Health Encyclopedia

Pleural Effusions

What are Pleural Effusions?

A pleural effusion is an abnormal accumulation of fluid between the two layers of the pleura—a dual membrane that lines the chest cavity and surrounds the lungs. This condition also is called simply “fluid in the chest.” The accumulation of fluid is triggered by existing illnesses or medical conditions that increase pressure on the lungs or irritate the pleura.

Pleural effusions are quite common, and many people with the condition have no symptoms at all. It’s not always just a consequence of other illnesses. It might be a symptom of several types of cancer—lung, breast, and ovarian cancer, lymphomas, and mesothelioma (cancer of the pleura)—that come in contact with the membrane.

The Mechanics of Pleural Effusions

Your body produces pleural fluid in small amounts to lubricate the surfaces of the pleura so your lungs, as they expand and contract, can move easily against the chest wall and diaphragm. Depending on the illness triggering the production of fluid, it might be watery (transudate) or rich in protein (exudate). Transudative pleural effusions are usually caused by abnormal lung pressure, while exudative effusions are usually the result of inflammation of the pleura. Doctors are able to zero in on the underlying cause by determining the make-up of the fluid.

Symptoms of Pleural Effusions

The most common symptoms, regardless of the characteristics of the fluid or the underlying cause, include:

  • Shortness of breath or rapid breathing
  • Sharp chest pain that is worse with cough or deep breath
  • Cough
  • Hiccups
  • Collapsed lung

It must be remembered that many people with pleural effusions experience no symptoms at all.

Causes of Pleural Effusions

Pleural effusions are caused by a variety of illnesses—from various cancers to cirrhosis to heart failure to lung infections such as pneumonia to asbestosis. The condition also can be brought on by reactions to certain drugs and chest injury. If the pleura is aggravated in any way—through pressure, inflammation, irritation, swelling—the body will start producing pleural fluid in abnormal amounts.

Diagnosing Pleural Effusions

There are numerous procedures at a doctor’s disposal to develop a diagnosis. They include:

  • Listening to the sound of the patient’s breathing with a stethoscope
  • Tapping on the patient’s chest and listening for a dull sound (indicating a fluid build-up)
  • Taking an x-ray to reveal the make-up and condition of the chest area
  • Performing a CT (computed tomography) scan to obtain additional “internal” details
  • Drawing fluid from the chest cavity by needle (thoracentesis) and analyzing its contents
  • Viewing the pleural space using a thoracoscope to examine its characteristics

Treating Pleural Effusions

Small pleural effusions might require nothing more than treating the underlying condition that triggered the build-up of fluid. Larger pleural effusions, particularly those that are taking up a lot of space normally occupied by the lungs and causing shortness of breath, are treated by draining the fluid from the chest. This process can dramatically relieve shortness of breath.

The same process used to extract a fluid sample for diagnostic purposes—thoracentesis—is used to drain all the accumulated fluid. The doctor might require an x-ray at that point to see how well the lung has expanded.

In most cases, it will be necessary to redrain the effusion one or more times. For that reason, the doctor probably will install a catheter—a more permanent drainage apparatus—during the initial draining session. The number of times the effusion is drained depends largely on the status of the underlying condition. Each time the effusion is drained, the lung may be drawn out a bit further until it regains its original, normal position.



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