Pericardial Effusion 

Definition

Pericardial effusion is the accumulation of fluid in the pericardial cavity — the potential space between the visceral and parietal layers of the pericardium.
It may result from any condition that affects the pericardium, including inflammation, trauma, infection, malignancy, or systemic diseases.

Normal Physiology

• Normally, the pericardial space contains 15–50 mL of serous fluid, acting as a lubricant.
• This small volume maintains friction-free cardiac motion and uniform transmission of intrathoracic pressures.

Pathophysiology

The hemodynamic impact of pericardial effusion depends on:

1. Volume of fluid
2. Rate of accumulation
3. Pericardial compliance (distensibility)

• Slow accumulation (e.g., in hypothyroidism or malignancy): the pericardium can stretch to hold up to 1–2 literswithout major symptoms.
• Rapid accumulation (e.g., trauma, rupture): even 150–200 mL can cause cardiac tamponade.

Causes / Etiology

Types of Pericardial Effusion 

Clinical Features

Symptoms

• Often asymptomatic if small or slowly accumulating.
• When symptomatic:
• Chest pain: dull, non-pleuritic, may improve by sitting up/leaning forward.
• Dyspnea, orthopnea
• Palpitations
• Dysphagia (large effusions compressing esophagus)
• Hoarseness (recurrent laryngeal nerve compression)

Signs

• Tachycardia
• Muffled / distant heart sounds
• Reduced apex impulse
• Pericardial friction rub (if active pericarditis present)
• Ewart’s sign: dullness to percussion below the left scapula due to compression atelectasis.
• Neck vein distension — if tamponade develops.
• Pulsus paradoxus — fall in systolic BP >10 mmHg during inspiration.

Complications

1. Cardiac Tamponade – hemodynamic compromise due to pressure on all cardiac chambers.
2. Constrictive pericarditis – chronic sequela of recurrent inflammation and fibrosis.

Investigations

1. ECG

• Low voltage QRS complexes.
• Electrical alternans (beat-to-beat variation in QRS amplitude) — due to swinging of the heart within the effusion.
• PR segment depression (if pericarditis present).

2. Chest X-ray

• “Water bottle” or flask-shaped cardiac silhouette.
• Clear lung fields (unless concomitant disease).
• May appear normal in small effusions.

3. Echocardiography – Gold Standard

• Direct visualization of fluid around the heart.
• Quantification of effusion size:
• Mild: <10 mm (≈50–100 mL)
• Moderate: 10–20 mm (≈100–500 mL)
• Severe: >20 mm (>500 mL)
• Assess for tamponade:
• Right atrial collapse (early diastole)
• Right ventricular diastolic collapse
• Plethoric IVC (no inspiratory collapse)
• Swinging motion of the heart

4. CT / MRI

• Better anatomical delineation and detection of loculated or posterior effusions.
• Useful in neoplastic or postoperative cases.

5. Pericardial Fluid Analysis

Performed after pericardiocentesis:

• Appearance: serous, bloody, purulent
• Protein, LDH: classify as exudate/transudate
• Cytology: for malignant cells
• Gram stain, culture, AFB stain
• ADA levels: for tubercular etiology

Diagnostic Algorithm for Pericardial Effusion Etiology

Step 1: Assess Hemodynamic Status

• Stable patient → proceed with detailed diagnostic work-up.
• Unstable patient / signs of tamponade → emergency pericardiocentesis, then diagnostic analysis of fluid.

Key clinical signs of tamponade: hypotension, tachycardia, raised JVP, pulsus paradoxus.

Step 2: Initial Clinical Evaluation

1. History
• Recent infection (viral symptoms, TB exposure)
• Autoimmune disease (SLE, RA, scleroderma)
• Malignancy (weight loss, known cancer)
• Uremia (CKD, dialysis)
• Hypothyroidism (fatigue, cold intolerance)
• Trauma or surgery

2. Physical Examination

• Heart sounds: muffled, friction rub
• Signs of systemic disease: rash, lymphadenopathy, thyroid enlargement

3. Basic Laboratory Tests

• CBC, ESR, CRP
• Renal function tests (uremia)
• Liver function tests
• Thyroid function tests
• ANA, RF, complements if autoimmune suspected
• HIV / viral serology if indicated

4. Chest X-ray

• Cardiac silhouette (size & shape)
• Pulmonary infiltrates, mediastinal masses

Step 3: Echocardiography

• First-line imaging for all patients
• Confirms presence, size, and distribution of effusion
• Detects tamponade physiology
• Can guide pericardiocentesis if needed

Step 4: Determine Need for Pericardiocentesis

Indications (according to ESC & ACC/AHA guidelines):

• Cardiac tamponade or severe hemodynamic compromise
• Moderate-to-large symptomatic effusion without clear cause
• Suspected bacterial, TB, or malignant effusion
• Diagnostic uncertainty for recurrent effusions

Notes:

• Small, asymptomatic, idiopathic effusions → serial monitoring
• Procedure is guided by echo or fluoroscopy

Step 5: Pericardial Fluid Analysis

If pericardiocentesis is performed:

Step 6: Advanced Imaging (if etiology unclear)

• CT Chest / MRI
• Detect loculated or posterior effusions
• Detect pericardial thickening or masses
• Evaluate for mediastinal or pulmonary malignancy
• PET-CT for suspected malignant or inflammatory causes

Step 7: Etiology-Oriented Testing

Based on clinical suspicion:

Step 8: Integration and Diagnosis

• Combine clinical features, labs, imaging, and fluid analysis
• Classify as:
1. Idiopathic / viral → most common
2. Infectious → TB, bacterial, viral
3. Autoimmune
4. Malignant
5. Metabolic / drug-induced
6. Post-traumatic / post-surgical
• Serial echocardiography is recommended for monitoring progression or resolution.

Management

A. General Principles

• Treat underlying cause (infection, autoimmune disease, malignancy, hypothyroidism, etc.)
• Monitor for tamponade physiology.

B. Medical Management

For small, hemodynamically stable effusions:

• Observation and serial echocardiography
• NSAIDs (Indomethacin/Ibuprofen) for inflammatory causes
• Colchicine (0.5–1 mg/day) – prevents recurrence in pericarditis-associated effusions
• Corticosteroids – for autoimmune or refractory cases
• Antibiotics / ATT – if bacterial or tubercular
• Thyroxine – in myxedema-related effusion
• Dialysis – in uremic effusion

C. Pericardiocentesis

Indications:

• Cardiac tamponade (emergency)
• Moderate-to-large effusions causing symptoms
• Diagnostic sampling
• Suspected bacterial or neoplastic cause

Approach:

• Subxiphoid or apical route under echo or fluoroscopic guidance
• Continuous ECG and BP monitoring
• Avoid rapid decompression (risk of right ventricular collapse)

Complications:

• Myocardial puncture
• Arrhythmia
• Coronary or internal thoracic artery injury
• Pneumothorax
• Infection

D. Surgical Management

• Pericardial window (subxiphoid or thoracoscopic) – for recurrent or loculated effusions.
• Pericardiectomy – for chronic recurrent effusion or constrictive pericarditis.

Intensive Care / Critical Care Role

Role of the Intensivist

• Hemodynamic monitoring: arterial line, CVP trends.
• Immediate recognition of tamponade: hypotension, rising CVP, pulsus paradoxus.
• Fluid therapy: cautious — maintain preload.
• Vasopressors: temporary bridge before drainage.
• Ultrasound-guided pericardiocentesis — life-saving procedure.
• Post-procedure monitoring for recurrence or complications.

Prognosis

• Depends on etiology:
• Viral/idiopathic: good prognosis.
• Malignant/uremic: poorer outcomes.
• Recurrence is common with autoimmune or neoplastic causes.

Key Differentials

• Pleural effusion
• Constrictive pericarditis
• Cardiomyopathy (dilated)
• Heart failure with pericardial effusion (secondary)