Morvan's fibrillary chorea. A case with possible manganese poisoning.

The clinical picture of Morvan's fibrillary chorea includes a. spontaneous muscular activity resulting from repetitive motor unit action potentials of peripheral origin (multiplets), b. autonomic dysregulation with profuse hyperhidrosis, and c. central nervous system involvement as shown by severe insomnia and hallucinosis. A case featuring all these symptoms is presented. Whereas known causative factors range from gold or mercury poisoning to autoimmune disorders, the presented case is the first one in which chronic manganese intoxication (occupational exposure) seems to be implicated. Manganese has been found to inhibit acetylcholine esterase, and, as a consequence, may produce peripheral and central cholinergic hyperactivity.