Today we had a case of autoimmune encephalitis, in a patient with a recent viral illness presenting with refractory status. Although ruling out infectious causes of encephalitis is imperative, do not forget autoimmune encephalitis, the most characterized of which is anti-NMDA. There are many other antibodies and autoimmune encephalitis syndromes, but acute behavioral changes, seizures, language dysfunction and dyskinesias after a viral illness +/- CSF pleocytosis or classic MRI features – without alternative causes – should make you suspicious.
Our take home points were;
- Know the broad differential categories for new onset seizures
- EEG is an important tool to rule out non-convulsive status
- There are many autoimmune encephalitides, including NMDA-R, that vary according to Ab target and clinical presentations
- Paraneoplastic encephalitis often overlaps with autoimmune, however antibodies target intracellular proteins
Picture from Fang and Juan, Neuroradiology 2019.