According to this study:

* The Bacterial Meningitis Score prediction rule accurately identifies the risk of bacterial meningitis in children.

* Using the prediction rule can assist in managing cases of suspected bacterial meningitis in patients with cerebrospinal fluid pleocytosis.

The Bacterial Meningitis Score prediction rule, a validated and accurate tool, is helpful in determining the risk of bacterial meningitis in children with cerebrospinal fluid pleocytosis, defined as a cerebrospinal fluid white blood cell count of 10 or more cells per microliter, according to a recently published study.

Because bacterial meningitis has grave consequences, children with cerebrospinal fluid pleocytosis are commonly hospitalized and given parenteral antibiotics as a precautionary measure, which may be burdensome to them as well as to the health care system. The Bacterial Meningitis Score was developed by several of the study authors who are on the Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. The score indicates that patients are at very low risk for bacterial meningitis if none of the following criteria is met: a positive cerebrospinal fluid Gram stain, a cerebrospinal fluid absolute neutrophil count (ANC) of at least 1,000 cells per microliter, a cerebrospinal fluid protein level of at least 80 mg/dL, a peripheral blood ANC of at least 10,000 cells per microliter, and seizure activity prior to or upon presentation. The purpose of the study was to validate the prediction rule in the context of widespread pneumococcal conjugate vaccination, which has greatly reduced the incidence of bacterial meningitis.

Children 29 days to 19 years old who presented to the EDs of 20 academic medical centers in the United States from January 2001 through June 2004 with cerebrospinal fluid pleocytosis and a subsequent diagnosis of meningitis were studied retrospectively. Patients who had received antibiotics within the 72 hours preceding lumbar puncture as well as those who had to be admitted to the hospital for other conditions, regardless of the risk of bacterial meningitis, were excluded, leaving 3,295 eligible study subjects.

It was discovered that only 121 (3.7%) of the patients had bacterial meningitis, while 3,174 (96.3%) had aseptic disease. Furthermore, only two patients, or 0.1% of the 1,714 considered to be at very low risk for bacterial meningitis according to the prediction rule, had bacterial meningitis, and both were less than two months old and infected with Escherichia coli rather than with one of the more common pathogens, such as Streptococcus pneumoniae, Neisseria meningitidis, and group B streptococci. Overall, the prediction rule yielded a sensitivity of 98.3%, and the researchers determined that 80% of the study patients had aseptic disease and had been hospitalized unnecessarily.

The limitations of the study include its retrospective design, the unavailability of blood culture results for 10% of the study participants, and the possibly incorrect ED coding of diagnoses. Nevertheless, the researchers believe that the Bacterial Meningitis Score prediction rule, which uses clinical and laboratory parameters that are easily obtained and evaluated in the ED, can assist clinicians in determining the risk of bacterial meningitis. However, they note that the clinical assessment of patients with cerebrospinal fluid pleocytosis who are suspected of having bacterial meningitis remains equally important in clinical decision making and management of the disease. --JC