Anti-LGI-1 Limbic Encephalitis and Autoimmune Epilepsy Following a Third Dose of COVID-19 Vaccination: A Case Report.

Anti-leucine rich glioma inactivated 1 (LGI-1) autoimmune encephalitis (AE) typically presents with cognitive impairment, faciobrachial dystonic seizures (FBDS) and hyponatraemia. Reports are growing of neurological complications following coronavirus disease 2019 (COVID-19) vaccination. Here we describe a 50 year old man who developed anti-LGI-1 limbic encephalitis and autoimmune epilepsy 4 days following a dose of the mRNA Pfizer COVID-19 vaccine (of note, his first two vaccinations were viral vector ChAdOX1-S). He presented with focal aware seizures characterised by short-lived episodes of confusion, emotional distress and déjà vu associated with palpitations. He also reported subacute progressive amnesia. He responded well to high-dose steroid and subsequent immunoglobulin therapy. To our knowledge, this is the first reported case of anti-LGI-1 AE following a mixed COVID-19 vaccination regimen. We aim to complement the early literature on this post-COVID-19 vaccination phenomenon.