Welding-related parkinsonism - Clinical features, treatment, and pathophysiology

Objective: To determine whether welding-related parkinsonism differs from i diopathic PD. Background: Welding is considered a cause of parkinsonism, bu t little information is available about the clinical features exhibited by patients or whether this is a distinct disorder. Methods: The authors perfo rmed a case-control study that compared the clinical features of 15 career welders, who were ascertained through an academic movement disorders center and compared to two control groups with idiopathic PD. One control group w as ascertained sequentially to compare the frequency of clinical features, and the second control group was sex- and age-matched to compare the freque ncy of motor fluctuations. Results: Welders were exposed to a mean of 47,14 4 welding hours. Welders had a younger age at onset (46 years) of PD compar ed with sequentially ascertained controls (63 years; p < 0.0001). There was no difference in frequency of tremor, bradykinesia, rigidity, asymmetric o nset, postural instability, family history, clinical depression, dementia, or drug-induced psychosis between the welders and the two control groups. A ll treated welders responded to levodopa. Motor fluctuations and dyskinesia s occurred at a similar frequency in welders and the two control groups. PE T with 6-[F-18]fluorodopa obtained in two of the welders showed findings ty pical of idiopathic PD, with greatest loss in posterior putamen. Conclusion s: Parkinsonism in welders is distinguished clinically only by age at onset , suggesting welding may be a risk factor for PD. These preliminary data ca nnot exclude a genetic contribution to susceptibility in these exposed indi viduals.