To Örebro University

BACKGROUND: Patients suffering from traumatic brain injury (TBI) are often treated in specialized neuro-intensive care units (NICU) using multi-modal monitoring to detect harmful secondary insults such as increased intra cranial pressure. In addition to different monitoring devices. serum biomarkers have been shown to provide additional important information regarding the patient. Elevated serum levels of S100B have been detected following TBI. cerebral ischemia. spontaneous intra-cerebral hematomas and edema formation. S100B is known to correlate to outcome. Severe secondary cerebral injuries have been shown to correlate to secondary peaks in serum levels of S100B. Increases of more than 0.1mug/L are considered pathological.

METHOD: 267 patients treated in the NICU for TBI with S100B samples obtained every 12 hours during a minimum of a 96-hour time period were included. Secondary increases of S100B after 48 hours following trauma were noted. All patients had at least 2 CT-scans and/or MRI scans performed.

RESULTS: 67 secondary injuries during the NICU stay were detected using MRI or CT-scans. The most common lesions were diffuse is- chemic injuries (29). edema (13). cerebral infarctions (11) and intracerebral hematoma (5). Looking at secondary peaks of S100B in detecting radiological verifiable cerebral lesions during the NICU stay. a cut-off level of more than 0.5mug/L the specificity was 100% and sensitivity 8.9%. Decreasing the cut-off level to 0.1mug/L a specificity of 95.9% and sensitivity of 64.2% was obtained. while a cut-off level of 0.05mug/L presented a specificity of 92.7% and sensitivity of 92.5%.

CONCLUSIONS: S100B is a sensitive marker for secondary cerebral injuries occurring in the NICU after TBI. A low cut-off point for the secondary peak of S100B (0.05 mug/L) increases sensitivity without any major deficit of specificity in detecting secondary injuries during the NICU stay.