Pneumoconiosis

Question 1

pneumoconiosis

Answer 1

the accumulation of mineral dusts inciting tissue reactions that range from minimal reversible stromal reactions to interstitial fibrosis that results in permanent scarring

Question 2

silicosis

Answer 2

a chronic lung disease due to inhalation of crystalline silica (usually quartz)

characterized by progressive parenchymal nodules and pulmonary fibrosis

upper lobe disease

Question 3

epidemiology of silicosis

Answer 3

most prevalent chronic occupational lung disease worldwide

risk is directly proportional to particle concentration, duration of exposure, and silica content of different rock types

Question 4

Describe the common histologic features of pneumoconiosis

Answer 4

1) acellular hyalinized collagen
2) layered collagen
3) thick capsule

Question 5

factors that increase dust deposition in the lung

Answer 5

exertion

younger age

close proximity to sources of dust

acute or chronic lung disorders

Question 6

fast phase clearance

Answer 6

half-time of 3.0 +/ 1.6 hrs

mucociliary clearance

does not remove all particles deposited in the larger airways

Question 7

slow phase clearance

Answer 7

half-time of 109 +/- 78 days

depends on lung scavenger cells (macrophages)

Question 8

pathogenesis of mineral dust pulmonary toxicity

Answer 8

injury due to dust particle inhalation

silica engulfed by macrophages to form nodules

mitochondria - ROS/RNS and DNA damage

apoptosis and fibrotic response

scarring of the lungs

Question 9

chronic silicosis

Answer 9

characterized by nodules that are typically located in the peribronchial regions with interstitial extension

Question 10

common CXR findings of chronic silicosis

Answer 10

small 1-3 mm nodules

symmetrical bilateral upper lobes

calcified nodules

hilar LN with eggshell clacification

Question 11

pulmonary function test for chronic silicosis

Answer 11

often normal early

later on will have - decreased lung volumes and diffusion capacity

eventual airway obstruction

Question 12

progressive massive fibrosis

Answer 12

a state of silicosis where nodules expand and coalesce into large massis that can undergo necrosis

Question 13

acute silicosis

Answer 13

characterized by diffuse fluid-filled alveolar spaces that consist of eosinophilic proteinaceous and surfactant-containing material

Question 14

pathology of acute silicosis

Answer 14

alveolar proteinosis, poorly formed nodules, intersitial infiltrates

Question 15

acute silicosis CXR

Answer 15

alveolar pattern - ground glass

Question 16

HRCT of acute silicosis

Answer 16

“crazy paving” - ground glass + septal thickening

Question 17

management of silicosis

Answer 17

avoidance

no established treatment - lung transplant

treat mycobacterial infections as silica impairs alveolar macrophages

Question 18

“angel wing” appearance

Answer 18

the symmetrical appearance of PMF

Question 19

coal worker’s pneumoconiosis

Answer 19

also called “black lung” or “antraco-silicosis”

due to chornic exposure to coal dust, graphite, and other forms of carbon

black nodules

carbon is less fibrogenic than quartz

Question 20

pathology of coal workers’ pneumoconiosis

Answer 20

greater dust burden

black lung nodules (randomly arranged)

black lymph nodes

centrilobular emphysema

coal-laden alveolar macrophages

coal macules can develop into PMF if many coalesce

Question 21

clinical manifestations of CWP

Answer 21

simple, complicated, and PMF

chronic bronchitis is a more prominent feature

an acute onset form of the disease does not occur

advanced disease can have cough, SOB, and cor pulmonale

Caplan’s Syndrome

Question 22

simple CWP

Answer 22

most common and typically occurs after low-dose coal exposure for more than 20 years

relatively asymptomatic but can develop cough and sputum production

Question 23

characteristic HRCT findings in CWP

Answer 23

focal emphysema

punctate opacities

subpleural nodules

PMF

cavitating masses

diffuse interstitial pulmonary fibrosis

bronchiectasis

Question 24

PFT in CWP

Answer 24

restricted lung volumes

reduced DLCO

mixed restricted/obstructive defects

in PMF, severe mixed restriction and obstruction

not as bad as silicosis

also no cancer risk!

Question 25

treatment of CWP

Answer 25

no established treatment look out for complicating mycobacterial infections

Question 26

asbestos-related diseases

Answer 26

asbestos naturally occurs in silicate fibers, ideal for construction long latency of 15-40 years from exposure to disease cause nonmalignant and malignant inflammatory pulmonary diseases

Question 27

asbestos fiber types

Answer 27

serpentine and amphibole fibers

Question 28

serpentine asbestos fibers

Answer 28

curly-stranded, curved structures 95% of insulation is chrysotile, which is a type of serpentine fiber not as bad as amphibole fibers

Question 29

amphibole asbestos fibers

Answer 29

straight, rod-like fibers more harmful than serpentine fibers amphibole hypothesis - crocidolite is especially more carcinogenic and fibrogenic accumulate more readily in the distal lung parenchyma, not as effectively cleared

Question 30

Describe the mechanism underlying free radical generation by asbestos fibers.

Answer 30

due to reactions occurring on surface of the mineral dusts mitochondrial dysfunction and activation of AMs or neutrophils attempt to take upf fibers coated with iron inside the macrophages and become **ferruginous bodies** **asbestos body** is used to define coated fibers where the core fiber is asbestos

Question 31

How does asbestos fibers proomte pulmonary toxicity?

Answer 31

induce AM mitochondrial H2O2 production via a Rac1-dependent mechanism ROS production activates NALP3 inflammasomes that trigger inflammatory signaling

Question 32

asbestos-induced pleural plaques

Answer 32

discreet collagenous material along parietal pleura of the mid-lower ribs and diaphragm latency is greater than 20 years prevalence varies with intensity of exposure long fibers are retained in the parietal pleura and can block the stomata fairly specific to asbestos exposure and rarely affects PFTs

Question 33

clinical manifestations of asbestos exposure

Answer 33

benign asbestos pleural effusions (BAPE) pleural plaques rounded atelectasis malignant mesothelioma asbestosis lung cancer

Question 34

rounded atelectasis

Answer 34

a distinct form of pleural/parenchymal thickening that is characterized by its major radiographic inding, the "comet tail sign" as pleural fibrosis progresses, it can entrap the underlying healthy lung and bronchovascular tissue

Question 35

malignant mesothelioma

Answer 35

rare tumor caused by all forms of asbestos no synergy with tobacco smoke latency period of \> 30 years

Question 36

clinical manifestation of malignant mesothelioma

Answer 36

male predominant, insiduous onset nonspecific symptoms such as fever, weight loss, night sweats, and fatigue dyspnea, nonpleuritic chest pain, and cough may also occur stain positive for vimentin, keratin, and calretinin

Question 37

management of malignant mesothelioma

Answer 37

cisplatinum +/- pemextred -\> 9-12 month survival chemo, radiation, and surgery -\> median survival 22 months

Question 38

favorable prognostic signs of malignant mesothelioma

Answer 38

\< 5% of total body weight loss tumor confined to the ipsilateral pleura epithelioid histology good performance status platelets \< 400,000 age \< 60

Question 39

asbestosis

Answer 39

slowly progressive, diffuse pulmonary fibrotic process present with exertional dyspnea 20 year latency period pleural plaques present in 80-90% similar IPF findings but with plaques PFTs show decreased lung volumes and DLCO below normal end-inspiratory bibasilar crackles, clubbing, and cor pulmonale

Question 40

diagnosis of asbestosis

Answer 40

a reliable exposure history an appropriate latency period characteristic chest radiograph of HRCT interstitial abnormalities reduced lung volumes and/or DLCO end-inspiratory crackles \*\*unlike IPF, asbestosis is slowly progressive

Question 41

What are the two most common causes of hard metal lung disease?

Answer 41

beryllium and cobalt

Question 42

berylliosis

Answer 42

identical to sarcoid clinically, radiographically, and pathologically an important early marker is the proliferation of T lymphocytes proliferating in the lung and the blood up to 10 years of latency PFT shows reduced volumes and DLCO slow decline that can result in cor pulmonale

Question 43

treatment for berylliosis

Answer 43

steroids are administered elimination of further exposure high correlation between berylliosis and lung cancer

Question 44

cobalt-associated disease

Answer 44

airway obstruction that resembles occupational asthma acute interstitial pneumonitis with features of hypersensitivity pneumonitis chronic diffuse interstitial fibrosis characteristic diagnostic feature is the presence of odd-appearing giant multinucleated cells