Pericardial Effusion

General Considerations

• Abnormal amount of fluid in the pericardial space, defined as the space between the visceral and parietal layers of the pericardium
• Normally contains about 20-50 cc of fluid
• Fat covers outside of heart and outside of pericardium sandwiching pericardial space between the two layers
  • Normal thickness of pericardium (parietal pericardium and fluid in space) is 2-4 mm

Clinical Findings

• Small effusions frequently produce no symptoms
• Chest pain or discomfort with a characteristic of being relieved by sitting up or leaning forward and worsened in the supine position\
• Syncope
• Palpitations
• Shortness of breath, tachypnea
• Muffled or distant heart sounds, tachycardia
• Hypotension
• Jugular venous distension
• Pulsus paradoxus
  • Decrease in systolic pressure with inspiration of more than 10 mm Hg
• Rate of accumulation of fluid is proportional to severity of symptoms
  • The faster the fluid accumulates, the more severe the symptoms
• Requires about 150-250cc before cardiac tamponade occurs
  • About 7-10% of those with pericardial effusion are at risk for developing tamponade
• Tamponade compresses heart and causes low cardiac output
• Most effusions do not lead to cardiac tamponade
• Size of cardiac silhouette is frequently increased
• Tamponade is rarely seen in association with pulmonary edema in the lungs

Causes

• Other causes
  • Serous fluid or transudate
• Congestive heart failure
• Hypoalbuminemia
• Irradiation
• Blood (hemopericardium)
• Rupture of ascending aorta or pulmonary trunk
• Coagulopathy
• Fibrin (produces exudate)
• Pyogenic infection, e.g. staph
• Uremia
• More common in chronic renal disease than acute

Imaging findings

• Conventional radiography
  • Suggestive but not usually diagnostic
• "Water bottle configuration" is symmetrically enlarged cardiac silhouette
• Major DDX is cardiomegaly
• Loss of retrosternal clear space
• Non-specific and frequently not valid
• "Fat-pad sign"
• Produced by separation of retrosternal from epicardial fat line >2 mm
• Uncommon but specific
• Rapidly enlarging cardiac silhouette with normal pulmonary vascularity
• Echocardiogram
• Study of choice
• Echo-free fluid between the visceral and parietal pericardium
• Early effusions accumulate posteriorly first
• > 1cm is usually defined as a “large” effusion
• CT
• May detect small effusions (50cc)
• Fluid-filled space surrounding the myocardium
• Early effusions accumulate posteriorly first

Treatment

• Medical treatment depends on cause and may include
  • Non-steroidal anti-inflammatory agents
• Colchicine
• Steroids
• Antibiotics
• Chemotherapeutic agents
• Pericardiocentesis
• Pericardial sclerosis for recurring effusions
  • Tetracycline, doxycycline, 5-fluorouracil
• Pericardial window
• Video-assisted thoracic surgery (VATS)
• Allows for wide resection of pericardium

Pericardial effusion. Frontal chest radiograph (above) demonstrates a markedly enlarged cardiac silhouette. The differential diagnosis would include cardiomyopathy and pericardial effusion. A single axial, contrast-enhanced CT scan of the chest at the level of the heart shows a large pericardial effusion (white arrows) surrounding the contrast-filled heart (LV=left ventricle). The red arrow points to the myocardium.
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