Asbestosis
Asbestosis is a scarring of lung tissue caused by the inhalation of asbestos fibers.
A portion of the fibers reach the alveoli (air sacs) where oxygen is transferred into the blood. Asbestos activates the lung's immune system and starts a reaction best described as an inflammatory process. Scavenger white blood cells (macrophages) try to break down the asbestos (phagocytosis) but are not successful, causing other cells (fibroblasts) to grow and form connective-tissue-based scars.
The formation of scar tissue or collagen in the lungs is known as fibrosis. The scar tissue slowly builds up, often reducing the lung's ability to deliver oxygen to the blood and remove carbon dioxide (reduced diffusion capacity). The total lung capacity or TLC may also be reduced. In severe cases, the impairment of lung function can strain the heart, or even result in heart disease, such as right-sided heart failure or "cor pulmonale."
Asbestosis and the Inflammatory Process
The inflammatory process starts within hours or days after inhalation of asbestos and injury at the cellular level begins shortly thereafter. In people who develop asbestosis, the inflammatory process continues to progress, fueled by indestructible asbestos fibers, even after exposure to asbestos ceases.
This asbestosis inflammatory process may continue undetected for decades causing no pain or respiratory symptoms. In many people, the process eventually produces symptoms-breathing abnormalities and radiographic changes. Usually, the first symptoms are shortness of breath and a dry cough. These symptoms often precede abnormalities on chest x-ray or pulmonary function tests. The period between exposure and diagnosis is called "latency" and may range from 10 to 50 years.
