To My Doctor:
What Physicians Need to Know About Silicosis
in Construction, Demolition, and Renovation Workers
June 1998
This document should be filed in the medical records of:
__________________________________________________________________________
Patient's name and social security number
__________________________________________________________________________
Patient's occupation and union affiliation
Construction, Demolition, and Renovation Workers Are At Risk of Developing
Silicosis
Crystalline silica is found in materials,such as those listed
in the box to the left, which are often present during construction, demolition,
and renovation projects. When these materials are made into a fine dust by tasks
such as those listed in the box below, the inhalation and deposition of these
fine particles can produce silicosis over time.
Many construction, demolition, and renovation occupations are at risk, including:
Other occupations that do not work directly with construction materials or
tasks involving silica may be exposed as bystanders if they are in the construction,
demolition, or renovation area when crystalline silica containing materials
are being used.
Definition and Clinical Features
Silicosis
is a diffuse, nodular, interstitial pulmonary fibrosis caused by a tissue reaction
to inhaled crystalline silica dust. It can take the acute form
under conditions of intense exposure but usually takes the chronic
form, requiring several to many years to develop. People who have silicosis
have increased susceptibility to infections such as tuberculosis, complicating
the patient's prognosis. There is also increasing evidence that crystalline
silica causes cancer and that individuals with silicosis are at increased risk
of developing lung cancer.
Except in its acute form, silicosis begins with few, if any, symptoms. When
clinical symptoms of silicosis are present, they could include cough and shortness
of breath of increasing severity. On physical examination, breath sounds may
be normal or distant and, with increased severity, there may be signs of right
heart failure. Evidence of pathological response to silica exposure exists well
before symptoms occur.
Chronic reactions, occurring after 10 or more years from first
exposure, involve nodular lesions, (bilateral, multiple, rounded opacities)
often more prominent in the upper lobes. In this simple
stage of silicosis, nodules are usually small (1 cm or less). There may be little
effect on pulmonary function at this stage.
Complicated silicosis or progressive massive fibrosis
(PMF) also usually develops in the upper lobes but the nodules go on to consolidate
and exceed 1 cm and encompass blood vessels and airways. Lung function may be
severely compromised, often with a mixed restrictive/obstructive pattern, but
either pure restriction or obstruction may be seen.
Acute reactions may appear within a few weeks to two years
after the onset of massive exposure. The distinguishing feature of acute silicosis
is intraalveolar deposits, similar to those seen with alveolar proteinosis.
In contrast to the nodular fibrosis seen in the chronic form, diffuse interstitial
fibrosis is not found. Silicosis developing in less than 10 years, the accelerated
form, has been described most often in sandblasters. In these cases, diffuse
fibrosis is likely to develop and may be located throughout all lobes of the
lung.
Progression of disease and radiographic findings can continue even
after exposure has ended.
Recommended Medical Surveillance
The following are recommended by the New Jersey Department of Health and Senior
Services as a baseline before exposure, then periodically as noted:
1.Occupational history to determine years
of exposure -- update annually. Inquire about the materials used and tasks performed
listed in the boxes on pages 1 and 2. In addition, inquire about employment
in non-construction industries with silica exposure -- foundries, quarries,
mining, tile, clay, pottery, glass, and cement manufacture.
2. Medical exam emphasizing the respiratory system -- annually.
3. Chest x-ray to look for evidence of abnormality. Posteroanterior
14" x 17" or 14" x 14", classified according to the 1980
Guidelines for the Use of ILO International Classification of Radiographs
of Pneumoconiosis by a certified class "B" reader, is recommended.
The ILO system has the distinct advantage of a standardized 
set
of comparison x-ray films. Names of B-readers are available from NIOSH. Information
on how to contact NIOSH is given at the bottom of the last page. The above box
gives recommendations for the frequency of x-rays. NOTE the
potential for excessive x-rays given the multiemployer nature of construction
and other possible construction exposures like asbestos for which OSHA may require
employers to provide x-rays.
4.Pulmonary Function Tests (PFT) to look for
evidence of respiratory impairment. Should include FEV1 (forced expiratory volume
in 1 second), FVC (forced vital capacity), and DLCO (diffusion capacity of the
lungs) -- annually. All PFT should use equipment and follow recommendations
issued by the ATS (American Thoracic Society) and be administered by a technician
who has successfully completed NIOSH-certified training.
5. A baseline PPD skin test for tuberculosis because people
who have silicosis have increased susceptibility. Repeat annually if there is
x-ray evidence of silicosis (1/0 or greater profusion category using the ILO
classification) or 25 years or longer exposure.
Reporting Guidelines
Physicians, radiologists, pathologists and other health care professionals should report cases of
silicosis to the health department in their state so that it can be determined whether silica
exposures are being controlled at the workplaces where the patient has been employed. Such
reporting is mandatory in many states, including New Jersey. (In NJ, call 800-772-0062 to
report cases or for reporting forms.)
If the state has no occupational health program, cases of concern should be discussed with
NIOSH (National Institute for Occupational Safety and Health) or the local OSHA (Occupational
Safety and Health Administration) office. Information on how to contact NIOSH and OSHA is
given at the end of this bulletin.
The following elements define a case of silicosis for reporting purposes:
Because silicosis is sometimes confused with sarcoidosis, asbestosis, coal miner's
pneumoconiosis, or other pneumoconiosis it is important that all chest x-rays be reviewed by a B-reader.
Medical Management of Silicosis
There is no known medical treatment to reverse silicosis, therefore prevention is critically
important. Removal from exposure may decrease the rate of disease progression. Corticosteroids
are not useful to reduce the progression of the disease. Appropriate treatment for heart failure
and tuberculosis should be begun if these complications exist. All individuals should be strongly
advised to stop smoking and offered smoking cessation information and support. Regular follow-up exams to assess progression and possibly to screen for lung cancer should be scheduled.
Individuals who develop silicosis should be given the option of transfer to silica-free jobs. In
order for this to be a realistic alternative, the individual should be able to maintain the same rate of
pay and benefits without loss of seniority.
For Additional Information
NIOSH::e-mail -- pubstaft@niosdt1.em.cdc.gov
1-800-35-NIOSH (1-800-356-4674) or 513-533-8328, fax 513-533-8573,
Internet site -- http://www.cdc.gov/niosh/silicpag.html
OSHA: Local offices are listed in the government section of the telephone directory, usually under United States Department of Labor or the state Department of Labor.
Internet site -- http://www.osha.gov has a directory of all offices. Or, call the national office for the number of your local office: 202-219-8151.
ATS (American Thoracic Society): Adverse Effects of Crystalline Silica Exposure. American Journal Respiratory and Critical Care Medicine, 1997; 155:761-765.