Pericardial effusion is best described as what?

• A. Collection of fluid or blood in the pericardium
• B. Blood clot in the heart chambers
• C. Accumulation of air in the pericardial space
• D. Calcification of pericardial layers

Answer: (A)

Abnormal collection of fluid within the pericardial sac surrounding the heart is what defines a pericardial effusion. The pericardial space normally contains only a small amount of lubricating fluid; when excess fluid accumulates, the effusion forms and can be serous, bloody, or purulent depending on the cause. This is distinct from a clot inside the heart chambers, which would be an intracardiac thrombus; from air in the pericardial space, which is pneumopericardium; and from calcification of the pericardial layers, which is seen with pericardial calcification often related to constrictive processes.