Patient is 49 yo F who presents to ED with few days of fever (T max 102F), progressive headache, neck stiffness. Patient denies any travel, rashes, sick contacts. Pt complains she can’t be in a well lit room or go outside without pain. You have a high suspicion for meningitis and so perform an LP.

CSF shows as follows:

WBC 100/mm3 (60% N, 35%L)

Protein 100

Glucose 40 (serum glucose 100)


Aside from a gram stain and culture, are there any other tools to help differentiate between viral and bacterial meningitis?

Cerebral Spinal Fluid Lactate has been more extensively investigated in the adult population. Some studies have found it to have a sensitivity of 93-94% and specificity of 96-97% at a cut-off level [1] with the cutoff being described between of 3.8 mmol/L [1]  and 3.9 mmol/L [2] in the adult population. In pediatrics, a recent article (studying patients from 1 mo to 15yr) found a cutoff of 3.0 mmol/L to be optimal cutoff in distinguishing bacterial and viral meningitis but recommend its use in conjunction with the validated Bacterial Meningitis Scoring system [4].



1. Viallon A, Desseigne N, Marjollet O. Meningitis in adult patients with a negative direct cerebrospinal fluid examination: value of cytochemical markers for differential diagnosis. Crit Care. 2011;15(3):R136. doi: 10.1186/cc10254. Epub 2011 Jun 6. PubMed PMID: 21645387

2. Sakushima K, Hayashino Y, Kawaguchi T, Jackson JL, Fukuhara S. Diagnostic accuracy of cerebrospinal fluid lactate for differentiating bacterial meningitis from aseptic meningitis: a meta-analysis. J Infect. 2011 Apr;62(4):255-62. doi: 10.1016/j.jinf.2011.02.010. Epub 2011 Mar 5. Review

3. Mekitarian Filho E, Horita SM, Gilio AE, Nigrovic LE. Cerebrospinal fluid lactate level as a diagnostic biomarker for bacterial meningitis in children. Int J Emerg Med. 2014 Feb 27;7(1):14. doi: 10.1186/1865-1380-7-14. PubMed PMID:24576334

4. Nigrovic LE, Malley R, Kuppermann N. Meta-analysis of bacterial meningitis score validation studies. Arch Dis Child. 2012 Sep;97(9):799-805. doi: 10.1136/archdischild-2012-301798. Epub 2012 Jul 4. Review. PubMed PMID: 22764093.


June 2024