Transcript
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Silicosis
Co, Eunice Victoria M. Co, Gregory Allan C.
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Sources and Exposure
Silica common, naturally-
occurring crystal
rock beds
main part of sand
forms dust during mining,quarrying, tunneling, andworking with many metalores
mines, quarries,foundries, and
construction sites, in themanufacture of glass,ceramics, and abrasivepowders, and in masonryworkshops
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Occupations at Risk
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Cases of Silicosis
mining establishment
of Delamar, Nevada
ruined by a dry-
mining process thatproduced a silicosis-
causing dust
the town was
nicknamed The
Widowmaker
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Cases of Silicosis
certain villages in
Northern Thailand
were called "villages
of widows" large number of
pestle-and-mortar-
making workers who
died early fromsilicosis
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Silicosis
potters disease, sand cuttersdisease or grinders rot.
one of the oldest occupationaldiseases
incurable lung disease
disease progresses even whenexposure stops
caused by inhalation of dustcrystalline
silica dust (SiO2)
quartz cristobalite
tridymite
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Formation of Silicosis
Composition Free silica
Higher percentage increased risk
Concentration
5 million particles per cubic foot (mppcf)
Particle size Respirable size reach alveoli: 1-3 microns or less
Time of exposure (duration)
6-7 years of contact Susceptibility of individual
Previous/concurrent lung infection
Age, smoking history
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Phagocytosis Theory
macrophages ingestthe dust particles
tumor necrosisfactors, interleukin-1,
leukotriene B4 andother cytokines
fibroblasts proliferateand produce collagen
around the silicaparticle
fibrosis and theformation of thenodular lesions
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Mechanical Theory
Insoluble
Sharp edged
Tissue irritation
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Chemical Theory
Silanol (SiOH)groups on surface ofparticles may reactwith cell membranes
Negative surfacecharge on SiO-groups may underliedirect toxicity
React with tissue andproduce Salicylic acid
http://upload.wikimedia.org/wikipedia/commons/4/4b/Silica.svg7/29/2019 occupational health - silicosis
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Colloidal Reaction Theory
Piezo Electric Theory
Electric discharge emitted when pressure is
applied to one end of crystal
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Immunologic Theory
Silicotics
High gamma globulin
Hyaline matter of
silicotic nodules Beta and gamma
globulin
http://www.osha.gov/SLTC/etools/silica/silicosis/silicosis.html7/29/2019 occupational health - silicosis
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Gross Pathology
Fibrotic chages
Milliary nodulations
Silicotic lung
Normal lung
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X-ray
normal x-ray silicosis (upper lobes) silicosis -- diffuse
http://images.google.com/imgres?imgurl=http://a248.e.akamai.net/7/248/430/20040913134745/www.merck.com/mrkshared/mmanual/plates/p75_3.jpg&imgrefurl=http://www.merck.com/mrkshared/mmanual/plates/75pla3.jsp&h=437&w=500&sz=63&tbnid=xj5yAJK0ZvIJ:&tbnh=110&tbnw=127&hl=en&start=13&prev=/images%3Fq%3Dsilicosis%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DNhttp://images.google.com/imgres?imgurl=http://www4.umdnj.edu/cswaweb/rad_teach/images/silic_10.jpg&imgrefurl=http://www4.umdnj.edu/cswaweb/rad_teach/silicosis.html&h=699&w=600&sz=347&tbnid=hddVe1MpbdoJ:&tbnh=138&tbnw=118&hl=en&start=18&prev=/images%3Fq%3Dsilicosis%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DNhttp://images.google.com/imgres?imgurl=http://a248.e.akamai.net/7/248/430/20040913134745/www.merck.com/mrkshared/mmanual/plates/p75_3.jpg&imgrefurl=http://www.merck.com/mrkshared/mmanual/plates/75pla3.jsp&h=437&w=500&sz=63&tbnid=xj5yAJK0ZvIJ:&tbnh=110&tbnw=127&hl=en&start=13&prev=/images%3Fq%3Dsilicosis%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DNhttp://images.google.com/imgres?imgurl=http://a248.e.akamai.net/7/248/430/20040913134745/www.merck.com/mrkshared/mmanual/plates/p75_3.jpg&imgrefurl=http://www.merck.com/mrkshared/mmanual/plates/75pla3.jsp&h=437&w=500&sz=63&tbnid=xj5yAJK0ZvIJ:&tbnh=110&tbnw=127&hl=en&start=13&prev=/images%3Fq%3Dsilicosis%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DN7/29/2019 occupational health - silicosis
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Histopathology
Fibrotic nodues
Concentric onion-skin arrangement of collagen fibers Central hyalinization
Cellular peripheral zone
Acute: PAS(+) alveolar exudate (alveolar
lipoproteinosis), cellular infiltrate of alveolar walls
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Occupational Safety and Health Adm inistrat ionis the mainfederal agency charged with the enforcement of safety andhealth legislation for the US Dept. of Labor
The permissible exposure limits refer to a time-weightedaverage (TWA) which shall not be exceeded for an 8-hourworkday within a 40-hour workweek.
OSHA class i f ies s i l ica glass dus t as a " nuisance dus t"w ith a TWA fo r total dust o f 15 mg/m3 and respirablefract ion o f 5mg/m3
The OSHA TWA for 100% sil ica quartz is 0.3mg /m3 total
dust and 0.1mg /m3 resp irable fract ion.
Concentration of coal mines respirable dust (avg of 4.9mg/m3)
General Occupational Health Standards, Volume I, State of Washington, Department of Labor and Industries.National Safety Council, Fundamentals of Industrial Hygiene, Second Edition. Chapter 7 , Particulates, pp 171-200. Chicago, Ill, 1979.
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Clinical Presentation: Signs and
Symptoms
Primary complaints:
Chronic dry cough
SOB w/ exercise
Chest tightness Insomnia, pleural pain and hemoptysis
Possible complications:
risk for TB
Progressive massive fibrosis
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Types of Silicosis
Asymp tomat ic s i l icos is Early cases of the disease do not present any symptoms
Chronic si l ico sis
after 1520 years of exposure to moderate to low levels of silicadust.
Patients with this type of silicosis may not have obvioussymptoms
SOB following physical exertion
Severe dry cough
fatigue loss of appetite
chest pains
fever
chest X-ray is necessary to determine if there is lung damage.
http://www.cdc.gov/niosh/silfact1.html
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Accelerated si l icosis
Silicosis that develops 510 years afterhigh exposure
to silica dust. Symptoms include severe shortness of
breath, weakness, and weight loss.
Acute s i l icos is
develops a few months to 2 years after exposure to
very high concentrations of silica dust. severe disabling SOB, pleuritic pain, weakness, and
weight loss, often leading to death.
http://www.cdc.gov/niosh/silfact1.html
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Diagnosis and TestsHistory
Jobs, hobbies, other activities - Exposure to silicadust
Physical Exam
chest expansion breath sounds
Request for:
1. Chest x-ray2. Pulmonary Function Tests (PFT)
3. PPD
http://www.who.int/mediacentre/factsheets/fs238/en/
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Chest X-Ray
Chest X-Ray Differential Diagnosis
Miliary TB
Histoplasmosis
Byssinosis
Bagassosis
Ground glass appearance- frank mottling Bilateral changes
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Chest X-Ray
Stages of disease by x-
ray:
1st Stage discrete
nodular circular shadows; 2mm diameter (present as
emphysema)
2nd Stage nodular
shadows in the whole lung;
some coalesce to form
higher opacities
3rd Stage massive
consolidation
http://emedicine.medscape.com/article/302027-overview
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PFT / PPD
Pulmonary Function Test- Spirometry
lung capacity
Prolonged expiratory phase
PPD
Screening for TB
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Prognosis
Incurable
Develop TB
Heart failure due to increased workload of the
heart to the lungs
Depend on the amount of damage to the
lungs
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Treatment
Silicosis is an irreversible condition with no
cure.
Treatment focus:
Maintain patient comfort
Slow the progression of silicosis
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Treatment
1. Stop further exposure
2. Stop smoking
3. Antibiotics and anti-TB drugs infections4. Cough suppressants
5. Chest physiotherapy
6. Oxygen administration7. Bronchodilators
Breathe easier
http://www.osha.gov/Publications/silicosis.pdf
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Prevention
Identify source
Use local exhaust ventilations
Water spray is often used where dust emanates
Control dust through dry air filtering
Do not eat, drink or smoke near crystalline silica dust.
Wash hands and face before eating, drinking or smokingaway from exposure area.
Use respiration equipment and protective clothing
Undergo medical examination
http://www.osha.gov/Publications/silicosis.pdf
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Extra slides
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Pathology
Fibrotic nodules are most common
usually less than 1 cm. in diameter
Spherical
hard and gray to black. On histologic examination:
Whorled appearance with concentrically arranged
collagen
On the periphery: aggregates of mononuclear cells: Lymphocytes
Fibroblasts
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Pathology
Progressive massive fibrosis Morphological
Central cavitation: related to amount of silica
Disability due to amt of destruction of tissue Radiological
Noduclar masses >2cm in diameter in a
background of silmple silicosis
Larger lesions: coalesce of smaller nodules Nodules: 5-10 cm in diameter
In the upper zones of the lungs= bilateral
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Pathology
Alveolar proteinosisHeavy exposure to finely particulate silica: sand
blasting, boiler scaling
Associated with diffuse fibrosis of the lung
Silicotic nodules not found
Dense eosinophilic material accumulate in alveolar
spaces = produce an appearance that resembles
alveolar lipoproteinsRadiology:
Linear fibrosis and reduced lung volume
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