Occupational
Lung DiseaseIntroduction: This group of lung diseases
is very common in industry, but is occasionally overlooked, particularly if the
person is also a smoker. There are many forms of dust at various work places,
some are organic, some inorganic (metal). In the case of exposure
to organic substances the resulting lung diseases are called "pneumonitis". Some
individuals are more sensitive than others and develop a hyperreactivity through
the production of antibodies and sensitization of immune cells to the organic
compounds, this is called "hypersensitivity pneumonitis". In the case
of exposure mainly due to nonorganic substances the
occupational lung disease is called a pneumoconiosis
and this will be discussed below.
| Occupational
lung diseases | | Name
of disease: | Description
of exposure: | | air
conditioner lung | similar to farmer's
lung, from mold spores in the air conditioner ducts |
| asbestosis
| from longterm exposure
to asbestos dust being incorporated into lung tissue |
| berylliosis | only
2% of persons, exposed to berryllium dust, get it; today mostly in aerospace industry
| | byssinosis | exposure
to cotton, hemp or flax dust causes bronchoconstriction |
| Caplan's
syndrome | coal dust
exposure in CWP patient with rheumatoid disease develops this acute nodular lung
disease | | coal
workers' pneumonitis (CWP), also called "black lung disease" | about
1 to 2% of coal mine workers exposed to coal dust develop progressive massive
fibrosis(PMF) | | exposure
to irritant gases | accidental
exposure to chlorine, sulfur dioxide, nitrogen dioxide, ammonia, hydrogen sulfide
and other gases can lead to acute lung damage | | humidifier
fever | toxins
from bacteria, fungi or amebas can cause a flu-like illness with breathing problems |
| red
cedar dust asthma | red
cedar dust can cause acute asthma and lung fibrosis in sensitized patients |
| sick
building syndrome | air-tight
buildings can cause elevated CO2 levels, aggravated by truck exhausts idling near
air vents adding noxious gases (nitrogen oxide, carbon monoxide, aldehydes and
other irritants) | | silicosis | silica
dust exposure from pottery work, from mining for silver, gold, copper, hard coal
and lead, but also from sandblasting or granite cutting etc. A late complication
is malignant mesothelioma. | Generally speaking,
the further a chemical compound can invade into the airways or lung tissue, the
more serious the tissue reaction.
It depends also on the reactivity of the chemical that intrudes and on the concentration
and length of exposure. With silicosis special clean-up cells of the lung tissue,
called "macrophages", try to engulf and inactivate the silica particles,
but fail and die off. In this process lytic enzymes are released that damage the
surrounding lung tissue leading to a fibrotic tissue reaction that narrows the
airway passages severely and leads to the end result of a nodular
lung fibrosis. A lung biopsy stained with special stains and viewed under polarized
light shows these rust colored silica
bodies. Asbestos exposure leads to a diffuse interstitial
fibrosis (=asbestosis) and can be detected due to these needle
like asbestos fibers that can be shown on iron stained histology
slides of a lung biopsy as shown here. Unfortunately very little can be done when
the damage is done after years of exposure to these substances. Prevention of
exposure to noxious substances is the key to avoiding the devastating effects
of lung fibrosis.There are some substances, which are inert.
For instance, exposure to iron oxide, tin or barium dust leads to siderosis, baritosis
and stannosis. This lung X-ray picture of a patient with siderosis
looks as if the patient should have breathing problems. However, the patient has
absolutely no symptoms and no disability as iron oxide is a substance that is
inert with no effect on lung tissue other than showing up on these diagnostic
tests. The same is true for baritosis and stannosis. Here is an overview
of a selection of common occupational lung diseases with links to sites that give
you more details regarding symptoms, diagnosis and treatment.
Signs
and symptoms: Symptoms vary from case to case and within a patient group
tend to be more symptomatic after a lengthy exposure (15 to 20 years or more)
to high concentrations of dust. At the same time symptoms are much more prominent,
if the patient has also been a heavy smoker or has had exposures to other noxious
substances that have led to chronic bronchitis or emphysema. The exposure to cigarette
smoke also predisposes the patient to lung
cancer, the symptoms of which would be overlapping. Generally speaking
shortness of breath on exertion and a chronic cough as well as a cyanotic (bluish
tinge) skin dicoloration are the
hallmarks of this patient group at the
later stages. However, a non smoker who has simple nodular silicosis, or simple
coal workers' pneumoconiosis (CWP) would not have any lung symptoms and only show
up abnormally on tests such as pulmonary function tests or X-rays. Details about
the above mentioned diseases can be found under the various links. Diagnostic
tests: A patient who is getting symptoms of coughing up phlegm and getting
short of breath when walking uphill on a slight incline where he was asymptomatic
before, needs a few screening tests done. Chest X-rays are a starting point along
with a thorough examination by a physician to check this patient out who who has
had perhaps a 20 year dust exposure working in a coal mine. Such a patient may
have this X-ray
finding of the lungs. As the findings are rather extensive, further
investigations with a CT scan and bronchoscopy have to be done by the lung specialist
to rule out lung cancer. In a case where it was thought that the patient was cured
from a previously treated tuberculosis, and who was symptom free for years, The
patient came down with new symptoms. Chest Xray, CT scan and bronchoscopy were
all done. After the biopsy material came back from the pathologist it was noted
that the patient had silico-tuberculosis. Exposure to silica dust makes the patient
much more vulneralbe to contract tuberculosis
and it is a much more chronic form of this disease. Silicosis is also associated
with malignant mesothelioma, an otherwise rare lung tumor of the pleural surfaces. Treatment:
Unfortunately there is no specific treatment for any of the occupational
lung diseases. Treatment is directed at making the patient's breathing more comfortable,
but the overall outlook (prognosis) is not changed. The most important step in
the therapy is to convince those who are still exposed to toxic substances for
the lungs, to remove this exposure. This includes a stop smoking program
and early retirement from the job that caused the disease. It may be that Workers'
Compensation is at least partially liable and depending on the jurisdiction this
may involve some possible legal action. A last resort, for those short of breath,
is using continuous oxygen
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