[Ten questions about pericardial effusion]

Although a new or worsening pericardial effusion is a diagnostic criterion for pericarditis, in clinical practice the presence of pericardial effusion does not necessarily imply the evidence of pericarditis. Up to 40-50% of cases of pericarditis do not show the presence of pericardial effusion (dry pericarditis). The clinician should first evaluate any related symptoms and signs (symptomatic vs asymptomatic), its size and hemodynamic impact, then rule out pericarditis and the presence of an underlying disease (e.g. cancer, systemic inflammatory diseases, renal failure, hypothyroidism). If no cause is apparent ("idiopathic effusion"), the decision to tap should be individualized and based on symptoms. A large, chronic pericardial effusion may have a good long-term prognosis even without routine drainage.In this paper, we will try to clarify common doubts and outline evidence-based approaches to diagnosis, therapy and follow-up of these patients, also addressing the possible complications and outcomes.