Asbestosis And Asbestos-Related Pleural Disease

Everyone talks about mesothelioma. And it should be discussed. It’s a horrible form of cancer with no cure. It deserves attention.

But breathing asbestos fibers can cause more than cancer. It can damage your lungs in other ways. About 2,000 people every year die either from asbestosis or with asbestos lung damage contributing to their deaths.

This damage falls into two categories: damage to the lungs, and damage to the tissues surrounding the lungs. Keep in mind that these forms of damage don’t exclude each other. A patient can suffer from one or more of them, all at the same time—and often does.

Asbestos-related pleural disease
The chest cavity that holds the heart and lungs is called the pleural cavity. It’s lined with delicate tissues that encircle and protect the lungs. These pleural tissues are especially sensitive to asbestos fibers, so if damage occurs, it usually shows first here.

The most common form of asbestos damage is called a pleural plaque. Pleural plaques happen in about half of the people who have been exposed to asbestos. They can take between twenty and thirty years to show on a chest x-ray although they may begin developing sooner.

Plaques are hardened thickenings on the outside surfaces of the lungs, usually about halfway down the sides of the lungs close to the chest wall, causing the lungs to jut slightly into the space in the pleural cavity. If the plaques are large, this loss of space for the lungs can make it more difficult to take a deep breath, but most pleural plaques are so small that people don’t even notice they have them.

These plaques don’t become cancer. They just sit there, although they can continue to grow through the years, even if the patient never goes near asbestos again. After more years have passed, pleural plaques can become calcified. If they grow large enough, they can completely encase the lung, at which point they require surgery.

Other powders and fibers can cause pleural plaques, too, including silica, talc, ceramics, and zeolite. But these seem to be less common, and when doctors find pleural plaques on their patients’ chest x-rays, they usually assume they were made by asbestos.

Besides pleural plaques, asbestos can also cause what’s called diffuse pleural thickening. This is similar to a pleural plaque, because it’s a thickening of the pleural tissues into the lungs’ breathing space. But thickening occurs on the chest walls, and often the asbestos fibers stitch the different layers of pleural tissue together.

Pleural thickening can happen as an aftereffect of some diseases, such as pleural TB, so doctors don’t consider it an asbestos signature like pleural plaques. When pleural thickening is caused by asbestos, it usually appears about fifteen years after the first exposure. It happens in about 10–15% of all people who were exposed to asbestos over a fairly long period of time.

Diffuse pleural thickening, like pleural plaques, can also grow through the years, until the lungs are left with very little breathing space at all. As this happens, the patient finds it harder and harder to draw in air, and suffers increasing shortness of breath and sometimes chest pain. Surgery may be necessary in the most severe cases.

Asbestosis
When asbestos fibers attack the lung itself, it’s called asbestosis. Potentially, this can be much more serious than either pleural plaques or pleural thickening, or even both of them combined, because those conditions, if they get bad enough, can be relieved somewhat with surgery. There is no cure for asbestosis short of a lung transplant.

About half of all people who breathed in large amounts of asbestos fibers over a lengthy period of time will develop asbestosis. It usually takes about fifteen to twenty years before it begins to show, although research suggests that the fibers attack the lungs much sooner than that. Asbestosis tends to start at the bottoms of the lungs and work its way upwards until the entire lung is consumed.

Asbestos fibers cause scarring inside the lungs when inhaled. This scar tissue is stiff, like a sponge left out of water. Scarred lungs don’t work air very well, so patients with asbestosis tend to suffer from shortness of breath, at first when they’re working, then even when they’re sitting still. This gets worse over time even if they never go near asbestos again.

Other symptoms include a dry hacking cough, fatigue, and sometimes chest pain. In more severe cases, the fingers and toes can become deformed, called clubbing.

As the disease progresses and the lungs provide less and less oxygen to the rest of the body, the situation becomes life-threatening. The most serious patients require supplemental oxygen. There is no drug or surgery that can stop the advance of the disease.

Because the damage caused by asbestos fibers takes so long to develop, many patients die of other causes—accidents, heart problems, other diseases—long before asbestosis gets bad enough to be life-threatening. As mentioned earlier, about 2,000 people each year die with asbestosis written on their death certificates. Of these, about 21% die of respiratory failure caused by asbestosis. Of the rest, 38% die from asbestos-related lung cancer, 9% from mesothelioma, and 32% from other causes, such as heart failure caused by asbestosis.