Diagnostic studies-encephalitis

(CID 2013;57:1114)

• CSF analysis: lymphocytic pleocytosis; PCR for HSV (95% Se & Sp), VZV; consider other PCR based on risk factors (CMV/EBV, HIV, JC, adeno/enterovirus, WNV)
• Consider testing for autoimmune etiologies and serologic viral testing in appropriate settings if CSF is unrevealing and there is no improvement with empiric HSV/VZV Rx
• MRI (CT if unavailable); HSV temporal lobe; W. Nile & Powassan thalamic hyperintensity
• EEG to r/o seizure; findings in encephalitis are nonspecific (temporal lobe focus in HSV)