Asbestosis Can Be Severely Disabling

Asbestosis Can Be Severely Disabling

Asbestosis and asbestos pleural disease are nonmalignant asbestos diseases that are slowly progressive. They can be severely disabling and potentially fatal. These asbestos diseases cause impairment of pulmonary function, including small airway obstruction, a reduction in lung capacity, breathing restriction, and a reduction in the ability to transfer oxygen from air into the blood. Approximately one in seven people who suffer from asbestosis eventually develop asbestos lung cancer (Asbestos Fact Sheet, Lung Cancer, American Cancer Society).

Asbestosis and asbestos pleural disease are the result of cumulative exposure to asbestos. In individuals who develop these asbestos diseases, every nontrivial occupational exposure to asbestos is significant.

Human lung showing asbestosis

Asbestos Diseases: 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. See Asbestosis Diagnosis for more details.