17: Occupational Lung Disease Flashcards
1
Q
**Occupational lung disease **definition
A
- Group of illnesses caused by repeated, extended exposure to single or severe exposure to irritating or toxic substances thatleads to acute or chronic respiratory ailments.
- Related to specific occupation
- Aggravated at work
2
Q
OLD pathogenesis
A
- Asthma/bronchitis: immunologic or nonimmunologic airway hyperreactivity
- Pneumoconioses: deposition > dust clearance; direct cytotoxicity; alveolar macrophage response –> granulomatous inflammation and fibrosis, cytokine recruitement
- Hypersensitivity pneumonitis: allergic response to inhaled organic antigens
3
Q
Particle size spectrum of OLD
A
- 5-10um: asthma or bronchitis
- 3-5um: bronchiolar dz
- 0-3um: ILD
4
Q
Occupational asthma
A
- Variable airflow limitation and/or airway hyperresponsiveness due to stimuli in occupation environment (9-15% adult asthma)
- Three types:
- Immunologic: latency period (1-2yrs) –> immunological sensitization, IgE mediated, 90% of cases, Sx improve after work
- Irritant-induced (nonimmunologic): exposure to ↑[irritants], damage to airway epithelium, 7% of cases, Sx w/in 24 hrs of exposure, no previous asthma Hx, not improved after work
- Work-aggravated: pre-existing asthma
5
Q
Silicosis
A
- Occupations that disturb earth’s crust, use silica-containing rock/sand
- Dx: Hx of exposure to silica (quartz, cristobalite, tridymite), abnormal CXR, exclusion of other etiologies
6
Q
Acute silicosis
A
- Exposure: weeks to 5 yrs
- Post-exposure onset: 1-3 yrs
- Sx: cough, constitutional Sx, dyspnea
- Radiology: basilar alveolar filling process
- Pathology: alveolar filling w/ PAS + lipo-proteinaceous material, interstitial thickening
7
Q
Accelerated silicosis
A
- Exposure: years
- Post-exposure onset: < 10 yrs
- Sx: same as acute + arthralgia
- PFTs: mixed obstructive-restrictive deficit
- Radiology: 2-6mm nodules, upper & posterior location, hilar LAN, +/- eggshell calcification
- Pathology: silicotic nodules (hyalinized center, concentrically arranged collagen, weakly birefringent particles, macrophages & lymphocytes at outer rim)
8
Q
Chronic silicosis
A
- Exposure: decades
- Post-exposure onset: 10-30yrs
- Sx: None, chronic cough, dyspnea
- PFTs: mixed obstructive-restrictive deficit
- Radiology & pathology same as accelerated silicosis
9
Q
Progressive massive fibrosis (PMF)
A
- Severest form of silicosis
- Exposure: decades
- Post-exposure onset: 10-30 yrs
- Sx: progressive dyspnea +/- cor pulmonale
- Mixed obstructive-restrictive deficit
- Radiology: coalescing nodules (>1cm) +/- central necrosis, hilar retraction upward, hyperinflation lower lung zones
- Pathology: coalescence of silicotic nodules
10
Q
Silicosis complications
A
- Mycobacterial dz: 2.8x > RR of TB
- Immune-mediated: ↑auto-Ab, ↑auto-immune dz
- Bronchitis/airflow obstruction
- Lung cancer
11
Q
Silicosis treatment
A
- Corticosteroids
- Whole lung lavage
- Transplantation
- Prevention (respirator mask)
12
Q
Asbestos-related lung disease
A
- Parenchymal: asbestosis
- Pleural: pleural plaques, BAPE & pleural thickening, atelectasis
- Malignancy: lung cancer, mesothelioma
- 15-35 yr latency from exposure
- Ongoing sites of major production:
- Amphobile: South Africa, Australia
- Chrysostile: Russia, China
13
Q
**Asbestosis **mechanism
A
- Exposure
- Injury: cell apoptosis, mitochondrial ROS production and DNA damage, macrophage phagocytosis, H2O2 production, cytokine release
- Fibrosis: myofibroblast proliferation
14
Q
Asbestosis diagnosis
A
- Hx of asbestos exposure
- Bilateral pleural plaques
- BAL fluid or Bx w/ increased [asbestos fibers] or [asbestos bodies] –> ferruginous bodies
- Characteristic HRCT findings
15
Q
Asbestosis
A
- Clinical: cough, dyspnea, diffuse interstitial fibrosis, restrictive PFTs
- Radiology: HRCT has lower lobe, subpleural, linear interstitial markings, parenchymal bands, intra/interlobular septal thickening, honeycomb change, pleural plaques
- Pathology: ↑asbestos bodies, UIP pattern
