Occupational lung diseases (Pneumoconiosis)

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Occupational lung diseases(Pneumoconiosis)
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• Pneumoconioses is a group of lung diseases which
  result from inhalation of dust in certain
  occupations.

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Classification of Pneumoconioses
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1. Benign Pneumoconioses

• Dust could not Produce fibrosis
• Examples include
• Baritosis pure Barium sulphate and oxide
• Siderosis ferric oxide
• Titanosis titanium oxide
• Chalkosis calcium salts

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2. Simple Pneumoconioses

• Inhaled dust causes only minimal fibrosis
• Examples
• Silicatosisinhalation of complex silicates (not
  free silica) eg clays
• Vegetable dust pneumoconioses
• Mill fever organic dust
• Byssinosis cotton dust
• Farmers lung moldy hay
• Grain asthma grain dust
• Tamarind asthma tamarind seed dust

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3. Complicated Pneumoconioses

• Produce Progressive Massive Fibrosis
• Examples
• Silicosis inhalation of free crystalline Silica
  SiO2
• Asbestosis inhalation of fibrous tri-magnesium
  silicates
• Talcosis inhalation of talc powder
• Coal miners pneumoconiosis inhalation of coal
  dust

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Factors affecting the development of disease by
deposited dust particles in the respiratory system
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1. Nature and chemical composition
2. Size of dust particles
3. Concentration of dust in atmosphere
4. Duration of exposure
5. Individual susceptibility

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1. Nature and chemical composition

• Organic dusts
• e.g. Cotton dust, grain dust
• Asthma bronchitis, non distinguishable

• Inorganic dusts
• E.g. Silica, Asbestos
• Massive progressive fibrous reaction in the lung

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2. Size of dust particles

• 10-5 µ Removed from upper respiratory tract
• 5-3 µ Deposited in the mid respiratory tract
• 3-1 µDeposited directly in the alveoli
• lt 1 µ Move in and out of the alveoli with air,
• may be deposited in alveolar wall by impaction,
  or being caught by alveolar movement

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Size of Dust
10- 5 µ - Upper Respiratory tract
5 - 3 µ Mid respiratory tract
3 - 1 µ Alveoli
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Study of some common Pneumoconioses

• 1. Silicosis

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Definition

• Pathological condition of the lung due to
  inhalation of particulate matter containing free
  silica or uncombined silica (SiO2)

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Common occupations with exposure to silica

• Mines
• Porcelain
• Sand bricks industry
• Glass industry
• Gun industry
• Grinding of metals using sand stone

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Pathology

• Fibrotic nodules develop by a particular process
  in which fibrous tissue is laid down in
  concentric rings around a central core of silica
  particles as an onion

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silicosis
Healthy lung
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Manifestions

• Symptoms
• shortness of breath while exercising
• fever
• occasional bluish skin at ear lobes or lips
• fatigue
• loss of appetite

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There are three kinds of silicosis, based on
amount of exposure and length of time

• 1.Chronic
• occurs after 10 or more years of mild
  overexposure to silica
• the most common of all types
• may go undetected for years
• 2. Accelerated
• develops between 5 and 10 years of moderate
  overexposure
• 3. Acute
• develops within weeks up to five years due to
  breathing very large amounts of silica

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Chest X-ray (Silicosis)
Nodular shadows of different sizes
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Study of some common Pneumoconioses

• 2. Asbestosis

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Definition

• Parenchymal lung fibrosis with or without pleural
  involvement due to inhalation of asbestos fibres.
• It is more dangerous than silicosis as it
  predisposes to bronchogenic carcinoma and
  mesothelioma of the pleura and peritoneum

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Asbestos fibers
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Asbestosis
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Complications

• Bronchogenic carcinoma
• Mesothelioma

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Prevention of Pneumoconioses
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Environmental measures

• Substitution of harmful dusts by non harmful
  substances
• Seggregation of dangerous processes
• Enclosure of machines releasing dust
• Ventillation
• Wetting precipitation of dust by spraying water
• Vaccum cleaning
• Protective devices masks

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Medical measures

• Preemployment examination
• Periodic examination
• Health education
• Nutrition
• Prohibition of smoking