Occupational Lung Disease. David Perlman, MD

Transcription

1 Occupational Lung Disease David Perlman, MD

2 What causes occupational lung diseases? Breathing bad stuff into your lung Mechanism of particle deposition Large particles (>0.5μM) Impaction Gravitational sedimentation Small particles (<0.5 μm) Diffusion Interaction with host defense mechanisms

3 Impaction The particle s momentum in air stream prevents it from making turn at a bifurcation. nasopharyngeal compartment tracheobronchial compartment

4 Sedimentation When gravitational forces on a particle are greater than air resistance and buoyancy, the particle will fall out of the air stream. As air moves deeper into the lung, air flow rate decreases. Sedimentation is proportional to: particle time in airway particle size and density respiratory rate (breaths/minute) nasopharyngeal compartment tracheobronchial compartment pulmonary compartment

5 Diffusion Particles have random motion, resulting in random impacts. Diffusion coefficient is: inversely related to particle size independent of particle density tracheobronchial compartment pulmonary compartment

6 Factors that affect particle deposition Size Density Shape (fiber vs. other) Charge Air velocity Respiratory rate Size of airway (individual variation) Hygroscopy (water attractiveness)

7 The Mucociliary Escalator ciliated cells Goblet cells AM containing a particle smooth muscle particle The mucocilliary escalator operates in the tracheobronchial region.

8 Clearance in the Pulmonary Compartment AM-mediated particle clearance endocytosis by lung epithelial cells absorption into blood Type I cell Type II cell Alveolar Macrophage Alveolus (Airspace) Fibroblasts Capillary Lumen

9 Mechanisms of Particle-Induced Lung Disease Inflammation Cytokine Activation Formation of ROS Transcription factor activation Accumulation of mesenchymal cells Deposition of ECM

10 Common occupational lung diseases Occupational Asthma Silicosis Asbestosis Hypersensitivity Pneumonitis Coal Workers Pneumoconiosis Chronic Beryllium Disease Inhalational Fever

11 Silicosis Caused by pronged exposure to silica dust Can have different presentations Classic Silicosis Accelerated Silicosis Acute Silicosis Associated Problems Immune mediated diseases TB Renal Disease Cancer

12 Silicosis: Exposure-Response

13 Silicosis Occupations at risk Sandblasting Miners including coal miners Quarry workers Millers Pottery Workers Foundry

14 Silica: Granite Quarry

15 Sandblasting

16 Silicosis Death by State

17 Silicosis Proportional Mortality Ratio for U.S. residents

18 Silicosis Clinical Features PFTs Can be obstructive Radiology CXR Rounded opacities 1-10mm Typically upper lung zones Hilar lymph node enlargement (eggshell calcification) CT scan Typically nodular opacities Can resemble interstitial pneumonia (mixed dust)

19 Silicosis

20 Silicosis

21 Silicosis

22 Silicosis Treatment No proven therapy Mainly symptom based Steroids for acute silicosis Whole lung lavage Lung transplant

23 Asbestos

24 Asbestos Related Disease Asbestosis Pulmonary Fibrosis caused by Asbestos exposure Lung Cancer Pleural Disease Pleural Plaques Diffuse pleural thickening Pleural effusion Rounded atelectasis Malignant Mesothelioma

25 Asbestosis Proportional Mortality Ratio for U.S. residents

26 Asbestosis Death by State

27 Calcified Pleural Plaque

28 Pleural Plaque on Diaphragm

29 Calcified Pleural Plaque

30 Benign Asbestos Pleural Effusion Usually asymptomatic Fluid often hemorrhagic (50%) Pleural fluid eosinophilia (25-50%) Often without plaques or asbestosis Can be short or long latency No clear dose-response relationship Resolves 3-4 months (can be up to 1 yr) May have mesothelial cells Unclear if it is risk factor for mesothelioma

31 Mesothelioma Tumor of mesothelial origin Pleural or peritoneal 70% cases caused by asbestos exposure Long latency period between exposure and development, years Dose-response relationship No proven therapy Poor prognosis

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33 Asbestos Synergy With Smoking

34 Hypersensitivity Pneumonitis Acute, subacute and chronic Immune response to inhaled antigen IgG mediated hypersensitivity reaction Delayed response Antigen usually organic substances (bacterial, fungal or animal protein) Some inorganic substances tolulene diisocyanate

35 HP Clinical Presentation Fever, SOB, Chest tightness/wheezing Late afternoon/evening (delay from exposure) Symptoms recur whenever exposed. Often just presents as chronic low grade dyspnea and/or cough. Can progress to chronic HP and fibrosis

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37 HP Diagnostic Criteria Known exposure to offending antigen(s) identified by: History of appropriate exposure. Aerobiologic or microbiologic investigations of the environment that confirm the presence of an inciting antigen The presence of specific IgG antibodies in serum against the identified antigen (serum precipitins) Compatible clinical, radiographic, or physiologic findings: BAL Respiratory (± constitutional) symptoms and signs, such as crackles on chest exam, weight loss, cough, breathlessness, febrile episodes, wheezing, and fatigue. Reticular, nodular, or ground glass opacity on chest radiograph or HRCT Altered spirometry and/or lung volumes (may be restrictive, obstructive, or mixed pattern), reduced DLCO, altered gas exchange either at rest or with exercise testing Lymphocytosis Usually with Low CD4:CD8 ratio (as opposed to sarcoid) Positive inhalation challenge testing Reexposure to environment Inhalation challenge to suspected antigen in hospital setting Histopathology showing compatible changes

38 HP Lung Biopsy Biopsy TBBX or surgical Small, poorly formed non-caseating granulomas Patchy cellular infiltrate of alveolar walls in bronchocentric distribution. Foamy macrophages Peribronchial fibrosis

39 HP Quick case 66 y.o. male referred for cough of acute onset, 3 months duration. Non-productive PFTs: Mild restriction No obvious occupational or home exposures

40 HP CT Scan Inspiration GG opacity Expiration Mosaic pattern

41 HP Quick case Bronchoscopy All cx negative Nucleated cells: 3540/ul, 52% lymphs CD4:CD8 Ratio 0.29 ( ) TBBx: Chronic inflammation Lymphocytes and plasma cells Airway centered process

42 HP Treatment Avoidance of Antigen Respiratory protective devices Prednisone? Inhaled corticosteroids

43 HP CT Scan Pre Treatment Post Treatment

44 Chronic Beryllium Disease Caused by chronic beryllium exposure Looks like sarcoid Hilar adenopathy Reticulonodular opacities Non-caseating granulomas on lung bx BLPT Treatment Steroids 2 nd line agents (similar to sarcoid)

45 CBD Occupational Exposure aerospace automotive parts computers construction trades dental supplies and prosthesis manufacture electronics industrial ceramics laboratory workers metal recycling mining of beryl ore (beryl ore extraction) nuclear weapons precision machine shops smelting/foundry tool and die manufacture welding

46 Inhalation Fever Febrile, flu-like syndrome related to occupational exposure No sensitization required Blunted response to repeated exposure (Monday morning malaise) Inflammatory cellular pulmonary infiltrate Cytokine activation systemic symptoms Resolve after exposure removed

47 Inhalation Fever Metal fume fever Organic Toxic Dust Syndrome Pontiac Fever Humidifier Fever Metal fumes Zinc Oxide Copper or Magnesium Contaminated vegetable matter Moldy Hay Compost Wood dust Water source with Legionella Humidifiers/AC Mill/Grain Fever Plant/Grain dust with endotoxins

48 Questions? Rocky Taconite