Occupational Environmental Lung Disease Flashcards
new associations between exposure and disease may be identified
nylon flock worker’s lung disease and diacetyl-induced bronchiolitis obliterans
Exposures to inorganic and organic dusts can cause interstitial lung disease that presents with——
decreased diffusing capacity
restrictive pattern
small rounded opacities
silicosis or coal worker’s pneumoconiosis
small linear opacities
asbestosis
a history of asbestos exposure, conventional computed tomography (CT) is more sensitive for the detection of pleural thickening, and high-resolution CT (HRCT) improves the detection of asbestosis.
Water- soluble gases
ammonia
dioxide
are absorbed in the lining fluid of the upper and proximal airways and thus tend to produce irritative and bronchoconstrictive responses
Less water soluble
nitrogen dioxide and phosgene
may penetrate to the bronchioles and alveoli in sufficient quantities to produce acute chemical pneumonitis
particles >10–15 μm in diameter
Particles <10 μm in size
diameter do not penetrate beyond the nose and throat
deposited below the larynx
Particles ~2.5–10 μm (coarse-mode fraction)
contain crustal elements such as silica, aluminum, and iron
mostly deposit relatively high in the tracheobronchial tree
particles <2.5 μm (fine-mode fraction)
toxic agents can deposit and be carried to the lower airway
fine particles are created primarily by the burning of fossil fuels or high-temper-ature industrial processes resulting in condensation products from gases, fumes, or vapors
smallest particles, those <0.1 μm in size
ultrafine fraction and make up the largest number of particles; they tend to remain in the airstream and deposit in the lung only on a random basis as they come into contact with the alveolar walls
penetrate into the circulation and be carried to extrapulmonary sites
ASBESTOS-RELATED DISEASESg
Asbestos: generic term for several different mineral silicates, includ-ing chrysolite, amosite, anthophyllite, and crocidolite
manufacture of fire-resistant textiles, in cement and floor tiles, and in friction materials such as brake and clutch linings.
major health effects from exposure to asbestos
pleural and pulmonary fibrosis, cancers of the respiratory tract, and pleural and peritoneal mesothelioma
diffuse interstitial fibrosing disease of the lung that is directly related to the intensity and duration of exposure.
Asbestosis
oxidative injury due to the generation of reactive oxygen species by the transition metals on the surface of the fibers as well as from cells engaged in phagocytosis.
thickening or calcification along the parietal pleura, particularly along the lower lung fields, the diaphragm, and the cardiac border.
hallmark of asbestosis
Irregular or linear opacities that usually are first noted in the lower lung fields are the chest radiographic hallmark of asbestosis.
heart border or a “ground-glass” appearance in the lung fields may be seen
Pulmonary function testing in asbestosis reveals a restrictive pattern with a decrease in both lung volumes and diffusing capacity
oldest known occupational pulmonary hazards,
free silica (SiO2), or crystalline quartz, is still a major cause of disease.
sandblasting in confined spaces, tunneling through rock with a high quartz content (15–25%), or the manufacture of abrasive soaps may develop acute silicosis with as little as 10 months of exposure
chest radiograph may show profuse miliary infiltration or consolidation, and there is a characteristic HRCT pattern known as “crazy paving”
long-term, less intense exposure, small rounded opacities in the upper lobes may appear on the chest radiograph after 15–20 years of exposure, usually without associated impairment of lung function
simple silicosis)
Calcification of hilar nodes may occur in as many as 20% of cases and produces a characteristic “eggshell” pattern.
The nodular fibrosis may be progressive in the absence of further exposure, with coalescence and formation of nonsegmental conglomerates of irregular masses >1 cm in diameter
complicated silicosis
These masses can become quite large, and when this occurs, the term progressive massive fibrosis (PMF) is applied.
COAL WORKER’S PNEUMOCONIOSIS (CWP)
50% of anthracite miners with >20 years of work on the coal face
prevalence of disease is lower in workers in bituminous coal mines
As in silicosis, the presence of these nodules (simple CWP) usually is not associated with pulmonary impairment.
Complicated CWP is manifested by the appearance on the chest radiograph of nodules ≥1 cm in diameter generally confined to the upper half of the lungs
Caplan syndrome
first described in coal miners but subsequently in patients with silicosis, is the combination of pneumoconiotic nodules and seropositive rheumatoid arthritis. Silica is often present in anthracitic coal dust and its presence may contribute to risk of PMF.
CHRONIC BERYLLIUM DISEASE
Beryllium
lightweight metal with tensile strength, good electrical conductivity, and value in the control of nuclear reactions through ability to quench neutrons
May cause
acute pneumonitis
more commonly associated with a chronic granulomatous inflammatory disease that is similar to sarcoidosis
Organic Dust
3
Cotton dust
Grain dust
Farmers dust lung
Cotton Dust (Byssinosis)
cotton dust (but also to flax, hemp, or jute dust) in the production o yarns for textiles and rope making are at risk for an asthma-like syndrome known as byssinosis.
The risk of byssinosis is associated with both cotton dust and endotoxin levels in the workplace environment.
Byssinosis is characterized
clinically as occasional (early-stage) and then regular (late-stage) chest tightness toward the end of the first day of the workweek (“Monday chest tightness”).
Exposed workers may show a significant drop in FEV1 over the course of a Monday workshift.
After >10 years of exposure, workers with recurrent symptoms are more likely to have an obstructive pattern on pulmonary function testing.
Grain Dust
presentation of obstructive airway disease in grain dust–exposed workers is virtually identical to the characteristic findings in cigarette smokers, i.e., persistent cough, mucus hypersecretion, wheeze and dyspnea on exertion, and reduced FEV1 and FEV1/FVC (forced vital capacity) ratio
Dust concentrations in grain elevators >10,000 μg/m3
obstructive ventilatory
byssinosis, endotoxin may play a role in grain dust–induced chronic bronchitis and COPD
Farmer’s Lung
exposure to moldy hay containing spores of thermophilic actinomycetes that produce a hypersensitivity pneumonitis (Chap. 282). A patient with acute farmer’s lung presents 4–8 h after exposure with fever, chills, malaise, cough, and dyspnea without wheezing
Patchy fibrosis
TOXIC CHEMICALS
283
Fluoropolymers such as Teflon
become volatilized upon heating. The inhaled agents cause a characteristic syndrome of fever, chills, malaise, and occasion-ally mild wheezing, leading to the diagnosis of polymer fume fever
Nylon flock- cause induce lymphocytic bronchiole ‘tis
Workers exposed to diacetyl which provide butter flavour in manufacture of microwave popcorn and other foods develop
Bronchiolitis obliterances
Disability i
the decreased ability to work due to the effects of a medical condition.
impairment
assess physiologic dysfunction,
individual be unable to do any work (i.e., total disability) before he or she will receive income replacement payments. Many state workers’ compensation systems allow for payments for partial disability.
Particulate matter emission from a coal-fired power plant may react in air to produce acid surfaces and aerosols
Sulfur dioxide
Oxides of nitrogen and volatile organic
compounds from automobile exhaust react with sunlight to produce ozone
