Pneumoconiosis Flashcards
pneumoconiosis
the accumulation of mineral dusts inciting tissue reactions that range from minimal reversible stromal reactions to interstitial fibrosis that results in permanent scarring
silicosis
a chronic lung disease due to inhalation of crystalline silica (usually quartz)
characterized by progressive parenchymal nodules and pulmonary fibrosis
upper lobe disease
epidemiology of silicosis
most prevalent chronic occupational lung disease worldwide
risk is directly proportional to particle concentration, duration of exposure, and silica content of different rock types
Describe the common histologic features of pneumoconiosis
1) acellular hyalinized collagen
2) layered collagen
3) thick capsule
factors that increase dust deposition in the lung
exertion
younger age
close proximity to sources of dust
acute or chronic lung disorders
fast phase clearance
half-time of 3.0 +/ 1.6 hrs
mucociliary clearance
does not remove all particles deposited in the larger airways
slow phase clearance
half-time of 109 +/- 78 days
depends on lung scavenger cells (macrophages)
pathogenesis of mineral dust pulmonary toxicity
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
chronic silicosis
characterized by nodules that are typically located in the peribronchial regions with interstitial extension
common CXR findings of chronic silicosis
small 1-3 mm nodules
symmetrical bilateral upper lobes
calcified nodules
hilar LN with eggshell clacification
pulmonary function test for chronic silicosis
often normal early
later on will have - decreased lung volumes and diffusion capacity
eventual airway obstruction
progressive massive fibrosis
a state of silicosis where nodules expand and coalesce into large massis that can undergo necrosis
acute silicosis
characterized by diffuse fluid-filled alveolar spaces that consist of eosinophilic proteinaceous and surfactant-containing material
pathology of acute silicosis
alveolar proteinosis, poorly formed nodules, intersitial infiltrates
acute silicosis CXR
alveolar pattern - ground glass
HRCT of acute silicosis
“crazy paving” - ground glass + septal thickening
management of silicosis
avoidance
no established treatment - lung transplant
treat mycobacterial infections as silica impairs alveolar macrophages