Normal CSF neuron-specific enolase and S-100 protein levels in patients with recent non-complicated tonic–clonic seizures

Abstract

Purpose: Increased concentrations of the nervous-system-specific proteins neuron-specific enolase (NSE) and S-100 protein (S-100) have been measured with lesions in the CNS. Elevated levels of serum NSE (s-NSE) have been found in status epilepticus, but also after single epileptic seizures. Because larger studies addressing cerebrospinal fluid (CSF) levels of NSE or S-100 have not been performed, we measured CSF NSE and S-100 after tonic–clonic seizures to search for evidence of neuronal and glial damage. Methods: 22 consecutive patients with single, previously undiagnosed and untreated tonic–clonic seizures were studied. Serum and CSF samples were collected within 24 h after seizure. 18 serum and CSF samples were measured from a control group. Results: The mean CSF NSE was 8.9 ng/ml (range 0–28 ng/ml) and s-NSE 8.2 ng/ml (range 5–15 ng/ml) in the patient group. The mean concentrations in the control group were 13.1 ng/ml (range 3–24 ng/ml) and 8.0 ng/ml (range 5–12 ng/ml) respectively. The mean CSF S-100 was 3.17 μg/l (range 1.45–7.02 μg/l) and serum S-100 0.05 μg/l (range 0–0.32 μg/l), and in controls 3.19 μg/l (range 1.52–5.13 μg/l) and 0.08 μg/l (range 0–0.28 μg/l). Conclusion: There were no significant differences between the mean concentrations of NSE or S-100 in CSF and serum between the epileptic group and controls. These results do not confirm the previous observation of elevated NSE-levels after tonic–clonic seizures, which argues against neuronal or glial damage after uncomplicated tonic–clonic seizures in unmedicated patients.