[Myoclonic encephalopathy due to bismuth salts. Negative search for an associated toxic element].

Five cases of bismuth associated encephalopathy have been observed in the area of Geneva (Switzerland). Thy typical clinical picture is described and the blood and urinary bismuth levels are analyzed in comparison with a group of patients on bismuth treatment but without encephalopathy. A link is established between these observations and previously reported cases of bismuth toxicity, and also with other toxic encephalopathies. With regard to pathogenesis, two hypotheses are discussed: alkylation of bismuth in vivo, and association with another neurotoxic element. With this in view, the urinary excretion of arsenic, lead and mercury was measured. The results were within normal limits.