In its earliest stages, pleural thickening has no symptoms. As more and more rigid scar tissue grows around the lungs, however, it becomes harder for them to fully expand when the patient breathes.
As the disease progresses, patients commonly experience chest pain and breathlessness (dyspnea). In an early 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.
Pleural Thickening Facts
- Symptoms may include chest pain and breathing difficulty.
- Caused by asbestos exposure and associated with pleural effusions.
- Also caused by conditions that inflame the pleural lung lining.
- Treated with medication and pulmonary rehabilitation.
Advanced pleural thickening may close off the space between the two layers of the pleura and encase the lung completely, causing restrictive lung disease. As a result, patients experience decreased lung volume and have to work harder to breathe.
Pleural thickening is often the result of prolonged exposure to asbestos. When a person inhales asbestos dust, the microscopic mineral fibers can become embedded in the pleura, triggering an inflammatory response that causes a chronic accumulation of fluid in the pleural space (pleural effusions) as well as the progressive buildup of fibrous scar tissue (pleural thickening).
Studies have shown pleural thickening occurs in 5 to 13.5 percent of asbestos-exposed workers. The condition may arise within a year of exposure, or it may not arise until decades later. In most cases, there is a latency period of 15 to 20 years between the initial asbestos exposure and a doctor’s diagnosis of pleural thickening.
Because any disease that causes acute inflammation of the pleura can also lead to pleural thickening, it is vital for a patient to keep any history of possible asbestos exposure in mind in order to ensure an accurate diagnosis.
Other causes of pleural thickening include:
- Chronic pneumonia
- Empyema (accumulation of pus in the pleura due to infection)
- Hemothorax (accumulation of blood in the pleura due to chest injury)
- Coronary artery bypass grafting surgery
- Radiation exposure
These other conditions are more likely to affect only one lung, while asbestos-related pleural thickening usually affects both lungs.
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Doctors can use a few different imaging scans to diagnose the pleural thickening:
- The condition is usually first spotted through a chest X-ray, in which pleural thickening appears as an irregular shadow on the pleura that extends over at least 25 percent of the chest wall.
- CT Scan:
- Doctors often use computed tomography scans to detect and diagnose pleural thickening, pleural plaques and asbestosis. CT scans can detect early signs of pleural thickening, when scar tissue is 1-2 mm in thickness.
- PET and MRI Scans:
- Doctors can use positron emission tomography scans and magnetic resonance imaging scans to distinguish between pleural thickening and pleural mesothelioma cancer, which can affect patients simultaneously.
The presence of pleural thickening is not enough to confirm a pleural mesothelioma diagnosis, but it can be a sign of significant asbestos exposure. Because catching mesothelioma in an early stage can lead to a wider range of treatment options, patients with asbestos-related pleural thickening should seek regular cancer screening.
Pleural thickening should not be confused with pleural plaques, another condition caused by asbestos exposure. Pleural plaques are firm, sometimes calcified lesions of scar tissue that grow in discrete patches on the pleura.
Plaques may 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 is irreversible, so doctors usually offer therapies to treat the disease’s symptoms. Prescription medications, such as bronchodilators and steroids, can make breathing easier for patients.
According to a 2015 Australian study, pulmonary rehabilitation can also significantly improve quality of life for patients with dust-related respiratory diseases, including pleural thickening. This type of rehabilitation involves moderate-intensity exercise training to help patients overcome their breathing difficulty and stay physically active.
For patients who smoke, quitting is essential after a diagnosis of pleural thickening. Smoking reduces lung function and increases the risk of developing other respiratory diseases.
Although treatment is typically limited to supportive and symptomatic care, some case reports have shown pleurectomy surgery to be effective in progressive cases. This aggressive treatment, usually reserved for patients with pleural mesothelioma, involves removing parts of the pleura and other nearby linings of the chest.
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Last Modified September 28, 2018
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