Asbestosis is the most frequent lung disease related to exposure of the lung to inorganic dust particles.
Causes of Asbestosis
Asbestos is a natural mineral product with resistance to heat and corrosion. The term asbestos is used for several mineral substances including chsyolite, and anosite. People working in these mines are
exposed to its fibres. Asbestos is used extensively in insulation products, fire-retardant material, cement, and flooring material. When asbestos fibers are inhaled, these are deposited in the terminal bronchi and alveoli. These fibers are very resistant to heat and corrosion. Normal protective mechanisms of the lung, when exposed to foreign particles, are ineffective against these fibers. Inflammatory reactions occur, resulting in scarring of the lung tissue or fibers.
Fibrosed lung is thick and normal gas exchange does not occur, leading to difficulty in respiration. The thickened lung tissue is not very elastic and resists to expansion during inspiration. This leads to increased work in breathing. This progresses ultimately to respiratory failure. People at risk include insulation workers, sheet metal workers, plumbers, pipe-fitters, plastic workers, chemical technicians, and heating, refrigeration, and air conditioning mechanics.
Symptoms may not appear until two to three decades after exposure. Symptoms only occur after permanent damage to the lung has happened. Once the exposure is stopped, progression of the disease halts.
- shortness of breath, initially on exertion, and finally, even at rest
- decreased exercise tolerance
- chest tightness
- clubbing or swelling of the nail beds
History- a detailed history including occupational history help in diagnosis
Physical examination- shows crackling at the lung bases upon auscultation
Chest x-ray- pleural thickening or plaques may be present
Pulmonary function tests- which shows a restrictive pattern
Arterial blood gas- may show abnormalities at later stages.
Treatment goal is to support the lung system and prevent further damage.
1) Stop smoking if you are a current smoker
2) Prevent lung infections- pneumococcal and influenza vaccines should be considered
3) Relief of symptoms can be done by a) bronchodilators and b) mucolytics
4) Aerosols can be used to thin the secretions.
5) Oxygen therapy may be needed at later stages
6) Lung transplantation surgery should be considered in later stages
Lung cancer, and
respiratory failure can occur.
Decrease occupational exposure.