Nice dodge there, Dr. Shadowfax. I'd like to review a couple of journal articles for all the ER folks out there who may not be familiar with the pediatric literature, to aid you in the management of patients such as the school-age kid with pleocytosis. I'm not sure about the literature in the adult world, since I stopped
caring following it closely a dozen years ago or more. In the world of kids though, it can be devilishly tricky to figure out which kids have aseptic (viral) and which have bacterial meningitis, particularly since the incredibly effective vaccines for Haemophilus influenza B and Streptococcus pneumonia have drastically reduced the number of kids who get bacterial meningitis in the first place.
Enter Dr. Lise Nigrovic from haavad (say hi while you're in Boston, Dr. S!), and her group's development of a multivariable predictive model to distinguish the two entities. Using a set of nearly 700 patients with meningitis (1:4 ratio of bacterial to viral meningitis), they first randomly-selected 1/3 of them as the "derivation set." They then analyzed this subgroup to find the variables that differ in patients with bacterial vs. viral sources of infection. They found a model that used a Bacterial Meningitis Score (BMS) with one point for any of the following:
- CSF Protein >= 80
- CSF ANC >= 1,000
- Peripheral ANC >= 10,000
- Seizure before or at presentation
- CSF Gram Stain + for bacteria
This study has since been validated in a multicenter study done in the era of widespread Pneumococcal-vaccine use.
Certainly there are many reasons for admitting a child at low risk (BMS = 0) of bacterial meningitis: vomiting, intractable pain, lack of appropriate follow-up, or lack of an appropriate (or sufficiently reassured) caregiver. However in many instances the BMS can be a useful tool in changing your disposition from "slam-dunk admit" to "home to rest and recover."
- Development and Validation of a Multivariable Predictive Model to Distinguish Bacterial From Aseptic Meningitis in Children in the Post-Haemophilus influenzae Era. PEDIATRICS Vol. 110 No. 4 October 2002, pp. 712-719
- Clinical Prediction Rule for Identifying Children With Cerebrospinal Fluid Pleocytosis at Very Low Risk of Bacterial Meningitis. JAMA Vol. 297 No. 1, January 3, 2007