Elevated S100B levels do not correlate with the severity of encephalopathy during sepsis

Background Sepsis-associated encephalopathy (SAE) is defined as a diffuse cerebral dysfunction induced by the systemic response to infection without any clinical or laboratory evidence of direct infectious involvement of the central nervous system. The astroglial protein S100B has been used as a marker of severity of brain injury and as a prognostic index in trauma patients and cardiac arrest survivors. We measured S100B serum levels in patients with severe sepsis to investigate if the severity of SAE correlated with an increase in S100B levels. Methods Twenty-one patients, with a diagnosis of severe sepsis, were included in this study. S100B levels were measured at intensive care unit (ICU) admission, 72 h and 7 days after admission. Their association with markers of brain dysfunction such as Glasgow coma scale (GCS), and EEG, and with sepsis-related organ failure assessment score (SOFA) and ICU mortality was investigated. Results Fourteen patients had elevated S100B levels. The levels did not correlate with GCS at admission, EEG pattern, or SOFA scores. Also, S100B levels did not differ between patients who recovered neurologically and those who did not (P = 0.62). Conclusions In severe sepsis, an increase in S100B does not allow the physicians to distinguish patients with severe impairment of consciousness from those with milder derangements or to prognosticate neurological recovery.