Mercury poisoning: review and quiz
March 6, 2013, 7:18 pm
Mercury: What’s In It For Kids? Baum CR. Clin Pediatr Emerg Med 2012 Dec;13:324-330.
Mercury toxicity is always a confusing subject, what with the different types — elemental, inorganic, organic — and uncertainties regarding the value of serum and urine mercury levels, as well as indications for chelation and what chelator to use.
This brief review does not delve deeply into the most vexing questions regarding mercury, but does provide a good summary of the 3 species and clinical presentation. Based on this article, the following is a quiz about the medical toxicology of mercury.
Elemental mercury, such as that found in old-fashioned thermometers, is the only common metal that is liquid a room temperature. If ingested, it is not absorbed by the GI tract. However if vaporized — as can happen if a significant spill is vacuumed up — in can be absorbed through the lungs. Elemental mercury, being inert, does not bind covalently to cellular components or enzymes. However, in the body, elemental mercury (Hg0) is oxidized to Hg2+ which has toxicity similar to that of inorganic mercury.
Toxicity presents with gastrointestinal, dermatologic, and neuropsychiatric symptoms. Headache, abdominal pain, cough and fever may be misdiagnosed as an infection. Diaphoresis, itching, and scaling of hands and feet are common. The syndrome of erethism includes neuropsychiatric symptoms such as irritability, shyness, social withdrawal, and tremor.
You don’t — it’s a job for environmental professionals. The area should be evacuated and ventilated, and the local poison control center contacted. The U.S. Environmental Protection Agency has posted guidelines for actions to take in case of spills.
Inorganic mercury can be found in certain cosmetic and traditional medications, as well as skin whiteners since it inhibits melanin production. It also is in some dyes, explosives, and laboratory reagents.
Since mercury salts are highly corrosive, acute ingestion produces oropharyngeal and abdominal pain, vomiting and diarrhea, hemorrhagic gastritis, and hypovolemic shock. Chronic exposure produces GI distress, diaphoresis, sympathetic overdrive, renal failure, and erethism. (Click on the question to reveal the answer.)
[Photograph of elemental mercury from wikipedia.org]