Pericardial Effusion
Pericardial effusion is an abnormal accumulation of fluid in the pericardial sac, the double-layered membrane surrounding the heart. This fluid buildup can range from small and asymptomatic to large volumes that compress the heart and impair its function. The condition has many potential causes including infection, inflammation, cancer, trauma, and heart failure, and requires careful evaluation to determine appropriate treatment.
What is it?
Pericardial effusion occurs when excess fluid accumulates in the pericardial space between the two layers of the pericardium—the fibrous sac that surrounds and protects the heart. Normally, this space contains a small amount of lubricating fluid (15-50 mL) that allows the heart to move smoothly during contraction. When fluid accumulates beyond normal levels, it can range from mild (50-100 mL) to moderate (100-500 mL) to large (greater than 500 mL) volumes.
The causes of pericardial effusion are diverse and include viral or bacterial infections (pericarditis), autoimmune diseases such as lupus or rheumatoid arthritis, cancer (especially lung cancer, breast cancer, or lymphoma), kidney failure (uremic pericarditis), heart attack, heart surgery, chest trauma, certain medications, and idiopathic cases where no cause is identified. The rate of fluid accumulation is critical—rapid accumulation of even small amounts can cause serious problems, while slowly developing large effusions may be better tolerated as the pericardium stretches gradually.
Important to Know
The most serious complication is cardiac tamponade, a life-threatening emergency that occurs when accumulated fluid compresses the heart and prevents it from filling properly with blood. This dramatically reduces cardiac output and blood pressure, potentially leading to shock and death if not treated immediately. Warning signs include severe shortness of breath, rapid heart rate, low blood pressure, chest pain, anxiety, and confusion. CT imaging can detect pericardial effusion, measure fluid volume, identify underlying causes such as tumors or inflammation, and help distinguish between simple fluid and more complex collections containing blood or infectious material. Treatment depends on the amount of fluid, rate of accumulation, underlying cause, and whether cardiac function is compromised, ranging from observation and treating the underlying condition to emergency pericardiocentesis (needle drainage) for tamponade.