A case of lithium-induced parkinsonism presenting with typical motor symptoms of Parkinson's disease in a bipolar patient.

Lithium is a mood stabilizer rarely associated with drug-induced parkinsonism (DIP). We present a case of an elderly woman with bipolar disorder who developed parkinsonian symptoms after chronic lithium administration despite therapeutic serum levels. Upon evaluation, classic parkinsonian signs of muscle rigidity, tremor, bradykinesia, freezing of gait, and cognitive decline were observed. Initially, she was diagnosed with Parkinson's disease (PD); however, DaTscan SPECT imaging clarified the diagnosis as DIP. As the daily lithium dosage was reduced, the patient's motor symptoms improved. This report emphasizes close monitoring of lithium levels in geriatric populations and the need to consider lithium-induced parkinsonism when PD symptoms appear in chronic lithium users.