Occupational Lung Dz

Question 1

Occupational Asthma

Answer 1

Immunologic: onset 1-2 years after exposure

Irritant induced: symptoms within 24 h of exposure
- due to direct damage to airway epithelium

Work aggravated: preexisting asthma worse at work

Airway hyperresponsiveness + IgE (for immunologic or work aggravated, not irritant induced)

Question 2

Silicosis

Answer 2

Inhaling silica –> direct toxicity to alveolar epithelium & is ingested by macrophages –> release of ROS, cytokines, etc. –> recruitment of inflammatory cells to the alveolar space

Can be acute, accelerated, chronic, progressive massive fibrosis

Acute: alveolar filling

Chronic & accelerated are similar, but accelerated is perhaps autoimmune/ related to increased reactivity to the particle
- silicotic nodules, eggshell calcification

PMF: coalescence of silicotic nodules = swirl of collagen

Higher risk of TB, immune mediated dz, bronchitis/airflow obstruction, lung cancer

Treat w corticosteroids, lung lavage, transplantation

Question 3

Coal Workers’ pneumoconiosis

Answer 3

Black lung disease: very similar to silicosis in all ways except histopathologically & microscopically- you see black areas

“coal macule” = pigment laden macrophages –> ingestion of coal dust w/recruitment of GFs, cytokines, and inflammatory mediators

Simple & complicated forms

Increased risk of TB

Question 4

Asbestosis

Answer 4

Exposure –> alveolar epithelial cell injury, recruitment of inflam cells, release of GFs, cytokines, proteases, ROS –> fibrosis: alveolar epithelial cell apoptosis, fibroblast prolif, collagen deposition

Bilateral pleural plaques, bronchiolar-alveolar fluid or biopsy with increased asbestos fibers or asbestos bodies

Cough, dyspnea, interstitial fibrosis, restrictive PFTs

HRCT: lower lobe subpleural linear interstitial markings, parenchymal bands, intra & interlobular septal thickening, honeycomb, pleural plaques

Question 5

Asbestos related pleural dz

Answer 5

Pleural plaques: acellular nodular bundles found on parietal pleura along 6-9 rib

Pleural adhesions: pleural inflam & fibrosis, can cause contraction of pleura & collapse of adjacent lung; comet tail appearance on CT (distinguish from tumor)

Question 6

Berylliosis

Answer 6

Granulomatous ILD, noncaseating- resembles sarcoidosis; distinguish based on immunologic rxn to Be

Dry cough, dyspnea, constitutional symptoms; can be latent 3 months-30 years

Crackles on lung exam +/- cutaneous nodules

+/- hypercalcemia, granulomatous hepatitis, nephrolithiasis

PFTs: mixed obstructive-restrictive pattern

Radiology: hilar LAN, upper lobe reticulonodular opacities, interstitial fibrosis, honeycomb

Question 7

Hypersensitivity Pneumonitis

Answer 7

Granulomatous interstitial pneumonia

2ndary to repetitive inhalation of organic Ag’s

Acute: flu like, within few hours of exposure

Subacute/chronic: cough, fatigue, dyspnea, weight loss, centrilobular nodules, reticular changes, fibrosis

CT: ground glass opacities, centrilobular nodules, air trapping

biopsy: loosely formed airway centered granulomas, interstitial lymphocytic infiltrate