Pleural thickening is a lung disease caused by extensive scarring that thickens the pleura, a thin membrane that covers the lungs. It is also known as diffuse pleural thickening, or DPT.
Pleural thickening is often a consequence of breathing asbestos fibres and dust into the lungs. If the asbestos fibres work their way into the pleura, they cause the pleural thickening condition.
The condition tends to cause sufferers a tightness of the chest and/or breathlessness, which is attributed to the reduced lung function that the thickening develops. Pleural thickening can be found on either one lung (unilateral disease) or both lungs (bilateral disease).
Small, localised areas of thickening of the pleura are referred to as pleural plaques, which do not generally cause breathlessness or interfere with lung function. Plaques can coexist with pleural thickening, but they feature much less extensive scarring and cause minimal, if any, lung impairment. Pleural thickening typically originates on the visceral layer of the pleura, which lines the lungs, while plaques often arise on the parietal pleura, which lines the rib cage.
Pleural thickening commonly occurs after a patient suffers pleural effusion, an excessive build-up of fluid in the pleural space.
What causes pleural thickening?
The main cause of pleural thickening is exposure to asbestos dust and fibres. Asbestos is a naturally occurring fibre that was widely used in construction and other industries until the late 1990s. Asbestos was commonly used to insulate and fire proof buildings, particularly in ceiling tiles, pipe insulation, boilers and spray coatings used on ceilings and walls.
People who worked in industries in which asbestos was regularly used are at higher risk of developing the disease. These include:
- Carpenters and joiners
- Plumbers, heating and ventilation engineers
- Electricians, electrical fitters
- Pipe fitters
- Metal plate workers, shipwrights, riveters
- Labourers in other construction trades
- Sheet metal workers
- Construction operatives
- Energy plant operatives
- Painters and decorators
- Building inspectors
- Vehicle body builders and repairers
- Metal working production and maintenance fitters
- Shipbuilding workers
- Railway engineering workers
It is possible to develop pleural thickening if you lived with someone who worked with and was exposed to asbestos. This happened when asbestos fibres were carried home on clothing and inhaled by others in the family. Some people who develop pleural thickening cannot remember coming into contact with asbestos and might not have been aware they were exposed to it at the time.
Other known causes of pleural thickening include trauma to the pleura, damage to the lungs caused by pneumonia and even infections of the lung. These causes are unrelated to asbestos exposure.
What are the symptoms of pleural thickening?
Anyone who is suffering from pleural thickening is likely to encounter some or all of the following symptoms:
- Shortness of breath
- Feeling of tightness across the chest
- General chest pain which is manifested typically after physical exertion
Depending on the progression of the disease, pleural thickening can be a debilitating disease which will substantially alter the quality of life of a sufferer.
In its earliest stages, the condition has no symptoms. As the disease progresses, patients may experience chest pain and breathlessness. In one study involving patients with moderate to severe pleural thickening, 95.5 percent complained of breathlessness, 65 percent described moderate breathlessness, and 11 percent described severe breathlessness.
It can also cause restrictive lung disease, which prevents the lungs from fully expanding. As a result, sufferers experience decreased lung volume and may have to work harder to breathe.
How is pleural thickening diagnosis?
There are several tests that doctors can use to diagnose the condition. On a scan of the chest, pleural thickening appears as a shadow on the pleura that extends over at least 25 percent of the chest wall.
The condition is commonly diagnosed through a chest X-ray, but diagnosis from the use of a CT scan is more reliable. Some studies have established that when compared to X-rays, high resolution CT scans can better detect pleural thickening, pleural plaques and asbestosis. CT scans can detect early signs of pleural thickening, when scar tissue is between 1mm and 2mm in thickness.
Many consultants will only support a compensation claim for a pleural thickening diagnosis if the patient’s lungs show a blunting of the costophrenic angle. The costophrenic angle is a gap beneath the base of the lowest point of the lung, where the diaphragm meets the base of the ribs. Gravity causes excess fluid, due to the pleural effusion, to build up in this gap below the lung. This fluid pushes the lung up, ‘blunting’ the costophrenic angle, and reducing the lung’s capacity.
In some cases, doctors will perform a positron emission tomography scan, known as a PET scan, to distinguish between pleural thickening and pleural mesothelioma (an incurable lung cancer), which can affect patients simultaneously. The presence of pleural thickening is not enough to confirm a mesothelioma diagnosis, but it can be a sign of significant asbestos exposure and promotes early detection of the condition.
Doctors may even be able to provide an early diagnosis for mesothelioma patients with the simultaneous use of PET and CT scans. Finding mesothelioma in its earliest stages can lead to a better prognosis and a wider range of treatment options.
Treating Pleural Thickening
There is no cure for pleural thickening. Once the damage has been done it is irreversible, although it is extremely important to have the condition diagnosed because it can go on to cause additional complications to your health.
However, there are some treatment options available. Most commonly, doctors offer therapies to treat the disease’s symptoms. They can prescribe pain medications and breathing exercises to help cope with the lung condition.
Smoking can lead to decreased lung function, so health care professionals recommend that patients stop smoking as soon as they are diagnosed with pleural thickening. By quitting, patients can also drastically cut the risk of developing more serious lung diseases.