Serum S100B levels in patients with cerebral and extracerebral infectious disease.

S100B has been shown to increase in cerebrospinal fluid (CSF) and serum after various neurological diseases and it has been postulated that S100B could serve as a serum marker for brain damage. However there is limited information concerning serum S100B levels in infectious diseases of the brain. Blood samples were collected from patients at the Department of Infectious Diseases at or soon after admission. The different diagnoses studied were bacterial meningitis, pneumonia, viral meningitis, cerebral abscess, enteritis, erysipelas, viral encephalitis and neuroborreliosis. A serum S100B level > 0.15 microg/l was defined as increased. 57 patients were included in the study. S100B was elevated in 33% of patients (19/57). 73% (8/11) of patients with bacterial meningitis showed increased levels compared to 7% (1/14) of patients with viral meningitis. Viral encephalitis showed the highest mean S100B levels (mean 0.58 microg/l). 25% (6/24) of patients with extracerebral infections showed raised S100B levels. S100B levels were generally higher in patients with cerebral infections than in extracerebral infections. However, both false negative and false positive S100B levels were observed which may limit the use of S100B as a brain specific serum marker.