Case Study: A 66-Year-Old Woman with Newly Developed Bilateral Upper Extremity Resting Tremors, Scans Without Evidence of Dopaminergic Deficit (SWEDD)
Scans Without Evidence of Dopaminergic Deficit (SWEDD) 1. Cause and Etiology SWEDD is not a disease itself, but rather a diagnostic categorization referring to patients who clinically present with Parkinsonian symptoms (e.g., tremor, bradykinesia) but whose dopamine transporter imaging (DaTscan) does not show evidence of dopaminergic neuron loss typically seen in Parkinson’s disease (PD) or other Parkinsonian syndromes. Underlying causes vary and include: Essential tremor (ET) Dystonic tremor Drug-induced parkinsonism Functional (psychogenic) movement disorders Vascular parkinsonism Atypical Parkinsonism without nigrostriatal degeneration 2. Pathophysiology Unlike true Parkinson’s disease, SWEDD patients do not show degeneration of the substantia nigra or dopaminergic neuronal loss in the striatum. Normal DaTscan indicates: Intact presynaptic dopaminergic terminals Absence ...