Pericardial Effusion vs Cardiac Tamponade

Pericardial Effusion

• Definition: Accumulation of fluid in the pericardial sac
• Can be: Small or large, acute or chronic
• Causes:
  • Infection (viral, TB)
  • Malignancy
  • Uremia
  • Autoimmune (SLE, RA)
  • Trauma
  • Post-MI (Dressler syndrome)
• Symptoms:
  • Often asymptomatic if fluid accumulates slowly
  • May have chest discomfort, dyspnea
• Physical Exam:
  • Muffled heart sounds
  • Dullness to percussion over left lung base (large effusion)
• CXR: Enlarged, "water bottle"-shaped heart silhouette
• EKG:
  • Low-voltage QRS
  • Electrical alternans (if large)
• Echo: Primary diagnostic tool; shows anechoic space around heart
• Tx:
  • Treat underlying cause
  • Pericardiocentesis if large or symptomatic

Cardiac Tamponade

• Definition: Pericardial effusion causing hemodynamic compromise due to pressure on the heart
• Medical Emergency
• Pathophysiology:
  • ↑ Pericardial pressure → ↓ ventricular filling → ↓ CO
• Key Causes:
  • Trauma (e.g., stab wound)
  • Malignancy
  • Aortic dissection
  • Post-cardiac surgery
• Symptoms:
  • Beck’s triad:
    • Hypotension
    • Muffled heart sounds
    • JVD
  • Pulsus paradoxus (>10 mmHg drop in SBP during inspiration)
  • Dyspnea, tachycardia, fatigue, chest discomfort
• EKG:
  • Low voltage
  • Electrical alternans (swinging heart)
• Echo:
  • Diastolic collapse of right atrium or ventricle
  • Swinging of heart in fluid
• CXR: May show enlarged cardiac silhouette if effusion is large
• Tx:
  • Urgent pericardiocentesis
  • IVF to maintain preload temporarily