LGI1 antibody encephalitis: an emerging cause of epileptic seizures in cats

Autoimmune encephalitis is a sterile inflammatory condition of the brain that can result in epileptic seizures, behavioural changes and other neurological abnormalities. Various forms of autoimmune encephalitis are now well characterised in humans. In recent years, a form of autoimmune encephalitis has been identified in cats in which autoantibodies are produced against the leucine-rich glioma-inactivated 1 (LGI1) protein expressed at synapses. Ongoing work to develop understanding of this important cause of seizures is progressing, alongside efforts to validate a diagnostic test. This article discusses the main features of LGI1-antibody encephalitis in humans, before discussing its typical clinical presentation in cats, and the approach to diagnostic investigations, treatment and outcome.