Letters Section Editor: Robert M. Golub, MD, Senior Editor.
To the Editor: Dr Nigrovic and colleagues1 studied the validation of a clinical prediction rule to identify children with cerebrospinal fluid (CSF) pleocytosis who are at low risk of having bacterial meningitis. I have a number of concerns about their conclusions.
First, 342 patients (10% of the study cohort) did not have blood cultures drawn but had examination of the CSF. Of these, only 3 patients had a positive CSF culture and therefore, by definition, meningitis. CSF pleocytosis with clinical improvement after less than 7 days of empirical antibiotic treatment does not exclude bacterial meningitis, even with a negative CSF culture.2,3 Clinical response is unlikely to be that rapid for pneumococcal meningitis.4 However, other forms of bacterial meningitis, such as Neisseria meningitidis, the second most common etiologic agent in their study, may be rapidly responsive to antibiotic treatment.2- 4 Thus, in the absence of a blood culture it is possible that not all of the 253 patients classified as unspecified aseptic meningitis (75% of those without blood cultures and with negative CSF cultures) truly had that diagnosis. For the same reason, exclusion of patients with a history of antibiotic use within only 72 hours of a lumbar puncture may not have been adequate to screen out patients who may have had partially treated bacterial meningitis.
Obaro S. Prediction Rule for Bacterial Meningitis in Children. JAMA. 2007;297(15):1653-1655. doi:10.1001/jama.297.15.1653