Asbestos-related disease is a lung and pleural disorder caused by inhalation of asbestos fibers. Asbestos-related illnesses include non-malignant disorders such as asbestosis, diffuse pleural thickening, pleural plaques, pleural effusions, spherical atelectasis and malignancies such as lung cancer and malignant mesothelioma.
People who work in jobs with exposure to high asbestos dust are at the highest risk of asbestos-related disease. However, asbestos exposure may also occur in workers 'homes because of the dust that accumulates in workers' clothing (occupational exposures). Asbestos-related illnesses can also occur as a result of non-occupational environmental exposures. Asbestos is extensively used in many building materials, therefore a large number of asbestos still reside in buildings built prior to restrictions on the use of asbestos applicable in many countries. Weathering and aging of such buildings can cause asbestos fragments to be released in the air and create potential hazards. Anyone who interferes with asbestos-containing materials during home care and renovation may be affected, although the risk is definitely difficult to measure.
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Pathophysiology
Asbestos fibers are inhaled into the upper and lower respiratory tracts when asbestos is released into the air. Some inhalation fibers are cleaned by mucociliary cleansing mechanisms but long thin asbestos fibers can reach the lower airways and alveoli, and can be maintained in the lungs for years. The amphibol fibers are not cleansed as effectively as serpentine and therefore accumulate more easily in the distal lung parenchyma. Asbestos fibers are recognized by the lungs as foreign objects and cause activation of the local immune system of the lung causing inflammation, cell and tissue damage. In the long run, this can lead to fibrosis, or rarely malignancy. From the lungs, some asbestos fibers (especially short fibers) can also migrate into pleural cavities and peritoneum.
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Abnormal asbestos-related pleural abnormalities include four types of pleural changes:
- pleural plaques
- Diffuse pleural thickening
- Benign asbestos pleural effusions
- Rounded atelectasis (folded lung)
Pleura seems more sensitive than the pulmonary parenchyma to the effects of asbestos fibers. Thus pleural diseases associated with asbestos can result from much lower doses than fibrotic changes in the lungs.
Pleural plaques
Pleural plaque is the most common manifestation of asbestos exposure, which affects up to 58% of workers exposed to asbestos. The prevalence among the general population exposed to the environment ranges from 0.53 to 8%. Pleural plaques are restricted areas bounded by hyaline fibrosis (thickening patches) of the parietal pleura and rarely visceral pleura that develop 20 to 40 years after the first exposure. Over time, usually over 30 years, they often become partly calcified. They consist of mature collagen fibers arranged in open-weave basket patterns and covered by flat or flat mesothelial cells. They have a shaggy white or pale yellow appearance and are usually distributed on posterolateral chest wall, diaphragm, and mediastinal pleura. The numbers and sizes vary. Pleural plaques are usually asymptomatic, but there is still some controversy about this topic. The relationship between pleural plaque and chest pain has been reported, but this has not been confirmed in more recent studies. Similarly, the relationship between pleural plaques and restrictive disorders with reduced diffuse capacity in pulmonary function tests has been described. This has not been a consistent and postulated finding that this may be linked to undetected early fibrosis. The pathogenesis of pleural plaques remains uncertain. The most likely explanation is that asbestos fibers reach the parietal pleura through a path through the lymphatic channels in which they stimulate an inflammatory reaction. Chest X-ray is a tool commonly used to diagnose pleural plaques but chest CT scans are more sensitive and specific in this regard. Pleural plaque is evidence of past asbestos exposure and shows an increased risk for the development of other asbestos-related diseases in the future. Pleural plaque itself is not pre-malignant. Individuals with pleural plaques are usually not compensated in most compensation systems.
Diffuse pleural thickening
Diffuse pleural thickening (DPT) is the unbounded fibrous thickness of the visceral pleura with an area of ​​parietal pleural obliteration and obliteration of the pleural space. This often extends to areas of the entire lobe or lung, with fibrotic areas involving costophrenic angles, apices, lung bases, and interlobar gaps. The thickness ranges from less than 1 mm to 1 cm or more and may extend up to several millimeters to the pulmonary parenchyma. The fibrous strands ("crow's feet") extending from the thickened pleura to the lung parenchyma can often be detected on CT scans. The thickening of the diffuse pleura develops 20 to 40 years after the first exposure. All types of asbestos can cause diffuse thickening of the pleura and dose related relationships have been described. It is thought that asbestos fibers that reach the pleura induce subpleural fibroblasts and mesothelial cells to produce scarring and collagen deposition, resulting in subpleural thickening. Pleural plaque is often adjacent to DPT although the latter is rare compared with pleural plaques. According to the Australian Surveillance of Workplace Based Respiratory (SABER) scheme, DPT accounts for 22% of all asbestos-related diseases. Usually begins with inflammation of the pleura accompanied by pleural effusion. Most patients complain of shortness of breath during activity, however, chest pain is also associated with this disorder. DPT has a significant impact on lung function, leading to a reduction in vital force capacity, reducing total lung capacity and spreading capacity. Restrictive disorders are a result of parietal adhesion with visceral pleura and possible diaphragmatic involvement. Medical imaging is needed for the diagnosis of diffuse pleural thickening. The appearance of postero-anterior chest radiography is an irregular continuous shadow of the pleura. In accordance with the International Labor Organization (2000) classification, diffuse pleural thickening is presumed to exist if there is a concentration of kostofrenic angle in continuity with> = 3 mm thickening of the pleura. CT scanning is more sensitive than chest radiography and can detect early pleural thickening (ie 1-2mm thickness). The most commonly used classification system defines diffuse diffuse thickening as continuous sheets of pleural thickening over 5 cm in width, more than 8 cm in craniocaudal level, and more than 3 mm in diameter. Most patients are only slightly disturbed by diffuse thickening of the pleura. Treatment options are limited but new onset or severe pain should be investigated to exclude malignancy. In most compensation systems, patients are eligible for compensation that matches the severity of disability.
Benign asbestos pleural effusions
Benign asbestos pleural effusions are exudative pleural effusions (fluid buildup between two pleural layers) after asbestos exposure. It is relatively uncommon and early manifestation of the disease after asbestos exposure, usually within 10 years of exposure. Effusions may be asymptomatic but uncommon, they can cause pain, fever, and shortness of breath. Effusions usually last for 3-4 months and then complete completely. They can also develop into diffuse thickening of the pleura. The diagnosis depends on the history of compatible asbestos exposure and the possible exclusion of other causes.
Round atelectasis
Round atelectasis (also known as Blesovsky or folded lung syndrome) develops from visceral thickened pleural infolding with parenchyma collapse of the intervention lung. It presents radiography as a mass and may be mistaken for a tumor. On the CT scan the chest appears as a rounded mass such as opacity in the peripheral lungs adjacent to the thickened pleura and with the curvilinear turbidity which is the bronchial and blood vessel (comet tail). Round atelectasis is the most common benign pleural disease associated with asbestos. Exposure to asbestos is the most likely cause today but can occur after other medical conditions. This is a chronic condition and is usually asymptomatic.
Asbestosis
Asbestosis is a chronic lung disease caused by scar tissue in the lungs, caused by prolonged exposure to asbestos. This is defined as diffuse interstitial pulmonary fibrosis due to asbestos exposure. It initially affects the lung base and usually manifests after 15 years or more of initial exposure. This occurs after high intensity and/or long-term exposure to asbestos. Asbestos-related fibrosis is progressive as it continues to develop in the lungs even if no further asbestos is inhaled. Scar tissue causes the alveolar wall to thicken, reducing the lung capacity that causes the patient to experience shortness of breath (dyspnea). Patients have an increased risk of heart failure and certain malignancies.
Malignant Mesothelioma
Malignant mesothelioma is an aggressive and incurable tumor caused by asbestos arising from the pleural mesothelial cells, the peritoneum (the lining of the abdominal cavity) and rarely elsewhere. Pleural mesothelioma is the most common type of mesothelioma, representing about 75 percent of cases. Peritoneal mesothelioma is the second most common type, consisting of about 10 to 20 percent of cases. Mesothelioma arises from 20 to 50 years after the initial exposure of asbestos. Symptoms include shortness of breath, chronic chest pain, cough, and weight loss. Diagnosing mesothelioma is often difficult and may include physical examination, chest x-ray and lung function tests, followed by CT scan and MRI. A biopsy is needed to confirm the diagnosis of malignant mesothelioma. Mesothelioma has a poor prognosis, with most patients dying within 1 year of diagnosis. Treatment strategies include surgery, radiotherapy, chemotherapy or multimodality treatment. Some tumor biomarkers (mesothelin-related proteins (SMRP), osteopontin and fibulin 3) have been evaluated for diagnostic purposes to enable early detection of this disease. New biomarkers such as volatile organic compounds measured in exhaling breath are also promising.
Asbestos can cause lung cancer that is identical to lung cancer from other causes. Asbestos exposure is associated with all major histologic types of pulmonary carcinoma (adenocarcinoma, squamous cell carcinoma, large cell carcinoma and small cell carcinoma). The latent period between exposure and development of lung cancer is 20 to 30 years. It is estimated that 3% -8% of all lung cancers are associated with asbestos. The risk of developing lung cancer depends on the level, duration, and frequency of asbestos exposure (cumulative exposure). Smoking and individual susceptibility are other factors that contribute to lung cancer. Smokers exposed to asbestos are at much greater risk of developing lung cancer. Smoking and exposure to asbestos have a multiplication effect (synergistic) on the risk of lung cancer. Symptoms include chronic cough, chest pain, shortness of breath, haemoptysis (coughing up blood), wheezing or hoarseness, weight loss and fatigue. Treatment involves surgical removal of cancer, chemotherapy, radiotherapy, or a combination of these (multimodality treatment). The prognosis is generally poor unless the cancer is detected at an early stage. Of all the patients diagnosed with lung cancer, only 15% survived for five years after diagnosis.
Medical article of asbestos disease
Thousands of scientific and medical articles have documented the human understanding of the dangers of asbestos on human life. This understanding is parallel to the growth of the industrial revolution, especially in textile and mining factories in the United Kingdom. This body of knowledge is often referred to in litigation as a state of the art or a benchmark to determine whether a company acts within the limits of negligent behavior. The following is a chronological list of some major pre-1950 scientific and medical articles relating to the medical and scientific community's knowledge of asbestos and diseases in humans:
See also
- Asbestos Disease Awareness Organization
References
Source of the article : Wikipedia
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