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Occupational Lung Disease TABLE 22. Key Features of Occupational Lung Diseases Occupational Pulmonary Disease Key Features Ainarays diseases Work-related asthma (occupation Key is to diagnose airways disease in conjunction with exposure. Preshift and postshift related asthma) spirometry serial peak flow measurements, methacholine challenge test, inhalational challenge test; serologic tests for specific antigens. Occupational COPD Pulmonary function tests showing obstruction; may develop in nonsmokers also. Diffuse parenchymal lung diseases High-resolution CT is the imaging modality of choice. Pulmonary function tests show mixed restrictive and obstructive physiology. Dust-related pneumocon iosis Silica (acute silicosis, chronic simple Silica exposure in industriesthat cut or grind silica-containing materials, sandblasting, silicosis, chronic complicated hydraulic fracking for natural gas. Silica exposure associated with increased risk for silicosis, accelerated silicosis) tuberculosis and autoimmune diseases. lmaging shows ground-glass, nodular, interstitial, or fibrotic in{iltrates. Coal (simple or complicated coal- Less common today given improved mine safety standards. lmaging shows nodular orfibrotic worker's pneumoconiosis) changes. Asbestos-related pleuropulmonary Long latency (>25 years)from exposure to onset. Amphibole asbestos more pathogenic than disease serpentine asbestos. Pulmonary fibrosis and pleural disease (effusions, plaques, pleural thickening). Metal-induced lung disease Cobalt: giant cell interstitial pneumonitis. lndium: pulmonary alveolar proteinosis. lmaging shows ground-glass opacities. Occupational hypersensitivity Typically acute or subacute in the occupational setting. pneumonitis Chronic beryllium disease (CBD) Beryllium use in aerospace, automotive, nuclear, and telecommunication industries. Exposure in a patient with a granulomatous lung disease should prompt consideration of CBD. Diagnosed by beryllium lymphocyte proliferation test. Lung malignancies Lung cancer (histologic subtypes vary with type of exposure), mesothelioma (strongly associated with asbestos exposure).

TABLE 22. Key Features of Occupational Lung Diseases Occupational Pulmonary Disease Key Features Ainarays diseases Work-related asthma (occupation Key is to diagnose airways disease in conjunction with exposure. Preshift and postshift related asthma) spirometry serial peak flow measurements, methacholine challenge test, inhalational challenge test; serologic tests for specific antigens. Occupational COPD Pulmonary function tests showing obstruction; may develop in nonsmokers also. Diffuse parenchymal lung diseases High-resolution CT is the imaging modality of choice. Pulmonary function tests show mixed restrictive and obstructive physiology. Dust-related pneumocon iosis Silica (acute silicosis, chronic simple Silica exposure in industriesthat cut or grind silica-containing materials, sandblasting, silicosis, chronic complicated hydraulic fracking for natural gas. Silica exposure associated with increased risk for silicosis, accelerated silicosis) tuberculosis and autoimmune diseases. lmaging shows ground-glass, nodular, interstitial, or fibrotic in{iltrates. Coal (simple or complicated coal- Less common today given improved mine safety standards. lmaging shows nodular orfibrotic worker's pneumoconiosis) changes. Asbestos-related pleuropulmonary Long latency (>25 years)from exposure to onset. Amphibole asbestos more pathogenic than disease serpentine asbestos. Pulmonary fibrosis and pleural disease (effusions, plaques, pleural thickening). Metal-induced lung disease Cobalt: giant cell interstitial pneumonitis. lndium: pulmonary alveolar proteinosis. lmaging shows ground-glass opacities. Occupational hypersensitivity Typically acute or subacute in the occupational setting. pneumonitis Chronic beryllium disease (CBD) Beryllium use in aerospace, automotive, nuclear, and telecommunication industries. Exposure in a patient with a granulomatous lung disease should prompt consideration of CBD. Diagnosed by beryllium lymphocyte proliferation test. Lung malignancies Lung cancer (histologic subtypes vary with type of exposure), mesothelioma (strongly associated with asbestos exposure). Exposures within the same industry can vary according to use occupational or environmental lung disease specialist is of best practices and the type of workplace. For example, coal appropriate. worker's pneumoconiosis in the United States has substan- tially decreased since the institution of federal safety stand- XEY POITTS ards. However, rates of coal worker's pneumoconiosis are o Presentations of occupational lung disease include rhini- higher for individuals who work for companies with fewer tis, reactive airways disease, reactive airways dysfunction than 50 employees and for those who work in thin seam qmdrome, COPD, pleural disease, diffirse parenchymal mines. Thin-seam mines appear to have higher crystalline lung disease, or malignancy. silica exposure and pose greater risk. Adequate determination o When an occupational lung disease is suspected, it is of exposure requires a clear description of job duties and essential to obtain a complete history including occupa- determination of the extent of dust exposure. Clinicians tion, type and efient of exposure, temporal relationship should also obtain a history ofadditional exposures from hob- of exposure to q.nnptoms and disease, and other exposues bies and the home environment (see Table 21). Key features of at home and from hobbies. the more frequently encountered occupational lung diseases are summarized in Table 22. When an occupational lung disease is suspected, clini- cians should request a Safety Data Sheet from the patient's Management employer; the Safety Data Sheet details chemical properties The key to management of occupational lung disease is and known health risks associated with substances within removal of the offending agent from the workplace or the the workplace. The U.S. Occupational Safefy and Health worker from the offending agent. Further investigation ofthe Administration requires that employers make this informa workplace to ensure the identification of all affected indi- tion available on request for employees who work with poten viduals is essential. tially harmful materials. Workers' compensation and determination of disability For individuals who have undiagnosed disorders, persis- related to the impairment attributed to occupational exposure tent unexplained symptoms, or permanent impairment may require referral to a specialist with expertise in occupa- possibly due to an occupational lung disease, referral to an tional lung disease.

Exposures within the same industry can vary according to use occupational or environmental lung disease specialist is of best practices and the type of workplace. For example, coal appropriate. worker's pneumoconiosis in the United States has substan- tially decreased since the institution of federal safety stand- XEY POITTS ards. However, rates of coal worker's pneumoconiosis are o Presentations of occupational lung disease include rhini- higher for individuals who work for companies with fewer tis, reactive airways disease, reactive airways dysfunction than 50 employees and for those who work in thin seam qmdrome, COPD, pleural disease, diffirse parenchymal mines. Thin-seam mines appear to have higher crystalline lung disease, or malignancy. silica exposure and pose greater risk. Adequate determination o When an occupational lung disease is suspected, it is of exposure requires a clear description of job duties and essential to obtain a complete history including occupa- determination of the extent of dust exposure. Clinicians tion, type and efient of exposure, temporal relationship should also obtain a history ofadditional exposures from hob- of exposure to q.nnptoms and disease, and other exposues bies and the home environment (see Table 21). Key features of at home and from hobbies. the more frequently encountered occupational lung diseases are summarized in Table 22. When an occupational lung disease is suspected, clini- cians should request a Safety Data Sheet from the patient's Management employer; the Safety Data Sheet details chemical properties The key to management of occupational lung disease is and known health risks associated with substances within removal of the offending agent from the workplace or the the workplace. The U.S. Occupational Safefy and Health worker from the offending agent. Further investigation ofthe Administration requires that employers make this informa workplace to ensure the identification of all affected indi- tion available on request for employees who work with poten viduals is essential. tially harmful materials. Workers' compensation and determination of disability For individuals who have undiagnosed disorders, persis- related to the impairment attributed to occupational exposure tent unexplained symptoms, or permanent impairment may require referral to a specialist with expertise in occupa- possibly due to an occupational lung disease, referral to an tional lung disease. 34

Pleural Disease I(EY POIilI TABTE 23. Key Physical Examination Findings in the . The key to management of occupational lung disease is Evaluation of a Pleural Effusion removal of the offending agent from the workplace or Finding Possible Causes of Pleural Effusion the worker from the offending agent; further investiga- tion of the workplace to ensure the identification of all Distended neck veins, 53 gallop, Heart failure pulmonary crackles affected individuals is essential. Bilateral dependent edema Hea rt failure, neph rotic syndrome, cirrhosis, hypoalbuminemia Surueillance Calf orthigh swelling, erythema, Pulmonary embolus For individuals at high risk for the development of pulmonary edema, tenderness disease, the use of health questionnaires and pulmonary func- Accentuated cardiac pulmonic Pulmonary embolus, tion screening is appropriate; such screening can also identifiz sound, right ventricular heave pulmonary arterial hypertension a new exposure and any associated risk for disease develop- ment. Surveillance systems that catalog sentinel cases of dis Lymphadenopathy Malignancy ease can help identify clustering of cases. A major Iimitation of Ascites Cirrhosis these databases is the failure olphysicians to report events. Friable, yellow nails Yellow nail syndrome Synovitis Rheumatoid arthritis

removal of the offending agent from the workplace or Finding Possible Causes of Pleural Effusion the worker from the offending agent; further investiga- tion of the workplace to ensure the identification of all Distended neck veins, 53 gallop, Heart failure pulmonary crackles affected individuals is essential. Bilateral dependent edema Hea rt failure, neph rotic syndrome, cirrhosis, hypoalbuminemia Surueillance Calf orthigh swelling, erythema, Pulmonary embolus For individuals at high risk for the development of pulmonary edema, tenderness disease, the use of health questionnaires and pulmonary func- Accentuated cardiac pulmonic Pulmonary embolus, tion screening is appropriate; such screening can also identifiz sound, right ventricular heave pulmonary arterial hypertension a new exposure and any associated risk for disease develop- ment. Surveillance systems that catalog sentinel cases of dis Lymphadenopathy Malignancy ease can help identify clustering of cases. A major Iimitation of Ascites Cirrhosis these databases is the failure olphysicians to report events. Friable, yellow nails Yellow nail syndrome Synovitis Rheumatoid arthritis Pleural Disease medical history such as heart failure, previous surgeries, and medications. The chest examination may reveal dullness to The pleural space is the space between the visceral and parietal percussion and diminished or absent fremitus and breath pleura, which cover the lung and the chest wall, respectively. sounds if the effusion is larger than 300 mL. There are several The physiologic function of this space is not well understood, other key physical examination findings that may suggest the but it has been suggested that it helps maintain positive cause of the effusion (Table 23). transpulmonary pressure, which prevents atelectasis. The two main abnormalities affecting the pleura result from the pres Diagnostic Imaging ence of either excess fluid (pleural efTusion) or excess air A chest radiograph should be performed as the first test in an (pneumothorax) in the pleural space. evaluation of a possible pleural effusion. The radiographic findings are variable, but abnormalities may be seen with as Pleural Effusion little as 200 mL on the posterior anterior chest radiograph or 50 mL on the lateral view (Figure ll). Each year more than 1 .5 million new cases of pleural effusion are Thoracic point of care ultrasonography is a helpful addi diagnosed in the United States. Most effusions are benign; how- tion to chest radiography lbr identification of small effusions, ever, approximately 16'X, are secondary to malignanry Heart fail particularly in patients who are semirecumbent, such as ure, pneumonia, and malignancy are the most common etiologies those who are critically ill (Figure 12). This imaging allows in the United States. Normally the pleural space contains only a estimation of the quantity of the fluid and determination of small amount of fluid (less than 15 mL). Pleural effusions result whether it is free flowing or loculated (i.e., with septations) from conditions that affect the rate of fluid entry from pleural (Figure 13). Ultrasonography is also associated with f'ewer capillaries and the ability of llmphatics to absorb the fluid. complications when it is used to guide pleural procedures XEY POIilT (such as thoracentesis). . Heart failure, pneumonia, and malignancy are the most The advantages of CT imaging with contrast include the common causes of pleural effusion in the United States. abilib/ to detect small amounts of pleural t'luid; the assessment of coexisting intrathoracic abnormalities, such as pulmonary masses and malignant pleural disease; and identification of an Evaluation empyema, as enhancement of the pleura around the fluid cre History and Physical Examination ates a lenticular shaped opacity (Figure fa). The cause of a pleural effusion is often suggested by patient history and physical examination. Symptoms typically include xiy PolilTs dyspnea, cough, and pleuritic chest pain. Elderly patients . A chest radiograph should be performed in the initial often present with atypical symptoms such as anemia, fatigue, evaluation of possible pleural effusion. and failure to thrive. Key questions include severity and . Thoracic ultrasound can characterize pleural effusions, duration of symptoms; constitutional symptoms such as quantify volume, and decrease complications when fevers, night sweats, and weight loss; occupation; recent ill used to guide pleural procedures. (Continued) ness, injury or travel; exposures (for example, asbestos); and

Pleural Disease medical history such as heart failure, previous surgeries, and medications. The chest examination may reveal dullness to The pleural space is the space between the visceral and parietal percussion and diminished or absent fremitus and breath pleura, which cover the lung and the chest wall, respectively. sounds if the effusion is larger than 300 mL. There are several The physiologic function of this space is not well understood, other key physical examination findings that may suggest the but it has been suggested that it helps maintain positive cause of the effusion (Table 23). transpulmonary pressure, which prevents atelectasis. The two main abnormalities affecting the pleura result from the pres Diagnostic Imaging ence of either excess fluid (pleural efTusion) or excess air A chest radiograph should be performed as the first test in an (pneumothorax) in the pleural space. evaluation of a possible pleural effusion. The radiographic findings are variable, but abnormalities may be seen with as Pleural Effusion little as 200 mL on the posterior anterior chest radiograph or 50 mL on the lateral view (Figure ll). Each year more than 1 .5 million new cases of pleural effusion are Thoracic point of care ultrasonography is a helpful addi diagnosed in the United States. Most effusions are benign; how- tion to chest radiography lbr identification of small effusions, ever, approximately 16'X, are secondary to malignanry Heart fail particularly in patients who are semirecumbent, such as ure, pneumonia, and malignancy are the most common etiologies those who are critically ill (Figure 12). This imaging allows in the United States. Normally the pleural space contains only a estimation of the quantity of the fluid and determination of small amount of fluid (less than 15 mL). Pleural effusions result whether it is free flowing or loculated (i.e., with septations) from conditions that affect the rate of fluid entry from pleural (Figure 13). Ultrasonography is also associated with f'ewer capillaries and the ability of llmphatics to absorb the fluid. complications when it is used to guide pleural procedures XEY POIilT (such as thoracentesis). . Heart failure, pneumonia, and malignancy are the most The advantages of CT imaging with contrast include the common causes of pleural effusion in the United States. abilib/ to detect small amounts of pleural t'luid; the assessment of coexisting intrathoracic abnormalities, such as pulmonary masses and malignant pleural disease; and identification of an Evaluation empyema, as enhancement of the pleura around the fluid cre History and Physical Examination ates a lenticular shaped opacity (Figure fa). The cause of a pleural effusion is often suggested by patient history and physical examination. Symptoms typically include xiy PolilTs dyspnea, cough, and pleuritic chest pain. Elderly patients . A chest radiograph should be performed in the initial often present with atypical symptoms such as anemia, fatigue, evaluation of possible pleural effusion. and failure to thrive. Key questions include severity and . Thoracic ultrasound can characterize pleural effusions, duration of symptoms; constitutional symptoms such as quantify volume, and decrease complications when fevers, night sweats, and weight loss; occupation; recent ill used to guide pleural procedures. (Continued) ness, injury or travel; exposures (for example, asbestos); and 35

Pleural Disease FTGURE 11./:Moderaterightpleural effusionthatlayersoverthelowerhemithorax.B:Largeleftpleural effusionwithmeniscussign(arimoffluidascendingthelateral pleural effusions. XEY POlf,?S (oottnusd) Indications for Thoracentesis HVC . Thoracic ultrasound is more sensitive than chest radiog- Once a pleural effusion is identified, the next diagnostic test to

FTGURE 11./:Moderaterightpleural effusionthatlayersoverthelowerhemithorax.B:Largeleftpleural effusionwithmeniscussign(arimoffluidascendingthelateral pleural effusions. XEY POlf,?S (oottnusd) Indications for Thoracentesis HVC . Thoracic ultrasound is more sensitive than chest radiog- Once a pleural effusion is identified, the next diagnostic test to raphy for the diagnosis of effusion in semirecumbent or consider is thoracentesis. supine patients, such as those who are critically ill, and Indications include pleural effusion of unknown cause and greater than 1 cm of fluid thickness on ultrasound or lat- in those with small effusions. eral decubitus radiograph. Thoracentesis should be performed with ultrasound guidance, as this allows for both a greater success rate and a reduced risk for solid organ puncture and ., iatrogenic pneumothorax. Right Pleural Effusion Pleural Fluid Analysis Lung The first step in pleural fluid analysis is assessing the appear 4i- ance ofthe pleural fluid (Table 24). The next step is to deter- Diaohraom {-' " mine whether it is a transudate or exudate. Transudates are the result of an imbalance between hydrostatic and oncotic pres- sures, as occurs with heart failure and cirrhosis. Exudates are the result of inflammation causing increased capillary perme- ability, impaired drainage by lymphatics, or both. There are many causes of exudative effusions, but the most common are infection and malignancy. Differentiation is commonly made using Light's criteria (Table 25). These criteria are very FIGURE 1 2. Moderate right-sided pleural effusion on ultrasound. sensitive for exudates-however, they are less specific, and

raphy for the diagnosis of effusion in semirecumbent or consider is thoracentesis. supine patients, such as those who are critically ill, and Indications include pleural effusion of unknown cause and greater than 1 cm of fluid thickness on ultrasound or lat- in those with small effusions. eral decubitus radiograph. Thoracentesis should be performed with ultrasound guidance, as this allows for both a greater success rate and a reduced risk for solid organ puncture and ., iatrogenic pneumothorax. Right Pleural Effusion Pleural Fluid Analysis Lung The first step in pleural fluid analysis is assessing the appear 4i- ance ofthe pleural fluid (Table 24). The next step is to deter- Diaohraom {-' " mine whether it is a transudate or exudate. Transudates are the result of an imbalance between hydrostatic and oncotic pres- sures, as occurs with heart failure and cirrhosis. Exudates are the result of inflammation causing increased capillary perme- ability, impaired drainage by lymphatics, or both. There are many causes of exudative effusions, but the most common are infection and malignancy. Differentiation is commonly made using Light's criteria (Table 25). These criteria are very FIGURE 1 2. Moderate right-sided pleural effusion on ultrasound. sensitive for exudates-however, they are less specific, and 36

I I I I Pleural Disease \ i L I t i t i t t, t t I I I \ I I L I L ttGURE 13. Comparisonof asimple(/)andcomplicated(8)pleural effusiononthoracicultrasound.Ahypoechoiceffusion(,4) maybetransudateorexudate.Amultiseptated I t (loculated) effusion (B) is exudate. I t I approximate$ 25% of transudates are misclassified as exu- I dates. In patients who have underlying heart failure and are L receiving diuretics, a serum NT-pro B-type natriuretic peptide I of greater than 1500 pg/ml is suggestive of a cardiac etiologr t for the effusion. Checking pleural fluid cholesterol is another i t accurate method for classi$ring an effusion as an exudate. I Exudative and transudative effusions have a wide range of I causes (Table 26). I

t accurate method for classi$ring an effusion as an exudate. I Exudative and transudative effusions have a wide range of I causes (Table 26). I i, In addition to characterizing a pleural effusion as a tran- sudate or exudate, other tests are often performed on the basis i of clinical suspicion. If infection is suspected, pH, glucose, cell count, Gram stain, and aerobic and anaerobic cultures should t be performed. If malignancy is suspected, cytological analysis of fluid should be performed. FIGURE 1 4. Climaging revealsan empyema,asenhancementof thepleura Cell Counts and Dffirential around the fluid creates a lenticular-shaped opacity. The red anow points to fluid Cell counts are useful for determining the cause of a pocket; the yellow arrow points to an area of pleural thickening. pleural effusion however, they are not disease-specific.

FIGURE 1 4. Climaging revealsan empyema,asenhancementof thepleura Cell Counts and Dffirential around the fluid creates a lenticular-shaped opacity. The red anow points to fluid Cell counts are useful for determining the cause of a pocket; the yellow arrow points to an area of pleural thickening. pleural effusion however, they are not disease-specific. T,ABLE 24. Pleural Fluid Characteristics and Diagnostic Considerations Appearance Possible Causes Additional Tests to Perform Bloody Malignancy, pulmonary embolus, trauma, Hematocrit: if >50% of the serum, it is a hemothorax; pneumonia, benign asbestos pleural effusion consider aortic rupture, myocardial rupture, and injuries to hilar structures, lung parenchyma, and intercostal vessels Milky Chylothorax (most commonly seen aftertrauma or in Triglyceride level patients with lymphoma) or cholesterol effusion (associated with tuberculosis and rheumatoid arthritis)

T,ABLE 24. Pleural Fluid Characteristics and Diagnostic Considerations Appearance Possible Causes Additional Tests to Perform Bloody Malignancy, pulmonary embolus, trauma, Hematocrit: if >50% of the serum, it is a hemothorax; pneumonia, benign asbestos pleural effusion consider aortic rupture, myocardial rupture, and injuries to hilar structures, lung parenchyma, and intercostal vessels Milky Chylothorax (most commonly seen aftertrauma or in Triglyceride level patients with lymphoma) or cholesterol effusion (associated with tuberculosis and rheumatoid arthritis) Yellow-green Rheumatoid pleurisy Serum rheumatoid factor Pleural fluid glucose <60 mg/dL (3.33 mmol/L) Dark green Bilothorax Bilirubin Dark brown/black Long-standing hemothorax, fungal infection, Hematocrit, cytology, fungal cultures malignancy Purulent Empyema pH, glucose, cell count, gram stain, aerobic and anaerobic cultures 37