Occupational Lung Disease Essay
Introduction. Occupational diseases represent a large group of nosological units, which cause great suffering and loss of capacity to earn a living among workers all over the world (International Labour Organization 4). They are widespread in any industrial country: the United States, the United Kingdom, China, India, Argentina, as well as countries of Eastern and Western Europe (International Labour Organization 5). The cost of treatment of occupational lung diseases is high. Many people working in various spheres are subjected to occupational diseases such as pneumoconiosis provoked by asbestos, silica, and coal dust, talcosis developed among workers of textile, rubber, paper, perfume, and ceramic, and other substances which elaborate dangerous toxins and harmfully affect human health while the work; OSHA standards are aimed at protecting people from having occupational diseases by means of prevention and treatment regulations directed at respiratory diseases.
Occupational hazards include vibration action, inhalation of chemicals, high gas content, impact of high or low ambient temperature, increase or decrease in atmospheric pressure, and humidity. The most common and studied are diseases associated with inhalation of dust. Dust occupational lung diseases belong to the most severe and widespread diseases among all types of occupational diseases, control of which is of great social importance. Main occupational diseases are dust pneumoconiosis, chronic bronchitis, and diseases of the upper respiratory tract. Occupational lung diseases occur in humans as a result of a sufficiently long exposure to toxic substances in the harmful environment. This happens when one or the other damaging agent exists in an inhale form that is able to penetrate the basal membrane of mucosa of the respiratory tract and deposit in the alveoli and bronchial mucosa, remaining there for a long time. Lungs may be impaired by mineral substances, organic dust particles suspended in the form of aerosols, and irritating gases.
Pneumoconiosis. Asbestos, silica, and coal dust have the most harmful effect on the respiratory tract. Pneumoconiosis is a group of chronic occupational lung diseases caused by prolonged inhalation of dust production (Cullinan and Reid 249). Pneumoconiosis is characterized by development of fibrosis (Karkhanis and Joshi), connective tissue nodules, and their conglomerates (units) in lungs and lymph nodes. Conglomerates may be necrotic, partially calcite, or disintegrate, forming a cavity. Pleura are thickened and fused and emphysematous bullas appear under the pleura. In the mucosa of nasal cavity, pharynx, larynx, trachea, and bronchi, atrophic and sclerotic changes appear, which is characteristic of pneumoconiosis and chronic bronchitis. Due to pathological changes in lungs of patients with pneumoconiosis, pulmonary ventilation is impaired, gas distribution and diffusion of oxygen in the alveoli are impaired as well, and respiratory failure develops, which is complicated by development of decompensate pulmonary heart. In addition, pneumoconiosis may be complicated with pulmonary tuberculosis.
According to the etiological basis, the following types of pneumoconiosis are distinguished (Karkhanis and Joshi 26):
Silicosis is pneumoconiosis caused by inhalation of quartz dust containing free silica, i.e. silica and its modification in the crystalline form: quartz, cristobalite, and tridymite. The highest prevalence has crystalline silica species of quartz, containing 97 – 99% of free SiO2. The quartz-bearing dust impacts the body in the process of mining as about 60% of all rocks are composed of silica.
Asbestosis is pneumoconiosis arising from inhalation of dust minerals containing silicon dioxide in a bound state with different elements: aluminum, magnesium, iron, calcium, and others (kaolinoz, asbestosis, talcosis, cement, mica, et al.).
Metallokoniozy is caused by dust pneumoconiosis metals: iron, aluminum, barium, tin, manganese, and some others (siderosis, aluminosis, baritoz, stanioz, manganokonioz, et al.).
Pneumoconiosis origins from mixed dust: a) with a high content of free silicon dioxide with more than 10%; b) with a composition free of silica or with its content of up to 10%.
Pneumoconiosis comes from organic dust: plants like byssinosis (dust cotton and linen), bagassosis (dust sugar cane), farm light (from agricultural dust containing mushrooms), synthetic (plastic dust), as well as from the effects of soot like industrial carbon.
Karbokoniozy (the cause of development is inhalation of carbon-containing dust) concerns anthracosis and grafitoz;
Hypersensitivity pneumonitis or pneumoconiosis is caused by dust inhalation of toxic and allergenic substances, including benzenes and amidoz.
Pneumoconiosis is also defined as rapid, slow, stable (non-progressive), and regressing. According to pathomorphology, pneumoconiosis is defined as interstitial, which is characterized by development of fibrosis of interstitial tissue; nodular that is characterized by presence of small rounded opacities (nodules) of 1.5-10 mm, and the one that is characterized by large, rounded, or irregular opacities (nodes).
There are several stages of development of pneumoconiosis:
Stage I is characterized by increased pulmonary pattern and deformation, presence of fibrosis, and mesh of small nodules in the middle of lungs, and seal of the roots of lungs. Pathological changes most often first appear in the lymph nodes of the roots of lungs, as well as in III-IV segments;
Stage II is characterized by formation of deformation roots, pulmonary emphysema, and a large number of small and medium-sized nodules throughout the lung parenchyma;
Stage III is characterized by marked fibrosis, presence of large knots, conglomerates, caverns, atelectasis, and bullous emphysema.
At the end of the 20th century, asbestos was used in all industrial countries at different enterprises (International Labour Organization 5). Asbestos causes asbestosis development, which leads to proliferation of connective tissue in lungs (fibrosis), increasing shortness of breath, and dry cough.
Furthermore, it can lead to isolated pleural disease and pleurisy is a risk factor for lung cancer. Its most dangerous complication is mesothelioma, which is a malignant tumor with lethal outcomes. It has been estimated that by 2029 nearly 500,000 deaths of patients with mesothelioma are expected in Western Europe (International Labour Organization 5).
Asbestosis is a specific fibro-sclerotic pulmonary disease, which develops from inhalation of dust containing silica bound with other elements (Mg, Ca, A1, Fe, and others.). Dust that causes asbestosis is present in many industries like rubber, cement, and others. Health hazard is related to mining, processing, loosening, mixing, and transporting minerals.
Asbestosis develops at a later date than silicosis and is often combined with silicosis (silikosilikatoz). Silicate dust is weaker than quartz. The most aggressive magnesium silicate dust is 3MgO 2SiO2 2H2O or chrysotile asbestos, a fibrous mineral. By inhalation of asbestos, dust in lungs leads to generalized fibrosis prevalent in a special form called asbestosis (Cullinan and Reid 250). Clinical-morphological features of the disease are determined by the structure of fibrous asbestos. Asbestos fibers are in most cases not phagocytized and are hindered by needle-like removal of lymph due to the nature of the dust. They penetrate the bronchi and injure mucous membranes, causing an inflammatory reaction. There is also a mechanical effect of asbestos dust. Asbestosis development occurs depending on concentration of dust in various periods, ranging from 3 to 11 years. Characteristic feature is presence of cells in the sputum asbestos with length of 30 – 70 mm and pale yellow fibers with a clavate extension at the ends. Clinically, asbestosis is accompanied by shortness of breath and cough, which is dry at first and then with phlegm. There are such symptoms as emphysema, chronic bronchitis, reduction in lung capacity, and changes in the cardiovascular system. There are 3 stages of asbestosis. Asbestosis is often complicated by chronic pneumonia, tuberculosis, and lung cancer.
Talcosis. Talcosis develops among workers of textile, rubber, paper, perfume, ceramic, and other industries who are in contact with talcum powder for 15 – 20 years. In case of benign talcosis, pulmonary fibrosis is interstitial and the severe stage means diffuse interstitial fibrosis with small nodular shadows (Karkhanis and Joshi 29). Talcosis is often complicated by emphysema and chronic bronchitis.
Silicosis. Silica (sand, quartz) and coal dust cause a disease, which is called silicosis. Silicosis is the most severe form of pneumoconiosis. This form of pneumoconiosis is the most common among miners of coal mines, but it is also found among other workers of the mining industry, particularly among drillers. Silicosis is revealed in ceramic, pottery, and mica production, when grinding on sandstone rocks and other works are related to generation of dust containing crystalline silica. Silicosis develops during different periods of work depending on the duration of dust exposure. Prevalence of speed and the degree of disease severity depend on working conditions, dispersion, and concentration of quartz dust. The severity of silicosis increases with increasing content in the dust-free SiO2. Silicosis of miners develops after 3 – 10 years or work and after 10 – 30 years among workers of porcelain enterprises. Currently, cases of silicosis are found mostly only among people with long working experience who have been previously exposed to high concentrations of dust.
The process of silicosis is characterized by development of nodular fibrosis, as well as proliferation of fibrous tissue along the bronchi, vessels, and around the alveoli and lobules. Pathological phenomena usually grow slowly and clinical symptoms do not always correspond to the severity of fibrosis. Thus, the main criteria of diagnosis and determination of the disease stage are radiographic changes. There are distinguished interstitial, diffuse, sclerotic, or mixed forms of nodular fibrosis. Depending on the clinical course, nature and severity of pulmonary tissue changes differ.
Development of emphysema, chronic bronchitis, and pulmonary heart is also typical for silicosis. Changes of immunological reactivity, metabolism, and disorders of the central and autonomic nervous system are also typical for silicosis. In the development process, there are stages of bronchitis with asthmatic component and bronchiectasis, but the most frequent complication of silicosis is tuberculosis. A characteristic feature of silicosis is its progression even after the person stops working in a dusty occupation. Clinically and subjectively, silicosis is characterized by shortness of breath, cough, and chest pain (Cullinan and Reid 252). Coal workers' pneumoconiosis is characterized by massive fibrosis of the lung tissue (Yang and Lin 438).
Other types of pneumoconiosis. Pneumoconiosis may also be caused by other types of dusts containing no silica: siderosis, aluminosis, apatitoz, baritoz, manganokonioz, antradoz, grafitoz, pneumoconiosis from sanding dust, and others. Metallokoniozy and karbokoniozy are developed in 15 – 20 years after the start of work in the profession. Often, there is a combination of fibrous processes and mild chronic bronchitis, which is usually the determining factor for diagnosing the disease.
Among metallokoniosis, the most notable is berylliosis (pneumoconiosis from inhaling beryllium dust and its compounds) (Karkhanis and Joshi 30), which is characterized by particular aggressiveness and manganokonioz (manganese pneumoconiosis). Manganokoniosis is developed by inhalation of aerosols and condensation, as well as disintegration of manganese and its compounds, oxides and salts of manganese found in the extraction of manganese ore, smelting of high-quality steels and alloys in arc welding, submerged arc welding, and others. The first signs of manganokoniosis appear after 4 – 5 years of work. Mangaiokoniosis, unlike berylliosis, is accompanied by a benign course, but it is also combined with chronic manganese poisoning manifested in the primary lesion of the nervous system.
Organic dust. Pneumoconiosis caused by organic dusts, i.e. byssinosis, is rare. Prolonged contact with organic dust causes a number of diseases. Byssinosis is caused by prolonged exposure to cotton dust, flax, hemp, jute workers, ginning and cotton mills, flax, and others. Dust generated during manufacturing operations involving coarse, low-grade raw materials may be contaminated with bacteria and fungi. "Lungs of farmer" appear due to the influence of moldy hay, which contains spores of fungi actinomycetes.
Cereal disease is caused by dust in working elevators. Organic dust may cause fibrosing alveolitis of lungs. Symptoms include shortness of breath with stertorous breathing as well as coughing, which appears when a patient tries to breathe in more deeply. The main symptom of clinical byssinosis is violation of bronchial patency developing under the influence of broncho-constrictive agents contained in cotton, linen, and other types of vegetable dust. In addition, fungal and bacterial contamination of organic vegetable dust is a source of protein material, which is a sensitizer. Main complaints include chest tightness, difficulty with breathing, shortness of breath after exertion, cough, and weakness. At first, these symptoms only occur when performing work after a break, which is the so-called "Monday symptom ", and later they become permanent, being complicated by persistent violations of broncho-pulmonary apparatus and cardiopulmonary failure. This lung impairment is characterized by specific radiographic changes and very early signs of respiratory failure at spirography.
Pneumoconiosis caused by mixed dusts. This type of pneumoconiosis includes electric welding pneumoconiosis, pneumoconiosis cutter, the refractory, steel makers, grinders, emery workers, and others. Electric welding pneumoconiosis develops in welders with long-term performance of work in poorly ventilated areas with a high concentration of welding aerosol containing iron oxide, manganese compounds, or fluorine. Pneumoconiosis proceeds favorably. Complaints include shortness of breath after a significant physical exertion and dry cough. Diffuse enhancement and deformation of lung pattern with numerous small focal seals are revealed. The 2nd stage of the disease includes chronic bronchitis and emphysema. In all cases of pneumoconiosis, severity of the process of pneumofibrosis depends on the structure and composition of dust exposure. For example, powdered anthracite coal is more dangerous than soft brown coal and shale.
Contacts with aerosols cause occupational asthma and obstructive bronchitis. As causes of these diseases, it is possible to define platinum salts, formaldehyde, wood dust (especially arborvitae), dandruff, and some animals on livestock farms, poultry farms, as well as grain and grain debris on the currents and elevators. Asthma symptoms include recurrent attacks of breathlessness with a difficulty of exhaling. Obstructive bronchitis manifests as cough and shortness of breath that is almost constant.
Association of Pneumoconiosis with Pulmonary Tuberculosis
Pneumoconiosis in advanced stages is often complicated by pulmonary tuberculosis (Karkhanis and Joshi 31). This combination is called konio-tuberculosis. The following types of konio-tuberculosis: silico-tuberculosis, antrako-tuberculosis, sidero-tuberculosis, and others. Given the nature of symptoms, they are treated as independent nosological forms of the disease. Koniotuberkulez is a combination of pneumoconiosis with pulmonary tuberculosis. Silicotuberculosis is a complication of silicosis with pulmonary tuberculosis. Tuberculosis is most commonly attached to silicosis of lungs. At stage I, silicosis tuberculosis joins 10-20%, at stage II – 20-60%, and at stage III – 60-80%. Tuberculosis among patients is caused by silicosis endogenous reactivation of residual changes in the lungs, hilar lymph nodes, or from exogenous superinfection. Lung lesions appear the first and then infiltrates and even cavities may emerge. Stages I and II of silicosis can be easily distinguished from tuberculosis. Silicosis is characterized by signs of respiratory failure and chronic bronchitis, it may even develop a pneumothorax, but there are no signs of tuberculosis intoxication. At stage III, lung silicosis is marked with fibrosis and conglomerates like infiltrates and cavities, which is why differential diagnosis is problematic. Silicotuberculosis is characterized by presence of calcified hilar lymph nodes. It is important to carefully collect history, in particular, to find out the length of service of a molder, miner, drifter, or sandblaster. In addition, it is difficult to diagnose early complications of silicosis tuberculosis when there is no selection of MW. If TB is attached to silicosis, patients develop persistent low-grade fever, weakness, fatigue, sweating, hot spots at the top of lungs, and increased erythrocyte sedimentation rate. In severe cases of silicotuberculosis, antituberculosis drugs are administered in combination with corticosteroids. If necessary, the therapy of chronic pulmonary heart is prescribed. Tuberculosis quite rarely complicates asbestosis in comparison with silicosis (Ross and Murray 305).
Dust bronchitis. Industrial dust can lead to development of professional bronchitis, pneumonia, asthma rhinitis, and bronchial asthma. Some dust is deposited on the mucosa of nose and bronchial tubes. Depending on the nature and concentration of dust in the air, it causes a different reaction of the nasal mucosa. Hypertrophic and atrophic rhinitis may develop.
Compounds of chromium and nickel sulfate cause ulcerative necrotic lesions of the mucous and even perforation of the nasal septum. Dust retained in the respiratory tract causes local processes like bronchitis and bronchiolitis. Dust bronchitis is the most common type of pathology. As dust reduction decreases incidence of pneumoconiosis and asthma, low concentrations of dust cause dust bronchitis. Dust bronchitis occurs by inhalation of moderately corrosive dust mixed with coarse dispersion (metal, plant, cement, etc.). The prevalence and timing of the development of the disease depend on concentration and chemical composition of dust, but as a rule bronchitis develops after 8 – 10 years of work in a relevant company. Bronchitis accompanied by allergenic dusts may result in broncho-spasm and asthma. Herbal dust from cotton, linen, and jute causes asthmatic bronchitis with exacerbations manifested after having some rest. In the future, these diseases are complicated by emphysema and pneumosclerosis.
Dust and pneumonia. Slag pneumonia occurs in the production of fertilizers among workers who have contact with wastes containing phosphorus salts. Severe pneumonia is possible with a large percentage of emphysema, which is sometimes fatal. Lipoid pneumonia occurs among workers exposed to significant concentrations of fine oil aerosols (mist).
Prevention and Treatment of Occupational Lung Diseases
Treatment of occupational lung diseases is a money-losing occurrence both for workers and their families and for the country in general. The International Labor Organization estimates that occupational diseases and accidents at enterprises result in a loss of 4% in global gross domestic product per year; as for the European Union’s costs amount annually to €145 billion (International Labour Organization 7). That is why, measures for prevention of occupational diseases should be elaborated. These programs occupy primary places in the national policy of the most industrially developed countries all over the world. These programs include different laws, which are aimed at controlling labor conditions of workers (International Labour Organization 10).
The state system of measures to combat silicosis has led to a significant improvement of working conditions and reduction of the level of dust in the air in mining, metallurgical, engineering, and other industries. As a result, there is a decreased incidence of pneumoconiosis, including the most severe kind that is silicosis (Bielowicz, Niewiadomski, and Nowak-Senderowska 63).
Based on the Occupational Health Services Convention of 1985 (No. 161), a profound national system of the Occupational Safety and Health Administration (OSHA) is essential to help employers organize good health surveillance for workers. Inspectors of the OSHA have to be informed about any case of occupational diseases in order to get adequate and true information concerning statistics of occupational diseases and to propose adequate measures for improving labor conditions of workers and preventing occasional lung diseases (International Labour Organization 10).
Implementation of modern ventilation systems and educational trainings for workers are the main principles of prevention of occupational lung diseases (Lahiri et al. 3). According to OSHA standards, employees must wear respirators. Also, the engineering control measures must be taken in order to prevent the disease development. The employer must guarantee the written program for occupational disease development, which must include the following provisions, the use of respirators, “medical evaluation of employees”, “fit testing procedures for tight-fitting respirators”, proper use of the respirators, “procedures and schedules for cleaning, disinfecting, storing, inspecting, repairing, discarding, and otherwise maintaining respirators”, “procedures to ensure adequate air quality, quantity, and flow of breathing air for atmosphere-supplying respirators”, and training of employees is regards to using the respirators (OSHA).
For verifying diagnosis of an occupational lung disease, establishing the fact of industrial dust presence is crucial. However, the diagnosis is also based on the patient's examination results, including bronchoscopy, chest CT scan, chest MRI, tests for pulmonary function investigation, and X-ray examination. Pneumoconiosis is characterized by typical features revealed during X-ray examination, chest MRI, etc. Thus, pericicatrical emphysema and bilateral irregular fibrotic masses with surrounding reticulations are the most typical symptoms of coal pneumoconiosis among miners. Presence of pleural plaques and parenchymal fibrosis are typical for asbestosis (Ross and Murray 305).
Treatment of occupational lung diseases is a rather difficult task, which is why in all developed countries particular attention is paid to prevention of these diseases and their early detection. The legislation stipulates implementation of technical and sanitary measures in enterprises with hazardous working conditions. An important role is played by preventive examination of workers that has to include medical examination, X-ray examination of lungs, and spirography.
Treatment of silicosis or any other type of pneumoconiosis may be aimed at removing industrial dust from respiratory tract, but this task is difficult and shows few positive results. Prevention of tuberculosis is essential, which is why all workers have to pass tuberculin skin test annually. In case of positive test, they have to be hospitalized and treated for mycobacterial infection (Ross and Murray 308). Smoking cessation programs are particularly essential for miners or other workers who work in conditions with prevalence of silica and other industrial dust because smoking may contribute to the severity of pneumoconisis.
Conclusion and Recommendations
In conclusion, pneumoconiosis is one of the most serious diseases, developed due to the conditions at work. Being one of the occupational diseases, pneumoconiosis is developed among a number of employees working in different spheres for many years. The problem of occupational lung disease has been raised on the national level and many countries have developed special rules and procedures aimed at protecting employees from gaining the occupational diseases and after they have already developed the one. OSHA standards have been developed in order to protect employees at their working places and to help them support their rights. The numbers of diseases employees can develop are numerous; therefore, OSHA follows the exact working conditions of employees in different organizations. Also, the procedures of prevention and treatment of the occasional diseases are regulated by different acts and standards developed by OSHA.
The further research in the sphere of occupational diseases development may be based on the practical implementation of the existing OSHA standards and linked to the companies’ standards developed. It may help see the differences and develop a new standard subjected to the particular conditions. The research may be conducted in relation to the time and length people spend in dangerous working conditions with the purpose to develop the specific rules which are going to limit the time people can occupy a specific position. The research should be linked to the healthcare and the condition of each employees, the working conditions, time people spend in the specific place, and the substances they breath. This research can help improve the existing OSHA standards and reduce the number of complications after acquiring the occupational lung diseases.