Neuron-Specific Enolase, S100B, and Glial Fibrillary Acidic Protein Levels as Outcome Predictors in Patients With Severe Traumatic Brain Injury

Abstract

The availability of markers able to provide an early insight related to prognostic and functional outcome of patients with traumatic brain injury (TBI) are limited. The relationship of clinical outcome with CSF neuron-specific enolase (NSE), S100B and glial fibrillary acidic protein (GFAP) levels in patients with severe TBI was investigated. Twenty patients with severe TBI (7 days at unit care) and controls were studied. Patients were grouped according to the outcome: (1) nonsurvival (n=5): patients who died; (2) survival A (n=15): CSF sampled between 1st and 3rd day from patients who survived after hospital admission; and (3) survival B (n=7): CSF sampled between 4th and 7th day from patients who survived after hospital admission and were maintained with intraventricular catheter up to 7 days. Up to 3 days, S100B and NSE levels (ng/mL) were significantly elevated in the nonsurvival compared with survival A group (S100: 12.45 ± 5.46 vs 5.64 ± 3.36; NSE: 313.20 ± 45.51 vs 107.80 ± 112.10). GFAP levels did not differ between groups. In the survival B group S100B, GFAP, and NSE levels were still elevated compared with control (4.59 ± 2.19, 2.48 ± 2.55, and 89.80 ± 131.10, respectively). To compare S100B and NSE for the prediction of nonsurvival and survival patients we performed receiver operating characteristic curves. At admission, CSF NSE level predicts brain death more accurately than S100B. Early elevations (up to 3 days) of S100B and NSE secondary to severe TBI predict deterioration to brain death. However, this feature was more prominently associated with NSE than S100B.