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Asbestosis is long-term
inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
and
scarring A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a na ...
of the
lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
s due to
asbestos fibers Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
. Symptoms may include
shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing disc ...
, cough,
wheezing A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...
, and
chest tightness Chest pain is pain or discomfort in the chest, typically the front of the chest. It may be described as sharp, dull, pressure, heaviness or squeezing. Associated symptoms may include pain in the shoulder, arm, upper abdomen, or jaw, along with n ...
. Complications may include
lung cancer Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissue (biology), tissues of the lung. Lung carcinomas derive from tran ...
,
mesothelioma Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The most common area affected is the lining of the lungs and chest wall. Less commonly the lining ...
, and
pulmonary heart disease Pulmonary heart disease, also known as cor pulmonale, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance (such as from pulmonic stenosis) or high blood pressure in the lungs. Chronic ...
. Asbestosis is caused by breathing in asbestos fibers. It requires a relatively large exposure over a long period of time, which typically only occur in those who directly work with asbestos. All types of asbestos fibers are associated with an increased risk. It is generally recommended that currently existing and undamaged asbestos be left undisturbed. Diagnosis is based upon a history of exposure together with
medical imaging Medical imaging is the technique and process of imaging the interior of a body for clinical analysis and medical intervention, as well as visual representation of the function of some organs or tissues (physiology). Medical imaging seeks to rev ...
. Asbestosis is a type of
interstitial pulmonary fibrosis Pulmonary fibrosis is a condition in which the lungs become scarred over time. Symptoms include shortness of breath, a dry cough, feeling tired, weight loss, and nail clubbing. Complications may include pulmonary hypertension, respiratory failu ...
. There is no specific treatment. Recommendations may include
influenza vaccination Influenza vaccines, also known as flu shots, are vaccines that protect against infection by influenza viruses. New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes. While their effectiveness varies fro ...
,
pneumococcal vaccination Pneumococcal vaccines are vaccines against the bacterium ''Streptococcus pneumoniae''. Their use can prevent some cases of pneumonia, meningitis, and sepsis. There are two types of pneumococcal vaccines: conjugate vaccines and polysaccharide va ...
,
oxygen therapy Oxygen therapy, also known as supplemental oxygen, is the use of oxygen as medical treatment. Acute indications for therapy include hypoxemia (low blood oxygen levels), carbon monoxide toxicity and cluster headache. It may also be prophylactica ...
, and stopping
smoking Smoking is a practice in which a substance is burned and the resulting smoke is typically breathed in to be tasted and absorbed into the bloodstream. Most commonly, the substance used is the dried leaves of the tobacco plant, which have bee ...
. Asbestosis affected about 157,000 people and resulted in 3,600 deaths in 2015. Asbestos use has been banned in a number of countries in an effort to prevent disease. Statistics from the UK's Health and Safety Executive showed that in 2019, there were 490 asbestosis deaths.


Signs and symptoms

The signs and symptoms of asbestosis typically manifest after a significant amount of time has passed following asbestos exposure, often several decades under current conditions in the US. The primary symptom of asbestosis is generally the slow onset of
shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing disc ...
, especially with physical activity. Clinically advanced cases of asbestosis may lead to
respiratory failure Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a rise ...
. When a stethoscope is used to listen to the lungs of a person with asbestosis, they may hear inspiratory "crackles". The characteristic pulmonary function finding in asbestosis is a restrictive ventilatory defect. This manifests as a reduction in lung volumes, particularly the
vital capacity Vital capacity (VC) is the maximum amount of air a person can inhale after a maximum exhalation. It is equal to the sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume. It is approximately equal to Forced Vital Capacity ( ...
(VC) and
total lung capacity Lung volumes and lung capacities refer to the volume of air in the lungs at different phases of the respiratory cycle. The average total lung capacity of an adult human male is about 6 litres of air. Tidal breathing is normal, resting breathin ...
(TLC). The TLC may be reduced through alveolar wall thickening; however, this is not always the case. Large airway function, as reflected by FEV1/FVC, is generally well preserved. In severe cases, the drastic reduction in lung function due to the stiffening of the lungs and reduced TLC may induce right-sided heart failure (
cor pulmonale Pulmonary heart disease, also known as cor pulmonale, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance (such as from pulmonic stenosis) or high blood pressure in the lungs. Chronic ...
). In addition to a restrictive defect, asbestosis may produce reduction in diffusion capacity and a low amount of oxygen in the blood of the arteries.


Cause

The cause of asbestosis is the
inhalation Inhalation (or Inspiration) happens when air or other gases enter the lungs. Inhalation of air Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...
of microscopic
asbestos Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
mineral fibers suspended in the air. In the 1930s, E. R. A. Merewether found that greater exposure resulted in greater risk.


Pathogenesis

Asbestosis is the scarring of lung tissue (beginning around terminal
bronchiole The bronchioles or bronchioli (pronounced ''bron-kee-oh-lee'') are the smaller branches of the bronchial airways in the lower respiratory tract. They include the terminal bronchioles, and finally the respiratory bronchioles that mark the start o ...
s and
alveolar duct A pulmonary alveolus (plural: alveoli, from Latin ''alveolus'', "little cavity"), also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where oxygen is exchanged for carbon dioxide. Al ...
s and extending into the alveolar walls) resulting from the inhalation of
asbestos Asbestos () is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic "fibrils" that can be released into the atmosphere b ...
fibers. There are two types of fibers: amphibole (thin and straight) and serpentine (curly). All forms of asbestos fibers are responsible for human disease as they are able to penetrate deeply into the lungs. When such fibers reach the alveoli (air sacs) in the lung, where oxygen is transferred into the blood, the foreign bodies (asbestos fibers) cause the activation of the lungs' local
immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...
and provoke an inflammatory reaction dominated by lung macrophages that respond to chemotactic factors activated by the fibers. This inflammatory reaction can be described as chronic rather than acute, with a slow ongoing progression of the immune system attempting to eliminate the foreign fibers.
Macrophage Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cel ...
s
phagocytose Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is ca ...
(ingest) the fibers and stimulate
fibroblast A fibroblast is a type of cell (biology), biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound ...
s to deposit connective tissue. Due to the asbestos fibers' natural resistance to digestion, some macrophages are killed and others release inflammatory chemical signals, attracting further lung macrophages and fibrolastic cells that synthesize fibrous scar tissue, which eventually becomes diffuse and can progress in heavily exposed individuals. This tissue can be seen microscopically soon after exposure in animal models. Some asbestos fibers become layered by an iron-containing proteinaceous material (
ferruginous body A ferruginous body is a histopathologic finding in interstitial lung disease suggestive of significant asbestos exposure (asbestosis). Asbestos exposure is associated with occupations such as shipbuilding, roofing, plumbing, and construction. T ...
) in cases of heavy exposure where about 10% of the fibers become coated. Most inhaled asbestos fibers remain uncoated. About 20% of the inhaled fibers are transported by cytoskeletal components of the alveolar epithelium to the interstitial compartment of the lung where they interact with macrophages and mesenchymal cells. The cytokines, transforming growth factor beta and tumor necrosis factor alpha, appear to play major roles in the development of scarring inasmuch as the process can be blocked in animal models by preventing the expression of the growth factors. The result is fibrosis in the interstitial space, thus asbestosis. This fibrotic scarring causes alveolar walls to thicken, which reduces elasticity and gas diffusion, reducing oxygen transfer to the blood as well as the removal of
carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
. This can result in shortness of breath, a common symptom exhibited by individuals with asbestosis. Those with asbestosis may be more vulnerable to tumor growth (mesothelioma) because asbestos decreases the cytotoxicity of natural killer cells and impairs the functioning of T helper cells, which detect abnormal cell growth.


Diagnosis

According to the
American Thoracic Society The American Thoracic Society (ATS) is a nonprofit organization focused on improving care for pulmonary diseases, critical illnesses and sleep-related breathing disorders. It was established in 1905 as the American Sanatorium Association, and ch ...
(ATS), the general diagnostic criteria for asbestosis are: * Evidence of structural pathology consistent with asbestosis, as documented by imaging or histology * Evidence of causation by asbestos as documented by the occupational and environmental history, markers of exposure (usually pleural plaques), recovery of asbestos bodies, or other means * Exclusion of alternative plausible causes for the findings The abnormal chest x-ray and its interpretation remain the most important factors in establishing the presence of pulmonary fibrosis. The findings usually appear as small, irregular parenchymal opacities, primarily in the lung bases. Using the
ILO Classification The ILO International Classification of Radiographs of Pneumoconioses is a system of classifying chest radiographs (X-rays) for persons with a (or, rarely, more than one) form of pneumoconiosis. The intent is to provide a standardized, uniform metho ...
system, "s", "t", and/or "u" opacities predominate. CT or high-resolution CT (HRCT) are more sensitive than plain radiography at detecting pulmonary fibrosis (as well as any underlying pleural changes). More than 50% of people affected with asbestosis develop plaques in the
parietal pleura The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips bet ...
, the space between the chest wall and lungs. Once apparent, the radiographic findings in asbestosis may slowly progress or remain static, even in the absence of further asbestos exposure. Rapid progression suggests an alternative diagnosis. Asbestosis resembles many other diffuse interstitial lung diseases, including other
pneumoconiosis Pneumoconiosis is the general term for a class of interstitial lung disease where inhalation of dust ( for example, ash dust, lead particles, pollen grains etc) has caused interstitial fibrosis. The three most common types are asbestosis, silicos ...
. The differential diagnosis includes
idiopathic pulmonary fibrosis Idiopathic pulmonary fibrosis (IPF), or (formerly) fibrosing alveolitis, is a rare, progressive illness of the respiratory system, characterized by the thickening and stiffening of lung tissue, associated with the formation of scar tissue. It is ...
(IPF),
hypersensitivity pneumonitis Hypersensitivity pneumonitis (HP) or extrinsic allergic alveolitis (EAA) is a syndrome caused by the repetitive inhalation of antigens from the environment in susceptible or sensitized people. Common antigens include molds, bacteria, bird dropping ...
,
sarcoidosis Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly af ...
, and others. The presence of pleural plaques may provide supportive evidence of causation by asbestos. Although lung biopsy is usually not necessary, the presence of asbestos bodies in association with pulmonary fibrosis establishes the diagnosis. Conversely, interstitial pulmonary fibrosis in the absence of asbestos bodies is most likely not asbestosis. Asbestos bodies in the absence of fibrosis indicate exposure, not disease. Image:Asbestos effect.jpg, Figure A shows the location of the lungs, airways, pleura, and diaphragm in the body. Figure B shows lungs with asbestos-related diseases, including pleural plaque, lung cancer, asbestosis, plaque on the diaphragm, and mesothelioma. Image:Asbestosis (7468458838).jpg, Extensive fibrosis of pleura and lung parenchyma. Image:Asbestosis - Asbestos body (7468457368).jpg, The arrow points to an uncoated segment of asbestos fiber in this ferruginous body. Image:Asbestosis - Pleural fibrosis & calcification (7468458058).jpg, Severe pleural fibrosis with focal calcification. Image:Asbestosis and non-small cell lung carcinoma, NOS (7469998482).jpg, The black arrows point to ferrugionous bodies that are located at the periphery of a focus of non-small cell lung carcinoma, NOS. File:Asbestosis_2.jpg, 61 yr old working industrially with asbestos for decades.


Treatment

There is no cure available for asbestosis.
Oxygen therapy Oxygen therapy, also known as supplemental oxygen, is the use of oxygen as medical treatment. Acute indications for therapy include hypoxemia (low blood oxygen levels), carbon monoxide toxicity and cluster headache. It may also be prophylactica ...
at home is often necessary to relieve the shortness of breath and correct underlying low blood oxygen levels. Supportive treatment of symptoms includes respiratory
physiotherapy Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, patient ...
to remove secretions from the lungs by postural drainage, chest percussion, and vibration. Nebulized medications may be prescribed in order to loosen secretions or treat underlying
chronic obstructive pulmonary disease Chronic obstructive pulmonary disease (COPD) is a type of progressive lung disease characterized by long-term respiratory symptoms and airflow limitation. The main symptoms include shortness of breath and a cough, which may or may not produce ...
. Immunization against
pneumococcal pneumonia Pneumococcal pneumonia is a type of bacterial pneumonia that is caused by Streptococcus pneumoniae (pneumococcus). It is the most common bacterial pneumonia found in adults, the most common type of community-acquired pneumonia, and one of the ...
and annual
influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms ...
vaccination is administered due to increased sensitivity to the diseases. Those with asbestosis are at increased risk for certain cancers. If the person smokes, quitting the habit reduces further damage. Periodic pulmonary function tests,
chest x-rays A chest radiograph, called a chest X-ray (CXR), or chest film, is a Projectional radiography, projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most ...
, and clinical evaluations, including cancer screening/evaluations, are given to detect additional hazards.


Society and culture


Legal issues

The death of
English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ide ...
textile worker
Nellie Kershaw Nellie Kershaw (c. 1891 – 14 March 1924) was an English textile worker from Rochdale, Lancashire. Her death due to pulmonary asbestosis was the first such case to be described in medical literature, and the first published account of disease att ...
in 1924 from pulmonary asbestosis was the first case to be described in medical literature, and the first published account of disease attributed to occupational asbestos exposure. However, her former employers (Turner Brothers Asbestos) denied that asbestosis even existed because the medical condition was not officially recognised at the time. As a result, they accepted no liability for her injuries and paid no compensation, either to Kershaw during her final illness or to her family after her death. Even so, the findings of the
inquest An inquest is a judicial inquiry in common law jurisdictions, particularly one held to determine the cause of a person's death. Conducted by a judge, jury, or government official, an inquest may or may not require an autopsy carried out by a coro ...
into her death were highly influential insofar as they led to a parliamentary enquiry by the
British Parliament The Parliament of the United Kingdom is the supreme legislative body of the United Kingdom, the Crown Dependencies and the British Overseas Territories. It meets at the Palace of Westminster, London. It alone possesses legislative supremacy ...
. The enquiry formally acknowledged the existence of asbestosis, recognised that it was hazardous to health and concluded that it was irrefutably linked to the prolonged inhalation of asbestos dust. Having established the existence of asbestosis on a medical and judicial basis, the report resulted in the first Asbestos Industry Regulations being published in 1931, which came into effect on 1 March 1932. The first lawsuits against asbestos manufacturers occurred in 1929. Since then, many lawsuits have been filed against asbestos manufacturers and employers, for neglecting to implement safety measures after the link between asbestos, asbestosis and mesothelioma became known (some reports seem to place this as early as 1898 in modern times). The liability resulting from the sheer number of lawsuits and people affected has reached billions of U.S. dollars. The amounts and method of allocating compensation have been the source of many court cases, and government attempts at resolution of existing and future cases. To date, about 100 companies have declared bankruptcy at least partially due to asbestos-related liability. In accordance with Chapter 11 and § 524(g) of the U.S. federal bankruptcy code, a company may transfer its liabilities and certain assets to an asbestos personal injury trust, which is then responsible for compensating present and future claimants. Since 1988, 60 trusts have been established to pay claims with about $37 billion in total assets. From 1988 through 2010, analysis from the United States Government Accountability Office indicates that trusts have paid about 3.3 million claims valued at about $17.5 billion.


Notable people

This is a partial list of notable people who have died from lung fibrosis associated with asbestos: *
Bernie Banton Bernard Douglas Banton AM (13 October 1946 – 27 November 2007) was an Australian social justice campaigner. He was the widely recognized face of the legal and political campaign to achieve compensation for the many sufferers of asbestos-relat ...
, social justice advocate *
Paul Gleason Paul Xavier Gleason (May 4, 1939 – May 27, 2006) was an American film and television actor. He was known for his roles on television series such as ''All My Children'' and films such as ''The Breakfast Club'', ''Trading Places'', and ''Die ...
, ''Breakfast Club'' actor *
Stephen Jay Gould Stephen Jay Gould (; September 10, 1941 – May 20, 2002) was an American paleontologist, evolutionary biologist, and historian of science. He was one of the most influential and widely read authors of popular science of his generation. Gould sp ...
, Harvard University professor, paleontologist, evolutionary biologist, and historian *
Nellie Kershaw Nellie Kershaw (c. 1891 – 14 March 1924) was an English textile worker from Rochdale, Lancashire. Her death due to pulmonary asbestosis was the first such case to be described in medical literature, and the first published account of disease att ...
, first person diagnosed with asbestos-related disease, 1924 * John MacDougall, politician *
Steve McQueen Terrence Stephen McQueen (March 24, 1930November 7, 1980) was an American actor. His antihero persona, emphasized during the height of the counterculture of the 1960s, made him a top box-office draw for his films of the late 1950s, 1960s, and 1 ...
, actor *
Theodore Sturgeon Theodore Sturgeon (; born Edward Hamilton Waldo, February 26, 1918 – May 8, 1985) was an American fiction author of primarily fantasy, science fiction and horror, as well as a critic. He wrote approximately 400 reviews and more than 120 sh ...
, writer


References


External links

* * * * * {{Authority control Asbestos Lung diseases due to external agents Pollution Occupational diseases Lung disorders Wikipedia medicine articles ready to translate