Abstract
Manganese (Mn) intoxication is known to induce parkinsonism. Mn-induced parkinsonism preferentially affect the globus pallidus in contrast to idiopathic parkinsonism where degeneration predominantly involves the nigral pars compacta. We describe a 51-year-old man who had been occupationally exposed to Mn. He had parkinsonian features including masked face, resting tremor, and bradykinesia. He also had a cock walk and a particular propensity to fall in a backward gait. There was no sustained therapeutic response to levodopa. A fluorodopa PET scan was normal. This case indicates that Mn-induced parkinsonism can be differentiated from idiopathic parkinsonism in that the former has unique clinical features and a normal fluorodopa PET scan.