SAN DIEGO – The first step in determining whether a patient has been exposed to a toxic substance is to conduct a thorough history, according to Dr. Peter J. Ziemkowski.
"First, get a good employment history," he advised at the annual meeting of the American Academy of Family Physicians. "You want to look at their current job, their longest-held jobs in the past, and any other significant jobs you can identify. Try to identify any exposure types they’ve had. You also have to figure out the time. Some things can present acutely. Other can have a long latency before their presentation."
A question to pose to patients is, Do you have any concerns about any exposure to hazards at work or home? "You want to identify if the chief complaint they’re coming in for had some relation to the exposure they’re concerned about, and any other specific triggers, such as symptoms of unknown etiology," said Dr. Ziemkowski of the department of family and community medicine at Western Michigan University, Kalamazoo.
Dr. Peter Ziemkowski
It’s also important to ask patients about their potential exposure to toxic substances from a nonoccupational standpoint. "We’re talking about exposures from hobbies, such as photographers who did their own darkroom work and were exposed to solvents," Dr. Ziemkowski explained. "Digital photography has actually removed some of those hazards. Other risks come with hobbies such as ceramics. The kilns themselves can produce carbon monoxide. Also, painters can be exposed to arsenic, cadmium, lead, chromium, and mercury," he added.
According to the Bureau of Labor Statistics, approximately 3.5 million nonfatal occupational illnesses and injuries occurred in the United States in 2011. "That required millions of dollars in required time off and work restrictions," said Dr. Ziemkowski.
He also noted several case reports of exposure to methylene chloride, which is used in many industrial processes and in products such as paint strippers and degreasers. "Methylene chloride in these solvents is rapidly metabolized to products including carbon monoxide, which can cause headaches and can precipitate cardiac arrest in susceptible patients," he said. "When they say to use these products in a well-ventilated area, they mean it!"
In addition, patients who work around certain metal products, fiberglass, epoxy, and resin "can get terrible skin reactions. Sometimes the time relation can be fairly distant," he noted.
Patients with a history of exposure to asbestos "really need a full physical exam," Dr. Ziemkowski said. For them, and other patients who present with symptoms potentially linked to a toxic substance, order lab and imaging tests that are specific to the condition. "You certainly have to consider the latency in terms of what you order," he said.
Dr. Ziemkowski recommended several resources for clinicians, including the Centers for Disease Control and Prevention’s Agency for Toxic Substances and Disease Registry, the National Center for Environmental Health, the National Institute for Occupational Safety and Health, and the Occupational Safety and Health Administration. Other organizations dedicated to the topic include the American College of Occupational and Environmental Medicine and the Association of Occupational and Environmental Clinics.
Dr. Ziemkowski said he had no relevant financial conflicts to disclose.