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Inorganic dust related Pneumoconiosis / Silicosis /Asbestosis/ Anthracosis Siderosis - Simplified.



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I. Definition
Pneumoconiosis is an Occupational lung disease and a Restrictive lung disease caused by the inhalation of organic & inorganic dusts, often in mines, industries and from agriculture, characterized by inflammation, coughing, and fibrosis”.
III. Classification of Pneumoconiosis
A. Origin of dust
i. Organic Dusts
ii. Inorganic Dusts
B. Type of dust
1. Silicosis
2. Silicatosis
3. Metaloconiosis
4. Carboconiosis
5. Mixed dust
6. Others
C. Group - Fibrosis
i. Major P
ii. Minor P
iii. Benign P

A. Origin of dust
i. Organic Dusts
1. Cane Fiber - (BAGASSOSIS)
2. Cotton Dust - (BYSSINOSIS)
3. Tobacco – (TOBACCOSIS)
4. Hay Grain Dust - (FARMER’S LUNG)
ii. Inorganic Dusts
1. Silica - SILICOSIS
2. Asbestoses - ASBESTOSIS
3. Iron - SIDEROSIS
4. Coal Dust - ANTHRACOSIS
5. Others

a. Clay – Silicosis,
b. Talc - Talcosis
c. Kaolin Clay - Silicosis
d. Feldspar (Non-fibrous silicates) - Silicosis
e. Mica - Mica pneumoconiosis
f. Tin dust – Stannosis
g. Calcium dust - Chalicosis

Silicosis
a. Introduction
• Silica - most common mineral in earth: in granite, sand, ore,kaolin etc. in most rocks.
• Silicosis is the major cause of permanent disability and mortality among the occupational diseases.
• It was first reported in India in 1947 from the Kolar Gold Mines.
• It was made a notifiable disease under the Factories Act in 1948 and Mines Act -1952.
• b. Causes
• - It is caused by inhalation of dust containing free silica dust or silicon dioxide (SiO2), either in crystalline or amorphous varieties.
- Clay dust, Talc, Koaline clay, Feldspar etc.
c. Occurrence / Occupational exposure
– Mining industry (coal, mica, gold, silver, lead, zinc, manganese and other metals ), pottery and ceramic industry,
• metal grinding, iron & steel industry, Sand blasting, building and construction work, rock mining, quarries and others.
d. Incubation period
- may vary from a few months up to 6 years of exposure.
e. Pathology
• Silicon dioxide is toxic for macrophages.
• The particles are ingested by the phagocytes which accumulate and block the lymph channels.
• A dense ‘nodular’ fibrosis known as ‘silicotic nodules’ rangin from 3-4 mm in diameter develop mainly in the upper lobes.
• These nodules are formed by death of macrophages
containing silica particles with the release of silica and the intracellular enzymes causing more and more fibrosis.
f. Clinical manifestations
• 5 % of diseases develop in 10 years.
• Onset is insidious
• Early manifestations are
- First symptom is dyspnoea on exertion (shortness of breath in exercise.
- irritant cough and
- pain in the chest
• Later manifestations are
- Impairment of Total Lung Capacity (TLC).
g. Radiologic findings
• Shows egg- shell hilar calcification and progressive massive fibrosis.
• It also shows snow-storm appearance in the lung fields.
• Emphysematous bullae are present in the upper zones then later affect the lower lobes.
h. Complications
• Silicosis is a progressive disease and silicotics are prone to pulmonary tuberculosis called ‘Silico-tuberculosis.
- Chronic bronchitis
- Cor pulmonale
- Pleural effusion
- Caplan’s syndrome
- Lung cancer
i. Management
• There is no effective treatment for Silicosis
• Fibrotic changes cannot be reversed
j. Control measures
• Control measures include:
a. Rigorous dust control measures
- Substitution, complete enclosure, isolation, hydro – blasting, good housekeeping, personal protective
measures i.e. masks or respirator with mechanical
filters or with oxygen substitution etc.
b. Regular physical examination of workers.
Category
Health
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