Pleural Effusion

Many people with pleural effusion have no symptoms at all. The most common symptoms, regardless of the type of fluid in the pleural space or its cause, are

Chest pain is usually of a type called pleuritic pain (the term pleurisy is no longer or only rarely used). Pleuritic pain may be felt only when the person breathes deeply or coughs, or it may be felt continuously but may be worsened by deep breathing and coughing. The pain is usually felt in the chest wall right over the site of the inflammation or infection that caused the effusion. However, the pain may be felt also or only in the upper abdominal region or neck and shoulder, which is called referred pain (see figure ). Pleuritic pain can be caused by disorders other than pleural effusion.

Pleuritic chest pain due to a pleural effusion may disappear as fluid accumulates. Large amounts of fluid can cause difficulty in expanding one or both lungs when breathing, causing shortness of breath.

A chest x-ray, which shows fluid in the pleural space, is usually the first step in making the diagnosis. However, small amounts of fluid may not be visible on a chest x-ray.

Ultrasonography of the chest can also be done to help doctors identify small accumulations of fluid.

Doctors may do thoracentesis Thoracentesis Thoracentesis is the placement of a needle through the skin into the chest cavity to withdraw a sample of fluid. In thoracentesis, fluid that has collected abnormally in the pleural space (termed... read more . In this procedure, a specimen of the fluid is removed for examination using a needle. The appearance of the fluid may help doctors determine its cause. Certain laboratory tests evaluate the chemical composition of the fluid and determine the presence of bacteria, including the bacteria that cause tuberculosis. The fluid specimen is also examined for the number and types of cells and for the presence of cancerous cells.

If these tests cannot identify the cause of the pleural effusion, other tests may be done.

CT scan more clearly shows the lung and the fluid and may show evidence of pneumonia, a mediastinal mass, a lung abscess, or a tumor that could be causing fluid to accumulate. Sometimes a radiopaque dye is injected during CT (CT angiography or venography) to look for problems with the pleura or with blood vessels, including pulmonary embolism Pulmonary Embolism (PE) Pulmonary embolism is the blocking of an artery of the lung (pulmonary artery) by a collection of solid material brought through the bloodstream (embolus)—usually a blood clot (thrombus) or... read more .

If a serious diagnosis still seems possible, doctors may insert a viewing tube into the chest (called thoracoscopy Thoracoscopy Thoracoscopy is the visual examination of the lung surfaces and pleural space through a viewing tube (a thoracoscope). Thoracoscopy is used to view the lung and the space surrounding the lungs... read more ). Occasionally, doctors need to obtain a sample (biopsy) of the pleura and/or lung. In about 15% of people with pleural effusion, the cause is not obvious after initial testing, and in some people a cause is never found, even after extensive testing.

Small pleural effusions may not require treatment, although the underlying disorder must be treated. Sometimes the person is given analgesics until the fluid is drained or drains away on its own.

Larger pleural effusions, especially those that cause shortness of breath, may require drainage. Usually, drainage dramatically relieves shortness of breath. Often, fluid can be drained using thoracentesis. An area of skin between two lower ribs is anesthetized, then a small needle is inserted and gently pushed deeper until it reaches the fluid. A catheter (thin flexible tube) is often guided over the needle into the fluid to lessen the chance of puncturing the lung and causing a pneumothorax. Although thoracentesis is usually done for diagnostic purposes, doctors may use this procedure to remove enough fluid at one time to relieve the person's shortness of breath.

When large amounts of fluid must be removed, a tube (chest tube) may be inserted through the chest wall. After numbing the area by injecting a local anesthetic, doctors insert a thin flexible tube into the chest between two ribs. Then doctors connect the tube to a water-sealed drainage system that prevents air from leaking into the pleural space. A chest x-ray is taken to check the tube’s position. Drainage can be blocked if the chest tube is incorrectly positioned or becomes kinked. If the fluid is very thick or full of clots, it may not flow out.