What is asbestosis?
Asbestosis is a process of lung tissue scarring caused by asbestos fibers. Because many other diseases also lead to lung scarring, other causes must be excluded first when a patient is found to have lung scarring (pulmonary fibrosis). Patients with particular x-ray findings or biopsy results must also have a remote history of asbestos exposure and a characteristically delayed development of the condition in considering asbestosis as a diagnosis. Smoking appears to increase the frequency and/or the rate of progression of asbestosis, possibly by preventing the efficient elimination of inhaled fibers from the airways.
What are symptoms and signs of asbestosis?
The clinical symptoms usually include slowly progressing shortness of breath and cough, often 20 to 40 years after exposure to asbestos. Breathlessness advances throughout the disease, even without further asbestos inhalation. In the absence of cigarette smoking, sputum (mucus coughed up from the lungs) production and wheezing are uncommon. The exception is workers who have been exposed to very high concentrations of asbestos fibers. Those workers may also develop symptoms as soon as 10 years after exposure. Other indications of asbestosis include abnormal lung sounds on examination, changes in the ends of the fingers and toes ("clubbing"), a blue tinge to the fingers or lips ("cyanosis"), and failure of the right side of the heart ("cor pulmonale").
What tests and studies are used to evaluate asbestosis?
Breathing abnormalities can be identified with lung function tests (pulmonary function tests or PFTs) or exercise tests that are performed at specialized laboratories. Asbestosis can produce both obstruction of airflow and restriction of lung inflation. In addition, the disease can affect the ability to transfer oxygen into the blood. With advanced disease, patients may have markedly reduced blood oxygen at rest and may need supplementary oxygen.
X-ray abnormalities include thickening of the lining of the lungs and tiny lines marking the lower portions of the lungs. However, up to 20% of patients have completely normal-appearing chest x-rays. These patients may demonstrate more subtle changes on computerized x-ray studies (computerized tomography, or CT scans). Up to 30% of patients with a normal chest x-ray who have been exposed to asbestos will have an abnormal high resolution (high definition) CT. The CT scan may be very useful in separating true asbestosis from other conditions that may have similar findings. However, even a CT scan may not identify disease of the lining of the lung (pleural disease) in patients with asbestosis. The proper role of CT scanning has not been fully established.
Laboratory studies may be abnormal (certain antibodies and markers of inflammation), but they do not specifically suggest asbestosis.
Occasionally, a biopsy and microscopic examination of the lung is used to diagnose asbestosis. Under microscopic examination, certain coated fibers (asbestos bodies) can be seen in association with a pattern of scarring. The amount of both coated and uncoated (transparent) asbestos has been linked to the severity of asbestosis. Because other particles may resemble asbestos, a conclusive identification may require scanning electron microscopy. Currently, detection of asbestos fibers in the lung tissue and fluids (sputum, secretions) can be used to make the diagnosis, along with a history of asbestos exposure and characteristic x-ray or CT results.
The currently available commercial form of asbestos, chrysotile, does not form asbestos bodies as easily as previously used fibers.
Asbestos Cancer - Overview
Over the course of the past century, millions of innocent people have been exposed to asbestos, a class of fibrous minerals known to cause a variety of cancers. Often referred to as "asbestos cancer," mesothelioma is the most common form of cancer caused by asbestos exposure. Other deadly forms of cancer are also caused by exposure to asbestos, such as lung cancer, gastrointestinal cancer, and colorectal cancer, just to name a few.
For many decades asbestos was considered an acceptable source of insulation, and thousands of materials made from asbestos were widely applied in industrial and domestic settings. Asbestos was found in countless products on the commercial market, in many factories, homes and public structures, and in a myriad of industries, such as railway production, shipbuilding, and energy production. For information about at-risk workplaces and products, please see Occupations at Risk for Asbestos Exposure and Products Containing Asbestos.
Of the millions of people who have been exposed to asbestos in the United States alone, thousands have developed life-threatening illnesses, many of which are aggressive cancers. Each year, approximately 10,000 Americans die from diseases caused by exposure to asbestos.
Asbestos: A natural material made up of tiny fibers which can lodge in the lungs and lead to cancer or scarring of the lungs. The cancer may be lung cancer or (mesothelioma), which is a cancer of the lining of the lungs or other internal organs. The scarring of the lungs is termed asbestosis. Exposure to asbestos usually occurs by breathing contaminated air in workplaces that make or use asbestos or in the air of buildings containing asbestos that are being torn down or renovated.
Asbestos is one of the health hazards of mining. To take a case in point, the small town of Libby, Montana was home through most of the 20th century to one of the world's largest vermiculite mines. Vermiculite, a mineral, is used in everything from insulation to animal feed to potting soil. But Libby's rich vermiculite deposit was laced with asbestos. Hundreds of miners and their families fell sick or died as a result of their exposure to the asbestos.
The following additional information is based on materials from the Agency for Toxic Substances and Disease Registry, a part of the Centers for Disease Control and Prevention (the CDC).
Asbestos is a group of six different fibrous minerals: The six minerals are amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite. They occur naturally in soil and rocks in some areas. Asbestos fibers vary in length and may be straight or curled. The fibers are resistant to heat and most chemicals.
Asbestos is used for a wide range of manufactured goods, mostly roofing shingles, ceiling and floor tiles, paper products, asbestos cement products, friction products (automobile clutch, brake, and transmission parts), textiles, packaging, gaskets, and coatings.
Asbestos mainly affects the lungs: Changes in the membrane surrounding the lung are common in workers exposed to asbestos. These lung changes are also sometimes found in people living in areas with high levels of asbestos in the air. Breathing very high levels of asbestos may result in a slow buildup of scar-like tissue in the lungs and in the membrane that surrounds the lungs. People with asbestosis have shortness of breath, often along with a cough and sometimes heart enlargement. This is chronic obstructive lung disease (COPD), a serious disease that can lead to disability or death.
Asbestos is a known carcinogen: There are two types of cancer caused by exposure to high levels of asbestos: cancer of the lung tissue itself and mesothelioma, a cancer of the membrane that surrounds the lung and other internal organs. Both of these are usually fatal. These diseases do not develop immediately, but show up only after many years.
Interactions between cigarette smoke and asbestos increase the chances of getting lung cancer. Studies of workers suggest that breathing asbestos can increase the chances of getting cancer in other parts of the body (stomach, intestines, esophagus, pancreas, kidneys), but this is not certain.
People who are exposed to lower levels of asbestos may also have an increased risk of developing cancer, but the risks are usually small and are difficult to measure.
It is not known whether ingesting (swallowing) asbestos causes cancer. Some people who had been exposed to asbestos fibers in their drinking water had higher-than-average death rates from cancer of the esophagus, stomach, and intestines. However, it isn't known whether this was caused by asbestos or by something else.
Medical tests: Chest X-rays cannot detect asbestos fibers, but can detect early signs of lung disease caused by asbestos. Other tests (lung and CAT scans), are also useful in detecting changes in the lungs.
Tests exist to measure asbestos fibers in urine, feces, mucus, or material rinsed out of the lung. However, low levels of asbestos fibers are found in these body fluids in nearly all people, so higher-than-average levels can only show that a person has been exposed to asbestos, not whether the person will experience ill health effects.
Regulations: In 1989, the US Environmental Protection Agency (EPA) banned all new uses of asbestos; uses established before this date are still allowed. The EPA has established regulations that require school systems to inspect for damaged asbestos and to eliminate or reduce the exposure by removing the asbestos or by covering it up. The EPA has set a limit of 7 million fibers per liter (MFL) as the concentration of long asbestos fibers that may be present in drinking water.
Asbestosis is a process of lung tissue scarring caused by asbestos fibers. Because many other diseases also lead to lung scarring, other causes must be excluded first when a patient is found to have lung scarring (pulmonary fibrosis). Patients with particular x-ray findings or biopsy results must also have a remote history of asbestos exposure and a characteristically delayed development of the condition in considering asbestosis as a diagnosis. Smoking appears to increase the frequency and/or the rate of progression of asbestosis, possibly by preventing the efficient elimination of inhaled fibers from the airways.
What are symptoms and signs of asbestosis?
The clinical symptoms usually include slowly progressing shortness of breath and cough, often 20 to 40 years after exposure to asbestos. Breathlessness advances throughout the disease, even without further asbestos inhalation. In the absence of cigarette smoking, sputum (mucus coughed up from the lungs) production and wheezing are uncommon. The exception is workers who have been exposed to very high concentrations of asbestos fibers. Those workers may also develop symptoms as soon as 10 years after exposure. Other indications of asbestosis include abnormal lung sounds on examination, changes in the ends of the fingers and toes ("clubbing"), a blue tinge to the fingers or lips ("cyanosis"), and failure of the right side of the heart ("cor pulmonale").
What tests and studies are used to evaluate asbestosis?
Breathing abnormalities can be identified with lung function tests (pulmonary function tests or PFTs) or exercise tests that are performed at specialized laboratories. Asbestosis can produce both obstruction of airflow and restriction of lung inflation. In addition, the disease can affect the ability to transfer oxygen into the blood. With advanced disease, patients may have markedly reduced blood oxygen at rest and may need supplementary oxygen.
X-ray abnormalities include thickening of the lining of the lungs and tiny lines marking the lower portions of the lungs. However, up to 20% of patients have completely normal-appearing chest x-rays. These patients may demonstrate more subtle changes on computerized x-ray studies (computerized tomography, or CT scans). Up to 30% of patients with a normal chest x-ray who have been exposed to asbestos will have an abnormal high resolution (high definition) CT. The CT scan may be very useful in separating true asbestosis from other conditions that may have similar findings. However, even a CT scan may not identify disease of the lining of the lung (pleural disease) in patients with asbestosis. The proper role of CT scanning has not been fully established.
Laboratory studies may be abnormal (certain antibodies and markers of inflammation), but they do not specifically suggest asbestosis.
Occasionally, a biopsy and microscopic examination of the lung is used to diagnose asbestosis. Under microscopic examination, certain coated fibers (asbestos bodies) can be seen in association with a pattern of scarring. The amount of both coated and uncoated (transparent) asbestos has been linked to the severity of asbestosis. Because other particles may resemble asbestos, a conclusive identification may require scanning electron microscopy. Currently, detection of asbestos fibers in the lung tissue and fluids (sputum, secretions) can be used to make the diagnosis, along with a history of asbestos exposure and characteristic x-ray or CT results.
The currently available commercial form of asbestos, chrysotile, does not form asbestos bodies as easily as previously used fibers.
Asbestos Cancer - Overview
Over the course of the past century, millions of innocent people have been exposed to asbestos, a class of fibrous minerals known to cause a variety of cancers. Often referred to as "asbestos cancer," mesothelioma is the most common form of cancer caused by asbestos exposure. Other deadly forms of cancer are also caused by exposure to asbestos, such as lung cancer, gastrointestinal cancer, and colorectal cancer, just to name a few.
For many decades asbestos was considered an acceptable source of insulation, and thousands of materials made from asbestos were widely applied in industrial and domestic settings. Asbestos was found in countless products on the commercial market, in many factories, homes and public structures, and in a myriad of industries, such as railway production, shipbuilding, and energy production. For information about at-risk workplaces and products, please see Occupations at Risk for Asbestos Exposure and Products Containing Asbestos.
Of the millions of people who have been exposed to asbestos in the United States alone, thousands have developed life-threatening illnesses, many of which are aggressive cancers. Each year, approximately 10,000 Americans die from diseases caused by exposure to asbestos.
Asbestos: A natural material made up of tiny fibers which can lodge in the lungs and lead to cancer or scarring of the lungs. The cancer may be lung cancer or (mesothelioma), which is a cancer of the lining of the lungs or other internal organs. The scarring of the lungs is termed asbestosis. Exposure to asbestos usually occurs by breathing contaminated air in workplaces that make or use asbestos or in the air of buildings containing asbestos that are being torn down or renovated.
Asbestos is one of the health hazards of mining. To take a case in point, the small town of Libby, Montana was home through most of the 20th century to one of the world's largest vermiculite mines. Vermiculite, a mineral, is used in everything from insulation to animal feed to potting soil. But Libby's rich vermiculite deposit was laced with asbestos. Hundreds of miners and their families fell sick or died as a result of their exposure to the asbestos.
The following additional information is based on materials from the Agency for Toxic Substances and Disease Registry, a part of the Centers for Disease Control and Prevention (the CDC).
Asbestos is a group of six different fibrous minerals: The six minerals are amosite, chrysotile, crocidolite, and the fibrous varieties of tremolite, actinolite, and anthophyllite. They occur naturally in soil and rocks in some areas. Asbestos fibers vary in length and may be straight or curled. The fibers are resistant to heat and most chemicals.
Asbestos is used for a wide range of manufactured goods, mostly roofing shingles, ceiling and floor tiles, paper products, asbestos cement products, friction products (automobile clutch, brake, and transmission parts), textiles, packaging, gaskets, and coatings.
Asbestos mainly affects the lungs: Changes in the membrane surrounding the lung are common in workers exposed to asbestos. These lung changes are also sometimes found in people living in areas with high levels of asbestos in the air. Breathing very high levels of asbestos may result in a slow buildup of scar-like tissue in the lungs and in the membrane that surrounds the lungs. People with asbestosis have shortness of breath, often along with a cough and sometimes heart enlargement. This is chronic obstructive lung disease (COPD), a serious disease that can lead to disability or death.
Asbestos is a known carcinogen: There are two types of cancer caused by exposure to high levels of asbestos: cancer of the lung tissue itself and mesothelioma, a cancer of the membrane that surrounds the lung and other internal organs. Both of these are usually fatal. These diseases do not develop immediately, but show up only after many years.
Interactions between cigarette smoke and asbestos increase the chances of getting lung cancer. Studies of workers suggest that breathing asbestos can increase the chances of getting cancer in other parts of the body (stomach, intestines, esophagus, pancreas, kidneys), but this is not certain.
People who are exposed to lower levels of asbestos may also have an increased risk of developing cancer, but the risks are usually small and are difficult to measure.
It is not known whether ingesting (swallowing) asbestos causes cancer. Some people who had been exposed to asbestos fibers in their drinking water had higher-than-average death rates from cancer of the esophagus, stomach, and intestines. However, it isn't known whether this was caused by asbestos or by something else.
Medical tests: Chest X-rays cannot detect asbestos fibers, but can detect early signs of lung disease caused by asbestos. Other tests (lung and CAT scans), are also useful in detecting changes in the lungs.
Tests exist to measure asbestos fibers in urine, feces, mucus, or material rinsed out of the lung. However, low levels of asbestos fibers are found in these body fluids in nearly all people, so higher-than-average levels can only show that a person has been exposed to asbestos, not whether the person will experience ill health effects.
Regulations: In 1989, the US Environmental Protection Agency (EPA) banned all new uses of asbestos; uses established before this date are still allowed. The EPA has established regulations that require school systems to inspect for damaged asbestos and to eliminate or reduce the exposure by removing the asbestos or by covering it up. The EPA has set a limit of 7 million fibers per liter (MFL) as the concentration of long asbestos fibers that may be present in drinking water.
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