A particularly troubling sign of asbestos exposure, pleural thickening, refers to an increase in the density of the tissues that line the lungs and chest cavity. If the thickening is localized in small spots, the spots are referred to as pleural plaques. However, if large areas are affected, it is known as diffuse pleural thickening. Though they appear similar, pleural plaques and thickening actually develop differently and have different prognoses. Unlike other symptoms of asbestos-related diseases such as pleural effusion, which can be treated or even resolve themselves, pleural thickening is permanent.
This thickening makes breathing difficult and may indicate more serious diseases. Healthy, normal pleura is elastic and flexible. However, if it is damaged or scarred, the elasticity is lost and the patient finds it very difficult to breathe, as the lungs are restricted and cannot properly expand. Although asbestos has been linked to pleural thickening, other causes of the condition are pleuritis, emphysema, and tuberculosis.
Asbestos and Pleural Thickening
Asbestos exposure normally takes about 15 years to produce the start of pleural thickening. It is not understood how asbestos exposure causes this thickening, but lymph node fibrosis and inflammation may play a part in this condition. The thickening of the pleura may be present in the absence of other asbestos-related disease. It is, however, a symptom of a disabling, chronic lung disease called asbestosis that causes breathing problems. Pleural thickening is also present in metastatic adenocarcinoma as well as mesothelioma, a rare cancer of the pleura that is related to asbestos exposure.
Tissue biopsy or computerized tomography (CT) scans, as well as tests of a patient’s pulmonary function, may be used in diagnosing suspected pleural thickening. Once a diagnosis is made, a treatment plan will most likely center on relieving pain and difficulty breathing, since there is no cure for pleural thickening. Asbestosis patients may gain relief with antibiotics and steroids and by inhaling medication through bronchodilators. In the event of fluid buildup, surgery may be recommended to drain the area. Successful treatment may control asbestosis, but unfortunately this asbestos-related disease is also incurable.
A 2008 study showed that incidences of diffuse pleural thickening are on the rise and are likely to surpass the number of malignant mesothelioma cases in the future. More research is required on the development and treatment of this serious lung condition.