Objective: S-100 protein is a sensitive marker of various brain diseases; however, its role in epilepsy is controversially discussed in the literature. We therefore studied the temporal profile of serial concentrations of S-100 protein in serum after secondarily generalized tonic-clonic seizures during video-EEG monitoring.

Methods: Ten patients with mesial temporal lobe epilepsy were prospectively studied. Serum S-100 protein was measured after a seizure-free period of > or =24 h (baseline) and 30 min, 3, 6, 12, and 24 h after a secondarily generalized tonic-clonic seizure of temporal lobe origin in nine and a convulsive status epilepticus in one patient.

Results: All S-100 levels were within the normal range, except for those of one patient at baseline. Mean values were 0.045 microg/L (range, 0.003-0.13 microg/L) at baseline, 0.038 microg/L (range, 0.003-0.09 microg/L) at 30 min, 0.036 microg/L (range, 0.003-0.08 microg/L) at 3 h, 0.034 microg/L (range, 0.003-0.07 microg/L) at 6 h, 0.034 microg/L (range, 0.003-0.08 microg/L) at 12 h, and 0.035 microg/L (range, 0.003-0.09 microg/L) at 24 h after seizure offset. There were no significant differences between mean concentrations at any interval postictally.

Conclusions: We could not detect any significant alterations in serum S-100 protein concentration either after a single secondarily generalized tonic-clonic seizure or after convulsive status epilepticus in patients with temporal lobe epilepsy. Our data do not confirm previous work, which suggested serum S-100 protein to be a suitable marker for epileptic seizures.