Mesothelioma is rapidly becoming the most recognizable of the health conditions caused by asbestos exposure, but it is only one of many. Asbestosis is a known carcinogen and an irritant which causes the body's immune system to react, and sometimes overreact, in its efforts to get it out of the body or break it down. Unfortunately, asbestos fibers are nearly indestructible, and the body's own protective response system can cause a great deal of damage.
Asbestosis is caused when the body releases cells to attack fibers of asbestos that have lodged in the lungs. When those cells are unable to dissolve the asbestos fibers, they often rupture, spilling their contents over the lung tissues and damaging the cells. That forms scar tissue that builds on scar tissue and may eventually encase the entire lung.
Scar tissue on the lungs seriously reduces the ability of the lungs to function. The more scar tissue there is, the more lung function is reduced. Asbestosis can get progressively worse, and become disabling and even fatal.
There is no cure for asbestosis, and the only treatments are to relieve the symptoms. Those treatments include respiratory treatments to remove secretions from the lungs, and oxygen.
Similar to asbestosis, pleural fibrosis is the formation of fibrous tissue on or around the lungs. It is caused by scarring of the lungs due to asbestos. It may be localized to just a few small areas on the lungs, or may spread across the entire surface of one or both lungs. The thick tissue hampers lung function, causing shortness of breath, chest tightness, chest pain and reduced lung function. Often, pleural fibrosis may only cause minor symptoms, but it may be seriously disabling. In that case, doctors may perform a pleurectomy, a surgery to remove the lining around the lungs.
Pleural fibrosis is often caused by a short but intense exposure to asbestos. The symptoms often don't appear until at least fifteen years after exposure. It is often discovered by accident when the lungs are X–rayed for another reason.
Pleural plaques are areas of scarring on the lungs that may calcify. They are most often caused by low, intermittent exposure to asbestos as opposed to the intense exposure that is often responsible for asbestosis. They are smooth, raised areas of fibrous collagen that form on the surface of the lungs after exposure to asbestos. They are often the first indicator of damage to the lungs caused by asbestos. Pleural plaques on their own are often asymptomatic, but depending on the number, size and position of the plaques, they may limit lung function or cause serious pain.
Often, when the lungs are damaged by asbestos, fluid collects in the chest cavity around the lungs. This is called pleural effusion. It is one of the major symptoms of pleural mesothelioma, but it may also happen when there is no cancer present. When there are pleural effusions with no cancer, it is called non–malignant pleural effusion.
Pleural effusions are the most common symptom of asbestos exposure in young men in their twenties and thirties. The latency period for the appearance of pleural effusions is often less than fifteen years, unlike most other asbestos–related conditions which may not show any symptoms for as many as thirty years.
The symptoms of pleural effusions include chest pain, shortness of breath, reduced lung function and chest tightness.
Why is Asbestos No Longer Used?
For the most part, asbestos is no longer used: many of the chemical and physical properties that made it so useful also make the substance hazardous to health. Due to the inert nature of asbestos, the body is unable to break it down when it is inhaled.
Long, thin asbestos fibers that enter the lungs become lodged there, and over time cause chronic irritation and inflammation. Heavy or repeated asbestos exposure causes a condition called asbestosis, in which chronic inflammation leads to the development of scar tissue in the lungs. The scar tissue cannot hold oxygen and is stiff and inflexible, leading to painful breathing and reduced lung capacity.
Asbestos exposure can also cause cancer. These cancers, called mesothelioma, can develop in different parts of the body (most commonly in the lining of the lungs, abdomen, or heart) after relatively small amounts of asbestos exposure. Mesothelioma cancers are difficult to diagnose and are highly treatment-resistant.
The link between asbestos exposure and lung cancer was noted as early as 1925, and established by 1955. There is a clear link between asbestos and lung cancer. A person who has been exposed to asbestos is five to six times more likely to develop lung cancer than a person who has had no or minimal exposure to asbestos. Asbestos also dramatically increases the risk of lung cancer in smokers. While smokers increase their risk of developing lung cancer by a factor of ten (a person who smokes cigarettes is ten times more likely to develop lung cancer than a person who doesn't), if that smoker was also exposed to asbestos, the risk of developing lung cancer is fifty times higher than that of a non-smoker who was not exposed to asbestos.
Asbestos has also been implicated in the development of a number of other cancers. The link to those cancers is more tentative, but a number of studies have noted an increased risk of the following cancers in those who have been exposed to asbestos fibers:
- stomach cancer
- colorectal cancer
- throat cancer
- cancer of the mouth
- esophageal cancer
- kidney cancer
- gastrointestinal cancer
- laryngeal cancer
- pharyngeal cancer
While these other cancers are also found in people who have not been exposed to asbestos, those who have been exposed to asbestos have an increased risk of developing them.