We present three patients with insidious onset of high-frequency atypical seizures, in association with atypical autoantibodies, with significant improvement with immunotherapy.

Autoimmune epilepsy (AE) is a relatively newly discovered epilepsy etiology. Although, It was described to present as New-Onset Refractory Status Epilepticus (NORSE). Our understanding of the clinical presentations and autoantibodies linked to AE is still sparse. 

Case Series

Case 1

A 44-year-old man presented with more than 10 years of recurrent episodes of mild confusion. Patient presented to our ER during one of these episodes where EEG revealed right temporal lobe status epilepticus. He had suboptimal response to multiple Antiepileptic Drugs (AEDs). MRI brain showed T2/FLAIR hyperintensities in the right frontal, parietal, and temporal lobes consistent with postictal effect. CSF was positive Neuronal Intermediate Filament (NIF) heavy chain antibodies

Treatment with plasmapheresis (PLEX) and intravenous immunoglobulin (IVIG) with a good response.

Case 2

A 73-year-old woman presented with daily episodes of mild confusion and falls over few months. EEG was consistent with frontal lobe seizures. MRI brain and CSF were unremarkable. She was treated with multiple AEDs, without adequate control. Serum paraneoplastic panel was positive for voltage-gated potassium channel antibodies. Seizures were controlled with PLEX.

Case 3

A 22-year-old woman presented with daily episodes of behavioral arrest and confusion few weeks after COVID-19 vaccination. EEG showed bitemporal seizures, refractory to AEDs, requiring pentobarbital induced coma. CSF and MRI brain were unremarkable. Thyroid peroxidase and anti-thyrotropin antibodies were highly elevated. Treatment with IVIG and PLEX for AE, with a prolonged recovery.

Seizures associated with AE appear to be trivial; however, it can have an aggressive course. Among antibodies have been reported in AE, NIF antibodies has not been reported. AE should be considered in patients with High-frequency of atypical seizures. Early initiation of immunotherapy is the key for disease control.