Asbestos Exposure and Pleural Thickening
Pleural thickening develops in the visceral pleura, the delicate membrane lining the lungs, after the lungs become inflamed. Inflammation can be a result of a number of issues, like another health condition, but is also commonly associated with prolonged asbestos exposure. Various studies have found that on average 5 – 13.5% of asbestos workers have developed diffuse pleural thickening anywhere from 2 to 34 years after being exposed to asbestos.
When exposed, the microscopic asbestos fibers may be inhaled or ingested, eventually becoming trapped in the pleura. The fibers will irritate the lung lining, which will cause chronic inflammation. Over time, this inflammation can lead to severe scarring of the lungs. The accumulating scar tissue can become so thick that the lungs may become severely impaired and can no longer properly expand when trying to inhale.
While pleural thickening is most often considered an asbestos-related disease, it may also develop as a result of other health conditions.
Other Causes of Pleural Thickening
- Bacterial pneumonia
- Hemothorax (excess blood in the pleural cavity)
- Infection, including tuberculosis
- Injury to the ribs or chest
- Lung contusions
- Empyema (buildup of pus in the pleural cavity)
- Pleural effusion
- Pulmonary embolism
- Tumors (benign or malignant)
Diagnosing Symptoms of Pleural Thickening
Like other asbestos-related diseases, it can take well over a decade for pleural thickening to develop and begin to present symptoms. On average, researchers have found the latency period to be around 15 to 20 years.
Pleural thickening is considered a progressive disease, meaning the symptoms often become more severe over time. In its early stages, pleural thickening is largely asymptomatic and will be more difficult to detect. The symptoms and diagnosis can also be a challenge if pleural thickening is a result of another health condition.
Common Symptoms of Pleural Thickening
- Chest pain
- Breathlessness (dyspnea)
- Persistent cough
- Pleural effusions (fluid buildup in the pleural space)
Diagnosing pleural thickening usually consists of imaging scans, like CT scans or x-rays. While x-rays will show a vaguer image, likely a shadow along the pleura, CT scans can help detect the irregular thickness of the pleura, even at earlier stages where the scar tissue is only a few millimeters thick. PET and MRI scans may also be needed to better distinguish pleural thickening from other lung diseases. If the doctor believes pleural thickening may be a sign of cancer or another condition, they may order other tests.
Pleural thickening may also sometimes be confused with another condition, pleural plaques. Though these two conditions may develop together in the body, they are very distinct in how they form and present symptoms. Pleural thickening begins in the visceral pleura, the membrane covering the surface of each lung. Pleural plaques develop in the parietal pleura, the outer membrane of the lungs that also connects to the chest cavity. Differentiating these pleural diseases will be important for developing the appropriate treatment plan.
Treatment for Pleural Thickening
Unfortunately, it is impossible to reverse or cure this extensive lung damage. The good news is that the condition on its own is not considered life-threatening, and its progression and symptoms can be managed with a variety of treatment methods.
Medical professionals will often recommend regular lung function tests, also called respiratory function tests. These tests can determine how well the lungs are working and can be a good way to monitor the disease progression. Doctors will likely test the lung volume (how much air the lungs can hold) and your diffusing capacity (transfer of oxygen to the bloodstream). With these results, doctors can make recommendations to try to improve lung function and manage symptoms.
Some studies have also found pulmonary rehabilitation can improve symptoms and quality of life for patients. This type of program can improve diet and nutrition changes, exercise recommendations, breathing strategies, and techniques to help conserve energy. A team of specialists will be able to develop a customized plan based on an individual’s needs.
It is important for patients to remember, however, that pleural thickening may be a symptom of another asbestos-related disease, which may not be realized in an initial diagnosis. If pleural thickening is simply a co-occurrence of asbestosis or pleural effusions, the conditions may still be able to be well managed with treatment and have a favorable prognosis. But, if this condition is a symptom of a more severe diagnosis, like pleural mesothelioma, the treatment plan and prognosis will change dramatically.
Pleural thickening alone is not enough to confirm a malignant mesothelioma diagnosis, so patients should take note of any other symptoms they may experience and keep an open dialogue with their doctor about their health.