This was an assignment in the second semester of Public Health school, that we had been given to talk about toxic materials and their effects on Health. I chose the color Blue in these slides, to match it with Blue Asbestos.

1. What is Asbestos?

2. Natural Occurring fibrous
mineral

4. Exposure Pathway

5. Exposure pathways
• Asbestos exposure occurs PRIMARILY through inhalation of
Fibrous dust.
• Asbestos fibers may result from mining, milling, and
weathering of asbestos-bearing rock
• And from the Manufacure, wear, and disposal of asbestos-
containing products.
• It is used in construction materials, mostly asbestos cement
products, Building insulation materials.

6. Exposure pathways
• Indoor air may become contaminated with fibers released
from building materials, espically if they are damaged or
crumbling.
• Common sources in homes (ceilings, pipe insulation, boiler
coverings, wallboard, and floor and ceiling tiles.
• Street dust may contain fibers form brake linings or crushed
asbestos-containing rock used in road constraction.

7. • Fibrous tremolite, the
asbestos commonly
found in talc, has been
found in play sand.
Exposure pathways
Source: https://en.wikipedia.org/wiki/Tremolite#/media/File:Tremolite_Campolungo.jpg
https://images.ctfassets.net/iyiurthvosft/featured-img-of-post-105551/803a0fa26d6fd8d5c2d351057bf6d925/featured-img-of-post-
105551.jpg?fm=jpg&fl=progressive&q=50&w=1200

9. Exposure pathways
• Drinking water supplies may become contaminated with
asbestos from erosion of natural land sources, discarded
mine and mill tailings, asbestos cement pipe..
• Most water supply concentrations are less than 1 million
fibers per liter, in some cases it exceeded 100 million
fibers per liter.

10. Can exposure to
asbestos occur due to
natural causes?

11. Previously asbestos
exposure was associated
mainly with mining and
milling of the raw material
and with workers engaged
in product manufacure.
Who’s at risk
Today most exposure
occure during repair,
renovation, removal, and
maintenance of asbestos
that was installed years
ago.

12. Who’s at risk
• Workers in the construction
trades are most heavily exposed
to asbestos

13. Who’s at risk
• In USA the most heavily exposed people are
construction tradespersons.
• Carpenters, utility workers, electricians,
pipefitters, steel mill workers, sheet metal
workers, boilermakers and laborers are at risk of
exposure

14. Who’s at risk
• Spouses and family members
can be exposed through
asbestos dust on workers‘ skin
and work clothing.
• Secondary exposure occurs
when fibers released to the air
are inhaled by persons no
directly handling asbestos

15. Who’s at risk
• Asbestos-related diseases
have occurred in family
members who had contact
with dust from an exposed
worker's clothes.
• Similar diseases were also
found in persons who grew up
within one-half mile of an
asbestos factory

16. Who’s at risk
• Cigarette smoke increases the risk of asbestos-
associated lung cancer.
• Smoking can cause through chemicals to
damage the DNA in the Lung Cell
• Asbestos fibers can also cause irreversible
damage to lung tissue and increase the risk of
lung diseases
• The combination of smoking and asbestos
exposure significantly raises the likelihood of
developing lung cancer

17. Biologic fate Metabolism
• The primary route of asbestos entry into the
body is through inhalation.
• Ingestion of asbestos fibers can occur also
through drinking or after mucociliary
clearance from the lungs
• The fate of ingested asbestos is still being
debated.
• Generally, only particles between 0.5 and 5
microns in diameter with a length-to-width
ratio of 3:1 will be deposited in the respiratory
regions of the lung (alveoli and terminal

18. Biologic fate Metabolism
• Larger particles tend to be filtered out in the
upper airway and nasopharynx.
• Smaller fibers tend to remain suspended in the
inspired air, and the majority are exhaled.
• However, asbestos is an exceptional substance:
fibers ranging from 5 to 10 microns in
diameter can also penetrate to the lower
respiratory regions of the lung, where they
may have destructive effects.

19. Biologic fate Metabolism
• The fibrous nature of asbestos makes the lungs’
defense mechanisms ineffective.
• Smaller, nonfibrous particles are normally
engulfed by macrophages and removed by
lymphatic or mucociliary mechanisms.

20. • The attempts by macrophages to engulf fibers can lead
to eventual disposition in various tissues of ferrous
material in a drumstick configuration called ferruginous
body (asbestos body)
Source:
https://commons.wikimedia.org/wiki/File:Asbestosis_-_Asbestos_bodies_%287468457674%29.jpg

21. • a. asbestos fibers in the lung and AM containing
Fe-rich inclusions respond as part of the body’s
immune response..
• d. the Fe-rich inclusions and other AM material
(including ferritin) are deposited on the fiber's
surface, initiating AFB formation
Source: https://particleandfibretoxicology.biomedcentral.com/articles/10.1186/s12989-023-00522-0/figures/7

22. Biologic fate Metabolism
• Asbestos fibers can also penetrate the terminal
bronchiolar level and enter the peribronchiolar
space resulting in a fibro-genic response.
• There is a tendency for fibrosis to occur first in
the lungs’ bases
• Fibrosis results from persistent release of
inflammatory mediators such as lysozymes,
interleukins, and fibroblast growth factors.

23. Biologic fate Metabolism
• Data do not clearly relate GI tumors to direct
ingestion of asbestos fibers.
• Some investigators believe this is caused by
fibers removed from the lungs’ upper
respiratory regions and the swallowed.
• Most reports suggest that ingested asbestos is
excreted with the feces.
• In Animal studies, asbestos fibers are capable
of penetrating the GI tract

24. Physiological effects (Harmful
effects)
• Asbestos primarily affects the respiratory system. The Immune
and cardiovascular systems, and Possibly the GI
(Gastrointestinal tract) system.

25. By Inhalation of asbestos and by ingestion subsequent to
mucociliary removal from the respiratory tract.
HOW
?

26. • What will happen after that is IMMUNOLOGIC
ABNOEMALITIES such as increased concentrations of
auto-anitbodies and depressed lymphocyte
responsiveness are usually mild or absent in persons
who have not developed the signs yet.

27. • Abnormalities have been observed in asbestos workers with
clinical signs and have been also reported in persons
environmentally exposed
• Most studies indicate that cell-mediated immunity can be
depressed in workers who have radiologic evidence of
asbestosis.
• Autoantibodies (rheumatoid factor, antinuclear antibodies)
are typically present in these workers.
• Caplan’s syndrome (the coexistence of pneumoconiosis
with rheumatoid changes) also has been noted.

28. • NO Deaths due to acute exposure to asbestos have
been reported.
• However, delayed death due to asbestosis and cancer
from chronic inhalation exposure has occurred.
• The risk of developing asbestos-assosicated disease
continues even after exposure has ceased.

29. • Cardiovascular effects are secondary to pulmonary changes.
Fibrosis in the lung can lead to increased resistance to blood
flow through the pulmonary capillary bed, resulting in
pulmonary hypertension and compensatory hypertrophy of
the right heart.

30. • History and Physical Examination:
• Typically, in such cases the medical
evaluation should include a thorough
medical and occupational history,
physical examination, chest X ray, and
pulmonary function tests.
Clinical Evaluation

31. • The Historical information should
include the source, intensity and
duration of exposure, time elapsed
since first exposure, and work history
of household members.
• The primary focus should be on the
lungs and pulmonary auscultation
History and Physical Examination:

32. • fine inspiratory rales in the posterior
and posterolateral lung bases,
audible on deep inspiration, may be
sings of fibrosis
History and Physical Examination:

33. • The differential diagnosis should be assessed,
because other diseases may confound the
diagnosis of asbestosis. (Rheumatoid arthritis)
• Chest-wall configuration, evidence of thoracic
surgery, and cardiac status may also affect the
diagnosis
• Most common lung findings associated with
asbestosis are (Dry rales, auscultated in the
History and Physical Examination:

34. Signs and Symptoms
Asbestosis Lung
cancer
Mesothelio
ma

35. Asbestosis
• Asbestosis is a chronic lung condition caused by
prolonged exposure to asbestos fibers
• Symptoms: Fatigue, weight loss, shortness of breath,
coughing, chest tightness, and eventually, respiratory
failure.
• The most common finding is pleural thickening,
often manifested as discrete pleural plaques.

36. Asbestosis
• When asbestos fibers are inhaled, they can become
lodged in the pleura, leading to irritation and
inflammation. Over time, this chronic irritation can
cause the pleura to thicken and stiffen. Pleural
thickening can restrict lung expansion and lead to
symptoms such as chest pain, shortness of breath,
and a reduced lung function.

37. Asbestosis
• Fibrosis can be
found symmetrically
in the lower aspects
of both lungs, and
this is associated
with pleural plaque
formation. Source: https://www.asbestos.com/mesothelioma/pleural-plaques/

38. Lung Cancer
• Lung cancer can‘t be differentiated form cancer
caused by other environmental factors, because they
produce the same symptoms.
• The differential diagnosis should include other
possible etiologies such as exposure to cigarette
smoke, arsenic, chloromethyl ethers, chromium,
nickel, and ionizing radiation.

39. Mesothelioma
• Mesothelioma is a rare and aggressive form of cancer that
primarily affects the mesothelium.
• Strongly linked to exposure to asbestos fibers
• Symptoms are sudden, but the onset is not, and the
latency period is 20 years or more.
• Diagnosis: CT scans or MRI scans, as well as biopsy
samples to confirm the presence of cancerous cells.

40. Laboratory Tests and Special
Procedures
• Basic Tool
• Fibrosis
• Thickening
• Not as a
screening
tool
• May be
useful
• Pulmonary
Function
Testing could
detect early
fibrosis
• Sputum
studies are
not useful
• Blood tests
are not useful

41. Treatment and
Management
• Patient education (Smoking cessation and
avoidance of pulmonary infections)
• Awareness of early symptoms is of other neoplasms
is important including: (hoarseness, sores in the
mouth, blood in the urine, blood in stool,
gastrointestinal symptoms)

42. Treatment and
Management
• Persons exposed should be advised of the
increased risk of lung cancer and the synergistic
effects of cigarette smoking.
• Follow-up of asymptomatic patients exposed to
asbestos is recommended

43. For Asbestosis Patients:
• They should avoid pulmonary irritants and guard
against lung infections.
• In the later stages, pulmonary rehabilitation may be
helpful
• Most pleural plaques are benign and require no
specific treatment.

44. For Mesothelioma Patients:
• Patients with mesothelioma have a 1-year
survival rate of less than 30%
• No efficacious treatment has been identified.

45. For Lung Cancer Patients:
• Treatment of asbestos-associated cancer does
not differ from treatment for other cancers.
• (Surgery, chemotherapy, radiation….)