Meningitis Tool Remains Useful In Vaccine Era

BOSTON, Jan. 3 -- The so-called Bacterial Meningitis Score remains a useful tool, even as the condition has become less common in the U.S., a collaborative research committee says.

Children with pleocytosis of the cerebrospinal fluid are routinely treated with parenteral antibiotics and admitted to the hospital, although few have bacterial meningitis, according to Lise Nigrovic, M.D., of Children's Hospital Boston.

The five-element Bacterial Meningitis Score was developed and validated as a clinical guideline to identify children at low risk for the condition, Dr. Nigrovic and colleagues said in the Jan. 3 issue of the Journal of the American Medical Association.

But with the advent of widespread pneumococcal conjugate vaccination, which has markedly reduced the occurrence of bacterial meningitis, it had been unclear whether the guideline was still valid, said Dr. Nigrovic, writing on behalf of the Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics.

To find out, the committee undertook a multicenter retrospective cohort study in the emergency departments of 20 U.S. academic medical centers, involving all children ages 29 days to 19 years from Jan. 1, 2001, to June 30, 2004, with CSF pleocytosis and who had not received antibiotic treatment before lumbar puncture.

CSF pleocytosis was defined as at least 10 white cells per microliter of fluid.

The Bacterial Meningitis Score classes patients as being at extremely low risk for the condition if they lack any of the following five factors:

• A positive CSF Gram stain.
• An absolute neutrophil count in the CSF of at least 1000 cells per microliter.
• CSF protein of at least 80 milligrams per deciliter.
• An absolute neutrophil count in the peripheral blood of at least 10,000 cells per microliter.
• And a history of seizure before or at the time of presentation.

In its initial and subsequent studies, the tool was shown to have a negative predictive value of 100% and a sensitivity approaching 100%, the researchers said.

The current study looked at 3,295 patients with CSF pleocytosis, of whom 121 (3.7%) had bacterial meningitis and 3,174 had aseptic meningitis.

Of the 1,714 patients categorized as at very low risk for bacterial meningitis by the Bacterial Meningitis Score, only two actually had the condition, the researchers found.

The sensitivity of the tool was thus 98.3% and the negative predictive value was 99.9%, Dr. Nigrovic and colleagues said.

The misclassified patients were younger than two months old and both proved to have E. coli meningitis and urinary tract infections, but with negative urinalyses at presentation, the researchers said.

Dr. Nigrovic and colleagues concluded that the Bacterial Meningitis Score remains a valuable tool, although they suggested that for patients with at least one Bacterial Meningitis Score risk factor or who are under the age of two months, physicians should err on the side of caution and administer parenteral antibiotics regardless.

And in all cases, they said, "the Bacterial Meningitis Score should be used in concert with careful clinical assessment of the patient."