The most common manifestation of exposure to asbestos are pleural plaques. Statistics indicate that more than half the people who were exposed to asbestos for a significant period of time have this condition. In many cases, the plaques appear even in people who have had minimal contact with asbestos fibres or asbestos dust.
Pleural plaques develop as small or large localised areas of fibrous thickening on what is known as the pleura, a double-layered membrane that surrounds the lungs. Though not very common, the thickening may also occur on the diaphragm and the rib cage.
Although this is the most common of all the asbestos exposure related health problems, it is the least threatening. Pleural plaques are benign and while they may calcify with time, they do not become cancerous.
Pleural Plaques: The Causes
Pleural plaques are almost exclusively caused by exposure to asbestos. The exposure could be direct as in workers employed in industries that use asbestos or it could be indirect. People who are indirectly exposed to asbestos include those who might live in the vicinity of any asbestos-related industry or those who could inhale the particles and dust that cling on to a worker’s clothes, skin and hair.
When asbestos fibres are inhaled, they enter the lungs and settle on the lining of the lungs or the pleura. These fibres are so miniscule in size that they are capable of penetrating right into the tissues of the lining. The straight, sharp shape of these fibres makes it difficult for the body to dislodge and expel them.
Over a period of time, this intrusion by the foreign bodies irritates the tissues of the lining, which react by getting inflamed and scarred. The tissues at the spot of intrusion gradually start to thicken and develop into pleural plaques. While it is not yet very clear exactly how this happens, it is thought to be a result of special lung cells that rush to the spot to get rid of the invaders. These special cells lay down scar tissue to deter further reaction. This scar tissue gets calcified over a period of time.
This whole process can take as long as 20 to 30 years.
Pleural Plaques: The Symptoms
Most people who suffer from this condition are completely asymptomatic. There are others however who suffer from discomfort in the lungs. It could be a feeling of tightness or a grating feeling in the chest.
Pleural plaques develop slowly and grow as the fibrotic scar tissue accumulates. In some cases the plaques stop growing after a while but in others they keep growing in size, eventually impairing the capacity of the lungs and making it difficult to breathe. This is thought to happen if there was extensive continued exposure to asbestos. If the plaques grow so much that they cover large areas of the pleura, it can cause considerable discomfort and chest pain.
For a long time doctors believed that the plaques had no effect on lung function but recent evidence shows that they can sometimes cause a decrease in total lung capacity and other measures of lung function. The extent to which lung function is affected depends on the extent and duration of exposure as well as the individual’s health.
Pleural Plaques: The Diagnosis
The gestation period for pleural plaques is ten to twenty years. This is because the calcification and thickening of the fibrous patches progresses very slowly. This long latency period makes it almost impossible to diagnose this condition immediately after exposure to asbestos.
The absence of any outward symptoms means that very rarely is a direct diagnosis made for pleural plaques. Most individuals and even doctors may not even suspect that there is anything wrong. The presence of pleural plaques is discovered incidentally while doing a radiography of the chest during a routine check or a check-up for some other symptoms. The calcification makes the thickened plaque patches highly visible on X-rays.
If the doctor suspects but cannot confirm the presence of pleural plaques after an X-Ray, a CT scan is then done. This is because only calcified plaques show up on the X-Ray. Plaques that are not calcified or are still in the early stages of calcification may not show up on X-Rays.
A CT scan makes it easier to detect the presence of pleural plaques, even those that are not calcified. In a CT scan, the areas of thickening can be seen clearly and if magnified, a basket weave pattern is visible in the scars, confirming the presence of plaques.
Pleural Plaques: The Treatment
Once you have been diagnosed with this condition, your doctor will advise you to do a few more tests to detect the presence of any other symptoms that are typical of exposure to asbestos.
There is no treatment that can cure pleural plaques and because they are non-cancerous, treatment is not necessary most of the time. Only in cases where the plaques are accompanied by pain in the chest, analgesics are prescribed to manage the pain.
Making a few lifestyle changes is strongly advisable after a diagnosis of pleural plaques. Quitting smoking is the most crucial of all as smoking could lead to other lung related conditions such as lung cancer or COPD – Chronic Obstructive Pulmonary Disease which are life-threatening. The fact that you have pleural plaques could mean you stand a higher risk of succumbing to these ailments.
After a diagnosis of pleural plaques, it is important to notify your doctor if you experience symptoms such as a chest pain, persistent cough, breathlessness or coughing up blood. If breathing does become labored or difficult, your doctor can perform a variety of treatments or refer you to a specialist.
Pleural Plaques: The Prognosis
Pleural plaques are benign. Moreover, they do not become cancerous under any condition nor do they put you at higher risk of developing a more serious asbestos-related disease such as lung cancer, Mesothelioma or asbestosis.
However, the presence of pleural plaques is a marker that says you were exposed to asbestos at some point of time. This means you may develop other symptoms related to asbestos exposure, making it necessary to go for regular investigations after a confirmed diagnosis.