Epilepsy is the most common neurologic disorder of childhood. In approximately 6-14% of all patients with epilepsy, complete seizure control is difficult to achieve with current antiepileptic treatments. Several current studies have shown in both animals and people that the lengthening of epileptic seizures and frequent recurrence increases the likelihood of neuronal damage. S-100B protein is the most analyzed brain derived peripheral biochemical marker in brain damage. This study aimed to evaluate interictal serum S-100B protein levels in children diagnosed with intractable epilepsy. A group of 32 patients with intractable epilepsy and 25 healthy controls were recruited. Serum S-100B protein levels were measured using a commercially available electrochemiluminescence immunoassay (ECLIA kit, as supplied and according to the manufacturer\'s standards. The serum S-100B protein levels of the patient group in the study were found to be 0.094±0.011 μm/L, and 0.083±0.014 μm/L in the age-matched control group. The difference between the groups was determined to be statistically significant (P=0.004). In conclusions, it can be said that as the serum S-100B protein levels of the patients with focal epilepsy were high compared to those of the control group, this can be reliable peripheral biomarker for neuronal damage in patients with focal intractable epilepsy.

The protein S-100B is a biomarker increasingly used within neurosurgery and neurointensive care. As a relatively sensitive, yet unspecific, indicator of CNS pathology, potential sources of error must be clearly understood when interpreting serum S-100B levels. This case report studied the course of a 46-year-old gentleman with a chronic subdural hemorrhage, serum S-100B levels of 22 μg/l, and a history of malignant melanoma. Both intra- and extra-cranial sources of S-100B are evaluated and imply an unclear contribution of several sources to the total serum concentration. Potential sources of error when interpreting serum concentrations of S-100B are discussed.