Clinical Improvement Following Delayed Initiation of Immunotherapy in a Case of LGI1 Antibody Encephalitis Presenting with Faciobrachial Dystonic Seizures Following COVID-19 Vaccination

Objective To demonstrate a case of suspected post-vaccine autoimmune encephalitis associated with leucine-rich glioma-inactivated protein (LGI1) antibodies with significant clinical improvement after initiation of immunotherapy nearly a year after symptom onset. Background Although the autoimmune encephalitides have overlap in presentation, some have unique manifestations (such as orofacial dyskinesias seen with NMDA encephalitis). These unique associations can serve as a clinical marker of response to treatment and even allow for earlier initiation of immunotherapy while awaiting results from antibody testing. LGI1 encephalitis characteristically presents with faciobrachial dystonic seizures (FBDS) that are refractory to anti-seizure medications (ASMs) but responsive to immunotherapy. Design/Methods Case report Results A previously healthy and highly independent 89-year-old woman developed what she described as abnormal posturing and spasms of the right shoulder two to three weeks after receiving the J&J COVID-19 vaccine. The abnormal movements progressed to involve the right side of her face and were refractory to multiple ASMs. EEG captured multiple events without epileptiform correlate. Several months later she developed paranoia, delusions, and hallucinations. Autoimmune encephalopathy panel returned positive for the LGI1-antibody around nine months after the onset of FBDS. Upon our initial exam, she had a fluctuating level of arousal, impaired recall of recent events, and was tangential in conversation. There were frequent, brief, repetitive, dystonic movements of the right side of the face consistent with FBDS. Admission was arranged for immunotherapy (intravenous methylprednisolone and intravenous immunoglobulin). Upon follow-up four weeks later, there was significant improvement in arousal and concentration with resolution of FBDS and delusions. Conclusions This case highlights a classic case of LGI1 encephalitis after vaccination presenting with FBDS and progressive cognitive changes. Despite immunotherapy being delayed, there was marked clinical improvement. It is important to recognize this entity and that it typically has a favorable outcome.