Most Common Causes of Pericardial Effusion
The most common causes of pericardial effusion are idiopathic (up to 50% in developed countries), viral infections (80-90% of cases in developed countries), tuberculosis (leading cause worldwide, especially in developing countries), malignancy, and uremia. 1
Etiological Classification
Infectious Causes
- Viral infections: Most common infectious cause in developed countries 1
- Includes coxsackieviruses, echoviruses, adenoviruses, and HIV
- Tuberculosis: Leading cause globally, particularly in developing countries 1
- Often associated with HIV infection, especially in sub-Saharan Africa
- Bacterial infections: Less common but more severe
- Fungal infections: Mainly in immunocompromised patients 2
- Includes Histoplasma, Coccidioides, Candida, Aspergillus
Autoimmune/Inflammatory Causes
- Systemic autoimmune diseases (5-15% of cases) 2
- Systemic lupus erythematosus
- Rheumatoid arthritis
- Sjögren's syndrome
- Scleroderma
- Systemic vasculitides
- Behçet's syndrome
- Sarcoidosis
- Inflammatory bowel diseases
Neoplastic Causes
- Malignancy: One of the most common causes of symptomatic pericardial effusion 2
- Primary tumors (rare): Mesothelioma most common
- Secondary/metastatic tumors (40 times more common than primary): 2
- Lung cancer
- Breast cancer
- Malignant melanoma
- Lymphomas
- Leukemias
Post-Cardiac Injury Syndromes
- Post-myocardial infarction pericarditis 2
- Post-pericardiotomy syndrome (after cardiac surgery) 2
- Post-traumatic pericarditis (iatrogenic or accidental) 2
Metabolic/Endocrine Causes
- Uremia: Common in end-stage renal disease (ESRD) patients 2
- Incidence has declined to about 5% in patients starting dialysis
- Hypothyroidism: Occurs in 5-30% of patients with hypothyroidism 1
- Can cause large effusions but rarely tamponade
Other Causes
- Heart failure: Common (25-30%) but typically small effusions 1
- Medication-induced: Procainamide, hydralazine, methyldopa, isoniazid, phenytoin, doxorubicin, amiodarone, and others 1
- Aortic dissection: Pericardial effusion found in 17-45% of cases 2
- Chylopericardium: Due to thoracic duct injury 1
- Cholesterol pericarditis: Occurs in tuberculous pericarditis, rheumatoid pericarditis, and trauma 1
Clinical Significance and Diagnostic Approach
The clinical presentation varies based on:
- Size of effusion (mild <10mm, moderate 10-20mm, large >20mm) 1
- Speed of accumulation (rapid accumulation can cause tamponade even with smaller volumes) 1
- Underlying etiology
Key Diagnostic Tools
- Echocardiography: Primary diagnostic tool for detection and assessment 2
- CT/MRI: Better for loculated effusions and associated chest abnormalities 2
- Pericardial fluid analysis: Essential for confirming malignant or infectious disease 2
Management Considerations
Management should be targeted at the underlying etiology whenever possible 2. Important considerations:
- Idiopathic effusions remain common despite extensive workup 1
- Asymptomatic patients without hemodynamic compromise may not need pericardiocentesis 3
- Pericardiocentesis is mandatory for cardiac tamponade and when bacterial or neoplastic etiology is suspected 4
- Large effusions have a theoretical risk of progression to cardiac tamponade (up to one-third) 5
Pitfalls and Caveats
- In patients with documented malignancy, nearly 2/3 of pericardial effusions are caused by non-malignant conditions (radiation pericarditis, opportunistic infections) 2
- Anticoagulation should be carefully considered in uremic patients as pericardial effusion is often bloody 2
- Pericardiocentesis is contraindicated in aortic dissection due to risk of intensified bleeding 2
- Diagnosing tamponade in pulmonary arterial hypertension is challenging as high right-sided pressures mask typical findings 1
Understanding the most common causes of pericardial effusion is essential for appropriate diagnostic workup and management, with the approach tailored to the specific etiology and hemodynamic significance of the effusion.