Makindo Medical Notes

Overview of Pericardial Effusion

Pericardial effusion is the accumulation of fluid in the pericardial cavity. This fluid may be serous, blood, pus, or chyle, depending on the underlying cause. While small, slow-developing effusions may be asymptomatic, rapid or large effusions can lead to life-threatening complications such as cardiac tamponade.

• Effusion can be chronic (e.g., due to TB or autoimmune conditions) or acute (e.g., following trauma or myocardial infarction).
• The pericardial sac typically holds 10-50 ml of fluid, but this volume can increase significantly with effusion, leading to pressure on the heart and impaired cardiac output.
• Rapid fluid accumulation raises intrapericardial pressure quickly, compressing cardiac chambers, impairing diastolic filling, and potentially resulting in tamponade.

Aetiology

• Physiologically, the pericardial sac holds a small amount of lubricating fluid, generally 10-50 ml.
• Effusion may result from various pathologies, including:
  • Infections: Tuberculosis, viral infections (e.g., Coxsackievirus), bacterial infections
  • Inflammatory diseases: Rheumatoid arthritis, lupus, scleroderma
  • Neoplastic causes: Metastatic breast, lung cancers, melanoma
  • Post-cardiac injury syndromes: Post-MI (Dressler's syndrome), post-surgery, or trauma
  • Other causes: Renal failure (uremic pericarditis), hypothyroidism, aortic dissection, or radiation therapy

Classification of Effusion

Pericardial effusion can be categorized based on several criteria, which help determine severity and management:

• Time-Based Classification
  • Acute or Subacute: Develops in less than 3 months
  • Chronic: Persists longer than 3 months
• Distribution
  • Circumferential: Fluid accumulates around the entire heart
  • Loculated: Fluid confined to a specific area, often due to adhesions or previous infections
• Haemodynamic Impact
  • None: Asymptomatic, minimal impact on cardiac function
  • Cardiac Tamponade: Compression of heart chambers, reduced cardiac output
  • Effusive-Constrictive: Combination of effusion and pericardial constriction, limiting heart movement
• Composition
  • Exudate: Often related to inflammation, infections, or malignancy
  • Transudate: Linked with systemic conditions like heart or kidney failure
  • Blood: Due to trauma or rupture of a cardiac structure
  • Air or Gas: Rare, typically from bacterial infections or after thoracic surgery
• Size
  • Mild: <10 mm
  • Moderate: 10-20 mm
  • Large: >20 mm

Causes of Pericardial Effusion and Tamponade

• Trauma (e.g., from accidents or cardiac procedures) leading to bleeding
• Complications of surgery or cardiology procedures, such as catheterization
• Tuberculosis (in endemic areas)
• Malignancies, especially metastatic breast or lung cancers, melanoma, and Hodgkin's disease
• Aortic dissection causing leakage into the pericardial space
• Post-myocardial infarction with wall rupture (day 3-10 post-infarct)
• Connective tissue diseases and renal failure (uremic pericarditis)

Clinical Presentation of Pericardial Effusion (Without Tamponade)

• General symptoms: Cough, weakness, fatigue, anorexia, palpitations, and dyspnoea.
• Respiratory symptoms: Dyspnoea on exertion, orthopnea, and paroxysmal nocturnal dyspnoea (PND).
• Systemic symptoms: Fever, malaise, and symptoms associated with underlying conditions (e.g., TB, malignancy).
• Pressure symptoms: Hoarseness due to recurrent laryngeal nerve compression, nausea from diaphragm irritation, and dysphagia from oesophageal compression.

Note: In cases with pulsus paradoxus, the pulse weakens on inspiration.

Clinical Presentation of Cardiac Tamponade

• Symptoms of tamponade: Severe breathlessness, chest discomfort, and signs of circulatory shock.
• Beck's Triad:
  • Distended jugular veins (elevated JVP)
  • Arterial hypotension (low blood pressure)
  • Muffled or distant heart sounds
• Elevated JVP with absent Y descent; significant in cases of TB or malignancy.
• Pulsus paradoxus: Systolic BP falls >10 mmHg during inspiration, often a hallmark of tamponade.
• Bronchial breath sounds in left axilla or base (Ewart's sign) due to left bronchial compression.
• Kussmaul's sign (JVP rise on inspiration) is usually absent in tamponade, often present in constrictive pericarditis.

Investigations

• Blood Tests:
  • Complete Blood Count (CBC): Anaemia and signs of infection
  • Inflammatory markers (CRP, ESR): Elevated in infections or autoimmune conditions
  • Renal function tests (U&E): Assess for uraemia as a possible cause
  • Thyroid function tests: Rule out hypothyroidism as a cause
  • Clotting profile: INR and coagulation screen for bleeding risk
• ECG: Low voltage complexes, sinus tachycardia, or electrical alternans; exclude STEMI.
• Chest X-Ray (CXR): Enlarged cardiothoracic ratio in large effusions, “water bottle” appearance.
• Echocardiography: Diagnostic tool showing effusion, chamber collapse (right atrium and ventricle), poor stroke volume, and back pressure with a dilated IVC.
• Advanced Imaging (CT, CMR): Useful for loculated effusions, pericardial thickening, or associated masses.
• Microscopy and Culture of Pericardial Fluid: Analysis for Gram stain, cultures, acid-fast bacilli, PCR, cytology, and tumor markers.

Management of Pericardial Effusion and Tamponade

• Emergency Care: ABCs, careful IV fluid administration, and pericardiocentesis for symptomatic tamponade. For cardiac arrest or severe tamponade, needle pericardiocentesis may be life-saving.
• Pericardiocentesis: Best performed under ultrasound guidance; insert needle below xiphisternum, angled toward the left shoulder. Insert catheter for ongoing drainage if needed.
• Medical Therapy: If inflammatory markers are elevated, consider NSAIDs, colchicine, or low-dose corticosteroids after infection is ruled out.
• Surgical Intervention: Pericardiectomy or pericardial window for recurrent or loculated effusions.