Pleural Thickening
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Diffuse pleural thickening is a disease that causes the pleura, layers of tissue around the lungs, to thicken.[1] Pleural thickening may be a symptom of mesothelioma and related conditions, or it may be benign. It causes difficulty breathing, shortness of breath, and chest pains.
About Pleural Thickening
Also known as pleural parenchymal scarring, pleural thickening is a thickening of the tissue around the lungs, called the pleura.[2]
- Pleural thickening can occur throughout the pleura but most often affects the visceral pleura (inner layer) rather than the parietal pleural (outer layer).
- Focal pleural thickening is a small area of the affected tissue, also known as a pleural plaque.
- When the thickening becomes extensive throughout the tissue, it is called diffuse pleural thickening.
- Pleural thickening can be bilateral—in both lungs—or unilateral—affecting just one lung.
- Significant thickening causes symptoms and makes breathing more difficult.
- Exposure to and inhalation of asbestos fibers is often associated pleural thickening, but there are other causes.
- Pleural thickening can be benign or malignant. When malignant, it is usually associated with pleural mesothelioma.
Is Pleural Thickening Normal?
Pleural thickening is not normal for healthy adults, but it is among the most common findings on chest X-rays. It is more common in men and in people who smoke or used to smoke. It is also more common in older adults.[3]
How Serious Is Pleural Thickening?
Pleural thickening can be a serious health problem because it restricts breathing and causes symptoms. In advanced stages, it can completely close the space between the parietal and visceral pleural layers, making it very difficult to breathe normally and without significant pain.
Pleural thickening can also indicate past asbestos exposure. Asbestos exposure is the main risk factor for pleural mesothelioma, an aggressive and terminal cancer. Not everyone with mesothelioma experiences pleural thickening, but it should lead to a cancer screening.
What Causes Pleural Thickening?
While pleural thickening is a common result of asbestos exposure, asbestos is just one potential cause of this condition:[1]
- When someone is exposed to asbestos over a long period of time, the fibers of this mineral often lodge in tissues like the lungs and pleura. In the pleura, asbestos fibers can trigger inflammation, resulting in fibrous scar tissue and collagen deposits. Pleural thickening caused by asbestos is often benign but may also be a symptom of malignant mesothelioma.
- Another medical condition that causes pleural thickening is a type of inflammation called fibrinous pleurisy and empyema. This condition is an accumulation of mucus in the space between the pleura.
- A pulmonary embolism, a blood clot in the vessels leading to the lungs, may also cause pleural thickening.
- Infections can cause pleural thickening. These include pneumonia and tuberculosis.
- Other potential causes of pleural thickening include rheumatoid lung disease, injuries to the chest area, such as broken ribs or blunt trauma, and cancer treatments like chemotherapy and radiation therapy.
Localized areas of thickening are called pleural plaques. These are not the same as diffuse pleural thickening. Plaques may precede malignant tumors but do not usually cause symptoms like difficulty breathing.
Who Is at Risk for Pleural Thickening?
Anyone with one of the conditions that can cause pleural thickening is at risk and should be evaluated. Asbestos exposure is a significant risk factor and most often occurred in older men who once worked in an industry that used asbestos:
- Construction and carpentry
- Demolition
- Pipefitting
- Stell milling
- Electrical work
- Heating and cooling
- Boilers
- Insulation
- Power plants
- Railroads
- Shipbuilding and repair
Navy veterans are also at significant risk because of the asbestos used on ships.
What Are the Symptoms of Pleural Thickening?
Pleural thickening is progressive, worsening with time. In earlier stages, it may not cause many symptoms, much like mesothelioma. This is why anyone exposed to asbestos should receive screenings early and often. As thickening worsens, a person may experience breathlessness and chest pain.[4]
When pleural thickening becomes severe, it may lead to a condition called restrictive lung disease. This occurs when the lungs become so encased in fibrous scar tissue that they cannot fully expand.
This causes decreased lung volume and forces the patient to work harder to breathe. When this condition becomes severe, it can lead to respiratory failure and death.
How Is Pleural Thickening Diagnosed?
Pleural thickening does not develop in everyone who is exposed to asbestos, but it is not uncommon. If you came into contact with asbestos on the job, get regular lung screenings.
Diagnosis for pleural thickening usually begins with a description of symptoms, including shortness of breath and chest pain, combined with known asbestos exposure.
After a physical exam, the next step is imaging the chest cavity. Imaging scans can show thickening, plaques, and other abnormalities in the chest. A chest X-ray is a typical first screening; although, it may not show everything necessary for diagnosis.
A CT, or computed tomography scan, gives a clearer picture of what is happening in the lungs and pleura. These scans are high resolution and allow doctors to distinguish between pleural thickening and pleural plaques.
Distinguishing between benign pleural thickening and malignant mesothelioma is not easy. A doctor may choose to follow a CT scan with a PET scan (positron emission tomography) to help determine if thickening is benign or cancerous.[4]
While this may not be enough for a firm diagnosis, it can determine if a biopsy is necessary. If pleural thickening is greater than one centimeter or there are nodules in the tissue, these are signs the thickening is malignant.
What Are the Treatments for Pleural Thickening?
Early diagnosis is essential because pleural thickening is progressive. It will only worsen without treatment. If caused by mesothelioma, early treatment is especially important. Damage caused by pleural thickening cannot be reversed, though treatment can slow progression and relieve symptoms.
Pain medication is a standard treatment for benign pleural thickening. A doctor may also prescribe bronchodilators to dilate airways. In addition, a patient may receive steroids to reduce inflammation.
Decortication surgery can remove some of the restrictive fibrous scar tissue; however, this is not a common procedure, especially if the thickening is related to other asbestos conditions like mesothelioma.[4]
Few mesothelioma patients are good candidates for surgical treatment, but for those who are, surgery can relieve symptoms of pleural thickening.
Other treatment strategies include respiratory aides, like oxygen tanks and respirators.[4]
What Is the Prognosis for Pleural Thickening?
The outlook for diffuse pleural thickening is highly dependent on several factors. If the underlying condition can be treated, the outlook is typically positive.
If the underlying cause is mesothelioma, the prognosis is poor and life expectancy is short. Mesothelioma is challenging to treat and nearly incurable. Treatments at an early stage may successfully relieve symptoms and slow the progression of damage to the pleura. Unfortunately, reversing the damage is not possible.
Life expectancy also depends on the underlying cause. For late-stage mesothelioma, it may be a year or less. For another cause, it depends on how treatable the underlying condition is.
Can I Get Compensation for Pleural Thickening?
If your pleural thickening resulted from asbestos exposure, you can seek compensation. An experienced lawyer can help you determine the workplaces and asbestos suppliers and manufacturers responsible for your exposure. You can then file a lawsuit or file a claim with an appropriate asbestos trust.
If you are a veteran, you can file for Veterans Administration benefits, such as disability compensation. The VA recognizes asbestos-related pleural thickening as a disability. The amount of compensation to which you are entitled depends on its severity and your symptoms.
If you have been diagnosed with pleural thickening and believe you were exposed to asbestos, talk to your doctor about the possibility of mesothelioma. Insist on screening for this type of cancer and understand your options for treating the symptoms of pleural thickening. With treatment and good management, you can experience some relief from this uncomfortable condition.
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Anne Courtney has a Doctor of Nursing Practice degree and is an Advanced Oncology Certified Nurse Practitioner. She has years of oncology experience working with patients with malignant mesothelioma, as well as other types of cancer. Dr. Courtney currently works at University of Texas LIVESTRONG Cancer Institutes.