Limbic Encephalitis Associated with Voltage-Gated Potassium Channel-Complex Antibodies: Patient Report and Literature Review

Background: The family of disorders associated with antibodies against neuronal surface antigens is a rapidly expanding category of autoimmune neurologic disease. Methods: Clinical and laboratory findings of a patient with voltage-gated Kv1 potassium channel (VGKC)-complex autoantibodies are reported and the literature is reviewed. Results: New-onset faciobrachial dystonic seizures, distal large and painful small fiber peripheral neuropathy, dysautonomia, cognitive and memory disturbances were associated with hypometabolism of the left temporal lobe without evidence of systemic malignancy in whole-body positron emission tomography with 2-deoxy-2-[fluorine-18] fluoro-D-glucose integrated with computed tomography. Brain MRI and cerebrospinal fluid were normal with absent intrathecal VGKC-complex antibodies consistent with extrathecal production. Epidermal nerve fiber studies confirmed small fiber neuropathy in association with abnormal autonomic laboratory testing. Discussion: Neurologic involvement associated with VGKC complex autoimmunity is a precisely delineated disorder involving the central, peripheral, and autonomic nervous system.