RESUMO
Pericardial effusions are a relatively common phenomenon, largely in part due to its many possible etiologies. Although a considerable amount of cases are idiopathic, careful history and physical examination will reveal the etiology in a vast majority of patients. The most effective tools, echocardiography and right heart catheterization, should be aimed not only at the diagnosis of the pericardial effusion, but also to the assessment of the severity of the pericardial effusion, since this will determine that individual patient's management. A small, asymptomatic pleural effusion of known etiology can be treated conservatively, mostly by treating the underlying cause and with careful observation for signs or symptoms of deterioration. Large effusions can be treated with closed pericardiocentesis after routine evaluation for possible etiologies. For patients presenting actual or impending tamponade, the definitive treatment is either closed or open pericardiocentesis, depending on fluid accumulation characteristics, and it should not be delayed for the administration of medical treatment (inotropes, intravenous fluids). Routine evaluation of pericardial fluid is warranted in those cases in which a clear etiology was not established prior to pericardiocentesis.