Occupational Respiratory Diseases
Workplace Exposures That Result in Occupational Respiratory Disease
Occupational respiratory disease can be defined as an acute or chronic disorder that arises from the
inhalation of an airborne agent in the workplace.
It can involve any of the 3 areas of the respiratory system:
1) The airways
2) The lungs or parenchyma
3) The pleura or covering of the lung
Occupational disease fall info several major categories:
1) Irritant reactions - airways
2) Asthmatic responses - airways
3) Hypersensitivity reactions - lung tissue
4) Pneumoconiosis or dust-related diseases - lung tissue
1) Irritant Reactions:
Characteristics of some common irritant gases and fumes.
Many gases, fumes and aerosols are acutely toxic to the respiratory tract causing
acute inflammation of the respiratory mucosa and parenchyma. Toxicity and effect
depends on the agents, water solubility and particle size. Highly soluble agents
dissolve readily in the secretions of the eyes, upper respiratory tract, nose,
pharynx and airways. Less soluble agents affect the small airways and lung
parenchyma. High concentrations, exercise or heavy work also have an impact.
Acute Bronchitis
- characterized by persistent oversecretion of mucous due to irritants
- plasma, the liquid part of blood leaks into airways and alveoli
- plasma becomes frothy when mixed with air and clogs up alveolar passages
- severe breathing problems especially if large areas are involved
- takes a long time to clear out the lungs
Characteristics Of Some Common Irritant Gases and Fumes
| Agent | Industrial Sources and Uses | Solubility in Water
|
|---|
Ammonia
| Production of fertilizers, explosives, various chemicals
| High
| Cadmium oxide
| Jewelry making, silver soldering and brazing, smelting, art pigments
| High
| Hydrogen chloride
| Pickling operations, chemical manufacturing, electroplating
| High
| Hydrogen fluoride
| Etching and polishing glass, plastics manufacturing, insecticides
| High
| Sulfur dioxide
| Paper and pulp manufacturing, smelting operations, chemical production,
combustion of coal
| High
| Chlorine
| Wide use in chemical industry, water purification, bleaching
| Moderate
| Vanadium Pentoxide
| Boiler scaling, chemical industry
| Moderate
| Mercury vapour
| Gold extraction, mercury lamps
| Low
| Oxides of nitrogen
| Chemical and fertilizer manufacturing, metal processing,silage, welding,
manufacturing of explosives
| Low
| Ozone
| Disinfectant bleaching, oxidizing agent
| Low
| | Phosgene
| Production of plastics, pesticides, combustion production of chlorinated
hydrocarbons
| Low
|
2. Asthmatic Response – Airway Disease
Occupational asthma is defined as variable airway narrowing related to exposure
in the working environment to airborne dusts, gases, vapours or fumes. It can
appear after a variable period of symptomless exposure to a sensitizing agent at
work. Another definition includes agents that produce bronchoconstriction by
mechanisms other than the immune system as seen in the highly reactive chemicals
of low molecular weight such as diisocyanates, formaldehyde and ozocarbanide.
Airway - Occupational Asthma
- response to some specific hazard in the workplace
- occurs mainly in small bronchi and bronchioles
- muscles in these airways contract in a spasm that narrows the airways
- chest tightening
- victim wheezes and struggles for breath
- thick, sticky mucous is secreted
- mucous is difficult to clear from airways
Reactive Airway Disease (RADS)
Variant of asthma
| Agent | Industries & Occupations
|
|---|
| Vegetable & Wood Dusts:
|
|---|
| Grain | Grain handlers
| | Flour (wheat/rye) | Millers, bakers
| | Coffee beans | Planters, processors
| | Castor beans | Oil producers
| | Tea dust | Tea workers
| | Tobacco | Tobacco workers
| | Western red cedar | Saw mills, carpenters
| | California redwood | cabinet-makers
| | Oak | other woodworkers
| | Mahogany | construction workers
| | Colophony (pine resin) | Electronics workers
| | Gum acacia | Printers
| | Animals, birds, shellfish:
|
|---|
| Rats | Animal handlers
| | Mice | laboratory workers, veterinarians
| | Guinea pigs |
| | Rabbits |
| | Pigeons | Pigeon breeders
| | Chickens | Poultry workers
| | Turkeys | Poultry workers
| | Crabs | Crab processors
| | Prawns | Prawn processors
| | Oysters | Oyster farmers
| | Enzymes |
| | Subtilisins | Detergent Manufacturing
| | Papain | Meat packaging
| | Trypsin | Pharmaceutical workers
| | Pepsin | Pharmaceutical workers
| | Metals:
|
|---|
| Platinum and salts | Platinum refining and plating
| | Chromium salts | Tanning or leather
| | Nickel | Metal plating
| | Cobalt | Manufacturing of hard metals
| | Vanadium | Manufacturing of hard metals
| | Miscellaneous:
|
|---|
| Toluene diisocyanate (TDI) | Manufacturing of polyurethance foam,
painters, plastics manufacturing
| | Diphenylmethane diisocyanate(MDI)
| Core makers in foundries, painters
| | Phthallic anhydride | Epoxy resins, plastics
| | Trimellific anhydride | Epoxy resins, plastics
| | Formaldehyde
| Hospital workers, laboratory technicians, chemical workers
| | Azodicarbonamide | Plastics and rubber workers
| | Ethanolamines | Solderers, spray painters, metal machining
|
3. Hypersensitivity Reactions
Lung - Allergic Alveolitis
- response to some specific hazard in the workplace, usually several hours
after exposure
- occurs in the alveoli and surrounding tissue
- alveolar walls become swollen and distribution of white blood cells is
disturbed
- symptoms of headaches, cough, fever, difficulty in breathing may last
for several hours and days
- symptoms are serious enough to warrant emergency treatment
- symptoms resolve spontaneously within several days on removal of the
patient from exposure
- may be a progression to lung fibrosis -from mild to severe
4. Pneumoconiosis Occupational Pulmonary Fibrosis
Involvement with the Lung Tissue
Fibrosis develops as a result of macrophages dying and spilling their enzymes
in the lung tissue.
- a thickened non-elastic tissue appears in the lung tissues causing
increased stiffness
- restricts small airways and alveoli to respond to pressure changes
- silica, asbestosis seen occasionally in people who are hypersensitive
to agricultural dusts
- silica can spread fibrosis
- established disease is called Progressive Massive Fibrosis or PMF
- it is usually fatal
| Condition | Agent(s) | Nature of Antigen
|
|---|
Farmer's lung
| Moldy hay, grain, straw
| Microployspora faeni, thermoactinomyces vulgaris
| Bird-breeder's lung
| Feathers and droppings
| Avian proteins
| Humidifier fever (air conditioner)
| Humidifier aerosols
| Thermophilic actinomyces, amoebae
| Bagassosis
| Moldy sugar cane
| Thermoactinomyces sacchari
| Mushroom worker's Lung
| Moldy barley
| Aspergillus clavatus
| Animal handler's lung
| Dust's dander
| Urine and serum proteins
| Diisocyanate alveolitis
| Polyurethane foam
| Toluene diisocyanate
| Pyrethrum alveolitis
| Insecticide aerosols
| Pyrethrums
|
Coal workers' pneumoconiosis
Asbestosis - asbestos workers and miners
Siderosis - welder's lung
Silicosis - miners, pottery making, foundry glass, tiles, bricks, berylliosis
Byssinosis - cotton workers' brown lung
|
