Function and Disorders of the Pleura

What Purposes It Serves and What Can Affect It

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The pleura is a vital part of the respiratory tract whose purpose it is to cushion the lungs and reduce any friction which may develop between the lungs, rib cage, and chest cavity.

Structure of the Pleura

The pleura specifically refers to the two membranes that cover the lungs. The space between the two membranes is called the pleural cavity which is filled a thin, lubricating liquid called pleural fluid.

The pleura is made up of two, distinct layers:

  • The visceral pleura is the thin, slippery membrane that covers the surface of the lungs and dips into the areas separating the different lobes (called the hilum.)
  • The parietal pleura is the outer membrane that lines the inner chest wall and diaphragm.

The visceral and parietal pleura join at the hilum of each lung, where the major bronchi, pulmonary arteries, and pulmonary veins enter the lung.

Conditions Affecting the Pleura

Under the influence of the lubricating fluid, the pleura membranes are able to glide atop each other, allowing the lungs to expand during inhalation and relax during exhalation. If the pleura becomes scarred, or if fluid builds up in the space between these membranes, it can restrict movement and interfere with breathing.

There are several conditions that can adversely affect the pleura. If inflammation is involved, the pain tends to be sharp and felt with each breath.

Pain that worsens with a deep breath is specifically referred to as pleuritic chest pain.

Among the conditions involving the pleura:

  • Pleurisy is an inflammation of the pleural membranes during which the surfaces become rough and sticky. It is most commonly caused by viral infections but can be caused by bacteria and autoimmune diseases such as rheumatoid arthritis and lupus.
  • Pleural effusion in the accumulation of excess fluid in the pleural space. When this happens, breathing can be impaired. Congestive heart failure is the most common cause of a pleural effusion.
  • Malignant pleural effusion refers to an effusion caused by lung cancer or other cancers that have spread (metastasized) to the lungs from other parts of the body, such as the cervix or stomach.
  • Pleural mesothelioma is a cancer of the pleura, is most commonly caused by occupational exposure to asbestos.
  • Pneumothorax is a condition where air collects in the pleural cavity. It may be caused by any number of things, including chest trauma chest surgery, and COPD.
  • Hemothorax refers to blood in the pleural cavity which can occur during chest surgery or trauma.

Treating Disorders of the Pleura

Disorders of the pleura can sometimes be symptom-free and resolve on their own. Other require medical intervention. Treatment will depend largely on the underlying cause of the disorder. If the excessive accumulation of fluid, blood, or air is involved, a chest tube may be used to help remove it.

Smaller pleural effusions may go away on their own; larger ones will need to be drained. This is usually done either by extracting fluid with a needle (thoracentesis) or using chemicals which cause the layers to stick together and press out the excess fluid (pleurodesis).

If persons with mesothelioma, a surgical procedure called a pleurectomy ​may be performed to remove a section of pleura to prevent the buildup of fluid. It also allows the surgeon to remove any tumors that have developed inside the chest.

Sources

  • Batra, H. and Antony, V. “Pleural mesothelial cells in pleural and lung diseases.” Journal of Thoracic Disease. 2015; 7(6):964-980.
  • Bertin, F. and Deslauriers, J. “Anatomy of the Pleura: Reflection Lines and Recesses.” Thoracic Surgery Clinics. 2011; 21(2):165-171.

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