Overview of Pericardial Effusion

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The pericardium (also called the pericardial sac) is a protective pouch surrounding the heart, that normally contains a small amount of lubricating fluid. With certain medical disorders the volume of this pericardial fluid can increase to abnormal levels. The excessive accumulation of fluid within the pericardial sac is called a pericardial effusion.

A pericardial effusion is a significant medical problem for two reasons.

First, if the pericardial effusion accumulates rapidly, or if it becomes very large, it can restrict the normal filling of the heart during diastole (the phase of the heartbeat in which the ventricles fill with blood). This condition, called cardiac tamponade, is a serious medical problem that produces significant symptoms (chiefly, extreme shortness of breath, weakness and fatigue), and which can become life-threatening.

Second, the presence of a pericardial effusion is often associated with a potentially serious underlying medical problem. If so, that problem needs to be identified.

So whenever a pericardial effusion is discovered, the doctor has two important jobs to do. First, the doctor must assess whether the effusion itself is compromising the function of the heart; and second, he or she must make every effort to determine which medical condition is causing the effusion in the first place.

What Are The Causes Of Pericardial Effusion?

Pericardial effusions can be produced by several medical disorders. The most common causes are:

What Are The Symptoms Of Pericardial Effusion?

Pericardial effusions are often accompanied by symptoms. Most commonly, however, the symptoms are due not to the effusion itself, but instead to the disease process that is causing the effusion. Pericarditis, Dressler's syndrome, autoimmune disorders, and infections involving the pericardium often produce inflammation and irritation of the pericardial sac, leading to chest pain, cough, or shortness of breath. In contrast, pericardial effusions caused by non-inflammatory conditions (for instance, hypothyroidism) often do not produce any symptoms at all.

But if the pericardial effusion should become large enough to compromise the function of the heart (that is, the effusion begins to produce cardiac tamponade), then the effusion itself begins to produce significant symptoms, including severe shortness of breath, extreme fatigue and weakness, and palpitations.

How Is A Pericardial Effusion Evaluated?

Most typically, a doctor will become alerted to the possibility of a pericardial effusion if a patient describes symptoms suggestive of pericarditis (or one of the other conditions listed above that can produce pericardial effusion), if an electrocardiogram shows evidence of pericarditis, or if a chest x-ray shows what appears to be an enlarged heart.

(When the pericardial sac has accumulated a large amount of fluid, the cardiac shadow on the chest x-ray can become larger than normal.) Once suspected, a pericardial effusion can be easily confirmed or ruled out by performing an echocardiogram.

When a pericardial effusion is diagnosed, it is important for the doctor to answer two specific questions. First, is the effusion producing any compromise of the patient's cardiac function (that is, is there evidence of cardiac tamponade)? And second, what medical disorder is causing the effusion?

Whether any degree of cardiac tamponade is present can generally be determined by evaluating the patient's symptoms, by conducting a careful physical examination, and with an echocardiogram.

Establishing the cause of the pericardial effusion may be straightforward (for instance, if there has been recent chest trauma, or a history of lupus), or it may take a certain amount of detective work. In general, a diagnosis usually can be made by taking a careful medical history, and with judicious blood testing (blood chemistries, complete blood count, thyroid function tests, and tests targeted at detecting autoimmune disorders). If the underlying cause for the pericardial effusion is still unknown, the doctor may want to test the pericardial fluid itself. This is done with a procedure known as a pericardiocentesis: withdrawing some of the pericardial fluid by means of a needle stick.

How Is A Pericardial Effusion Treated?

The immediate treatment of a pericardial effusion depends on whether or not any degree of cardiac tamponade is present. If so, a pericardiocentesis should be performed right away, to drain the effusion and restore normal cardiac function.

If there is no cardiac tamponade, then in general the treatment is aimed at the underlying medical cause. In most cases, once the underlying cause is brought under control, the pericardial effusion will also resolve.

In some rare cases, despite optimal treatment of the underlying cause, the pericardial effusion will persist. A pericardial effusion that is present for at least three months is considered a chronic pericardial effusion. Because a chronic, persistent pericardial effusion can progress at any time to cardiac tamponade, these long-lasting pericardial effusions are usually treated by repeated pericardiocentesis, or by pericardiectomy (surgery to remove some or all of the pericardium).

Fortunately, in the large majority of cases, pericardial effusions resolve without the need for invasive therapeutic procedures.


Maisch B, Seferovic PM, Ristic AD, et al. Guidelines on the diagnosis and management of pericardial diseases executive summary; The Task force on the diagnosis and management of pericardial diseases of the European society of cardiology. Eur Heart J 2004; 25:587.

Shabetai R. Pericardial effusion: haemodynamic spectrum. Heart 2004; 90:255.

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