Pericardial Effusion


A pericardial effusion occurs when a significant amount of fluid fills the pericardial space.

Individuals without pericardial effusion have a small amount of pericardial fluid (15 mL to 50 mL), which helps promote cardiac chamber interaction by allowing the heart to move freely without restriction.

When pericardial fluid accumulates slowly, the pericardium can expand to accommodate as much as 2 liters of fluid. However, when acute, only a small volume can increase intrapericardial pressures, resulting in clinical symptoms.


Pericardial effusions can be caused by multiple disease states, including any process that results in pericarditis or myocarditis. The inflammatory reaction in these disease states can result in fluid accumulation in the pericardial space.

The causes of pericardial effusions are summarized below:






Cardiac surgery

Systemic lupus



Radiation therapy

Rheumatoid arthritis

Hypothyroidism and uremia (metabolic)

Bacterial (SBE)

Minoxidil, penicillins, methylsergide


Heart, liver, renal failure

Fungal (rare)

Coronary perforation

Dressler's syndrome

Hemorrhage (aortic dissection, trauma, free wall rupture)


Right ventricular perforation


Pericardial infarction






Multiple infectious etiology of a pericardial effusion exist. The most common cause of a pericardial effusion, historically, has been tuberculosis; however, in the United States this is relatively rare. A pericardial effusion from tuberculosis can occur in isolation without any pulmonary manifestations. Viral pericarditis or myocarditis are associated with a pericardial effusion, most commonly the Coxsackie B virus. Bacterial pericarditis resulting in a pericardial effusion is life-threatening and can be associated with bacterial endocarditis. A pericardial abscess requiring surgical drainage can occur in this setting. Fugal pericardial involvement is rare.

Iatrogenic pericardial effusions are common after cardiac surgery and frequently require drainage. Pericardial effusions caused by radiation therapy are less common due to the dose reduction possible today. For unclear reasons, the drugs minoxidil, penicillins and methysergide have been shown to cause pericardial effusion. Hemorrhage into the pericardium during invasive procedures such as percutaneous coronary intervention causing coronary perforation, or pacemaker insertion causing right ventricular perforation, can be serious.

Autoimmune reactions can cause pericarditis, and thus pericardial effusions. Systemic lupus erythematosus can be primary or drug-induced (hydralazine, quinidine or isoniazid), the latter is detected by measuring anti-histone antibodies. Rheumatoid arthritis and scleroderma are other collagen vascular disorders that cause autoimmune pericarditis and pericardial effusions. Dressler’s syndrome is an autoimmune reaction that occurs after myocardial infarction, causing pericarditis and an associated effusion. Idiopathic pericardial effusions are likely autoimmune mediated; however, as the name implies, this remains unclear.

Miscellaneous causes include malignancy, of which lung cancer, breast cancer and Hodgkin’s lymphoma are the most common. Theoretically, any malignancy can cause a pericardial effusion. Hypothyroidism and uremia are metabolic causes of a pericardial effusion and result from increased capillary permeability in these disease states. Increased hydrostatic pressure causing a pericardial effusion is present in congestive heart failure. Liver and renal failure result in decreased oncotic pressure, contributing to pericardial fluid accumulation. Hemorrhage into the pericardium from trauma, aortic dissection or left ventricular free wall rupture after an MI can occur. Transmural MI can sometimes infarct the pericardium, as well cause an inflammatory reaction, pericarditis and a pericardial effusion.


Pericardial effusions are best diagnosed by echocardiography, which is validated to estimate the size and location, and determine if hemodynamic compromise is present causing cardiac tamponade. Right ventricular diastolic collapse would indicate cardiac tamponade.

The chest X-ray shows a markedly enlarged cardiac silhouette termed "water-bottle heart." Chest X-ray will show a “globular heart” with significant heart enlargement.

CT can detect the presence of a pericardial effusion; however, it is not accurate to estimate size.

The 12-lead ECG may show low voltage, pericarditis (if present) or electrical alternans.

Analysis of the fluid via pericardiocentesis is different than analyzing fluid from a pleural effusion or ascites. Pericardial fluid is not classified into transudate and exudate, thus parameters such as lactate dehydrogenase (LDH) and protein levels are not necessary. Instead, the fluid appearance is described (i.e. clear, yellow, bloody), the fluid is microscopically examined for cytology to detect malignancy, and cultures can be sent. Measuring ADA (adenosine deaminase) can help detect tuberculosis as the cause of a pericardial effusion.


Symptoms from a pericardial effusion are related to pericarditis, if present, or cardiac tamponade.

Physical Examination

A large pericardial effusion can muffle the heart sounds, making them soft or even inaudible. A pericardial friction rub from pericarditis may be present. Ewart’s sign is dullness to percussion at the left lung base due to compressive atelectasis from a large pericardial effusion. Auenbrugger’s sign is an epigastric bulge due to a large pericardial effusion extending subxiphoid. Compression of this bulge may cause hemodynamic compromise and cardiac tamponade.

Physical exam findings of cardiac tamponade include sinus tachycardia, elevated jugular venous pressure with inspiration, pulsus paradoxus and, rarely, Kussmaul’s sign.

Pulsus paradoxus reflects a decrease in systolic BP with inspiration of more than 12 mm Hg. Pulsus paradoxus also occurs in severe asthma or COPD exacerbations.


Many pericardial effusions do not require any therapy. However, if there is concern for cardiac tamponade, pericardiocentesis can be performed percutaneously. This is done via a subxiphoid approach using a needle to drain the fluid under echocardiographic and/or fluoroscopic guidance. This is done for both therapeutic and for diagnostic purposes. A surgical approach using a “pericardial window” is performed when there is concern that the pericardial fluid will accumulate, such as with a malignant pericardial effusion.