What are the causes of pericardial effusion?

Causes of Pericardial Effusion

Pericardial effusion can be caused by a wide range of conditions, with malignancy, infections, autoimmune diseases, and iatrogenic causes being the most common etiologies. 1, 2

Infectious Causes

• Viral infections: Most common cause in developed countries (80-90% of cases) 2
• Tuberculosis: Leading cause worldwide, especially in developing countries and in HIV-positive patients 2
• Bacterial infections: Can cause purulent pericarditis requiring surgical drainage 1, 2
• Fungal infections: Including Histoplasma, Coccidioides, Candida, and Aspergillus, primarily in immunocompromised patients 2

Neoplastic Causes

• Secondary malignancies: 40 times more common than primary tumors 2
  • Lung cancer, breast cancer, melanoma, lymphomas, and leukemias 1
  • Often presents with hemorrhagic effusion 1
  • May be the initial sign of malignant disease 1
• Primary tumors: Rare (mesotheliomas, angiosarcomas, fibrosarcomas) 1
• Important note: In almost two-thirds of patients with documented malignancy, pericardial effusion is caused by non-malignant diseases (radiation pericarditis, other therapies, opportunistic infections) 1

Autoimmune/Inflammatory Causes

• Systemic autoimmune diseases: Account for 5-15% of cases 2
  • Systemic lupus erythematosus
  • Rheumatoid arthritis
  • Scleroderma
  • Sjögren syndrome
  • Systemic vasculitides
  • Behçet syndrome
• Autoreactive pericarditis: Immune-mediated inflammation 1
• Sarcoidosis: Granulomatous inflammation affecting the pericardium 2

Post-injury/Iatrogenic Causes

• Post-myocardial infarction: Dressler syndrome 2
• Post-pericardiotomy syndrome: Following cardiac or thoracic surgery 2
• Post-traumatic pericarditis: Following chest trauma 2
• Radiation-induced: Can occur 6-30% of patients after radiation therapy, may present years later 1, 2
• Medication-induced:
  • Chemotherapies: Anthracyclines, cyclophosphamide, cytarabine, imatinib, dasatinib, interferon-α, arsenic trioxide, docetaxel, 5-fluorouracil 1
  • Other drugs: Procainamide, hydralazine, methyldopa, isoniazid, phenytoin, amiodarone, mesalazine, clozapine, minoxidil 2
• Aortic dissection: Present in 17-45% of cases, causing hemopericardium 2

Metabolic/Other Causes

• Uremia: Common in end-stage renal disease patients (5% in patients starting dialysis) 2
• Hypothyroidism (myxedema): Occurs in 5-30% of patients with hypothyroidism; effusions may be large but rarely cause tamponade 2
• Heart failure: Right ventricular failure and increased right-sided filling pressures can cause small effusions 2
• Chylopericardium: Effusion composed of chyle due to thoracic duct injury 2
• Cholesterol pericarditis: Clear fluid with high cholesterol content 2
• Anorexia nervosa: Can cause pericardial effusion 2

Idiopathic

• When no specific cause can be identified despite thorough investigation 3
• Can be acute or chronic 3

Diagnostic Approach

Determining the etiology of pericardial effusion requires:

1. Imaging: Echocardiography (primary tool), CT/MRI (better for loculated effusions) 2
2. Pericardial fluid analysis: Essential for confirming malignant or infectious disease 2
3. Pericardial biopsy: Reserved for recurrent or persistent effusions without defined etiology 1

Management Considerations

• Treatment should target the underlying etiology whenever possible 2
• Pericardiocentesis is mandatory for cardiac tamponade and suspected bacterial or neoplastic etiology 2
• Intrapericardial treatment may be considered for specific causes:
  • Neoplastic effusions: Cisplatin (lung cancer) or thiotepa (breast cancer) 1
  • Autoreactive/lymphocytic effusions: Triamcinolone 1
  • Uremic effusions: Triamcinolone alongside intensified dialysis 1

Prognostic Factors

• Size classification: Mild (<10mm), moderate (10-20mm), large (>20mm) 2
• Large asymptomatic effusions have up to one-third risk of progression to cardiac tamponade 4
• In-hospital mortality for acute pericarditis is approximately 1.1%, increasing with age and severe co-infections 2
• Recurrences affect approximately 30% of patients within 18 months after acute pericarditis 2

Understanding the diverse causes of pericardial effusion is essential for appropriate management and treatment of this common clinical finding.