Occupational & Traumatic Disorders

Question 1

Define acute respiratory distress syndrome

Answer 1

Manifestation of severe acute lung injury

Question 2

Define acute lung injury

Answer 2

Abrupt onset of hypoxemia and bilateral pulmonary infiltrates in the absence of heart failure

Question 3

Both ARDS & ALI involve inflammation-associated increases in _______.

Answer 3

1. pulmonary vascular permeability
2. edema
3. epithelial cell

Question 4

Define diffuse alveolar damage (DAD)

Answer 4

Histologic manifestation of ARDS/ALI

Question 5

Describe the pathophysiology of ARDS/ALI

Answer 5

Injury → neutrophil recruitment & endothelial activation/injury → release of proteases, ROS → leakage of proteins into alveoli → hyaline membrane → interference w/gas exchange.

Question 6

Answer 6

• blue arrow: collapsed alveoli
• black arrows: hyaline membranes formed due to damage (these interfere with gas exchange & decrease lung compliance)

Question 7

Answer 7

Organizing phase of ALI/ARDS. About one week after the initial injury, fibroblasts begin to proliferate within the alveolar walls.

• Yellow arrow: scattered residual alveoli containing proteinaceous fluid
• Yellow circle: alveolar wall which is thickened by loosely arranged fibroblastic tissue (i.e. granulation tissue).

Question 8

ARDS/ALI clinical presentation

Answer 8

1. Tachypnea
2. Dyspnea → hypoxemia
3. Respiratory acidosis (⇡ PCO₂)

(mechanical ventilators often become necessary)

Question 9

Prognosis of ARDS/ALI

Answer 9

40% mortality

(survivors may heal with fibrosis → chronic pulmonary disease)

Question 10

CXR findings of ARDS/ALI

Answer 10

Diffuse bilateral infiltrates

Question 11

Define pneumoconiosis

Answer 11

Lung disease caused by the inhalation of mineral or organic dust or chronic or vapors

(typically occupational disease)

Question 12

Many cases of pneumoconiosis results in _______.

Answer 12

pulmonary fibrosis

(regulations limiting worker exposure have decrease this)

Question 13

List 4 factors that increase the likelihood of pneumoconiosis development

Answer 13

1. Amount of dust retained in the lungs
2. particle size of 1-5 micrometers in diameter
3. Particle solubility
4. genetics

Question 14

The most common chronic occupational disease in the world

Answer 14

Silicosis

(type of pneumoconiosis)

Question 15

Define silicosis

Answer 15

Fibrosing lung disease caused by inhalation of silicon dioxide (silica) particles

Question 16

most commonly implicated particle in silicosis

Answer 16

Quartz

Question 17

Silica occurs in both crystalline and amorphous forms. _____ is more fibrogenic. ______ is more pathogenic.

Answer 17

• Crystalline
• Amorphous

Question 18

Pathogenesis of silicosis

Answer 18

macrophages phagocytize a silica particle → become activated → inflammatory mediators released → fibrosis

Question 19

Answer 19

Silicosis

(Black Arrow: dense fibrosis)

Question 20

Answer 20

silicotic nodule composed of dense collagenous fibrous connective tissue

(these coalesce)

Question 21

Answer 21

Silicotic nodule w/birefringent silica particles

Question 22

3 Occupations at risk for silicosis

Answer 22

1. miners
2. Sand blasters
3. Quartz stone cutters

Question 23

CXR findings for silicosis

Answer 23

Fine nodularity in the upper zones of the lung

Question 24

silicosis is associated with an increased susceptibility to ______

Answer 24

tuberculosis

(“slow to kill” disease; most patients do not developed dyspnea until they have massive fibrosis)

Question 25

Define asbestos

Answer 25

a family of hydrated silicates that form fibers

Question 26

Occupational exposure to asbestos is linked to ______(6).

Answer 26

1. pleural plaques
2. Pleural effusion
3. Pulmonary interstitial fibrosis (asbestosis)
4. Lung carcinoma
5. Mesothelioma
6. Laryngeal, ovarian malignancies

Question 27

The oncogenicity related to asbestos-related disease is due to the _____.

Answer 27

Generation of free radicals and adsorption of carcinogens on to the fibers

Question 28

Answer 28

asbestosis

Question 29

Define asbestosis

Answer 29

interstitial fibrosis due to asbestos exposure

Question 30

Answer 30

Asbestos bodies (golden-brown beaded batons)

Question 31

Answer 31

pleural plaques due to asbestos exposure

Question 32

Define hypersensitivity pneumonitis

Answer 32

Immune-mediated lung disorders caused by exposure to inhaled organic antigens (bacterial, fungal or animal proteins)

Question 33

Hypersensitivity pneumonitis is also known as

Answer 33

Extrinsic allergy alveolitis

(important to recognize these disorders early)

Question 34

Farmer’s lung: source of antigen

Answer 34

Thermophilic actinomycetes spores in warm moist air

Question 35

Pigeon breeder’s lung: source of antigen

Answer 35

Proteins from serum, excreta or feathers of birds

Question 36

Humidifier lung: source of Antigen

(air conditioner)

Answer 36

thermophilic bacteria and heated water reservoirs

Question 37

hypersensitivity pneumonitis pathogenesis: type III hypersensitivity

Answer 37

complement and Igs in vessel walls

Question 38

Hypersensitivity pneumonitis pathogenesis: Type IV hypersensitivity

(delayed type: after 2-3 days)

Answer 38

noncaseating granulomas

Question 39

Hypersensitivity pneumonitis clinical symptoms: acute attack (4)

Answer 39

1. Fever
2. Dyspnea
3. Cough
4. Leukocytosis

Question 40

CXR findings: hypersensitivity pneumonitis

Answer 40

Interstitial infiltrates

Question 41

Hypersensitivity pneumonitis: Long-term exposure symptoms

Answer 41

Progressive respiratory failure with a restrictive pattern

Question 42

Answer 42

hypersensitivity pneumonitis: noncaseating interstitial granuloma containing a Langhans giant cell (yellow arrow) consistent with a type IV hypersensitivity reaction.

(If exposure to the offending antigen persists, then the patient can go on to develop interstitial fibrosis, obliterative bronchiolitis and honeycombing).