Immunotherapy responsive startle with antibodies to voltage gated potassium channels

Antibodies to potassium channels (VGKC-Ab) were first associated with acquired neuromyotonia and its variant with CNS involvement, Morvan's syndrome. Recently, VGKC-Ab were found in patients with non-paraneoplastic limbic encephalitis (LE), characterised by personality changes, seizures and memory impairment. These patients may respond to immunotherapies. Thus the association of VGKC-Ab and non-paraneoplastic LE established the concept of a potentially reversible autoimmune encephalopathy. We describe a patient with startle syndrome and VGKC-Ab, without neuromyotonia or LE, who responded dramatically to plasma exchange (PE) and immunosuppression, adding to the spectrum of disorders associated with VGKC-Ab.