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Snapshot
  • A 45-year-old woman presents to the emergency room for chest discomfort and shortness of breath for the past few hours. She has a past medical history of systemic lupus erythematosus. Physical exam reveals hypotension, muffled heart sounds, distended jugular veins, and positive pulsus paradoxus. An echocardiogram (ECG) reveals low voltages and electrical alternans. Imaging shows an enlarged cardiac silhouette on radiography. A team is consulted for an emergent pericardiocentesis.
Introduction
  • Clinical definition
    • accumulation of fluid in the pericardial sac that restricts ventricular filling
  • Epidemiology
    • risk factors
      • pericarditis
      • malignancy
      • uremia
      • systemic lupus erythematosus
      • malignancy
      • tuberculosis
      • penetrating trauma
  • Etiology
    • pericardial effusion
    • hemorrhage into the pericardial sac
    • iatrogenic
  • Pathoanatomy
    • pericardium
      • the pericardium is an elastic sac that can stretch to accommodate normal cardiac volume expansion
        • however, if stretched beyond normal physiological expansion, the pericardium will stiffen
  • Pathogenesis
    • cardiac tamponade
      • increased pericardial pressure from the fluid accumulation causes compression of the cardiac chambers
        • this results in decreased cardiac output and blood pressure
    • pulsus paradoxus
      • normally, inhalation increases venous return → expands the right ventricle
        • in cardiac tamponade, the stiff pericardium will prevent the free wall from expanding
        • the only area for the right ventricle to expand is the interventricular septum, which will compress the left ventricle
          • compression of the left ventricle → decreased filling of the left heart → decreased blood pressure 
  • Associated conditions
    • ruptured ascending aortic dissection
    • ventricular free wall rupture from myocardial infarction
  • Prognosis
    • in acute cases, cardiac tamponade can develop rapidly
    • in chronic cases, cardiac tamponade will develop gradually, as the pericardium can adjust slowly to the increased pressure over time
Presentation
  • Symptoms
    • chest pain
    • fatigability
    • often unresponsive to fluid resuscitation
  • Physical exam
    • Beck triad
      • muffled heart sounds
      • jugular venous distention 
      • hypotension
    • cardiac
      • ↑ heart rate
      • pericardial rub if the patient has an inflammatory pericarditis
    • pulsus paradoxus 
      • a decrease in blood pressure > 10 mmHg during inhalation 
    • pulmonary
      • shortness of breath
      • lung fields are typically clear
    • extremities
      • cold and clammy
      • peripheral cyanosis
Imaging
  • Echocardiography
    • indications
      • for diagnosis of cardiac tamponade
      • most accurate test
      • for all patients
    • findings
      • diastolic collapse of the right heart
      • fluid in the pericardial space
      • swinging of the heart within the effusion
  • Radiography
    • indication
      • for all patients
    • views
      • chest
    • findings
      • enlarged cardiac silhouette seen only in subacute cardiac tamponade
      • in acute cases, pericardium will not accommodate build up of > 200 cc of fluid, which is required to appear enlarged on radiography
Studies
  • Electrocardiogram (ECG)
    • indications
      • for all patients
    • findings
      • low voltage
      • electrical alternans  
        • variations in the height of the QRS complex
        • from swinging of the heart in the chest
  • Right heart catheterization
    • indication
      • typically not performed as an initial test
    • findings
      • equilibration of pressures in all 4 chambers during diastole
  • Making the diagnosis
    • based on clinical presentation, ECG, echocardiogram, and chest radiography
Differential
  • Constrictive pericarditis
    • distinguishing factors
      • also has pulsus paradoxus, but also presents with
        • Kussmaul sign
          • increase (or absence of decline) in jugular venous pressure with inhalation
        • pericardial knock
  • Tension pneumothorax
    • distinguishing factors
      • decreased or absent breath sounds
      • hyperresonant percussion
Treatment  
  • Management approach
    • all approaches focus on removal of the fluid in the pericardium
  • Conservative
    • close monitoring and volume expansion
      • indication
        • cardiac tamponade without hemodynamic compromise
        • modalities
          • serial echocardiographs
          • intravenous bolus of fluids
  • Procedural 
    • percutaneous pericardiocentesis  
      • indication
        • first-line treatment
  • Operative
    • surgical drainage
      • indications
        • patients with coagulopathy or need for biopsy
        • purulent pericarditis
        • traumatic cardiac tamponade
    • surgical drainage with pericardial window placement
      • indication
        • patients with chronic pericardial effusions
        • patients who decompensate
Complications
  • Death
 

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