Cerebrospinal fluid anion gap in meningitis

Cerebrospinal fluid lactate in meningitis and meningococcaemia

Cerebrospinal fluid (CSF) lactate values were measured in 26 children with meningitis (12 bacterial, 9 aseptic, 5 partially treated) and five children with meningococcaemia without meningitis. A reference range (0.5-3.2 mmol/l) was established from 100 control children. Amounts of lactate were significantly raised in bacterial meningitis (mean 6.5, range 4.5-10.2) compared with aseptic meningitis (mean 2.6, range 1.1-4.0) but this finding gave little practical help as the bacterial origin of the meningitis was clear from other CSF findings. High values (5.7) in a case of tuberculous meningitis (TBM) suggest that the test may be helpful when other CSF findings are inconclusive. Unless the CSF lactate is raised, the test is of minimal value in partially treated meningitis (mean 3.4, range 1.4-6.2). The previously unobserved finding of increased CSF lactate in meningococcaemia without meningitis (mean 3.9, range 3.1-5.0) supports the view that raised CSF lactate values in bacterial meningitis are not solely due to the presence of neutrophils. Literature relating to CSF lactate is reviewed.

Cerebrospinal fluid C-reactive protein in the laboratory diagnosis of bacterial meningitis

Samples of cerebrospinal fluid from 112 cases of suspected meningitis were tested for the presence of C-reactive protein (CRP), using a qualitative and quantitative slide test. Bacterial meningitis was confirmed in 34 patients, based on CSF and blood culture results, and/or elevated CSF white blood cell (WBC) count and typical biochemical profile. There were 8 patients with early onset, and 3 who had received prior antimicrobial therapy among the 5 neonates, 23 children, and 6 adults with bacterial meningitis. Organisms recovered from CSF, and/or blood, included Haemophilus influenzae 14, Streptococcus pneumoniae 9, Streptococcus group B-5, Staphylococcus aureus 2, E. coli 2 and Klebsiella pneumoniae 1. Slide test was positive for CRP in 33 cases, giving a sensitivity of 97% which compared favourably with elevated CSF protein 33%, decreased CFS glucose 64.7% CSF glucose/blood glucose less than 1/2, 85%, raised CSF WBC 38.2%, raised CSF PMN 61.7%, CSF culture positive 88.2%, and CSF gram-positive 82.5%. Slide test was positive for CRP in 1 of 78 CSF samples negative for bacterial meningitis, giving a specificity of 98%. It was concluded that testing of CSF for CRP is a simple, rapid and accurate method for the laboratory diagnosis of bacterial meningitis, which is particularly appropriate for areas lacking adequate laboratory facilities.

Comparison between cerebrospinal fluid concentrations of glucose, total protein, chloride, lactate, and total amino acids for the differential diagnosis of patients with meningitis

The purpose of this study was to compare the ability of cerebrospinal fluid (CSF) concentrations of glucose, protein, chloride, lactate, and total amino acids, as well as CSF/blood glucose ratio to distinguish bacterial meningitis from aseptic meningitis. 56 patients with proven bacterial meningitis, 102 patients with aseptic meningitis, and 108 controls were investigated. On admission CSF lactate determination was the most sensitive and the most efficient test to distinguish bacterial meningitis from aseptic meningitis. In patients with bacterial meningitis reexamined after 24-48 h of treatment with antibiotics and compared with patients with aseptic meningitis also reexamined 24-48 h after admission determination of CSF total amino acids was the most sensitive and efficient test.