Autoimmune Encephalitis with VGKC and Anti-LGI1 Antibodies after Asymptomatic COVID-19: A Case Report

Objectives: To report a patient diagnosed with asymptomatic COVID-19 infection who acutely presented with autoimmune encephalitis involving both anti-LGI-1 and anti-VGKC channels. Methods: Patient data were obtained from medical records from the Torrecárdenas University Hospital, Almeria, Spain. The patient was a 34-year-old female who experienced a generalized tonic-clonic seizure and psychomotor restlessness despite being asymptomatic for respiratory symptoms but having confirmed COVID-19 through PCR testing. Serum tests revealed the presence of anti-Voltage-Gated Potassium Channel antibodies (VGKC) and anti- Leucine-Rich Glioma-Inactivated 1 (LGI1) antibodies, while Cerebrospinal Fluid (CSF) analysis detected anti- VGKC antibodies. Magnetic Resonance Imaging (MRI) demonstrated bilateral medial temporal lobe signal changes with lesions in the claustrum and basal ganglia, typically associated with limbic encephalitis in cases with positive anti-VGKC and anti-LGI1 antibodies. Furthermore, the patient exhibited cognitive dysfunction, mental disorders, and hyponatremia, all of which are common features of anti-LGI1 encephalitis. The patient was diagnosed with autoimmune encephalitis involving both anti-LGI-1 and anti-VGKC channels. The patient displayed significant clinical improvement and decreased antibody titers following treatment. Consequently, we propose that double- positive antibodies played a pivotal role in this case. Discussion: Our case raises awareness of the occurrence of rare autoimmune encephalitis following asymptomatic COVID-19 infection.