What is Asbestosis?
Asbestosis is a chronic inflammatory lung disease that occurs due to long- term exposure to asbestos fibres .
Asbestosis is a breathing disorder caused by inhaling asbestos fibers. Prolonged accumulation of these fibers in your lungs can lead to scarring of lung tissue and diminished breathing capacity. 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).
Asbestosis particularly affects the parenchymatous tissues of the lungs and has gained increased significance due to its link to mesothelioma and to other forms of lung and laryngeal cancer. Asbestosis is also frequently associated with Chronic Obstructive Pulmonary Disease (COPD).
Asbestosis, as a medical problem, was recognized early in the 20th century. A few decades later studies established asbestosis as a predisposing factor for bronchogenic carcinoma and malignant mesothelioma. The developed countries have started recognizing the harmful effects of asbestos and have replaced it with synthetic metal fibres. Legislations have been passed globally to curtail its use in industries.
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"). Asbestosis can be a progressive disease even after exposure to asbestos has stopped.
Signs and symptoms develop when damage and scarring caused by the asbestos fibers lead to stiffness in your lung tissue so that your lungs can't contract and expand normally (a form of pulmonary fibrosis). Once exposure to asbestos is stopped, however, the fibrosis does not progress.
Some asbestosis symptoms include:
* Shortness of breath, initially only with exertion, but eventually even while resting
* Decreased tolerance for physical activity
* Coughing
* Chest pain
* Finger clubbing in some cases
Although most of these signs and symptoms are similar to those of other breathing disorders, such as asthma, the way in which they develop is different. In asbestosis the effects of the disease are insidious, occurring over months and years.
Diagnosing Asbestosis
The diagnosis of asbestosis is made when there is a history of asbestos exposure and positive results from a clinical exam. There is a well-defined latency period of approximately 20 years or more between the initial exposure to asbestos and the development of asbestos related calcification and scarring.
Asbestosis can be diagnosed by the following tests:
The severity of asbestosis is generally related to the amount and duration of exposure to asbestos. Effects of the disease may be so mild as to cause almost no symptoms. Or the condition may create such a reduced flow of oxygen as to be disabling or even fatal. Asbestosis may lead to the following conditions:
Patients with asbestosis, like others with chronic lung disease, are at a higher risk of serious infection, low oxygen levels in the blood, and heart failure. These patients also may not recover as quickly from viral and bacterial infections. In addition, they may be at increased risk for certain fungal and unusual infections that take advantage of diseased or scarred lung tissue. The medical management of these patients should focus special attention on preventing and rapidly treating these infections. Flu and pneumococcal vaccinations are a part of routine care for these patients. There is, however, no treatment or cure for asbestosis. In particular, steroid and immune-based therapies have not been shown to benefit these patients.
There's no treatment to reverse the effects of asbestos on the alveoli. Treatment focuses on preventing progression of the disease and relieving symptoms. The most important factor in keeping the condition from worsening is to eliminate exposure to asbestos. For most people, scarring of lung tissue doesn't begin or progress once exposure has ended.
The following may be components of asbestosis treatment:
© 1998-2008 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research. Terms of Use.
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"). Asbestosis can be a progressive disease even after exposure to asbestos has stopped.
Signs and symptoms develop when damage and scarring caused by the asbestos fibers lead to stiffness in your lung tissue so that your lungs can't contract and expand normally (a form of pulmonary fibrosis). Once exposure to asbestos is stopped, however, the fibrosis does not progress.
Some asbestosis symptoms include:
* Shortness of breath, initially only with exertion, but eventually even while resting
* Decreased tolerance for physical activity
* Coughing
* Chest pain
* Finger clubbing in some cases
Although most of these signs and symptoms are similar to those of other breathing disorders, such as asthma, the way in which they develop is different. In asbestosis the effects of the disease are insidious, occurring over months and years.
Diagnosing Asbestosis
The diagnosis of asbestosis is made when there is a history of asbestos exposure and positive results from a clinical exam. There is a well-defined latency period of approximately 20 years or more between the initial exposure to asbestos and the development of asbestos related calcification and scarring.
Asbestosis can be diagnosed by the following tests:
- Chest X-ray- irregular opacities in the lower lobes, heart border becomes shaggy. In the late stages of disease, there is a honey-comb likeness and volume loss. X rays can show shadows or spots on the lungs or an indistinct or shaggy outline of the heart that suggests the presence of asbestosis.
- CT scan- scarring and thickening can be seen on the chest x-ray and CT, but the CT scan can detect calcifications around the lung (typical of asbestosis) more often. It is considered the most accurate means for detecting asbestos related abnormalities.
- PFTs- pulmonary function testing is used to test for loss of lung volume, and for the impairment of movement of oxygen across the air sacs. Pulmonary function tests can be used to assess a patient's ability to inhale and exhale, and a computed tomography scan (CT) of the lungs can show flat, raised patches associated with advanced asbestosis.
- Blood tests are used to measure concentrations of oxygen and carbon dioxide.
The severity of asbestosis is generally related to the amount and duration of exposure to asbestos. Effects of the disease may be so mild as to cause almost no symptoms. Or the condition may create such a reduced flow of oxygen as to be disabling or even fatal. Asbestosis may lead to the following conditions:
- High blood pressure in your lungs. Asbestosis-related scar tissue may eventually compress or obliterate your lungs' small blood vessels, causing high blood pressure in your lungs' arteries (pulmonary hypertension).
- Heart problems. Pulmonary hypertension can lead to enlargement and failure of your heart's right ventricle (cor pulmonale). Your heart consists of four chambers — two upper chambers called atria and two lower chambers called ventricles. Your right ventricle assists in pumping oxygen-poor blood from your organs and tissues to your lungs, where your blood receives a new boost of oxygen. As your pulmonary arteries narrow, your heart's right ventricle must work harder to pump blood through the lungs. Initially, the heart tries to compensate by thickening its walls and dilating the right ventricle to increase the amount of blood it can hold. But this measure only works temporarily, and eventually — after a period of a few years — the right ventricle weakens and fails from the extra strain.
- Lung cancer. If you smoke and have asbestosis, your chances of developing lung cancer increase greatly, especially if you smoke more than a pack a day. Tobacco smoke and asbestos both contribute to each other's cancer-causing (carcinogenic) effects, so that the combination of both risk factors together is more dangerous than the effects of either risk factor alone.
- Other lung damage. Exposure to asbestos can lead to other health complications including changes in the thin membranes covering your lungs and lining your chest cavity (pleural membranes). Pleural changes may be the first signs of asbestos exposure and may include pleural thickening, the formation of calcium deposits in the pleura (plaques), and an abnormal accumulation of fluid between the membranes (pleural effusion). Pleural effusion itself is benign and doesn't increase your risk of asbestosis or malignant mesothelioma.
- Other cancer. Prolonged exposure — 20 years or more — to asbestos can also lead to malignant mesothelioma. Diagnosis and treatment of this cancer is often difficult. Malignant mesothelioma may occur even many years after exposure has stopped.
Patients with asbestosis, like others with chronic lung disease, are at a higher risk of serious infection, low oxygen levels in the blood, and heart failure. These patients also may not recover as quickly from viral and bacterial infections. In addition, they may be at increased risk for certain fungal and unusual infections that take advantage of diseased or scarred lung tissue. The medical management of these patients should focus special attention on preventing and rapidly treating these infections. Flu and pneumococcal vaccinations are a part of routine care for these patients. There is, however, no treatment or cure for asbestosis. In particular, steroid and immune-based therapies have not been shown to benefit these patients.
There's no treatment to reverse the effects of asbestos on the alveoli. Treatment focuses on preventing progression of the disease and relieving symptoms. The most important factor in keeping the condition from worsening is to eliminate exposure to asbestos. For most people, scarring of lung tissue doesn't begin or progress once exposure has ended.
The following may be components of asbestosis treatment:
- Smoking cessation. If you smoke, it's important to stop, particularly because of the extremely heightened risk of lung cancer. In addition, smoking may cause emphysema, which further reduces your lung reserves.
- Vaccinations. Because of your impaired lung condition, treat a cold or a bout of the flu promptly to avoid complications. Your doctor may advise you to receive flu and pneumonia vaccines.
- Medications. The complication of pulmonary hypertension is often treated with medications to expand or relax blood vessels, and blood-thinning medications to prevent blood clots from forming and obstructing narrowed vessels.
© 1998-2008 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research. Terms of Use.
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