Occupational lung diseases Flashcards
Which type of cancer accounts for 55-75% of occupational cancers?
Lung cancer (even though only 4-8% of all cancers are occupational)
85-90% of male mesotheliomas are caused by…
occupational asbestos exposure
What exposure accounts for 50% of occupational cancers?
Asbestos exposure
Why do we still see asbestos-related pneumoconioses and cancers despite improving trends in work exposures and occupational diseases?
Because of long latency periods
What is the latency of a disease?
The period between the exposure to a pathogen and onset of symptoms.
What pulmonary disease occurs immediately (within 24 hours) of exposure to irritants?
RADS: reactive airway dysfunction syndrome
What pulmonary disease occurs many hours after a repetitive exposure?
Hypersensitivity pneumonitis
What pulmonary disease take days, weeks, months, years to develop before becoming symptomatic and improves on weekends and vacations?
Asthma
What are two main dust-related occupational diseases?
- Asbestos-related
- Silica-related
How long does asbestosis take to develop?
20 years after asbestos exposure
How long does mesothelioma take to develop?
30 years after exposure (even if exposure is minimal)
How long does it take for plaques, pleural effusions and pleural thickening to develop (asbestos)?
10-20 years after exposure
How long does simple silicosis take to develop?
15 years
(acute silicosis < 5 years)
(accelerated silicosis 5-15 years)
What are the two major categories of occupational lung disease? Define them
- Pneumoconiosis: Dust inhalation
- Airway disease: Inhalation of low or high grade molecular weight compounds
Name 2 important diseases that fall under pneumoconiosis and 2 important diseases that fall under airway disease.
Pneumoconioses:
* asbestosis
* silicosis
Airway disease:
* Occupational asthma
* Reactive airways dysfunction syndrome (RADS)
How can we measure the intensity of exposure to dusts? (3)
- History (job type, duration)
- Radiologic findings (more interstitial lung abnormalities = more cumulative exposure)
- Microscopy of lung biopsy
* Asbestos: count fibres of asbestos bodies
* Silicosis: count silicotic nodules
What is asbestos? What are its two major types?
What subtype is most common in Quebec?
Naturally occuring mineral, fibrous magnesium silicate
Two major types:
1. serpentine (93% of commerial use)
* Chrysotile (subtype): most common in Quebec
2. amphibole (7% of commercial use)
What are some common asbestos products and uses?
Thermal insulation
Cement products
Fireproof panels
Flooring
Roofing
etc.
Commonly exposed jobs (asbestos)
Insulators
Plumbers, pipe-fitters, steam-fitters
Electricians, carpenters, laborers
Janitors, cleaners in old buildings
Welders, grinders, cutters, machinists
Brake/clutch automechanics
etc.
What are some non-occupational asbestos exposures? (3)
- Geographic (living near mines)
- Domestic (washing spouse’s clothes)
- Environmental (household items/insulation)
Why is vermiculite insulation dangerous?
It is often contaminated by asbestos
Describe the dose-response relationship for asbestos and the diseases it can cause.
Low exposure (<1 fibre-year): pleural plaques and thickening (benign)
Intermediate exposure (1 fibre-year): mesothelioma
High exposure (25 fibre-years): asbestosis
Benign (non-cancerous) asbestos-related disease can be…(2)
- Pleural (envelope of the lung)
* hyaline plaques
* diffuse pleural thickening
* pleural effusion - Parenchymal (lung itself)
* asbestosis
Hyaline plaques (asbestos) (3)
- Indicate exposure to asbestos
- Do not affect lung (asymptomatic)
- Not compensatable
