Manganism Studies

A 33-year-old right-handed male presented complaining of a 2-year history of progressive cognitive slowing, rigidity, tremors, slowing of movements, and gait instability leading to falls. On examination, he had a Mini-Mental Status Examination (MMSE) score of 29, slowed saccadic eye pursuit, hypomimia, cogwheel rigidity, a 3- to 4-Hz tremor, and a "cock-walk" gait. His symptoms and signs were similar to idiopathic Parkinson's disease; however, he was young, inattention and forgetfulness occurred early in the course of the disorder, levodopa was unhelpful, and his gait was atypical. His work up for secondary causes of parkinsonism was negative, except for increased signal intensity on T1-weighted magnetic resonance image (MRI) in the bilateral basal ganglia. Typical etiologies for that finding were ruled-out, which led to further inquiries into the patient's lifestyle. He was a welder, and discussion with his employer revealed that he used a steel-manganese alloy, he often worked in a confined ship's hold, and he did not use a respiratory mask. Because manganese toxicity can produce increased T1-weighted signal intensities in the basal ganglia, the authors tested his serum and urine manganese, and both were elevated. This patient emphasizes the importance of a careful occupational history in persons presenting with atypical manifestations of a neurodegenerative disorder. It also lends support to the hypothesis that welding can produce enough exposure to manganese to produce neurologic impairment.

Huang CC, Chu NS, Lu CS, Chen RS, Calne DB.

Department of Neurology, Chang Gung Memorial Hospital and Medical College, Taipei, Taiwan.

We studied the long-term clinical course of five patients with chronic manganese intoxication. The mean scores of the King's College Hospital Rating Scale for Parkinson's disease increased from 15.0 +/- 4.2 in 1987 to 28.3 +/- 6.70 in 1991 and then to 38.1 +/- 12.9 in 1995. The deterioration was most prominent in gait, rigidity, speed of foot tapping, and writing. Tissue concentrations of manganese in blood, urine, scalp hair, and pubic hair returned to normal. Follow-up MRIs did not show paramagnetic high-signal intensity on T1-weighted images. The data indicate that clinical progression in patients with manganese parkinsonism continues even 10 years after cessation of exposure.