Silicosis

• Cause of permanent disability and mortality
• Caused by inhalation of dust containing free silica or silicon dioxide (SiO2)
• First reported in India in 1947 from Kolar Gold Mines (Mysore)
• Silica exposure occurs in industries like:
  • Mining of:
• Coal
• Mica
• Gold and Silver
• Lead, Zinc, Manganese etc.
  • Pottery and ceramic
  • Sand blasting
  • Metal grinding
  • Building and construction
  • Rock mining
  • Iron and steel etc.
• Higher the concentration of free silica in the dust, greater the hazard
• Longer the duration of exposure, the greater the risk of developing silicosis
• Incubation period may vary from months up to 6 yr. of exposure depending upon previously discussed factors
• Particles ae ingested by phagocytes, these phagocytes block the lymph channels
• Pathology:
  • Dense ‘nodular’ fibrosis
  • Nodules range from 3 – 4 mm in diameter
• Clinically:
  • Insidious onset
  • Early manifestations include
• Irritant cough
• Dyspnea on exertion and
• Pain in the chest
  • Impairment of TLC common in advanced stage
• Lab investigations:
  • Xray: ‘snow – storm’ appearance
• Silicosis increases the proneness to tuberculosis
• No effective treatment as Fibrotic changes irreversible
• Prevention and control of silicosis:
  • Rigorous dust control measures
  • Regular physical examination of workers
  • Silicosis is a notifiable disease under Factories Act 1948 and Mines Act 1952

References:

• Chapter 1 - Dust: Definitions and Concepts; Hazard Prevention and Control in the Work Environment: Airborne Dust WHO/SDE/OEH/99.14 available at: http://www.who.int/occupational_health/publications/en/oehairbornedust3.pdf, accessed on 16th Feb 2017
• Park’s Textbook of Preventive and Social Medicine

Types of Pneumoconiosis: Pneumoconioses

Silicosis: Silicosis

Anthracosis: Anthracosis

Byssinosis: Byssinosis

Bagassosis: Bagassosis

Asbestosis: Asbestosis

Farmer’s Lung: Farmer’s Lung

Lecture on Pneumoconiosis: Occupational Health