Occupational Lung Diseases and Asbestos Exposure Overview | Dr. Alireza Safaeian

1. Dr. AlirezaSafaeian Occupational Medicine Specialist

2. Occupational lung diseases • Occupational lung diseases are a broad group of diagnoses caused by the inhalation of dusts, chemicals, or proteins • The severity of the disease is related to the material inhaled and the intensity and duration of the exposure. • Even individuals who do not work in the industry can develop occupational disease through indirect exposure. • These diseases have been documented as far back as ancient Greece and Rome

3. Occupational lung diseases • Pneumoconiosis • Occupational Asthma • COPD • H.P. (Hypersensitivity pneumonitis) • Occupational Respiratory Infections • Occupational lung cancers

4. Pneumoconiosis • A group of interstitial lung diseases caused by the inhalation of certain dusts and the lung tissue’s reaction to the dust. • There is a long delay (up to ten years or more) between exposure and onset of disease,

5. Other forms pneumoconioses Pneumoconiosis The main types: Asbestosis Silicosis coal workers’ pneumoconiosis can be caused by inhaling dusts containing : Aluminum Antimony Barium Graphite Iron Kaolin Mica Talc mixed-dust pneumoconiosis Byssinosis: exposure to cotton dust

6. Asbestosis

7. Introduction (Asbestos) • Naturally occurring material • Hydrate silicate with variable magnesium content • Fibrous structure: length to width more than 3/1

8. Types of Asbestos

9. Others: Types of Asbestos The most common commercial forms: Chrysotile - “White asbestos” Amosite - “Brown asbestos” Crocidolite - “Blue asbestos” Tremolite(sometimes found in vermiculite) Actinolite Anthophyllite All types of asbestos have been associated with all of the malignant and non-malignant conditions,

10. Properties of Asbestos • Naturally occurring fibrous minerals • Good tensile strength • Flexible • Heat resistant • Electrical resistance • Good insulation • Chemical resistant • Resistant to breakdown by acid, alkali, water, heat, and flame Asbestos ore Because of these unique properties, asbestos was used extensively in variety of products. Asbestos fibers

11. Uses of Asbestos in industry • Insulation • Textiles • Cements • Friction materials (brake linings, Clutch casings) • Construction • mining & milling, • shipyard • sheet metal worker • plumbers & pipefitters • Steamfitter • plasterboard worker • transport • Acoustic products • Automobile undercoating • Floor tiles • Fire-fighting suits • Fireproof paints • Roofing materials • Ropes • Steam pipe material Asbestos has been used for centuries, but greatly increased during and after World War II in ship insulation .

12. Examples of Uses of Asbestos Sheet vinyl containing asbestos Sprayed-on fireproofing material These products may be found in homes and buildings constructed before 1981. Vinyl asbestos flooring

13. Damaged asbestos pipe insulation This damaged pipe insulation is a health hazard to persons working around it, handling it or removing it. Asbestos fibers are visible on the torn edges.

14. Asbestos Roofing Material

15. Cement-asbestos pipe (Transite) Cement-asbestos pipe, sometimes called Transite, was used underground and above ground in years past and may show up in pipe replacement jobs, building demolition jobs or excavations.

16. Asbestos Ceiling Tile Tile close-up

17. Asbestos shingles and siding Found in older houses – not to be confused with newer asbestos-free cement siding. There is little hazard unless disturbed. The top right hand picture shows a siding replacement job with broken green asbestos shingles which would have released dust and fibers into the air if done incorrectly. Removal done correctly

20. Exposure history • Onset & latency -more than 20 years for fibrosis & plaque -several years for pleural thickening • Duration -more than 6 months for fibrosis & plaque -shorter for pleural thickening

21. Exposure history • Intensity • direct exposure : insulator • bystander exposure : sheet-metal worker • indirect exposure : family members

22. Exposure limit • OSHA (PEL) : 0.1 fiber /cm 3 (TWA) Short time exposure : 1 fiber / cm3 • Reducing in asbestos usage from 1970 in USA • Asbestos ban from 1989 by EPA

24. Malignant Asbestos-related disease Non-malignant Parenchymal Asbestosis Asbestos-Related Pleural Abnormalities Lung Carcinoma mesothelioma

25. Parenchymal Asbestosis • Diffuse interstitial fibrosis with: • Restrictive pattern of disease on pulmonary function testing (but can see mixed pattern) • Impaired gas exchange • Progressive exertionaldyspnea • Radiographic changes: >10 years • Latency period: more than 20 years

26. Chest Radiograph Findings: Parenchymal Asbestosis • Small, irregular oval opacities • Interstitial fibrosis • “Shaggy heart sign” List of certified B Readers: http://www.cdc.gov/niosh/pamphlet.html

31. Asbestos-Related Pleural Abnormalities • Four types of abnormalities: • Pleural plaques • Benign asbestos pleural effusions • Diffuse pleural thickening • Rounded atelectasis • Mostly asymptomatic, though some can cause dyspnea or cough • Latency periods: 10-30 years (shorter latency is for pleural effusion)

32. Chest Radiograph Findings: Asbestos-Related Pleural Abnormalities • Pleural plaques • Areas of pleural thickening • Sometimes with calcification • Pleural effusions • Diffuse pleural thickening • Lobulated prominence of pleura adjacent to thoracic margin (over ¼ of chest wall) • Interlobar tissue thickening • Rounded atelectasis • Rounded pleural mass • Bands of lung tissue radiating outwards

33. Lung Carcinoma • Risk depends on: • Level, frequency, and duration of exposure • Time elapsed since exposure • Age at time of exposure • Smoking history (synergistic) • Individual susceptibility factors (under investigation) • Latency period: 20-40 years

34. Chest Radiograph Findings: Mesothelioma • Pleural effusions • Pleural mass • Diffuse pleural thickening

35. Clinical Presentation

36. Physical Examination • Focus on lungs, heart, digits, and extremities • Pulmonary auscultation to detect bibasilar inspiratoryrales(not always present) • Observation of other signs, such as clubbing of the fingers and cyanosis

37. HRCT Indication: Equivocal CXR , significant symptom with unremarkable CXR , pleural obscuring abnormalities -Prone views for assess basilar, posterior and subpleural regions • Septal thickening : intra lobular or interlobular • Subpleural lines and opacities • Parenchymal bands • Ground-glass • honeycombing

38. Diagnosis Based on : Exposure + Clinic + CXR + PFT • Exposure : sufficient intensity , 6months duration , 20 years latency • ILO classification: 1/0 or greater on CXR • PFT : restrictive or mixed • HRCT • Biopsy : exclusion of malignancy

39. Management • Unfavorable response to corticosteroids and immunosupressive agents : case-by-case in progressive alveolitis • Therapy is supportive : -bronchodilator , ipratropium , inhaled steroid -oxygen -treatment of infections

40. Management -stopping of exposure -Influenza and pneumococcal vaccines -Smoking cessation

41. Medical surveillance • No clear evidence for the benefit • Spiral CT : early detection against risk and cost of evaluating false positive

42. Medical surveillance • Exposed worker with normal CXR & PFT : CXR and PFT every 2 to 5 years (based on the latency period) • ILO 1 or sign or symptom : annual CXR and full PFT every 2 years • Isolated pleural thickening : CXR and PFT biannually (more frequently if presence of increasing symptoms or pleural involvement)

43. Silicosis

44. Introduction: Most common pneumoconiosis in world (occupational exposure to crystalline silica) *quartz,cristobalite,tridymite,… OSHA(PEL) :100 μg/m3

45. High risk trade for Crystalline Silica Exposures • Tunneling • Hard-rock mining • Sandblasting • Quarrying • Stonecutting • Foundry work • Ceramics work • Abrasive work • Brick making • Paint making • Polishing • Stone drilling • Well drilling

46. Crystalline Silica Exposures

47. Silica-induced diseases • Chronic bronchitis • Emphysema • Silicosis • Tuberculosis • Lung cancer • Collagen vascular diseases

48. Silicosis Depends on exposure intensity and quartz content of dust • Chronic simple ( classic ) silicosis • Chronic complicated ( PMF ) silicosis • Accelerated silicosis • Acute silicosis

49. Simple silicosis: • No symptoms or Breathlessness Dyspnea(initially with exercise), Cough with or without sputum • P/E: often normal but may rales or decreased breath sound. • CXR: Rounded opacities(1-10mm) *Eggshell calcification • PFT: often normal but may restrictive(mainly) obstructive or mixed pattern.