Serum neurofilament light as biomarker of seizure‐related neuronal injury in status epilepticus

Biomarkers of neuronal damage in status epilepticus (SE) would be of great relevance for clinical and research purposes. In a retrospective cross‐sectional study, serum neurofilament light chain (NfL) levels were measured in patients with SE (30 subjects), patients with drug‐resistant epilepsy (30 subjects), and healthy controls (30 subjects). Serum NfL levels were higher in patients with SE (median = 26.15 pg/ml) compared to both epilepsy patients (median = 7.35 pg/ml) and healthy controls (median = 6.81 pg/ml; p < .001). In patients with SE, serum NfL levels showed a high correlation with cerebrospinal fluid (CSF) NfL (τ = .68, p < .001) as well as with CSF total tau (t‐tau) levels (τ = .627, p < .001); they were higher in SE lasting >24 h (p = .013), in refractory/superrefractory SE (p = .004), and in patients who died within 30 days or who presented a worsening of clinical conditions (p = .001). Values of >28.8 pg/ml predicted 30‐day clinical worsening or death (odds ratio [OR] = 10.83, 95% confidence interval [CI] = 1.96–59.83, p = .006) and SE refractoriness (OR = 9.33, 95% CI = 1.51–57.65, p = .016). In conclusion, serum NfL levels are increased in SE and correlate with SE treatment response, duration, and outcomes, therefore representing a promising biomarker of seizure‐related neuronal damage.