CERES i
|

_ Respirologist says that asthma

worsens with exposure to dust

f you develop cedar dust asthma and seek a

Workers Compensation claim in British Co-

lumbia, chances are that you will have a visit

with Dr. Moira Yeung. She is the foremost ex-

pert on the disease who works as a respirolo-

gist in the University of British Columbia’s
Department of Medicine.

Dr. Yeung is also a researcher and an expert on
occupational lung disease who has over 20 years
of experience in studying and treating those with
cedar dust asthma.

“I see a lot of patients,” says Dr. Yeung, who
over the past two decades has seen over 700 peo-
ple with cedar dust asthma. “Not everybody who is
exposed to cedar dust is affected but I must em-
phasize that it has an awful lot to do with the de-
gree of exposure.”

The higher the exposure to cedar dust, the more
likely the individual will develop asthma. But if
there is no exposure, there is no asthma.

The asthmatic reaction to cedar dust can include
coughing, chest tightness constriction of the
bronchial tubes leading to difficulties in breathing.

; The body responds in an allergic way to the presence

f plicatic acid which is found in western red cedar.

The name for plicatic acid is actually taken from
the latin specie name for western red cedar (thuja
plicata). The acid has also been found in eastern
white cedar but is not found in other wood species
such a fir, pine, spruce, hemlock and balsam.

Can an individual off the street just walk in and
get a cedar dust asthma attack? The answer is no.
There has to be repeated exposure before an indi-
vidual becomes “sensitized” to the allergen and
then the body responds.

“Once you develop a sensitivity to something,
there is a lot of allergic inflammation of the air-
ways,” says the Doctor.

Smooth muscle contraction of the bronchial
tubes and diffuse inflammation, redness and
swelling along the lining of the bronchial tubes
will narrow the lumen and make breathing very
difficult.

About 50% of those who ever develop the dis-
ease will do so within the first two years. But there
are workers who will take 10-20 years or more to
become sensitized and develop allergic reaction.”

“Once the individual develops the disease, they
will get progressively worse if they continue to be
exposed,” says Dr. Yeung. “In the beginning it is
very difficult to recognize the relationship because
they don’t have a problem immediately when they
go to work.”

But Dr. Yeung says that at the onset of the dis-
ease, symptoms are often present after a worker
goes home at the end of the day.

It is very important to report symptoms early
because all the studies show that occupational
asthma detected early and removed from the job
site early, will bring complete recovery.

“If the individual is removed as soon as they
have a problem, then it is likely that they will re-
cover,” she says. “But if they have symptoms for
several years before they leave the industry, they
don’t recover.”

An interesting fact about the disease is pointed
out by Doctor Yeung.

“Ninety-five percent of patients with cedar dust
asthma never have asthma before they enter the
industry, then after being exposed for a period of
time they have difficulties in breathing.”

TESTING PROCEDURE

To test whether or not a patient has cedar dust
asthma, Dr. Yeung gives them an aerosol contain-
ing an extract of western red cedar containing pli-
catic acid. This is called a “challenge test.”

After waiting a while the patient is tested on a
respirometer. Then an accurate reading on lung
function can be taken.

“We can distinguish, by giving plicatic acid in
small doses, if the individual has been sensitized
to cedar dust,” say Dr. Yeung. “The test is very
straightforward.”

WORKERS’ COMPENSATION

If the Workers Compensation Board suspects an
individual has cedar dust asthma, they will send
that person to Dr. Yeung. After diagnosis the Dr.
will make recommendations to the WCB.

Unfortunately, as Dr. Yeung points out, the WCB
does not have a clear policy on how to deal with
these patients. Recognition of a claim doesn’t
mean that the worker will benefit from it, she says.

Most of the time workers have to go back to
work in the same situation as before.

“What I would like to see is that once the condi-
tion is recognized, that the subject can be re-
trained for another job.

Even though Dr. Yeung has made repeated sub-
missions to the WCB over the years, she feels that
the Board is not tackling the problem of those
with cedar dust asthma in a progressive way.

Although workers often go back with some drug
treatment to alleviate the symptoms and are given
some personal protective equipment, the asthma
will not go away and oftern gets worse.

Masks and medication are not good treatment
she says.

“I don’t think that anyone should have to take
treatment in order to work,” she adds.

She also points to the fact that personal protec-
tive equipment such as the Racal respirator appa-
ratus, is very-difficult to wear, especially for those
who are not in more stationary positions.

It is tough for a millwright or an electrician to
wear a breathing helmet and power pack when
trying to work in many cramped work spaces.

Asthma is a reversible condition. With good
treatment, lung function can return to normal.

¢ Many workers elect to wear dust masks to filter
out the small particles.

“When this happens the WCB will then say there
is no disability,” say Dr. Yeung. “But that is often
really not the case.

NEW GUIDELINES

Dr. Yeung, who has chaired a group of experts
of the American Thoracic Socity (ATA) says that
new guidelines have to be set up for assessing
claims because although a person can have normal
lung function with medication, there may be side-
effects from medications that are not being taken
into consideration during evaluations. Moreover
the individuals’ bronchial tubes may still be quite
irritable and it is difficult for them to find jobs
with no exposure to irritants.

The new ATS guidelines also look at the type of
medications and how they being taken in addition
to examining how irritable the bronchial tubes of
the patient are.

Then an overall score, which will determine
grades of impairment, is calculated from the pa-
tient’s lung function, irritability result, and reac-
tion to medication.

These ATA guidelines, developed in 1993, for as-
sessing occupational asthma are now used in the
provinces of Ontario, and Quebec. They are also
used in various U.S. states such as Iowa, Califor-
nia, New York, and Washington.

ALTERNATIVE EMPLOYMENT

If a worker gets cedar dust asthma, they can ei-
ther find another job or go back to the same place
with personal protective equipment and possibly
medication.

In these days of high unemployment in the for-
est industry, it is hard to find another job which
has the same pay and benefits. For those with less
formal education or English language skills, find-
ing a new job at the same level can be even
tougher. So only some people who get cedar asth-
ma may come forward.

“Im sure that a lot of incidences of occupational
asthma are unreported,” says Dr., Yeung.

She says that she see a disproportionate number
of patients from small shake and shingle mills
which tend to have poorer ventilation systems and
high concentrations of cedar dust.

Many of the smaller operations are also non-
union and tend to have occupational health and
safety committees which are less active or non-
functional.

Dr. Yeung recommends that health and safety
committees be aware of the hazards of cedar dust.

“The uniqueness of cedar dust asthma is that
you are not losing an arm or a leg that people can
see,” she comments. “But the disease can be ex-
tremely debilitating.”

LUMBERWORKER/JUNE, 1995/9