Pneumology

A physician who induces asthma attacks!

Pneumologist Manon Labrecque does not beat around the bush when it comes to diagnosing occupational asthma: she asks workers to take a deep, deep breath, and inhale the allergenic substance in question until they have an asthma attack. “It may seem extreme on the face of it, but it’s the only way to scientifically prove the link between asthma and the allergenic product,” explains Dr. Labrecque. “Of course, we carefully control the conditions under which the patient is exposed to the allergen, and we stop the procedure at the first sign of symptoms, that is, when the volume of air exhaled drops by 20%.”

To prove that workers are indeed affected by substances found in their workplace, this researcher runs a laboratory that is the only one of its kind in Canada, in collaboration with researchers Jean-Luc Malo, André Cartier and Catherine Lemière. Located in Montreal’s Sacré-Cœur Hospital, it includes a particle generator and a vapour generator as well as two immersion rooms where subjects are put in direct contact with the product suspected of causing their pulmonary problems. Auto-body workers have walked into these rooms with a piece of metal, a paintbrush and a can of paint in an effort to reproduce their working conditions. In general, exposure is repeated over three days, starting with five minutes, 30 minutes and then one hour.

Dr. Labrecque is currently taking part in a province-wide screening program among 4,000 workers from the car industry (those who paint or assemble) to diagnose asthma in its early stages and reduce its long-term effects. Even though the disease is recognized by the Conseil de santé et sécurité au travail (CSST), it is still difficult to diagnose. “In France and the United States, where tests such as these do not exist, workers are often severely affected by the time the occupational asthma has been diagnosed. In some cases, it’s too late. Here, we have the advantage of being able to intervene quickly.”

Labour unions see the lab at the Sacré-Coeur Hospital as a unique place designed to protect the health of their members. “When we can establish a correlation between a substance and a case of occupational asthma, the worker must be relocated,” explains Manon Labrecque. Each year, over 200 workers file into this lab.

During the Forum Express’s visit, Mario Caron was under the care of Manon Labrecque’s team. This employee of an industrial brewery, whose asthma condition has been worsening over the last 12 years, thinks he may have developed an allergy to hops. But Mr. Caron is also a welder, so his problem may stem from his exposure to metals. “We can put various substances in the particle-generator, like flour, grains and sawdust,” explains medical lab technician Julie Vallée. At his third session, Mr. Caron had still not had an induced asthma attack.

Auto-body workers and sawmill workers are not the only ones affected by occupational asthma. Our experts reported many cases of bakers who were actually allergic to flour. According to Dr. Labrecque, “Anyone who is exposed to a volatile substance on a repeated basis can develop asthma. For a baker, this could lead to a very serious situation.” Over 200 products that are present in various workplaces have been identified as potential causes of occupational asthma.