[A case of welder presenting with parkinsonism after chronic manganese exposure]

A 56-year-old welder working for 30 years developed postural instability and writing clumsiness since October, 1998. Neurologic findings revealed dystonia of the bilateral shoulders and distal four limbs as well as parkinsonism such as masked face, bradykinesia, rigidity, and retropulsion. Brain MRI showed hyperintensity lesions on T1-weighted images in the bilateral globus pallidus, midbrain, pontine tegmentum, dentate nucleus and cerebral white matter, which reduced in size and density after ten months. The diagnosis of manganese poisoning was made by the high manganese levels of both serum and urine, and by the marked elevated urinary manganese level after administration of the cheleting agent. We pointed out the diagnostic significance of brain MRI in patients with chronic manganese exposure.