Anthracosis & Coal Worker's Pneumoconiosis Notes

Interstitial Restrictive Lung Diseases

  • Pneumoconiosis: Occupational exposure-related lung disease.
    • Coal Workers' Pneumoconiosis: Coal miners.
    • Silicosis: Silica miners, sand blasters.
    • Asbestosis: Construction workers, shipyard workers.

Coal Workers’ Pneumoconiosis (CWP)

  • Caused by inhalation of coal particles and other dust.
  • May lead to emphysema and chronic bronchitis (independent of smoking).
  • Types:
    • Asymptomatic anthracosis.
    • Simple CWP.
    • Complicated CWP or Progressive Massive Fibrosis (PMF).

Anthracosis

  • Definition: Asymptomatic, milder pneumoconiosis due to carbon accumulation in lungs.
  • Cause: Repeated exposure to air pollution, smoke, or coal dust.

Pathogenesis

  • Inhaled carbon pigment engulfed by alveolar/interstitial macrophages.
  • Accumulation in connective tissue along lymphatics.
  • Location: Pleural lymphatics, organized lymphoid tissue along bronchi, or lung hilus.

Macrophage Activity

  • Macrophages pick up particles and release chemokines:
    • Interleukin-1
    • Interleukin-18
  • Immune cells damage alveolar epithelium.
  • Fibroblasts deposit extracellular matrix.

Simple Coal-Workers’ Pneumoconiosis

  • Gross Pathology:
    • Small, black focal lesions (<5 mm) throughout the lung, more in upper lobes.
    • Coal macules (nodules if palpable).
    • Air spaces dilated around macules: centrilobular emphysema.
    • Blackish pigment on pleural surface and regional lymph nodes.
  • Histology:
    • Coal macules: aggregates of dust-laden macrophages in alveoli and bronchiolar/alveolar walls.
    • Increased reticulin and collagen in coal macules.
    • Distended respiratory bronchioles/alveoli surrounding macules without significant alveolar wall destruction.

Progressive Massive Fibrosis (PMF)

  • Gross Pathology:
    • Larger, hard, black scattered areas (>2 cm), sometimes massive.
    • Usually bilateral, more often in upper lung parts posteriorly.
    • Masses may break down centrally (ischemic necrosis or TB), forming cavities with black semifluid.
    • Pleura and regional lymph nodes blackened and fibrotic.
  • Histology:
    • Fibrous lesions: Dense collagen and carbon pigment.
    • Thickened walls and obliterated lumina of respiratory bronchioles/pulmonary vessels in massive scars.
    • Scanty inflammatory infiltrate of lymphocytes/plasma cells around massive scars.
    • Markedly dilated alveoli surrounding scars.