Asbestos-Mesothelioma

Asbestosis

noreply@blogger.com (Unknown) — Tue, 27 Sep 2011 01:13:00 -0700

Asbestosis is a chronic inflammatory and fibrotic medical condition affecting the parenchymal tissue of the lungs caused by the inhalation and retention of asbestos fibers. It usually occurs after high intensity and/or long-term exposure to asbestos (particularly in those individuals working on the production or end-use of products containing asbestos) and is therefore regarded as an occupational lung disease. People with extensive occupational exposure to the mining, manufacturing, handling or removal of asbestos are at risk of developing asbestosis. Sufferers may experience severe dyspnea (shortness of breath) and are at an increased risk for certain malignancies, including lung cancer but especially mesothelioma. Asbestosis specifically refers to interstitial (parenchymal) fibrosis from asbestos, and not pleural fibrosis or plaquing.

Signs and symptoms

The signs and symptoms of asbestosis do not manifest until after an appreciable latency (time since first exposure), often several decades under current conditions in the US. The primary symptom of asbestosis is generally the slow onset of dyspnea, especially on exertion. Clinically advanced cases of asbestosis may lead to respiratory failure. On auscultation of the lungs, the physician may hear inspiratory rales.

The characteristic pulmonary function finding in asbestosis is a restrictive ventilatory defect. This manifests as a reduction in lung volumes, particularly the Vital Capacity (VC) and Total Lung Capacity (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 the more 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). In addition to a restrictive defect, asbestosis may produce reduction in Diffusion Capacity and arterial hypoxemia.

Pathogenesis

Asbestosis is the scarring of lung tissue (around terminal bronchioles and alveolar ducts) resulting from the inhalation of asbestos fibers. There are two types of fibers: amphibole (thin and straight) and serpentine (curved). The former are primarily 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 lung's local immune system and provoke an inflammatory reaction. This inflammatory reaction can be described as chronic rather than acute, with a slow ongoing progression of the immune system in an attempt to eliminate the foreign fibers.Macrophages phagocytose (ingest) the fibers and stimulate fibroblasts to deposit connective tissue. Due to the asbestos fibers' natural resistance to digestion, the macrophage dies off, releasing cytokines and attracting further lung macrophages and fibrolastic cells to lay down fibrous tissue, which eventually forms a fibrous mass. The result is interstitial fibrosis. The fibrotic scar tissue 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.

Diagnosis

According to the American Thoracic Society (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 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 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 pneumoconioses. The differential diagnosis includes Idiopathic Pulmonary Fibrosis (IPF), Hypersensitivity pneumonitis, sarcoidosis, and others. The presence of pleural plaquing 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.

Treatment

There is no curative treatment for asbestosis. Oxygen therapy at home is often necessary to relieve the shortness of breath and correct underlying hypoxia. Supportive treatment of symptoms includes respiratory physiotherapy 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. Immunization against pneumococcal pneumonia and annual influenza vaccination is administered due to increased sensitivity to the diseases. Patients are at increased risk for certain malignancies. If the patient smokes, cessation reduces further damage. Periodic PFTs, chest x-rays, and clinical evaluations, including cancer screening/evaluations, are given to detect additional hazards.

Legal Issues

The death of English textile worker Nellie Kershaw 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 bereaved family after she had died. Even so, the findings of the inquest into her death were highly influential insofar as they led to a parliamentary enquiry by the British Government. 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 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.

(From various sources)

The Information About Asbestosis Mesothelioma

noreply@blogger.com (Unknown) — Fri, 8 Apr 2011 22:41:00 -0700

Asbestos Litigation

If you or someone you know has an asbestosrelated disease - like asbestosis, lung cancer, or mesothelioma - then you are angry, hurt, and you probably hold the company responsible for not warning you of the dangers of asbestos. You know that either you or your loved one was exposed to asbestos fibers decades ago when it was used in a wide array of products. So now what do you do? One common course of action is to bring a lawsuit against the asbestos manufacturer.

To do that, you need an asbestos lawyer. One of the topics in this section is devoted to help you make the right decision in choosing the right asbestos lawyer for your case. You can also read about company liability and how asbestos manufacturers tried to prevent knowledge of the hazards of asbestos from reaching the public.

Asbestos Disease

The most common forms of asbestos disease are pleural plaques, asbestosis, lung cancer, and mesothelioma. Asbestosis is a chronic, prolonged lung disease that is caused by continuous inhalation of asbestosparticles. However, asbestosis is not cancerous. The second form, mesothelioma is a cancer that attacks mesothelium and is most commonly found in the lung. Mesothelioma is rare or nonexistent in non-asbestos exposed populations but is becoming more common among asbestos-exposed individuals. In the United States, there is no other known proven cause of mesothelioma other than asbestos. Unlike other forms of lung cancer, mesothelioma is a cancer of the lining of the lungs and not a cancer that occurs inside the lung. Mesothelioma causes the cells of the mesothelium to become abnormal and infinitely reproduce.

A normal mesothelium cell (or any cell for that matter) can only reproduce a certain amount of times. This keeps certain cells from invading other cells. Cancer occurs when those cells become mutated and their limits are removed, allowing them to reproduce uncontrollably. These abnormal cells then form a lump that is known as a tumor. In a benign tumor the abnormal cells do not spread into surrounding areas, but malignant tumors do have the ability to spread. If the tumor is left untreated then it may spread and destroy the neighboring tissue. Sometimes cells can even break off the original tumor and spread to other organs and tissue through the bloodstream or the lympathic system. The lympathic system is part of the immune system. It is a complex system that includes the bone marrow, the thymus and the spleen, and lymph nodes throughout the body that are connected by a network of lympathic vessels. When the cancer cells reach a new site they may continue to divide and form a new tumor, which is referred to as a secondary tumor or a metastasis.

Mesothelial cells line the chest cavity, the abdominal cavity, and the cavity around the heart. They also cover the outer surface of most internal organs. The tissue that is formed by these mesothelial cells is called mesothelium. Mesothelium helps protect the organs by producing a lubricating fluid that lets organs move around. This fluid makes it easier for the lungs to expand and move around inside the chest during breathing. The mesothelium in the chest is called the pleura and the mesothelium around the abdomen is known as the peritoneum. The mesothelium around the heart (or the pericardial cavity, a sac like space around the heart) is called the pericardium.

The asbestos disease mesothelioma has a long latency period, where it is present but not evident or active. The disease can lie dormant for ten to sixty years after being exposed to asbestos. Because of this, it is often hard to determine the cause of mesothelioma.

History of Asbestos

Asbestos has been used for more than 2,000 years. It was named by the Ancient Greeks, its name meaning "inextinguishable". The Greeks also noted its harmful biological effects. Even though the Greek geographer Strabo and the Roman naturalist Pliny the Elder both observed the "sickness of the lungs" in the slaves that wove asbestos into cloth, they were in such awe of asbestos' seemingly magical properties that they ignored the symptoms.

The Greeks used asbestos for the wicks of the eternal flames of the vestal virgins, as the funeral dress for the cremation of kings, and as napkins. It is rumored that Romans would clean asbestos napkins by throwing them in the fire. The asbestos cloth would come out of the fire whiter than it went in, so the Romans named asbestos "amiantus", meaning "unpolluted".

Use of asbestos declined during the Middle Ages, yet some say that Charlemagne had asbestos tablecloths. Marco Polo was also shown items made from asbestos cloth on his travels.

Asbestos use was brought back in the 1700s, but did not become popular until the Industrial Revolution during the late 1800s. It then began to be used as insulation for steam pipes, turbines, boilers, kilns, ovens, and other high-temperature products. Ancient observations of the health risks of asbestos were either forgotten or ignored.

At the turn of the twentieth century, researchers began to notice a large number of deaths and lung problems in asbestos mining towns. In 1917 and 1918, it was observed by several studies in the United States that asbestos workers were dying unnaturally young.

The first diagnosis of asbestosis was made in 1924. A woman had been working with asbestos since she was thirteen. She died when she was thirty-three years old, and an English doctor determined that the cause of death was what he called "asbestosis". Because of this, a study was done on asbestos workers in England. Twenty-five percent of them showed evidence of asbestos-related lung disease. Laws were passed in 1931 to increase ventilation and to make asbestosis an excusable work-related disease. It would take the United States ten more years to make these steps.

In the 1930s major medical journals began to publish articles that linked asbestos to cancer. The re-discovery of asbestos-related diseases were put on the back burner for several years due to the emergence of silicosis (a lung disease caused by silica dust inhalation). The affected workers brought $300 million in lawsuits against their employers. This served as a warning to the asbestos companies, and afterwards they tried to cover up the health effects of asbestos. Asbestos companies continued to use asbestos in manufacturing and construction. Despite that many materials, such as fiberglass insulation, were created to replace asbestos, companies that used asbestos ignored the safer alternatives. They ignored the danger for the sake of profits, much like the tobacco industry. The conduct of the asbestos companies is especially egregious, however, because the victims were largely exploited workers who were unaware of the serious health risks they were exposed to on a daily basis.

What Is Asbestos

Asbestos is the common name for any variety of silicate materials that are fibrous in structure and are more resistant to acid and fire than other materials. It has two forms, serpentine and amphibole, and is made of impure magnesium silicate. Asbestos is used for thermal insulation, fire proofing, electrical insulation, building materials, brake linings and has been used in numerous industries.

Serpentine and amphibole asbestos both exhibit physical and chemical resistance to high temperatures and applied force. The raw ore of both forms is made up of fibrous strands. The strands then continue to split into smaller and thinner fibers as disturbance continues and increases. Asbestos' ore form will initially divide into visible strands, fiber bundles, and individual fibers. But then those visible strands, bundles, and fibers will continue to split into microscopic fibers, bundles, and strands. The splitting can continue on to minute levels of microscopic levels of detection. This process is unique to asbestos and is why airborne asbestos is such a problem. The fibers can become so small that they remain airborne longer and pass undetected by the respiratory dust defenses.

Physical characteristics differentiate the serpentine and amphibole forms. Serpentines divide into curly, wavy fibers that show little resistance to being bent or spiraled. Amphibole fibers are needlelike shards that show great resistance to being bent or curled. Serpentines are like man-made wool in appearance, where amphiboles are like man-made fiberglass.

In addition to the two forms, there are three main types of asbestos: chrysotile, amosite, and crocidolite. Chrysotile asbestos is serpentine and amosite and crocidolite are amphibole. Chrysotile is the chief commercial asbestos today. Amosite is used in insulating materials and crocidolite is used for making asbestos-cement products.

Canada is a chief producer of asbestos, which has some of the largest asbestos mine fields in the world. Other producers are Russia, Zimbabwe, the Republic of South Africa, Cyprus, and the United States of America.

Asbestos is a potent carcinogen, that is, a cancer-causing substance, and is a serious health hazard. It is the known cause of pleural plaques, asbestosis, mesothelioma, and causes cancers of the lung, esophagus, and colon. Diseases caused by asbestos have a long latency period, usually taking ten to forty years before showing any symptoms of the disease. This is especially apparent today, when people who worked with installing asbestos as insulation and other materials in the 1970s are just now coming to realize that they are developing cancer at alarming rates.