Term
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Definition
| anthracotic pigment is a type of carbon dust containing silica that is deposited in connective tissue along lymphatic distribution and under the pleura of the lungs of coal workers/city dwellers. it tends to be asymptomatic, but can lead to simple or complicated coal workers pneumoconiosis (PMF - progressive massive fibrosis w/resultant compromise –leading to infection) |
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Term
| how does coal workerÂ’s lung appear and feel grossly? |
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Definition
| dark, black and fibrotic. it will feel firm and rough b/c spongy consistency is lost. |
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Term
| what is the least severe of the coal-related lung diseases? |
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Definition
| anthracosis, which is commonly seen in smokers and urban dwellers, is due to inhaled carbon pigment *engulfed by alveolar or interstitial macrophages that accumulate in the connective tissue along the lymphatics or in organized lymphoid tissue along the *bronchi/lung hilus. linear streaks of anthracotic pigment are seen on autopsy |
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Term
| what is simple coal workers pneumoconiosis (CWP)? where in the lung is it most commonly seen? what can it contribute to? |
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Definition
| simple CWP is characterized by coal *macules (contain multiple carbon laden macrophages) and *nodules (contain small amounts of a delicate network of collagen fibers). simple CWP is most commonly seen in the *upper lobes/upper part of lower lobes. simple CWP may contribute to *centrilobular emphysema (destruction of the alveoli). think lawsuits. |
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Term
| what is complicated coal workers pneumoconiosis? |
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Definition
| complicated CWP occurs on a background of simple CWP over multiple years of development. it appears as multiple blackened scars which consist of dense collagen and pigment *often w/central necrosis (mimics TB). the nodules seen in simple CWP coalesce and increase in scar formation, resulting in severe respiratory impairment |
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Term
| what is the clinical course of coal workers lung? |
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Definition
| usually CWP starts as a benign disease w/little effect on lung function. in a minority of cases, progressive massive fibrosis (PMF) develops which can lead to pulmonary dysfunction, pulmonary HTN, and cor pulmonale. complicated CWL can increase chances of bronchitis and emphysema |
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Term
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Definition
| the *most common occupational disease in the world, which is due to inhalation of crystalline silicon dioxide. silicosis presents after decades of exposure as slowly progressing pneumocosis. |
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Term
| who is at risk for silicosis? |
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Definition
| many occupations including sandblasters and mine workers |
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Term
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Definition
| heavy exposure over months to years can lead to a *lipoproteinaceous material within the alveoli |
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Term
| what forms does the silica in silicosis appear in? |
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Definition
| silica can appear in crystalline and amorphous forms. the crystalline forms: quartz, crystobalite, tridymite are much more fibrotic BUT when *mixed with other minerals, quartz as a less fibrogenic effect. |
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Term
| what happens to the silica once inhaled? |
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Definition
| the particles interact w/epithelial cells and macrophages. the *silica often destroy the engulfing macrophage while *other macrophages are activated by the silica and release their *mediators: IL-1, TNF, fibronectin, lipid mediators, ROS, and fibrogenic cytokines (these mediators are often the major source of fibrosis). |
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Term
| how does silicosis appear histologically? |
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Definition
| silicosis consists of nodules with concentric layers of hyalinized collagen surrounded by a dense capsule of very condensed collagen, which is the body's attempt to wall off the destruction. *polarized microscopy reveals birefringent silica particles |
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Term
| what may the nodules and lymph nodes progress to over the course of progressive silicosis? |
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Definition
| nodules in silicosis may progress to *hard collagenous scars (due to consolidation) and the lymph nodes may have *eggshell calcification (calcium surrounding a zone lacking calification) (this fibrotic nodular pattern can mimic TB and sarcoid - need to *differentiate w/polarizing microscopy) |
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Term
| how is silicosis diagnosed? |
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Definition
| silicosis can be detected on a *routine CXR. dyspnea develops *later in the course along with general impairment of pulmonary function which can limit activity |
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Term
| is there an increase susceptibility to TB w/silicosis? |
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Definition
| yes, this is due in part to *depression of cell mediated immunity and inhibition of macrophages to kill mycobacteria (TB can spread more rapidly through living conditions associated with these working enviroments) |
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Term
| what is asbestos? what can occupational exposure of it lead to? |
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Definition
| a family of crystalline silicates that form fibers, which with occupational exposure (over years) can lead to *localized fibrous plaques and *pleural effusions |
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Term
| what are diseases commonly related to asbestos? |
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Definition
| interstitial fibrosis (unbreakdownable substance produces fibrosis), lung CA, mesotheliomas (tumor of the pleural surface), laryngeal and possibly extrapulmonary tumors including *colon CA (good chance you are swallowing this material as well) |
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Term
| what can determine the pathogenicity of asbestos toxicity? |
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Definition
| concentration, size, shape, solubility |
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Term
| what are the 2 forms of asbestos? |
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Definition
| serpentine and amphibole (know these 2) |
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Term
| what is the serpentine chrysotile type of asbestos? how do they deposit in the lungs? |
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Definition
| curly and flexible fibers that account for *most asbestos used in the industry. these are more likely to be impacted in the upper respiratory passages and *trapped by mucociliary action. once they are trapped in the lungs, they gradually leach from the tissues b/c they are *more soluble than amphiboles |
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Term
| what are the amphiboles type of asbestos? |
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Definition
| this includes crocidolite, amosite, tremolite, anthophyllite, and actinolyte. the amphiboles are *straight and stiff and can align themselves in the airway (more aerodynamic) - therefore they can be *delivered deeper into the lung and can penetrate epithelial cells and the interstitium. the *longer, thinner fibers tend to be more pathogenic than the shorter thicker ones. *ONLY amphibole exposure correlates with mesothelioma* |
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Term
| can both amphiboles and serpentine asbestos be fibrogenic? how do increasing doses associate w/disease? |
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Definition
| both forms of asbestos are fibrogenic and increasing doses are associated with a higher incidence of asbestos related illness |
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Term
| how does asbestosis associate with CA? |
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Definition
| asbestos can act as a tumor initiator and tumor promoter; the *fibers release ROSes and *toxic chemicals can be absorbed by the fibers (such as tobacco smoke -> CA). when smoking and asbestos are combined, there may be a 55x increase in risk of lung CA |
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Term
| what does the occurrence of asbestosis depend on? |
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Definition
| the occurrence of asbestosis depends on the interaction of the *inhaled fibers with *lung macrophages and other parenchymal cells. the initial injury occurs at *bifurcations of small airways and ducts where asbestos fibers land and penetrate. |
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Term
| how do the lung macrophages respond to asbestos? |
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Definition
| the lung macrophages *attempt to ingest and clear fibers and are activated to *release chemotactic factors and fibrogenic mediators which amplify the response. if this exposure occurs chronically, persistent release of the mediators eventually leads to *generalized interstitial pulmonary inflammation and *interstitial fibrosis (looks like silicosis) |
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Term
| what is the morphology of asbestos? |
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Definition
| asbestosis is marked by pulmonary interstitial fibrosis with the presence of *asbestos bodies - which are *golden brown, fusiform (cylindrical), or beaded rods w/a translucent center and consist of asbestos fibers coated with an *iron-containing proteinaceous material* called ferruginious bodies. the iron comes from phagocyte ferritin (left after the phagocyte dies) |
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Term
| how does asbestosis progress? |
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Definition
| asbestosis begins around the *respiratory bronchioles and alveolar ducts and extends to *adjacent sacs and *alveoli. the fibrous tissue distorts the architecture, *creating enlarged airspaces enclosed by thick walls *w/honeycombing* of certain areas (firm lung w/open airspaces) |
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Term
| how does the progression of asbestosis occur in the lungs in terms of location? |
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Definition
| asbestosis begins in the *lower lobes and *subpleurally. eventually the middle and upper lobes become affected and *scarring may eventually narrow the pulmonary arteries and arterioles, leading to *pulmonary HTN and *cor pulmonale |
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Term
| what are pleural plaques? does their level correlate with the level of exposure? do they contain asbestos bodies? what may result as a consequence of their existence? |
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Definition
| pleural plaques are well-circumscribed plaques made of *dense collagen and *calcium that develop w/asbestosis mostly on the *anterior and posterolateral portion of the *parietal pleura and on the *domes of the diaphragm. the size and number of plaques *does not correspond with the level of exposure or the time since exposure *nor do they contain asbestos bodies. *pleural effusions are possible as a result of asbestosis (may result in compression atelectasis) |
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Term
| what kinds of disease are linked to asbestos exposure? how does cigarette smoking associate with either of these diseases? |
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Definition
| lung CA (5x higher risk) and mesotheliomas (1000x greater risk). *cigarette smoking greatly increases the risk of lung CA concomitant w/asbestos exposure - but not mesothelioma |
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Term
| how do pts with asbestosis present clinically? |
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Definition
| pts with asbestosis present with *dyspnea (increases in severity over time), *cough w/sputum production, and *CXR: irregular linear densities especially in the *lower lobes w/a possible formation of a honeycomb pattern. asbestosis may progress to resp failure, cor pulmonale and death. |
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Term
| where do malignant mesotheliomas arise from? how does smoking correlate with its appearance? what is often found in high levels in the lungs in pts w/mesothelioma? is there a genetic component to mesothelioma incidence? |
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Definition
| malignant mesotheliomas arise from the *visceral or *parietal pleura in the thorax. there is no increased risk of mesothelioma in asbestos workers who some. *asbestos bodies are often increased in the lungs of pts with mesothelioma. deletions in chr 1p, 3p, 6p, 9p, or 22q are associated with mesothelioma formation. |
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Term
| what is the morphology of mesotheliomas? |
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Definition
| mesotheliomas can spread in the *pleural space and can have *bloody effusions (compression or contraction atelectasis). they may extend to the lung itself, which may be encased in a *thick layer of soft gelatinous grayish pink tumor tissue. |
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Term
| what are the 2 predominate cell types found in mesotheliomas? |
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Definition
| epithelioid and sarcomatoid |
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Term
| what characterizes the epithelioid type of cell found in mesotheliomas? |
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Definition
| the the epithelioid type of cell is cuboidal, columnar or flattened and forms tubular or papillary structures resembling an *adenocarcinoma. however, the epithelioid type of mesothelioma cells differs from that found in adenocarcinomas by *strong perinuclear staining of keratin and *staining for calretinin |
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Term
| what characterizes the sarcomatoid type of cell found in mesotheliomas? |
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Definition
| the sarcomatoid type of cell resembles a *spindle cell sarcoma cell |
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Term
| can there be mixed mesothelioma cells? |
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Definition
| yes, mixed type cells can be found in mesotheliomas that have both epithelioid cells and sarcomatoid elements |
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Term
| what is seen via EM in mesotheliomas? |
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Definition
| *long, slender microvilli* - which is the gold standard of dx |
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Term
| what is the clinical course of mesotheliomas? can they spread? what is the prognosis? |
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Definition
| chest pain, dyspnea, pleural effusions. if the lung is invaded directly, the mesothelioma may spread to the lymph nodes, liver or distant organs. the prognosis is poor. (mesotheliomas may also arise in the peritoneum, pericardium and genital tract) |
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