Progression after chronic manganese exposure.
We report a longitudinal follow-up study on six patients with chronic manganese-induced parkinsonism following cessation of manganese exposure. Compared with the 1987 study, their parkinsonian symptoms showed a slow progression, particularly in gait disturbances such as freezing during turning and walking backward with retropulsion. The mean disability scores on the King's College Hospital Rating Scale were 15.0 +/- 4.2 in 1987 and 28.3 +/- 6.7 in 1991 (p = 0.003, paired t test). Review of the video records also confirmed a worsening of parkinsonism, especially in difficulty turning. Three of six patients receiving levodopa treatment had an initial improvement. The response decreased after 2 to 3 years. During the therapy, they did not develop on-off fluctuation or dyskinesia. We conclude that patients with manganese-induced parkinsonism may develop increasing neurologic dysfunction long after cessation of exposure and that their responses to levodopa are different from those of patients with Parkinson's disease.
Huang
C C
CC
Department of Neurology, Chang Gung Medical College and Memorial Hospital, Taipei, Taiwan.
Lu
C S
CS
Chu
N S
NS
Hochberg
F
F
Lilienfeld
D
D
Olanow
W
W
Calne
D B
DB
D000328:Adult; D002908:Chronic Disease; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008345:Manganese / Q000009:adverse effects*; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology; D009422:Nervous System Diseases / Q000139:chemically induced; D016273:Occupational Exposure; D010302:Parkinson Disease, Secondary / Q000139:chemically induced* / Q000188:drug therapy
D008345:Manganese; D007980:Levodopa