Elderly-Onset Paroxysmal Kinesigenic Dyskinesia: A Case Report.

Paroxysmal kinesigenic dyskinesia (PKD) is characterized by transient and recurrent involuntary movements that are triggered by a sudden movement. Here, we report an elderly female patient with a 1-month history of paroxysmal rigidity of the right limb. As the symptoms were characterized as paroxysmal, transient, and repetitive, her condition was initially thought to be epilepsy. Subsequent examinations showed no abnormality in the continuous video-electroencephalogram (EEG) monitoring, magnetic resonance imaging (MRI), fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT), and genetic testing. The final diagnosis was identified as clinically diagnosed PKD, and the symptoms were well controlled after oxcarbazepine treatment. To our knowledge, this is the first report to show elderly-onset PKD. This case expands our understanding of the age of onset of PKD. However, it is necessary to differentiate PKD from reflex epilepsy and hysteria attacks. For patients with typical clinical manifestations, we should adhere to the standard diagnostic workflow for the efficient diagnosis of PKD, aiming at avoiding misdiagnosis and mistreatment.