Pericardial effusion

• Pericardial effusion is where excess fluid collects within the pericardial sac. Pericardial effusion can be acute or chronic.
• The effusion can be made of: 

  • Transudates (low protein content) 
  • Exudates (associated with inflammation)
  • Blood
  • Pus 
  • Gas (associated with bacterial infections)
• Pericardial effusion is when the potential space of the pericardial cavity fills with fluid. This creates an inward pressure on the heart, making it more difficult to expand during diastole
• Cardiac tamponade - large pericardial effusion that raises the intra-pericardial pressure. Reduced filling of the heart during diastole = reduced cardiac output
• Transudative effusions:

  • Increased venous pressure reduces draining from the pericardial cavity
  • Congestive heart failure
  • Pulmonary hypertension
• Exudative effusions may occur in any inflammatory process affecting the pericardium (pericarditis), such as in:

  • Infection (e.g., tuberculosis, HIV, coxsackievirus, Epstein–Barr virus and other viruses)
  • Autoimmune and inflammatory conditions (e.g., systemic lupus erythematosus and rheumatoid arthritis)
  • Injury to the pericardium (e.g., after myocardial infarction, open heart surgery or trauma)
  • Uraemia (raised urea) secondary to renal impairment
  • Cancer
  • Medications (e.g., methotrexate)
• Rupture of the heart or aorta can cause bleeding into the pericardial cavity, resulting in a rapid-onset cardiac tamponade. Rupture may be the result of:

  • Myocardial infarction
  • Trauma
  • Aortic dissection (type A)
• Slowly developing, chronic effusions, may initially be asymptomatic. As pressure rises, symptoms can develop, which may include: 

  • Chest pain
  • Shortness of breath
  • A feeling of fullness in the chest
  • Orthopnoea (shortness of breath on lying flat)
• The effusion may compress surrounding structures, causing additional symptoms:

  • Phrenic nerve compression can cause hiccups
  • Oesophageal compression may cause dysphagia (difficulty swallowing)
  • Recurrent laryngeal nerve compression may cause a hoarse voice
• Signs of cardiac tamponade = beck's triad:

  • Hypotension
  • Muffled heart sounds
  • Increased JVP
• Signs on examination include:

  • Quiet heart sounds
  • Pulsus paradoxus (an abnormally large fall in blood pressure during inspiration, notably when palpating the pulse)
  • Hypotension
  • Raised JVP
  • Fever (with pericarditis)
  • Pericardial rub (with pericarditis)
• An echocardiogram is the investigation of choice. It can be used to:

  • Diagnose pericardial effusion
  • Assess the size of the effusion
  • Assess the effect on the heart function (haemodynamic effect)
• Fluid analysis can be performed on the pericardial fluid to diagnose the underlying cause, including:

  • Protein content (to distinguish between transudative or exudative)
  • Bacterial culture
  • Viral PCR
  • Cytology and tumour markers (for cancer)
• There are two components to treating a pericardial effusion:

  • Treatment of the underlying cause (e.g., infection)
  • Drainage of the effusion (where required)
• Inflammatory causes (pericarditis) may be treated with:

  • Aspirin
  • NSAIDs
  • Colchicine
  • Steroids
• There are two options for draining an effusion:

  • Needle pericardiocentesis (echocardiogram guided)
  • Surgical drainage
• A pericardial window is a surgical procedure where a portion of the pericardium is removed, creating a “window” or fistula, that allows fluid to drain from the pericardial cavity into the pleural cavity or the peritoneal cavity.