OCCUPATIONAL LUNG DISEASE Flashcards
Which of the following particle size fractions primarily deposit in the upper respiratory tract (nose and throat)?
A) <0.1 μm
B) <2.5 μm
C) 2.5–10 μm
D) >10–15 μm
Answer: D) >10–15 μm
Rationale: Particles larger than 10–15 μm have high settling velocities in air and do not penetrate beyond the nose and throat, making them more likely to deposit in the upper respiratory tract.
Which size fraction is most responsible for carrying toxic agents deep into the lower airways?
A) 2.5–10 μm
B) <2.5 μm
C) >10 μm
D) 5–15 μm
Answer: B) <2.5 μm
Rationale: Fine-mode particles (<2.5 μm) have the highest number concentration and surface area, allowing toxic agents to deposit deep in the lower airways, making them a significant concern for respiratory health.
Which particle size category is referred to as the “ultrafine fraction” and may penetrate into the circulation?
A) 10–15 μm
B) 2.5–10 μm
C) <0.1 μm
D) 1–5 μm
Answer: C) <0.1 μm
Rationale: Ultrafine particles (<0.1 μm) are the smallest in size, tend to remain suspended in the airstream, and may deposit randomly in the alveoli. If deposited, they can penetrate into the bloodstream and reach extrapulmonary sites.
Why do coarse-mode particles (2.5–10 μm) primarily deposit in the tracheobronchial tree?
A) They have low settling velocity and remain airborne for long periods.
B) Their size and weight make them more likely to settle in the upper airways.
C) They are highly soluble in lung fluids.
D) They are generated from combustion processes.
Answer: B) Their size and weight make them more likely to settle in the upper airways.
Rationale: Coarse-mode particles (2.5–10 μm) are larger than fine and ultrafine particles, leading to deposition relatively high in the tracheobronchial tree due to their aerodynamic properties and gravitational settling.
Which of the following radiographic findings is most specifically indicative of prior asbestos exposure?
A) Ground-glass opacities
B) Pleural plaques
C) Honeycombing of the lung parenchyma
D) Cavitary lesions in the upper lobes
Answer: B) Pleural plaques
Rationale: Pleural plaques, seen as thickening or calcifications along the parietal pleura, particularly in the lower lung fields, diaphragm, and cardiac border, are a hallmark of past asbestos exposure.
*Past exposure to asbestos is specifically indicated by pleural plaques on chest radiographs, which are characterized by either thickening or calcification along the parietal pleura, particularly along the lower lung fields, the diaphragm, and the cardiac border. Without additional manifestations, pleural plaques imply only exposure, not pulmonary impairment. Benign pleural effusions also may occur.
How long is the typical latency period between initial asbestos exposure and the development of lung cancer?
A) 1–5 years
B) 5–10 years
C) 15–19 years
D) 30–40 years
Answer: C) 15–19 years
Rationale: Lung cancer associated with asbestos exposure typically has a latency period of at least 15–19 years from the time of first exposure.
Lung cancer is the most common cancer associated with asbestos exposure. The excess frequency of lung cancer (all histologic types) in asbestos workers is associated with a minimum latency of 15–19 years between first exposure and development of the disease.
Which asbestos-related disease can develop after a relatively short exposure of ≤1–2 years?
A) Asbestosis
B) Pleural effusion
C) Lung cancer
D) Mesothelioma
Answer: D) Mesothelioma
Rationale: Unlike lung cancer, which requires prolonged exposure, mesothelioma has been associated with relatively short-term asbestos exposure of ≤1–2 years, occurring even decades prior.
What type of pulmonary function test findings are characteristic of asbestosis?
A) Obstructive pattern with increased lung volumes
B) Restrictive pattern with decreased lung volumes and diffusing capacity
C) Mixed obstructive and restrictive pattern with hyperinflation
D) Normal lung volumes with decreased expiratory flow rate
Answer: B) Restrictive pattern with decreased lung volumes and diffusing capacity
Rationale: Asbestosis leads to a restrictive lung disease pattern, characterized by reduced lung volumes and diffusing capacity. Mild airflow obstruction may also be present due to peribronchiolar fibrosis.
Which of the following occupations is NOT a major source of silica exposure?
A) Stonecutting
B) Foundry work
C) Textile manufacturing
D) Sandblasting
Answer: C) Textile manufacturing
Rationale: Major occupational sources of silica exposure include mining, stonecutting, sandblasting, and foundry work. Textile manufacturing does not typically involve silica exposure.
What is the primary mechanism by which silica exposure leads to pulmonary fibrosis?
A) Direct toxicity to alveolar epithelial cells
B) Oxidative injury and macrophage dysfunction
C) Activation of eosinophils leading to allergic pneumonitis
D) Deposition of silica in airway smooth muscle
Answer: B) Oxidative injury and macrophage dysfunction
Rationale: Silica exposure leads to oxidative injury and alveolar macrophage dysfunction, which contribute to inflammation, fibrosis, and an increased risk of lung infections.
Which imaging finding is characteristic of acute silicosis?
A) Honeycombing of the lung parenchyma
B) Crazy paving pattern on HRCT
C) Tram-track sign on chest X-ray
D) Cavitary lesions in the upper lobes
Answer: B) Crazy paving pattern on HRCT
Rationale: Acute silicosis can present with a “crazy paving” pattern on HRCT, which is also seen in pulmonary alveolar proteinosis. This pattern consists of interlobular septal thickening and ground-glass opacities.
What is a hallmark radiographic feature of simple silicosis?
A) Lower lobe reticular opacities
B) Small rounded opacities in the upper lobes
C) Pleural plaques with calcification
D) Peribronchial cuffing
Answer: B) Small rounded opacities in the upper lobes
Rationale: Simple silicosis is characterized by small rounded opacities in the upper lobes, which may appear after 15–20 years of exposure and are often asymptomatic.
Which of the following conditions is a serious complication of silicosis that leads to significant functional impairment?
A) Progressive massive fibrosis (PMF)
B) Pneumothorax
C) Acute respiratory distress syndrome (ARDS)
D) Pleural effusion
Answer: A) Progressive massive fibrosis (PMF)
Rationale: PMF occurs when silicotic nodules coalesce into large fibrotic masses, leading to significant restrictive and obstructive lung impairment.
Why are individuals with silicosis at higher risk for tuberculosis?
A) Silica directly enhances mycobacterial growth
B) Silica causes alveolar macrophage dysfunction
C) Silicosis leads to hyperactive immune responses
D) Silica exposure alters airway mucus production
Answer: B) Silica causes alveolar macrophage dysfunction
Rationale: Alveolar macrophages play a crucial role in defending against tuberculosis. Silica exposure impairs their function, increasing susceptibility to Mycobacterium tuberculosis and other opportunistic lung infections.
Which of the following conditions is associated with long-term silica exposure besides silicosis?
A) Bronchial asthma
B) Autoimmune diseases such as rheumatoid arthritis
C) Idiopathic pulmonary hypertension
D) Pulmonary embolism
Answer: B) Autoimmune diseases such as rheumatoid arthritis and scleroderma.
Rationale: Silica has immunoadjuvant properties, making individuals with silicosis more susceptible to autoimmune diseases such as rheumatoid arthritis and scleroderma.
Which occupational lung disease is silica exposure classified as a probable cause of by the International Agency for Research on Cancer (IARC)?
A) Mesothelioma
B) Lung cancer
C) Chronic obstructive pulmonary disease (COPD)
D) Hypersensitivity pneumonitis
Answer: B) Lung cancer
Rationale: The International Agency for Research on Cancer (IARC) classifies silica as a probable lung carcinogen due to epidemiologic evidence linking long-term exposure to an increased risk of lung cancer.
What is the most common radiographic finding in simple CWP?
A) Honeycombing in the lower lobes
B) Small, rounded opacities in the upper lungs
C) Pleural plaques with calcification
D) Consolidation with air bronchograms
Answer: B) Small, rounded opacities in the upper lungs
Rationale: Similar to silicosis, simple CWP is characterized by small, rounded opacities in the upper lung fields, typically without significant pulmonary impairment.
What is a key difference between simple and complicated CWP?
A) Simple CWP is symptomatic, while complicated CWP is always asymptomatic
B) Simple CWP has nodules <1 cm, while complicated CWP has nodules ≥1 cm
C) Simple CWP occurs only in bituminous coal miners, while complicated CWP affects anthracite miners
D) Simple CWP causes COPD, while complicated CWP does not
Answer: B) Simple CWP has nodules <1 cm, while complicated CWP has nodules ≥1 cm
Rationale: In simple CWP, nodules are typically smaller than 1 cm and usually do not impair lung function. In complicated CWP, nodules ≥1 cm develop, which can progress to PMF.
Which of the following conditions is associated with the combination of pneumoconiotic nodules and seropositive rheumatoid arthritis?
A) Caplan syndrome
B) Goodpasture syndrome
C) Löffler syndrome
D) Kartagener syndrome
Answer: A) Caplan syndrome
Rationale: Caplan syndrome is characterized by the presence of pneumoconiotic nodules in patients with seropositive rheumatoid arthritis. It was first described in coal miners but is also seen in patients with silicosis.
Which of the following industries has the highest occupational exposure risk for Chronic Beryllium Disease (CBD)?
A) Coal mining
B) High-technology electronics manufacturing
C) Textile production
D) Asbestos removal
Answer: B) High-technology electronics manufacturing
Rationale: Beryllium is commonly used in high-technology electronics, ceramics, and alloy manufacturing, where workers are at risk of exposure and developing CBD.
Chronic Beryllium Disease (CBD) closely resembles which other pulmonary condition?
A) Tuberculosis
B) Sarcoidosis
C) Silicosis
D) Asbestosis
Answer: B) Sarcoidosis
Rationale: CBD shares clinical, radiographic, and histopathologic features with sarcoidosis, including noncaseating granulomas, but is distinguished by a positive beryllium lymphocyte proliferation test (BeLPT).
What diagnostic test is most useful for distinguishing Chronic Beryllium Disease (CBD) from sarcoidosis?
A) Chest X-ray
B) Serum calcium levels
C) Beryllium lymphocyte proliferation test (BeLPT)
D) Pulmonary function test
Answer: C) Beryllium lymphocyte proliferation test (BeLPT)
Rationale: The BeLPT identifies a specific cell-mediated immune response to beryllium, which distinguishes CBD from sarcoidosis.
What is the primary immune mechanism involved in Chronic Beryllium Disease?
A) Type I hypersensitivity (IgE-mediated)
B) Type II hypersensitivity (antibody-mediated)
C) Type III hypersensitivity (immune complex-mediated)
D) Type IV hypersensitivity (delayed-type, T-cell mediated)
Answer: D) Type IV hypersensitivity (delayed-type, T-cell mediated)
Rationale: CBD is characterized by a delayed-type hypersensitivity reaction involving beryllium-specific CD4+ T cells, leading to granulomatous inflammation.
What histopathologic feature is characteristic of Chronic Beryllium Disease?
A) Caseating granulomas
B) Noncaseating granulomas
C) Alveolar proteinosis
D) Ferruginous bodies
Answer: B) Noncaseating granulomas
Rationale: Like sarcoidosis, CBD is characterized by noncaseating granulomas in lung tissue, often requiring biopsy for definitive diagnosis.
Which human leukocyte antigen (HLA) allele is associated with an increased susceptibility to Chronic Beryllium Disease?
A) HLA-B27
B) HLA-DR4
C) HLA-DP with glutamic acid at position 69
D) HLA-A3
Answer: C) HLA-DP with glutamic acid at position 69
Rationale: Susceptibility to CBD is strongly associated with HLA-DP alleles that contain glutamic acid at position 69 of the β chain, promoting an immune response to beryllium.
What type of lung function abnormality is most commonly seen in Chronic Beryllium Disease?
A) Purely restrictive pattern
B) Purely obstructive pattern
C) Mixed restrictive and/or obstructive pattern with reduced diffusing capacity
D) Normal lung function
Answer: C) Mixed restrictive and/or obstructive pattern with reduced diffusing capacity
Rationale: Pulmonary function tests in CBD may show a combination of restrictive and obstructive deficits, as well as a decreased diffusing capacity (DLCO), similar to sarcoidosis.
Which of the following occupations carries the highest risk for developing byssinosis?
A) Coal mining
B) Cotton textile manufacturing
C) Shipbuilding
D) Electronic circuit assembly
Answer: B) Cotton textile manufacturing
Rationale: Byssinosis, also known as “Monday chest tightness,” is associated with exposure to cotton dust and endotoxins, primarily affecting workers in the textile industry.
What is the primary characteristic symptom of early-stage byssinosis?
A) Wheezing throughout the entire workweek
B) Chest tightness at the beginning of the workweek
C) Progressive pulmonary fibrosis
D) Acute fever and chills
Answer: B) Chest tightness at the beginning of the workweek
Rationale: Early-stage byssinosis presents with chest tightness occurring at the end of the first workday of the week, typically referred to as “Monday chest tightness.”
A worker in a grain storage facility presents with chronic cough, mucus hypersecretion, and wheezing. What other risk factor significantly increases their chances of developing obstructive airway disease?
A) Vitamin D deficiency
B) Lack of exercise
C) Cigarette smoking
D) Exposure to cold temperatures
Answer: C) Cigarette smoking
Rationale: The effects of grain dust exposure are additive to those of cigarette smoking, increasing the risk of obstructive lung disease, similar to chronic bronchitis and COPD.
A farmer presents with fever, chills, cough, and dyspnea 6 hours after handling moldy hay. What is the most likely diagnosis?
A) Tuberculosis
B) Farmer’s lung
C) Byssinosis
D) Coal worker’s pneumoconiosis
Answer: B) Farmer’s lung
Rationale: Farmer’s lung is a hypersensitivity pneumonitis caused by inhalation of thermophilic actinomycetes spores from moldy hay, leading to acute symptoms 4–8 hours post-exposure.
How does pulmonary function testing typically change in workers with long-term exposure to cotton dust?
A) Increased total lung capacity (TLC)
B) Reduced forced expiratory volume in one second (FEV1) over the course of a workshift
C) Increased residual volume (RV)
D) Normal lung function with no significant changes
Answer: B) Reduced forced expiratory volume in one second (FEV1) over the course of a workshift
Rationale: A significant drop in FEV1 over the workshift is a hallmark of byssinosis, especially in affected workers at the beginning of the workweek.
