The Involuntary Movements of Chronic Mercury Poisoning

Three siblings were poisoned by the accidental ingestion of organic mercury and a fourth sibling, a newborn, was poisoned by the transplacental transfer of organic mercury. All developed prominent involuntary movement including resting tremor, ataxia, chorea, athetosis, and myoclonus. Previous descriptions of mercury poisoning, both organic and inorganic, have noted similar movement disorders. The pathogenesis of the involuntary movements is not entirely clear. One of the diagnostic considerations in a patient who acquires otherwise unexplained involuntary movements should be chronic mercury poisoning.