Modification of Chronic Manganese Poisoning

Abstract

Six patients with hypokinetic forms of chronic manganese poisoning received slowly increasing oral doses of L-dopa up to 8.0 gm per day distributed through the day. Five showed striking reduction or disappearance of rigidity and of hypokinesia, marked improvement of postural reflexes and restitution of balance. In the sixth L-dopa induced weakness, increased muscular hypotonia, increased tremor and aggravation of hypokinesia. This sixth was greatly improved by D,L-5-hydroxytryptophane (3.0 gm per day). Two patients with severe dystonia from chronic manganese poisoning were markedly improved by L-dopa. Most of the effects of L-dopa disappeared a few days after substitution of placebo for the drug. In sharp contrast to Parkinsonian patients, the present subjects have not shown choreoathetoid movements thus far. In eight persons with normal extrapyramidal function, who served as controls, slow increases in oral doses of L-dopa up to 1.0 gm six times a day induced muscular hypotonia but no weakness.