A disorder characterized by fluid collection within the pericardial sac, usually due to inflammation. [CTCAE] Fluid accumulation within the PERICARDIUM. Serous effusions are associated with pericardial diseases. Hemopericardium is associated with trauma. Lipid-containing effusion (chylopericardium) results from leakage of THORACIC DUCT. Severe cases can lead to CARDIAC TAMPONADE. [MeSH]
