Septic Embolism

Epidemiology

  • Incidence: increasing frequency (due to increasing use of indwelling catheters/devices and increasing incidence of IV drug abuse)

Etiology

  • Endocarditis (Right-Sided) (see Endocarditis)
    • Embolism from right-sided valvular vegetations
  • IV Drug Abuse
    • Most common etiology
    • Direct embolism of foreign material to pulmonary circulation from injection site
  • Obstetric-Gynecologic Procedures
    • Embolism from pelvic vein injection
  • Pelvic Vein Thrombophlebitis (due to septic abortion and post-partum uterine infection)
    • Was previously the most common etiology, prior to the current era of IVDA and increasing CVC use
    • Emboli from pelvic veins
  • Chronic Central Venous Catheter (see Central Venous Catheter)
    • Common etiology
    • Embolism from material on line
  • Chronic Indwelling Vascular Devices
    • Embolism from material on device
  • Lemierre’s Syndrome (see Lemierre’s Syndrome)
    • Embolism from internal jugular vein thrombophlebitis

Physiology

  • Purulent material with fibrin thrombus is embolized to lungs
  • Small pulmonary vessel obstruction by septic emboli can occur (however, major consequence is usually infection, not obstruction)

Diagnosis

  • Sputum GS/C+S
  • CXR/Chest CT Patterns
    • Multiple Pulmonary Nodules/Nodular Infiltrates
      • Location: typically lower zone predominance
      • Shape: typically 2-4 cm (round, wedge-shaped, or ill-defined nodules)
      • Calcification: none
      • Cavitation: common (usually thin-walled) -> nodules may evolve over hours-days and may form lung abscesses
  • V/Q Scan
  • Pulmonary Angio
  • Blood C+S: variably positive
    • Usually diagnostic of endocarditis, Lemierre’s syndrome

Clinical Manifestations

Pulmonary Manifestations

  • Productive Cough
  • Dyspnea
  • Fever
  • Hemoptysis
  • Pleuritic Chest Pain

Cardiac Manifestations

  • Endocarditis (see Endocarditis): may occur with or may complicate septic embolism

Treatment

  • Remove embolic source: remove catheter if this is the source
  • Antibiotics: necessary
  • Anticoagulation: safe (but controversial)
  • Proximal Ligation or Resection of Infected Veins: may be required

Prognosis

  • Mortality: variable (dependent on source of septic emboli)

References

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