The Enigma of Parkinsonism in Chronic Borderline Mercury Intoxication
A 47 year old female dentist suffered from hemiparkinsonism which had started eighteen months earlier and was manifested mainly by resting tremor and cogwheel rigidity. A baseline quantitative urinary mercury excretion was 46 micrograms/day. The patient was treated with chelating agent d-penicillamine for a week. Chelation therapy resulted in clinical improvement of parkinsonism and in dynamic changes in daily urinary mercury excretion with a prompt increase to 79 micrograms/day, a subsequent decline followed by increase in the mercury urinary excretion. After a week chelation therapy was stopped. During a follow-up period of five years, the neurological status remained unchanged after the initial penicillamine-induced improvement. This case may be evidence, therefore, of a rare clinical variant of elemental mercury intoxication associated with parkinsonism, in the absence of most classical neuropsychiatric signs of chronic mercurialism.
Finkelstein Y, Vardi J, Kesten MM, Hod I. Neurotoxicology. 1996 Spring; 17(1):291-5. 8784840 PubMed