Table 5.

Evaluation of new symptoms in patients with prior autoimmune encephalitis. This is a difficult area but several guidelines can be offered:

• The clinical findings are paramount. Worsening of the specific neurological findings without an alternative cause trumps antibody tests, radiology, and CSF analysis.

• Progression of findings on MRI (such as T2 signal changes in the temporal lobes) often supports disease activity.

• Seizures usually resolve with treatment of the autoimmune encephalitis. Therefore new or worsened seizures may suggest relapse.

• If the CSF is bland and the antibody response is no longer present, the patients’ symptoms are less likely to be due to the autoimmune encephalitis.

• If the CSF shows signs of inflammation, this favors and active disease process.

• CSF results may be ambiguous: the antibody response persists but there is no evidence of inflammation.

• Sera titers are not generally useful since antibody response can persist in the sera and not the CSF or vice versa.

• CSF titers may be useful with these caveats: samples from different time points must be studied carefully side by side in a skilled lab, the titer must change by at least two points of measurement (e.g. not 1:10 to 1:20). A significant increase in titer compared to CSF obtained during a remission favors a relapse.