable bacterial meningitis. Of those 245 patients, 85 (35%) had received antibiotic pretreatment. After adjustment for patient age, duration and severity of illness at presentation, and bacterial pathogen, longer duration of antibiotic pretreatment was not significantly associated with cerebrospinal fluid white blood cell count, cerebrospinal fluid absolute neutrophil count. However, antibiotic pretreatment was significantly associated with higher cerebrospinal fluid glucose and lower cerebrospinal fluid protein levels. Although these effects became apparent earlier, patients with >or=12 hours of pretreatment, compared with patients who either were not pretreated or were pretreated for <12 hours, had significantly higher median cerebrospinal fluid glucose levels (48 mg/dL vs 29 mg/dL) and lower median cerebrospinal fluid protein levels (121 vs 178 mg/dL). CONCLUSIONS: In patients with bacterial meningitis, antibiotic pretreatment is associated with higher cerebrospinal fluid glucose levels and lower cerebrospinal fluid protein levels, although pretreatment does not modify cerebrospinal fluid white blood cell count or absolute neutrophil count results.

Clinical prediction rule for identifying children with cerebrospinal fluid pleocytosis at very low risk of bacterial meningitis.

CONTEXT: Children with cerebrospinal fluid (CSF) pleocytosis are routinely admitted to the hospital and treated with parenteral antibiotics, although few have bacterial meningitis. We previously developed a clinical prediction rule, the Bacterial Meningitis Score, that classifies patients at very low risk of bacterial meningitis if they lack all of the following criteria: positive CSF Gram stain, CSF absolute neutrophil count (ANC) of at least 1000 cells/microL, CSF protein of at least 80 mg/dL, peripheral blood ANC of at least 10,000 cells/microL, and a history of seizure before or at the time of presentation. OBJECTIVE: To validate the Bacterial Meningitis Score in the era of widespread pneumococcal conjugate vaccination. DESIGN, SETTING, AND PATIENTS: A multicenter, retrospective cohort study conducted in emergency departments of 20 US academic medical centers through the Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. All children aged 29 days to 19 years who presented at participating emergency departments between January 1, 2001, and June 30, 2004, with CSF pleocytosis (CSF white blood cells > or =10 cells/microL) and who had not received antibiotic treatment before lumbar puncture. MAIN OUTCOME MEASURE: The sensitivity and negative predictive value of the Bacterial Meningitis Score. RESULTS: Among 3295 patients with CSF pleocytosis, 121 (3.7%; 95% confidence interval [CI], 3.1%-4.4%) had bacterial meningitis and 3174 (96.3%; 95% CI, 95.5%-96.9%) had aseptic meningitis. Of the 1714 patients categorized as very low risk for bacterial meningitis by the Bacterial Meningitis Score, only 2 had bacterial meningitis (sensitivity, 98.3%; 95% CI, 94.2%-99.8%; negative predictive value, 99.9%; 95% CI, 99.6%-100%), and both were younger than 2 months old. A total of 2518 patients (80%) with aseptic meningitis were hospitalized. CONCLUSIONS: This large multicenter study validates the Bacterial Meningitis Score prediction rule in the era of conjugate pneumococcal vaccine as an accurate decision support tool. The risk of bacterial meningitis is very low (0.1%) in patients with none of the criteria. The Bacterial Meningitis Score may be helpful to guide clinical decision making for the management of children presenting to emergency departments with CSF pleocytosis.