A pericardial effusion is an abnormal amount of fluid between the heart and the pericardium, which is the sac surrounding the heart. Pericardial effusions are associated with many different medical conditions. Most pericardial effusions are not harmful, but large pericardial effusions can cause problems by impairing heart function.
The pericardium is a tough, layered sac that wraps around the heart. When the heart beats, it slides easily within the sac. Normally, only 2 to 3 tablespoons of clear-yellow pericardial fluid are present between two layers, which lubricates the heart's movements within the sac.
In pericardial effusions, significantly larger amounts of pericardial fluid accumulate. Small pericardial effusions may contain 100 milliliters of fluid. Very large pericardial effusions may involve more than two liters of fluid.
Causes of Pericardial Effusion
Most pericardial effusions are caused by inflammation of the pericardium, a condition called pericarditis. As the pericardium becomes inflamed, extra fluid is produced, leading to a pericardial effusion.
Viral infections are one of the main causes of pericarditis and pericardial effusions. Infections causing pericardial effusions include cytomegalovirus, coxsackieviruses, echoviruses, and HIV.
Other conditions that can cause pericardial effusions include:
Injury to the pericardium or heart from a medical procedure
In a large number of people with pericardial effusion, no cause can be identified. These are called idiopathic pericardial effusions.
Symptoms of Pericardial Effusion
When a pericardial effusion is caused by pericarditis, the main symptom is chest pain. The chest pain may be made worse by deep breathing and lessened by leaning forward. When pericarditis is causing a pericardial effusion, other symptoms may include: