What is Asbestosis?

Asbestosis is a respiratory disease caused by prolonged exposure to asbestos. It is also called diffuse pulmonary fibrosis (1). The disease starts when a person inhales asbestos fibers. Most exposure happens as a result of employment in an industry that requires regular contact with asbestos. Family members can be exposed when employees bring asbestos fibers home on their clothing. People living close to areas where asbestos has been mined or processed can also be exposed from fibers in the ambient air, though current regulations make that far less likely than it was in the past.

During exposure, asbestos fibers travel down through the trachea and into the lungs where some ultimately make it all the way to the alveoli. Alveoli are little pockets in the lungs where oxygen is taken into the blood stream in exchange for carbon dioxide that is then exhaled. When the asbestos fibers get into the alveoli, the alveoli produces cells called macrophages whose job it is to keep the tissue free from foreign substances. Macrophages attack and destroy most particles that reach the lungs, but some asbestos fibers are too long for the macrophage to completely engulf; part of the asbestos fiber sticks out on one or both sides. When this happens, the fluid macrophages use to break down the foreign substance leaks out of the cell and onto the alveoli itself. The fluid irritates the cells it comes in contact with, and if exposure continues, the cells build up scar tissue.

As the scar tissue covers more parts of the lungs, and becomes heavier, it makes the exchange of oxygen for carbon dioxide in the alveoli less and less efficient. The scar tissue also reduces the flexibility and elasticity of the lungs, making it more difficult for them to expand sufficiently to fully inhale. The inflexibility means the muscles have to work harder potentially causing fatigue, blood vessels are under pressure that can cause high blood pressure of the lungs, also known as pulmonary hypertension.

Asbestosis takes many years to make itself known, usually not showing up for 20, 30 or even more years after exposure to the asbestos. At first there are no symptoms, or very mild symptoms that are easily ignored. These symptoms include such things as being out of breath when exercising, things that also be caused by asthma or even just being out of shape. As the condition progresses, however, the symptoms get worse. The sufferer may be unable to get a full breath of air even when he or she is not exercising, and the person may feel pain when the lungs are expanded on inhalation. There is also a chance that the person’s fingertips become thickened in a condition known as clubbing.

Asbestosis can lead to further complications as well. As mentioned above, asbestosis can lead to pulmonary hypertension. When this happens the blood vessels thicken and the right ventricle of the heart also becomes thickened and enlarged. This is called cor pulmonale (2). Cor pulmonale can lead to failure of the right side of the heart. Research has shown that people who have asbestosis also have a greater chance of developing malignant mesothelioma. This is a cancer of the lining of the lungs.

There is no cure for asbestosis, but the symptoms are treatable with medication for improving respiratory function, and with oxygen to assist the body in getting sufficient oxygen into the blood stream. There is ongoing research into new medications that will assist in the oxygen/carbon dioxide transfer, and with medications to thin the blood to reduce some of the pressure in the vessels and strain on the heart.