Heavy Metal

Toxic heavy metals can weigh down a person’s health, says Dr. Ross Myerson, medical director for occupational and environmental health at Washington Hospital Center in Northwest.

Acute conditions generally are easier to diagnose. Persons with chronic problems who are exposed to low-level contamination can manifest symptoms as they accumulate more of the metals in their bodies.

“The treatment has to be individualized for the poison and patient,” Dr. Myerson says. “Most metals can be chelated.”

Chelation therapy often is used to remove toxic heavy metals, such as arsenic, cadmium, lead or mercury, from the body. In most cases, the process can be accomplished intravenously, by mouth or through shots with the appropriate drug for the corresponding metal.

The word “chelation” comes from the Greek word “chele,” which means “to claw.” The chelating agents bind to the metals and carry them through the bloodstream to be released in the urine, Dr. Myerson says.

“Chelating basically traps the metal in a chemical complex in a form that you can excrete it,” he says. “If you have a heavy body burden, you will not rid the person of heavy metals with just one treatment.”

Removing the source of exposure from the person’s life is essential in a complete recovery, Dr. Myerson says. The origin of the problem usually is easier to determine in acute situations.

Further, chelating is not always a benign procedure, he says. Because the metals travel through the kidneys before excretion, the organs must be strong enough to endure the process. Therefore, the treatment usually is done slowly and can take repeated therapy to complete.

Unless it’s an emergency, patients should not undergo chelation therapy if they have kidney disease or damage, liver disease, a brain tumor or an underactive thyroid. In most instances, women should not use chelation therapy if they are pregnant or trying to conceive a child. In these instances, the body must excrete the metal on its own.

Several prescription drugs are used to chelate toxic metals, says Tomas Guilarte, professor of environmental health sciences at the Bloomberg School of Public Health at Johns Hopkins University in Baltimore. He holds a doctorate in environmental health sciences.

Lead has no known biological function in the body, so any amount of it can be toxic, he says. Other metals, including zinc and manganese, which are essential trace elements, are physiologically relevant. When they appear in the body in excess amounts, however, they also become poisonous.

Most patients are diagnosed for treatment through blood, hair or urine tests, but manganese toxicity can be confirmed through magnetic resonance imaging (MRI), Mr. Guilarte says. The areas where the metal is deposited appear whiter on the scan.

“If you had an exposure a year ago, it might not show up in the blood,” Mr. Guilarte says. “Elimination of manganese from the blood is much quicker than from the brain.”

In general, people who regularly work with metals, such as welders, should be tested for heavy-metal poisoning if they are feeling ill.

The effects of lead in children may not be seen until years after exposure. If lead enters 2-year-old children, even if it is chelated, the metal can lower the children’s intelligence quotient by the time they are 5 years old, says Dr. Walter Rogan, epidemiologist at the National Institute of Environmental Health Sciences at Research Triangle Park in North Carolina.

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