1) Pneumoconiosis refers to lung diseases caused by inhaling mineral dust including coal workers' pneumoconiosis and silicosis. 2) Silicosis results from inhaling crystalline silica and presents as nodular lesions in the lungs. Chronic exposure over many years leads to fibrosis. 3) Asbestosis is caused by inhaling asbestos fibers which penetrate deep into the lungs and cause interstitial fibrosis over time with extensive exposure. Asbestos is also linked to pleural plaques, mesothelioma, and lung cancer.

1. PNEUMOCONIOSIS
Dr Vijay Shankar S

3. 28TH APRIL
WORLD DAY
FOR SAFETY & HEALTH AT WORK
is an annual international campaign to promote safe, healthy
and decent work. Has been observed by the International
Labor Organization (ILO) since 2003.

4. Theme-2014
“Safety and health in the
use of chemicals at work“

5. Theme-2015
• “Join in building a culture of prevention on
Occupational Safety and Health”

7. PNEUMOCONIOSIS

8. Introduction
 Coined from the Greek (pneumo = lung,
konis =dust) & introduced in the 19th
century to describe lung diseases due to
the inhalation of mineral dust
 May have been first described by
Hipprocrates in a metal digger’s difficulty
in breathing

10. PATHOGENESIS- GENERAL ASPECTS
• The development of a pneumoconiosis depends
on
1. the amount of dust retained in the lung and
airways;
2. the size, shape, and therefore buoyancy of the
particles;
3. particle solubility and physiochemical
reactivity; and
4. the possible additional effects of other
irritants (e.g., concomitant tobacco smoking).

11. • In general, only a small percentage of
exposed people develop occupational
respiratory diseases,
implying
a genetic predisposition to their development!!

12. COAL WORKERS
PNEUMOCONIOSIS

14. THE SPECTRUM
Asymptomatic
anthracosis
Simple CWP
with little to no
pulmonary
dysfunction
Complicated CWP, or
progressive massive
fibrosis (PMF), in
which lung function
is compromised

16. SILICOSIS

17. Silicosis
 Has been recognized for hundreds of
years as occupational hazard of
stonecutters
 Silica comprises some 25% of earth’s
crust
 Degree of exposure varies considerably
with the type of rock mined
– Sandstone consist of 100% silica

18. High Risk Occupations

19. Foundry worker Sand blasting
Hard rock mining
Stone cutting

20. SILICA
CRYSTALLINE AMORPHOUS
Quartz,
crystobalite, and
tridymite

21. Silicosis
 Silicosis refers to the lung disease
attributed to the inhalation of
crystalline silicon dioxide (silica)
 Most common occupational lung disease
worldwide
 Estimated 1 million workers are exposed
to high levels of silica

22. PATHOGENESIS
Inhalation of crystalline silica
Interact with epithelial cells &
macrophages
Release of mediators
fibrosis

24. Pathology
Pathology of silicosis is based on
chronicity, incubation time & level
of exposure

25. Classification
 Chronic or Classic Silicosis
 Accelerated Silicosis
 Acute Silicosis

26. Chronic Silicosis
 Most common form
 Exposure 20-40 yrs
 Hallmark of chronic
form is the silicotic
nodule or islet
 Silicotic islet develops
in the hilar lymph nodes
& calcify
 Disease progress to
fibrosis of the upper
lobe

27. Accelerated Silicosis
 Similar to chronic silicosis but exposure is
shorter & heavier (<10yrs)

28. Acute Silicosis
 Intense exposure to
high silica dust occurs
over months
 Acute silicosis may
show features similar to
pulmonary alveolar
proteinosis with silica
particles identified in
proteinaceous material
 Rarely seen in the US

29. Clinical Features
 Dyspnea-initially with exercise
 Cough with or without sputum
 Wheezing or chest tightness which can
lead to respiratory failure

30. Chest X-ray of Uncomplicated
Silicosis
 Enlargement of hilar nodes may precede
parenchymal disease
 Uncomplicated silicosis has small round
opacities
 Egg-shell calcification of the hilum is
suggestive of silicosis
 Occasional can calcify

32. morphology

33. Complication of Silicosis
 M. tuberculosis/
Atypical
mycobacterium
 Rates of TB range
from 5-43%
 Factors that may
influence is the stage &
type of disease (acute
silicosis high risk for
TB)

34. Complications of Silicosis
 Cor pulmonale
 Spontaneous
pneumothorax
 Collagen vascular
disease (scleroderma)
 Lung Cancer

35. ASBESTOSIS

36. Milling
Metal fabrication
Building insulation Electrical insulation

37. ASBESTOS
AmphiboleSerpentine
Most commonly used
Chrysotile
More flexible and curved
Likely to be impacted in
upper respiratory passages
Less commonly used
Amosite, Crocidolite,
anthophyllite, tremolite
Stiff and short
Likely to delivered deeper into
the lungs

38. Asbestos related lung diseases
• Produces 4 major categories of human disease
– Pulmonary fibrosis (asbestosis)
– Benign asbestos-related pleural response
– Bronchogenic carcinoma
– Mesothelioma

39. Pathogenesis

40. PATHOGENESIS
Inhalation of asbestos
Interact with epithelial cells &
macrophages and penetrate the
alveoli
Release of mediators
INTERSTITIAL
fibrosis
ALSO ACT AS TUMOR INITIATOR
AND PROMOTER
CARCINOGENESIS

41. Pathologic features
• Begin in lower lobes and sub pleura
• Early stages – minimal fibrosis
• Late stages- extensive fibrosis- destroys the
architecture-dilated/cystic air spaces-
honeycombed appeareance

42. Microscopy
 Asbestos bodies: asbestos fibres coated with a film of proteins
rich in iron.
 Golden brown, fusiform or beaded rods.
 coating is thickest at ends - Dumbell shape
 form when macrophages phagocytose asbestos, iron derived
from phagocyte ferritin.

43. • Ferrugious bodies : other inorganic
particles/fibres coated with similar protein
iron complex

44. Clinical Diagnosis of Asbestosis
 Earliest symptom is insidious onset of
breathlessness with exertion
 Clubbing of digits (32-42%), râles(32-64%)
 Cough, wheezing & sputum production are
unusual; if present can be attributed to
cigarette smoking

45. Pleural Disease Associated with
Asbestosis
 Pleural Plaques
 Pleural Thickening
 Pleural Effusion
 Mesothelioma

46. Pleural Plaques
 Smooth white raised lesions located on the posterolateral
aspect of the parietal pleura or diaphragm
 Plaques vary in size & shape
 Asymptomatic in pts without parenchymal disease
 Presence of plaques is associated with likelihood of
developing parenchymal disease
 Rarely seen before 20yrs after exposure

49. Pleural Thickening
 Diffuse or focal
 Pleural thickening are
often associated with
parenchymal disease
 Asbestos bodies can
be found in visceral
pleura
 Can cause symptoms

51. Pleural Effusions
 May persist for months-years
 Symptoms - chest tightness, pleuritic chest
pain, fever, dyspnea
 May reoccur on same side or opposite side
after yrs of exposure
 Effusions maybe bloody

53. Mesothelioma
 Arise in the pleura &
peritoneum
 80% occur in men
exposed to asbestos in
the workplace or
living near the mines
 Smoking does not
enhance prevalence of
disease

55. Lung Cancer & Asbestos
 First recognized in 1930
 Average latency period 20-30 yrs
 Association of lung cancer with smokers &
asbestos exposure is multiplicative
 Adenocarcinoma & squamous cell carcinoma

56. Summary
 Coal workers pneumoconiosis.
 Know the difference between Asbestosis &
Silicosis.