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Diseases A–Z

Pleurisy

Causes | Symptoms | Wet pleurisy | Dry pleurisy | Treatment

Pleurisy is an inflammation of the pleura- a two-ply membrane that both encloses the lung and lines the chest cavity.

People have two pleurae, one around each lung. The pleurae act as a protective wrapping, fitting snugly over your lungs. Pleurae are made up of two layers. Normally, there is no space between the inner and outer layer. The layers are joined at the edges, so that the pleura might be compared to a closed balloon, completely empty of air and wrapped tightly around the outside of each of the lungs.

Normally, there is nothing but a thin layer of Iubricating layer of fluid between the inner pleural lining and the outer one. The smooth pleura linings and lubricating fluid allow your lungs to move freely in your chest, as they do in normal breathing.

In people with pleurisy, the two layers of pleura get inflamed (red & swollen). This can create a space between the layers called the pleural cavity (cavity means space). In wet pleurisy, this space can fill up with fluid that can get infected.

What causes pleurisy?

Pleurisy can arise from various causes and take various ways to develop, sometimes with excess fluid in the pleural cavity ("wet pleurisy") and sometimes without ("dry pleurisy"), sometimes accompanied by no pain sometimes very painful.

There are two kinds of pleurisy. A "primary" pleurisy is an inflammation arising in the pleural tissues themselves, from a germ that attacked them directly, or perhaps from an injury or growth. A "secondary" pleurisy is an added effect from some other chest disease - pneumonia, for instance - in which the germs reach the pleura as well as the lungs themselves, or tuberculosis, or lung abscess, or tumour of the lung; almost anything wrong in the chest.

The symptoms and course of primary and secondary pleurisy may be exactly the same, with only the cause different.

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Symptoms of pleurisy

People with pleurisy may experience:

  • pain: pain during each breath, pain when you move, and extreme pain when you cough or sneeze
  • shallow and difficult breathing
  • dry coughing
  • weakness
  • headache
  • loss of appetite
  • chills
  • fever
  • rapid heartbeat

These symptoms could be cased by pleurisy, or they could be caused by another disease; only a doctor can tell. If you have these symptoms, or if you think you have pleurisy, see your doctor right away.

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How pleurisy happens

Pleurisy may be acute - appearing, giving trouble for a period, and then disappearing. It may be chronic - hanging on, the pain steady or recurring often, the interference with breathing and other normal activity an enduring burden. Whether acute or chronic, pleurisy can be either dry or wet, painful or free of pain.

Dry pleurisy is an inflammation that has not formed fluid. It can be very painful, especially when the swollen outer layer is stretched on breathing. A grating sensation may be distinctly felt by the victim when the two layers, both perhaps stiffened and swollen, rub against each other. Oddly enough, however, it is only the outer lining, next to the chest wall, that feels pain. The one next to the lung has no pain nerves.

Again, the inflammation of dry pleurisy may subside and the pain go away, even though the grating of the roughened tissues may still be felt. Or it may turn into wet pleurisy, with the accumulation of fluid. The fluid may be absorbed and become a dry pleurisy again.

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Wet pleurisy (pleurisy with effusion) involves fluid that may arise from any of several causes. One may be the inflammation itself, which causes an outpouring of blood and lymph (supplementary body fluid). A chest injury with bleeding is an example of another possible source of fluid.

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The effects of pleurisy

When dry pleurisy heals, it leaves strands of fibrous tissue (adhesions) strung between the lung and the wall of the chest, tying them together. Sometimes these adhesions are so extensive that they limit the movement of the lungs. But usually the soreness disappears and the adhesions stretch so much that they no longer cause any difficulty.

In wet pleurisy, the fluid builds up in the pleural cavity. There may be enough to restrict the movement of the lungs and therefore the ability to breathe. On the other hand, the increasing fluid may separate the linings so that movement of the chest wall and of the sensitive outer lining is limited - causing pain to subside.

A large amount of fluid displaces the heart as well as the Iung. The lung may remain compressed or displaced and fail to return to its full capacity because of thickening of the pleura after the fluid has been absorbed.

Fluid that is relatively clear may give little trouble and be readily absorbed in time. But if the fluid becomes infected - as it may do - it turns into pus and may lead to further complications. This condition, called "empyema," is very serious.

The pus sometimes breaks through the lung wall and into the air passages, where it may be coughed up. Removal of the pus by drainage is usually needed for the patient to recover.

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How is pleurisy treated?

The inflammation of pleurisy is treated by attacking the infection that may have caused it. A pleurisy caused by some lung disease is treated, first of all, by identifying the underlying disease and giving whatever treatment is available for it.

To limit the pain of pleurisy, limiting the movement of the lungs may be desirable. The doctor may suggest lying on the sore side in a special way - for example, on a firm surface - to limit breathing movement on that side enough to reduce the stretching of the sore tissues and therefore the pain. He may also prescribe medication for the pain itself.

For dry pleurisy, such treatment is generally enough. In wet pleurisy, the doctor may decide to remove the fluid by drawing it out with a needle. Timing of this is important, since the fluid may come back if it is removed too soon. On the other hand, if it's not done early enough dense adhesions may form, resulting in permanent breathing difficulty.

The main treatment is that for the primary cause of the inflamed pleura.

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