Low Yield of Routine Cerebrospinal Fluid Analysis to Assess for An Autoimmune Etiology in Patients with Chronic Seizures of Unknown Cause.

In this study, we examined the yield of routine cerebrospinal fluid (CSF) analysis to assess for an autoimmune etiology in patients with chronic seizures of unknown cause. Forty-seven patients were included. Six of 47 (13%) had inflammation on routine CSF analysis, none of whom were diagnosed with seizures related to autoimmune encephalitis (AE). Meanwhile, 2/47 (4%) were diagnosed with seizures related to AE, neither of whom had inflammation on routine CSF analysis. Routine CSF analysis to assess for an autoimmune etiology in patients with chronic seizures of unknown cause is low yield, and has suboptimal specificity and sensitivity for seizures related to AE.