Biomarkers of Encephalitis

The development of encephalitis presents a dilemma to the clinician as during the early stages, when treatment would be most effective, the symptoms can be nonspecific with a broad differential. Imaging tests (e.g. magnetic resonance imaging and computed axial tomography scan), blood and urine tests as well as lumbar puncture are used to isolate and identify viruses, and together with careful and continuous neurological assessment provide data that may be suggestive of viral encephalitis. In the case of post-infectious or autoimmune encephalitis, a more intense investigation is needed to generate an accurate diagnosis. In addition to imaging tests and electroencephalography, blood and cerebrospinal fluid (CSF) need to be analyzed for evidence of inflammation and the presence of antibodies against cellular antigens. In recent years clinicians and investigators have pursued biomarkers that can aid in the diagnosis as well as prognosis and monitoring of patients with encephalitis. These biomarkers are increasingly important in the recognition and treatment of inflammatory and autoimmune central nervous system (CNS) disorders. This chapter will review the current literature of emerging biomarkers in the different types of encephalitis.