Occupational ILD - Management

Remove exposure

• Most occupational ILDs have no treatment with established efficacy³
• The first line of action is to limit, or if possible, remove exposure of the causative agent³
  • Well-known agents (silica, asbestos) may have recommended exposure limits based on cumulative exposure doses³

Support

Symptom management includes supportive care, such as oxygen therapy, antibiotics if associated infections occur, and pulmonary rehabilitation³

Anti-inflammatories/steroids

Occupational ILD resulting in a specific immune response (such as chronic beryllium disease [CBD]) may benefit from anti-inflammatory therapies such as prednisone¹

Prevent

Management of occupational ILD in one individual also represents an important step in disease prevention - limiting or removing exposure from coworkers who also may have been exposed³

FEATURES OF ASBESTOSIS

Physiological findings: Interstitial fibrosis, pleural effusion, plaques in the pleural and diaphragmatic space, and pleural thickening - pleural abnormality in over 90% of patients.³

Exposure: Latency of 15-40 years can result from long— or short-term exposure to asbestos fibers.³

Exposure risk: Construction and building maintenance, mining, milling, ship repair or construction, automobile or railroad work, insulation work, number and duration of exposure(s).³

Symptoms: Dyspnea, dry cough, crackles, clubbing, cor pulmonale (in advanced disease).³

Progression: Local inflammation is activated by inflammasomes.¹ Pathologic lesion begins with peribronchiolar fibrosis, extends to the alveolar wall. Cumulative or repeated exposure can influence progression.³

Diagnosis: Chest radiography or computed tomography (CT) scan, physiologic symptoms matched with slow disease course, occupational history consistent with exposure, exclusion of other ILD, biopsy not always needed.³

Radiographic findings: Lower zone reticular opacity, honeycombing, pleural disease.³

Treatment: No known treatment. Remove or limit exposure. Supportive care includes treatment of occurrent infections, oxygen therapy, pulmonary rehabilitation, avoidance of tobacco.³

FEATURES OF SILICOSIS^1,3

Physiological findings: 3 forms can develop depending on exposure: chronic simple (most common), accelerated, and acute.

Exposure: Inhalation of crystalline silica or silica dust. Chronic simple: latency of 10-40 years; accelerated: higher exposure, latency of 5-10 years; acute: high exposure over months to 2 years.

Exposure risk: Mining, construction, tunneling or road work, sandblasting, foundry or granite/stone work, production of silica flour, ceramics, or glass.

Symptoms: Dyspnea, productive cough, pulmonary obstruction/restriction.

Progression: Local inflammation is activated by inflammasomes.¹ Chronic simple, accelerated, and acute silicosis have a similar presentation with increasing severity. The adjoining of individual nodules results in complicated silicosis. Masses of fibrosis can develop in both chronic simple and accelerated silicosis. Acute silicosis presents similarly to alveolar proteinosis. Exposure increases risk of developing other lung diseases, infection such as tuberculosis, cancers, and certain autoimmune disorders.

Diagnosis: Chest X-ray or CT scan, biopsy not always needed.

Radiographic findings: Upper lobe nodular opacities, hilar adenopathy (10% cases show an eggshell pattern), <5 mm pulmonary nodules (individual or coalesced, i.e., fibrosis masses >1 cm), fibrotic lesions.

Treatment: Supportive care and removal from exposure similar to asbestosis. Screening for tuberculosis infection recommended.

FEATURES OF COAL-EXPOSURE RELATED ILD

Despite declining usage of coal, increased mechanization, and an associated decrease in rates of coal-related lung disease since the 1970s, mining continues to present a substantial health risk.¹²

Physiological findings: Pneumoconiosis, chronic airway diseases with restrictive, obstructive, or mixed-pattern pulmonary function, emphysema, abnormal gas exchange, chronic bronchitis (estimated to occur in 35% of US coal miners).

Exposure: Inhalation of coal mine dust.

Exposure risk: Coal mining — continues to represent a large source of employment in the United States, China, and worldwide.

Symptoms: Cough, productive sputum, shortness of breath, wheezing, emphysema.

Progression: Coal dust induces inflammatory responses and fibrosis via the release of cytokines. Disease can progress from pneumoconiosis to massive fibrosis, emphysema, and chronic bronchitis. Disease progression can be exacerbated by tobacco use and exposure to silica dust.

Diagnosis: Occupational history, radiographic chest X-rays or CT scans, pulmonary function tests. Lung biopsy positive for inflammatory and fibrotic lesions with associated emphysema can confirm diagnosis.

Radiographic findings: Nodules in the upper zone, progressive fibrosis, fibrotic scars, irregular opacities.

Treatment: No specific treatment. Focus is on removal or reduction of exposure, prevention with proper protective gear, and surveillance programs to monitor health. Supportive care and occasionally whole-lung lavage have been used.

FEATURES OF CHRONIC BERYLLIUM DISEASE (CBD)³

Physiological findings: Granulomatous disease similar to sarcoidosis occurring after exposure and sensitization to beryllium. Primarily impacts the lung but can affect other organs as well.

Exposure: Dust or fumes of pure beryllium, beryllium alloy, or beryllium oxides. Sensitization in 2%-10% of people exposed. Wide ranging latency of 2 months to 40 years.

Exposure risk: Sensitization to antigens can increase susceptibility to developing ILD with continued exposure. Exposure often occurs when working with nuclear weapons, aerospace, and defense industries, electronics, ceramics, metal recycling and alloy working, dental prostheses manufacture, living or working near beryllium production facility.

Symptoms: Can be asymptomatic, or cause dyspnea, dry cough, fatigue, weight loss, fever, night sweats, myalgias, crackles, subcutaneous nodules; in advance cases, also cyanosis, clubbing of the digits, heart failure, pulmonary obstruction/restriction, ventilation and gas exchange abnormalities during cardiovascular exercise.

Progression: Exposure activates the adoptive and innate immune response. Most patients progress slowly while others present rapidly.

Diagnosis: Beryllium lymphocyte proliferation test, history of exposure reaction to beryllium on blood or bronchoalveolar lavage, lung inflammation on bronchoscopy or chest X-ray/CT scan.

Radiographic findings: Similar to sarcoidosis, diffuse bilateral opacities, nodules in the middle and upper pulmonary zone, hilar adenopathy (20%-30% of cases), honeycombing and/or masses and emphysema can occur in advanced cases.

Treatment: Although there are no approved therapies, corticosteroids are often used empirically. In addition, removal from exposure along with supportive care.