Sick sinus syndrome: A harbinger of anti-LGI1 encephalitis.

Autoimmune encephalitis usually presents with short-duration neuropsychiatric syndromes, mainly behavioral with cognitive dysfunction, recurrent seizures, and movement disorders. Among them, anti-LGI1 encephalitis has faciobrachial dystonic seizure as a pathognomic feature. The two cases reported here exemplify another peculiar feature of anti-LGI1 encephalitis, which has rarely been reported and is therefore not typically emphasized. Both cases were initially treated for cardiac symptoms until the full-blown features of encephalitis became evident. The key to preventing adverse outcomes is early detection, as anti-LGI1 encephalitis is largely reversible when treated early with immunotherapy, whereas a delay in diagnosis can lead to permanent damage or fatal outcomes.