A pure parkinsonian syndrome following acute carbon monoxide intoxication.

A 50-year-old woman with carbon monoxide (CO)-induced parkinsonism was found to have bilateral lucencies of the globus pallidus on computed tomographic (CT) scan consistent with old necrotic lesions. She showed no clinical response to levodopa therapy, although she did improve with anticholinergic therapy. It is suggested that the parkinsonism in this patient is due to the pallidal lesions demonstrated on CT scan, and that such pallidal-related parkinsonism may not respond to dopaminergic therapy.