Hashimoto's Encephalopathy Presenting with Acute Cognitive Dysfunction and Convulsion.

Hashimoto's encephalopathy is an immune-mediated disorder characterized by acute or subacute encephalopathy related to increased anti-thyroid antibodies. Clinical manifestations of Hashimoto's encephalopathy may include stroke-like episodes, altered consciousness, psychosis, myoclonus, abnormal movements, seizures, and cognitive dysfunction. Acute cognitive dysfunction with convulsion as initial clinical manifestations of Hashimoto's encephalopathy is very rare. We report a 65-year-old man who developed acute onset of cognitive decline and convulsion due to Hashimoto's encephalopathy.