Serial cerebrospinal fluid neurofilament concentrations in bacterial meningitis

Neurofilament (NF) is one of the major cytoskeleton proteins of neurons. We investigated the concentrations of the heavy subunit of NF (NF-H) in cerebrospinal fluid (CSF) as biomarkers of neuronal injury in bacterial meningitis. Concentrations of NF-H in CSF of 26 children with bacterial meningitis and in 16 control subjects were measured by ELISA. The CSF NF-H levels were elevated in 22 of the 26 children (85%) with bacterial meningitis. The peak CSF NF-H level occurred at a median period of 10.5 days after onset of illness (range, 1 to 35 days). The peak CSF NF-H levels of the patients with neurological sequelae (n=4) were significantly higher than those without sequelae (n=22) (7.06 vs. 2.46 ng/mL as median, p=0.048). There was no significant difference in CSF NF-H levels between patients with and without severe neurological sequelae up to day 14 of illness, but the CSF NF-H levels in patients with sequelae were significantly higher than in those without sequelae after day 14 of illness (2.04 vs. 1.19 ng/mL as median, p=0.024). We suggest that neuronal injury occurs in bacterial meningitis regardless of the presence or absence of neurological sequelae.