OCCUPATIONAL LUNG DISEASES - PNEUMOCONIOSES

LABORATORY DATA

Bloodwork is generally nonspecific and not useful Pulmonary function tests: Reduced lung volumes, particularly the vital capacity and total lung capacity Decreased pulmonary compliance Absence of airflow obstruction by spirometry (normal ratio of the forced expiratory volume in one second to forced vital capacity)

RADIOGRAPHIC FINDNGS

Chest roentgenogram: •Small bilateral parenchymal opacities with multinodular or reticular pattern, often with associated pleural abnormalities •Interstitial process typically begins in lower lung zones •Bilateral mid-lung zone plaques on parietal pleura •Honeycombing and upper lobe involvement develop in advanced stages of disease Hilar and mediastinal lymphadenopathy are not seen with asbestosis and should suggest presence of another process

Chronic silicosis - most common form of the disease; most blank chronic occupational disease in world Hallmark of chronic silicosis - blank The mature lesion is characterized by a central a

Chronic silicosis - most common form of the disease; most common chronic occupational disease in world Hallmark of chronic silicosis - silicotic nodule The mature lesion is characterized by a central area of whorled hyalinized collagen fibers, with a more peripheral zone of dust-laden macrophages. Silica crystals are weakly birefringent on polarization.

Three clinicopathologic types of silicosis described:

Chronic silicosis, typically follows exposure, measured in decades (10 - 30 years), to respirable dust usually containing less than 30% quartz - Most common Accelerated silicosis, follows shorter, heavier exposure (within 10 years) Acute silicosis (silicoproteinosis), follows intense exposure to fine dust of high silica content, such as that found in sandblasting industries, for periods measured in weeks to months rather than years - Rare

Coal Workers Pneumoconiosis

Coal workers' pneumoconiosis (CWP) is a distinct pathologic entity resulting from the deposition of coal dust in the lungs.

MALIGNANT MESOTHELIOMA

Diffuse lesion which spreads over pleural surface and ensheaths the lung with thick tumor Associated with pleural effusions and direct invasion of thoracic structures

ASBESTOS areas of exposure

Exposure to asbestos: •Mining and milling of the fibers •Industrial applications of asbestos: textiles, cement, friction materials, insulation, shipbuilding •Roofing, plumbing Nonoccupational exposure to airborne asbestos: •Regular exposure to soiled work clothes brought home by asbestos worker •Renovation or demolition of asbestos-containing buildings •Environmental exposure in the neighborhood of industrial sources, and natural environmental exposure to geological sources

Focal blankr emphysema, occurs within and around the coal macule; together they form characteristic lesion of CWP The coal nodule is a palpable lesion that, in addition to dust-laden macrophages and reticulin, contains a substantial number of haphazardly arranged blank blank

Focal centriacinar emphysema, occurs within and around the coal macule; together they form characteristic lesion of CWP The coal nodule is a palpable lesion that, in addition to dust-laden macrophages and reticulin, contains a substantial number of haphazardly arranged collagen fibers

Asbestos Bodies

Golden brown, fusiform or beaded rods with translucent center made of asbestos fibers coated with iron-containing proteinaceous material. Arise when macrophages (alveolar and interstitial) attempt to phagocytose asbestos fibers Once fibers are phagocytosed by macrophages release of proinflammatory factors along with fibrogenic mediators is stimulated Iron assumed to come from phagocyte ferritin

MANAGEMENT AND CONTROL Once established, the fibrotic process of chronic silicosis is thought to be irreversible. Management of the individual case is thus directed toward preventing progression and the development of complicated disease. A change in occupation to an environment free of silica-containing dust should be advised

MANAGEMENT AND CONTROL Once established, the fibrotic process of chronic silicosis is thought to be irreversible. Management of the individual case is thus directed toward preventing progression and the development of complicated disease. A change in occupation to an environment free of silica-containing dust should be advised

what fibers are seen which is an indication for mesothelioma?

Naturally occurring fibers - hydrated magnesium silicates. •Tensile strength, chemical properties suited for construction and insulation. •Asbestos fibers - two categories based on shape •Serpentine fibers - long, curly strands (eg. chrysotile) -accounts for over 90 percent of the asbestos in US -less toxic than the amphibole fibers -Because of structure (curve), serpentine fibers more likely to get impacted in upper respiratory tract and removed by mucociliary elevator •Amphibole fibers - long, straight, rod-like structures. (eg. crocidolite, amosite, tremolite, and others) •more pathogenic especially for induction of mesothelioma, because of aerodynamic properties and solubility

PATHOGENESIS

PATHOGENESIS •After inhalation, silica particles (crystalline are more fibrogenic than amorphous) are phagocytosed by macrophages • •Release of inflammatory mediators, especially IL-1 and IL-18 • •The surface characteristics of the silica particles determine their redox potential and ability to react with hydrogen, oxygen, and nitrogen. • •Freshly fractured silica, such as that generated during sandblasting, is more toxic to the alveolar macrophages than "aged" silica probably because of its increased redox potential

PLEURAL PLAQUES:

PLEURAL PLAQUES: common manifestation of asbestos exposure. Circumscribed plaques of dense collagen, often calcified; number and size do not correlate with level of asbestos exposure PLEURAL PLAQUE: HISTOLOGYdense layers of collagen; do not contain asbestos bodies, may be calcified (WebPath)

Patient with chronic silicosis may present without symptoms for assessment of an abnormal chest radiograph

Posteroanterior radiograph showing features of progressive massive fibrosis (PMF) with "eggshell" calcification of the hilar nodes, in keeping with complicated silicosis, in a man who had shoveled sand in a glass factory

Pulmonary function test:

Pulmonary function test: •Usually shows a restrictive defect in advanced disease •Features including obstruction Chronic beryllium disease •Documented exposure to beryllium •Evidence of lung disease compatible with the diagnosis •Positive Beryllium lymphocyte proliferation test (BeLPT) performed on blood or BAL fluid. http://clevelandcliniclabs.com/assets/pdfs/technical-briefs/lpt-43060.pdf

Radiographic changes may precede development of symptoms Usual finding is d In later stages of the disease, p Clinical features of chronic beryllium disease similar to those of pulmonary sarcoidosis: •Dyspnea, cough, chest pain, weight loss, fatigue, and arthralgias •Physical signs may include crackles, but signs of lung disease are often absent

Radiographic changes may precede development of symptoms Usual finding is ill-defined nodular or irregular opacities; hilar adenopathy seen in approximately 40% of cases, but usually mild In later stages of the disease, patchy fibrosis occurs with adjacent hyperinflation or distortion and extensive honeycombing Clinical features of chronic beryllium disease similar to those of pulmonary sarcoidosis: •Dyspnea, cough, chest pain, weight loss, fatigue, and arthralgias •Physical signs may include crackles, but signs of lung disease are often absent

The lung in this photo came from the autopsy of a 66-year-old coal miner. It essentially shows intensely blackened scars which microscopically reveal abundant carbon-laden macrophages with extensive fibrosis consisting of dense collagen with some areas of central necrosis. What is the best classification for this occupational lung disease (see attachment)? A. Anthracosis B. Simple coal workers pneumoconiosis C. Progressive massive fibrosis D. Hypersensitivity pneumonitis E. Idiopathic pulmonary fibrosis

Rationale: a. Incorrect - anthracosis is simply inhaled carbon pigmant engulfed by alveolar or interstitial macrophages which accumulate in the connective tissue along the lymphatics; there is no organized fibrosis or necrosis b. Incorrect - simple CWP consists of coal macules (1 to 2 mm) and coal nodules with a delicate network of collagen fibers. The massive scarring and distortion seen in this photo does not yet occur c. Correct - This photo and its description is complicated CWP which is also known as progressive massive fibrosis d. Incorrect - Hypersensitivity pneumonitis is an interstitial lung disease which is brought on by exposure to organic dusts (farmer's lungs, for example) and can be reversed when the offending antigen is removed. It is very unlikely to cause such scarring or black lungs e. Incorrect - Idiopathic pulmonary fibrosis does cause extensive fibrosis and distortion with honeycombing similar to some of these changes but it has a specific microscopic pattern known as usual interstitial pneumonia (UIP) showing temporal heterogeneity, and carbon laden macrophages and black lung are not a major finding. There is no mention of UIP in the microscopic description of this na mais direta

A 37-year-old man has respiratory problems which progressively worsen over the course of the work week and improve on the weekends and on vacation. This is most typical of: A. Asbestos exposure B. Acute silicosis C. Chronic berylliosis D. Occupational asthma E. Complicated coal workers pneumoconiosis

Rationale: a. Incorrect - asbestos exposure would not improve on weekends or vacation just because the individual would presumably be away from the source of asbestos. The asbestos fibers would already be inhaled and, despite that, asbestos exposure has a latency period of 20 to 40 years b. Incorrect - acute silicosis would not be expected to improve because the particles have already been introduced into the respiratory system; it is progressive c. Incorrect - chronic berylliosis is a chronic condition with no indication that it would improve on weekends or vacation d. Correct - Occupational asthma is the best answer because asthma is a reversible condition based on bronchial smooth muscle constriction triggered by an antigen in the work environment which would not be present on the weekends and on vacation e. Incorrect - complicated CWP is the end point of a progressive disease caused by exposure to coal dust

SILICOSIS

Silicosis is a fibrotic lung disease attributable inhalation of crystalline silica, usually in the form of quartz and, less commonly, as cristobalite and tridymite Mining, tunneling, and excavating Miner, driller, tunneler, developer, stoper Quarrying Driller, hammerer, digger Stonework Cutter, dresser, driller, polisher, grinder, mason Foundries Molder, knockout man, fettler, coremaker, caste Ceramics Workers at any stage of process if products are dry Others Glass making, boiler scaling, traditional crafts, stone grinders, gemstone workers, dental technicians, concrete reconstruction

Smoking increases •5 x increase in lung cancer (bronchogenic carcinoma) when exposed to asbestos •55 x increase in lung cancer (bronchogenic carcinoma) when exposed to asbestos and is a smoker •Increased incidence of lung cancer (bronchogenic carcinoma > mesothelioma)

Smoking increases the attack and/or progression rate of asbestosis, probably by interfering with mucociliary clearance of inhaled fibers •5 x increase in lung cancer (bronchogenic carcinoma) when exposed to asbestos •55 x increase in lung cancer (bronchogenic carcinoma) when exposed to asbestos and is a smoker •Increased incidence of lung cancer (bronchogenic carcinoma > mesothelioma)

Which of the following occupational exposure pulmonary diseases is most associated with tuberculosis? A. Silicosis B. Berylliosis C. Asbestosis D. Coal workers' pneumoconiosis E. Malignant mesothelioma

a

Development of a pneumoconiosis: A. Is not influenced by a smoking history B. Is independent of the quantity of dust in the lungs C. Is influenced by the size and shape of particles D. Occurs only by occupational exposure E. Is not affected by particle solubility

a. Incorrect. The development of a pneumoconiosis depends on the amount of dust in the lung; the size, shape, and buoyancy of the particles; the solubility of the particles; and additional effects of other irritants such as tobacco smoke. Although in most cases these diseases occur through occupational exposure, nonoccupational exposure may also lead to some pneumoconiosis. b. Incorrect. The development of a pneumoconiosis depends on the amount of dust in the lung; the size, shape, and buoyancy of the particles; the solubility of the particles; and additional effect of other irritants such as tobacco smoke. Although in most cases these diseases occur through occupational exposure, nonoccupational exposure may also lead to some pneumoconiosis. c. Correct. The development of a pneumoconiosis depends on the amount of dust in the lung; the size, shape, and buoyancy of the particles; the solubility of the particles; and additional effect of other irritants such as tobacco smoke. Although in most cases these diseases occur through occupational exposure, nonoccupational exposure may also lead to some pneumoconiosis. d. Incorrect. The development of a pneumoconiosis depends on the amount of dust in the lung; the size, shape, and buoyancy of the particles; the solubility of the particles; and additional effect of other irritants such as tobacco smoke. Although in most cases these diseases occur through occupational exposure, nonoccupational exposure may also lead to some pneumoconiosis. e. Incorrect. The development of a pneumoconiosis depends on the amount of dust in the lung; the size, shape, and buoyancy of the particles; the solubility of the particles; and additional effect of other irritants such as tobacco smoke. Although in most cases these diseases occur through occupational exposure, nonoccupational exposure may also lead to some pneumoconiosis.

PNEUMOCONIOSIS Development depends on •Amount in lungs •Size, shape, buoyancy •Solubility and physiochemical reactivity •Additional irritants (smoking) Most dangerous 1 - 5 um Macrophages ingest particles and immune system is stimulated

abnormal condition of dust in the lungs Development depends on •Amount in lungs •Size, shape, buoyancy •Solubility and physiochemical reactivity •Additional irritants (smoking) Most dangerous 1 - 5 um Macrophages ingest particles and immune system is stimulated

A 35-year-old, non-smoking coal miner who has been working for four years, has a routine physical examination. He is asymptomatic and auscultation of his lungs reveals no abnormalities bilaterally. A chest x-ray is pending. Histologically the most likely finding in his lungs would be: A. Malignant mesothelioma B. Coal macules and focal emphysema C. Progressive massive fibrosis D. Desquamative interstitial pneumonia E. Honeycomb fibrosis

b

A 58-year-old retired male construction worker has been experiencing increasing dyspnea and weight loss for several months. Chest imaging studies reveal a large mass which appears pleural based. The mass is biopsied and histologically shows a biphasic pattern of epithelioid and sarcomatoid malignant cells. Which of the following will most likely also be associated with this disease? A. Necrotizing granulomas B. Pleural plaques C. Silica nodules D. Coal macules E. Non-necrotizing granulomas

b

The lung in the attached photograph comes from the autopsy of a 65-year-old man who had progressive massive fibrosis. It shows intensely blackened scars which microscopically consisted of abundant carbon-laden macrophages with extensive fibrosis consisting of dense collagen with some areas of central necrosis. What was this man's most likely occupation? A. Pigeon breeder B. Coal miner C. Landscaper D. Ship builder E. Electrician

b

This attached microphotograph shows a nodule of concentric interlacing layers of hyalinized collagen which was present in the lung of a 60-year-old man. Microscopic polarization revealed the presence of birefringent particles (not seen here). What is most characteristic of this occupational lung disease? A. There is a direct association with the development of malignant mesothelioma B. It is thought to be associated with an increased susceptibility to tuberculosis C. The birefringent particles within the nodules represent asbestos bodies D. Necrotizing granulomas are often also present and are diagnostic of this disease E. This microscopic finding is diagnostic of sarcoidosis

b

This attached photograph shows a malignant tumor which was pleural based and encased the lung of a 63-year-old shipbuilder who died within nine months of initial diagnosis. It was most likely associated with exposure to: A. Coal dust B. Asbestos fibers C. Beryllium D. Bird droppings E. Quartz crystals

b

A 54-year-old quarryman has a chest x-ray which shows eggshell calcifications in his hilar lymph nodes. A small nodule is also discovered in his left upper lung lobe which is sampled. The nodule shows concentric layers of dense hyalinized collagen. Microscopic polarization of the nodule reveals birefringent particles. Based on these findings, what was this man most likely exposed to? A. Asbestos B. Coal C. Silica D. Beryllium E. Hay

c

Chronic beryllium disease in the lungs is most likely histologically associated with: A. Dense layers of collagen with calcification B. Concentric bundles of collagen with birefringent particles C. Non-necrotizing granulomas D. Blackened, distorted scar tissue E. Malignant mesothelioma

c

The above photomicrograph represents a histological finding in the lungs of a 68-year-old retired shipbuilder who began smoking 1 pack of cigarettes per day when he was 20 years old. Lung auscultation reveals bibasilar, fine end crackles. His pulmonary function tests are significant for reduced vital capacity and reduced total lung capacity. His chest X-ray reveals small bilateral parenchymal opacities with a reticular-nodular pattern and bilateral mid-lung zone calcified pleural plaques. Exposure to what substance is most responsible for all these findings? A. Silica B. Beryllium C. Asbestos D. Tobacco E. Coal

c

This nodule of concentric, interlacing layers of hyalinized collagen shown above was present in the lung of a 52-year-old male. Polarization revealed the presence of birefringent particles. What is this representative of: A. Necrotizing granuloma B. Non-necrotizing granuloma C. Silicotic nodule D. Coal macule E. Asbestos bodies

c

A 70-year-old retired construction worker has been experiencing progressive worsening dyspnea. Physical examination reveals peripheral edema, jugular venous distention, and bilateral clubbing of his fingers. A chest x-ray shows bilateral parenchymal opacities with a reticular nodular pattern and the presence of calcified pleural plaques. A pleural based tumor is identified. His pulmonary function tests include a reduced total lung capacity. Which of the following findings in the lung is most related to the diagnosis of this pneumoconiosis? A. Silica crystals B. Anthracotic pigment C. Asbestos bodies D. Noncaseating granulomas E. Amyloid deposition

c. Correct. The presentation and x-ray findings of pleural plaques with a likely mesothelioma (pleural based tumor) and PFTs indicating a restrictive lung disease are consistent with asbestosis. Asbestos bodies are likely to be found in the lung.

A 60 year old mason complains of shortness of breath, which has become progressively worse during the past year. A chest Xray shows small nodular shadows in both lungs. PFTs reveal a pattern consistent with restrictive lung disease. The patient subsequently develops congestive heart failure and expires. Autopsy discloses numerous small fibrotic nodules in both lungs. Histological examination of these nodules show concentric, whorling, interlacing dense, hyalinized collagen fibers with no granulomas. What is the most likely diagnosis? A. Tuberculosis B. Asbestosis C. Anthracosis D. Silicosis E. Sarcoidosis

d

A 75 year old man who had worked in a shipyard dies of chronic lung disease. Autopsy reveals extensive pulmonary fibrosis, and iron stains of lung tissue show numerous ferruginous bodies. The dome of the diaphragm shows the presence of pleural plaques. What is the most appropriate diagnosis? A. Anthracosis B. Sarcoidosis C. Tuberculosis D. Asbestosis E. Silicosis

d

An autopsy on a 60-year-old retired coal miner reveals heavily pigmented black lungs which histologically show multiple intense blackened scars greater than 2 cm. Some of these areas are confluent and large, with necrosis present in the center. His lungs also show evidence of progressive massive fibrosis. This disease process: A. Develops in over 90% of cases of simple coal workers' pneumoconiosis B. Could have been cured if the patient had lived C. Is most often present in patients who have heavy exposure to lead D. Involves the release of interleukins and tumor necrosis factor E. Most often produces confluent non-necrotizing granulomas

d

At the autopsy of a 60-year-old sandblaster who died of an acute myocardial infarction, the lungs appear fibrotic bilaterally. Histological examination reveals interstitial fibrosis and scattered nodules showing hyalinized collagen with birefringent crystals upon polarization. This is most likely to represent: A. Amyloidosis B. Sarcoidosis C. Asbestosis D. Silicosis E. Tuberculosis

d

Chronic beryllium disease

multisystem disorder characterized by noncaseating (non-necrotizing) granulomas that occur throughout the body; primary manifestation is in the lung, esp. affects upper lobes On histopath exam, chronic beryllium disease is characterized by presence of lymphocytic (helper/inducer T cell) alveolitis, as well as noncaseating epithelioid granulomas indistinguishable from those of sarcoidosis

•Accelerated silicosis, changes similar to those seen in chronic silicosis •Nodules develop •More diffuse interstitial pulmonary fibrosis may also develop •With disease progression in both chronic and accelerated silicosis, the nodules become confluent, leading to the development of •Also known as complicated silicosis

•Accelerated silicosis, changes similar to those seen in chronic silicosis •Nodules develop sooner (after 3 to 10 years of exposure), and are more cellular than fibrotic in nature. •More diffuse interstitial pulmonary fibrosis may also develop •With disease progression in both chronic and accelerated silicosis, the nodules become confluent, leading to the development of progressive massive fibrosis (PMF) •Also known as complicated silicosis

BERYLLIOSIS acute vs chronic

•Acute beryllium disease in humans: attributed to toxic, dose-related lung injury characterized by acute inflammatory reactions in the upper airways, bronchiolitis, pulmonary edema, and chemical pneumonitis. •Recovery usual, but 17% of cases progress to chronic beryllium disease •Chronic Berylliosis - First described in US in 1946 by Hardy and Tabershaw: 17 fluorescent lamp workers presented with a syndrome of advanced pulmonary granulomatous disease Occurs in industries such as metal machining, ceramics, and nuclear weapons manufacturing

ASBESTOS EXPOSURE •Asbestosis - pneumoconiosis caused by inhalation of blank blank •Characterized by slowly progressive, diffuse blank blank •Pulmonary disorders associated with asbestos exposure include: •Asbestosis •blank blank (focal and diffuse benign pleural plaques), pleural effusions •Malignancies (non-small cell and small cell carcinoma of the lung as well as malignant mesothelioma)

•Asbestosis - pneumoconiosis caused by inhalation of asbestos fibers. •Characterized by slowly progressive, diffuse pulmonary fibrosis •Pulmonary disorders associated with asbestos exposure include: •Asbestosis •Pleural disease (focal and diffuse benign pleural plaques), pleural effusions •Malignancies (non-small cell and small cell carcinoma of the lung as well as malignant mesothelioma)

•Association between silicosis and blank has long been recognized. •May be related to the fact that crystalline silica inhibits ability of pulmonary macrophages to kill phagocytosed blank •Rates for active blank in silicotic patients range from 2- to 30-fold more than those in the same workforce without silicosis •Risk for developing blank blank is doubled

•Association between silicosis and tuberculosis has long been recognized. •May be related to the fact that crystalline silica inhibits ability of pulmonary macrophages to kill phagocytosed mycobacteria •Rates for active tuberculosis in silicotic patients range from 2- to 30-fold more than those in the same workforce without silicosis •Risk for developing lung cancer is doubled

PATHOGENESIS OF ASBESTOS-INDUCED DISEASES •Direct toxic effects of fibers on pulmonary blankl cells •Release of various mediators (blanks) by inflammatory cells •Chronic deposition of fibers and persistent release of mediators lead to interstitial •Asbestos - blank initiator and promotor; effects may be mediated by reactive free radicals •Deleterious reactive oxygen and nitrogen free radicals may be formed either via reactions catalyzed by iron molecules within asbestos fibers or because of the activation of inflammatory cells •Free radicals can react with and damage cellular macromolecules disrupt DNA to give rise to malignancy

•Direct toxic effects of fibers on pulmonary parenchymal cells •Release of various mediators (reactive oxygen species, proteases, cytokines, and growth factors) by inflammatory cells •Chronic deposition of fibers and persistent release of mediators lead to interstitial pulmonary inflammation and interstitial fibrosis •Asbestos - tumor initiator and promotor; effects may be mediated by reactive free radicals •Deleterious reactive oxygen and nitrogen free radicals may be formed either via reactions catalyzed by iron molecules within asbestos fibers or because of the activation of inflammatory cells •Free radicals can react with and damage cellular macromolecules disrupt DNA to give rise to malignancy

CLINICAL FINDINGS

•Most patients asymptomatic for at least 20 to 30 years after the initial exposure •Latency period between exposure and symptoms inversely proportional to intensity of asbestos exposure •Insidious onset of breathlessness with exertion (dyspnea) •Progresses even in absence of further asbestos exposure •Bibasilar, fine end-inspiratory crackles •Clubbing •Cor pulmonale •Peripheral edema •Jugular venous distension •Hepatojugular reflux •Right ventricular heave or gallop •May lead to resp failure or death Cough, sputum production, and wheezing are unusual - if present, tend to be because of cigarette smoking rather than asbestos-induced lung disease More advanced disease can be associated with hypoxemia at rest

Complicated CWP (PMF)

•On background of simple CWP after many years •Multiple, intense blackened scars greater than 1 cm •Micro shows dense collagen and pigment; center of lesion may be necrotic because of ischemia •PMF develops in about 10% of cases of simple CWP •Leads to worsening lung function, pulmonary hypertension, and cor pulmonale

•Pleural involvement - blank of asbestos exposure •Benign exudative pleural effusions •Occur within 15 years of first exposure •May resolve spontaneously, but leave visible blunting of the costophrenic angle or thickening of the visceral pleura Exclusion of associated malignancy

•Pleural involvement - hallmark of asbestos exposure •Benign exudative pleural effusions •Occur within 15 years of first exposure •May resolve spontaneously, but leave visible blunting of the costophrenic angle or thickening of the visceral pleura Exclusion of associated malignancy

Beryllium

•Ranks number 50 in abundance among the chemical elements. •Occurs most commonly in gemstones and minerals such as beryl, emeralds, and aquamarine. •Most important industrial application of beryllium is in the manufacture of alloys (metal mixtures). •In very small amounts, adds strength, durability, and temperature stability to alloys.

•Symptoms of cough and sputum reported by most coal miners are likely a result of dust-induced chronic bronchitis •Breathlessness during exertion usually caused by associated chronic airflow limitation or by development of fibrosis •Hallmark of simple CWP on the posteroanterior chest radiograph is presence of

•Symptoms of cough and sputum reported by most coal miners are likely a result of dust-induced chronic bronchitis •Breathlessness during exertion usually caused by associated chronic airflow limitation or by development of fibrosis •Hallmark of simple CWP on the posteroanterior chest radiograph is presence of small rounded opacities in the lung parenchyma

•The coal dust macule and nodule - accumulation of large amounts of relatively inert dust in the lung •As the lung burden of dust increases, •Trigger the release of cytokines, includingblank and blank, which set in motion inflammation and fibrogenesis •Also the release of blank which contribute to associated emphysema

•The coal dust macule and nodule - accumulation of large amounts of relatively inert dust in the lung •As the lung burden of dust increases, alveolar macrophages are activated and reactive oxygen species are released •Trigger the release of cytokines, including interleukins and tumor necrosis factor, which set in motion inflammation and fibrogenesis •Also the release of proteases which contribute to associated emphysema

Coal Workers Pneumoconiosis •The primary lesion in CWP is the coal blank •Seen on macroscopic examination as a small (up to 4-mm) pigmented lesion •Distributed initially in blanks, although lower lobes may later become involved On micro examination: Coal macule =

•The primary lesion in CWP is the coal macule •Seen on macroscopic examination as a small (up to 4-mm) pigmented lesion •Distributed initially in upper lobes, although lower lobes may later become involved On micro examination: Coal macule = stellate aggregation of dust and dust-laden macrophages, around respiratory bronchioles, with reticulin fibers and variable amount of collagen