Septic Pulmonary Emboli

 

General Considerations

  • Age
    • Majority <40 years
  • Predisposed
    • IV drug abusers
    • Alcoholism
    • Immunodeficiency
    • CHD
    • Dermal infection (cellulitis, carbuncles)
  • Sources
    • Tricuspid valve endocarditis
      • Most common cause in IV drug abusers
    • Pelvic thrombophlebitis
    • Infected venous catheter or pacemaker wire
    • Arteriovenous shunts for hemodialysis
    • Drug abuse producing septic thrombophlebitis (eg, heroin addicts)
    • Peritonsillar abscess
    • Osteomyelitis
  • Organism
    • S. aureus
    • Streptococcus

Clinical Findings

  • Sepsis
  • Cough
  • Dyspnea
  • Hemoptysis
    • Sometimes massive
  • Chest pain
  • Shaking chills
  • High fever
  • Severe sinus tachycardia
  • Location
    • Predilection for lung bases

Imaging Findings

  • Multiple round or wedge-shaped densities
  • Cavitation
    • Frequent
    • Usually thin-walled
  • Migratory
    • Old ones clear and new ones arise
  • Pleural effusion is rare
  • Hilar and mediastinal adenopathy can occur
  • CT findings
    • Multiple peripheral parenchymal nodules
    • Cavitation or air bronchogram in more than 89%
      • Cavities are thin-walled and may have no fluid level
    • Wedge-shaped subpleural lesion with apex of lesion directed toward pulmonary hilum (50%)
    • Feeding vessel sign = pulmonary artery leading to nodule (67%)

 

Differential Diagnosis of Small Cavitary Lung Lesions

Septic emboli

Rheumatoid nodules

Squamous or transitional cell metastases

Necrotizing Granulomatosis

 

Complications

  • Empyema (39%)

 

 

septic emboli

septic emboli

Septic Emboli. Upper photo. Coronal-reformatted CT of the chest shows multiple peripheral masses, most with cavitation (white arrows). Lower photo: Axial CT of chest demonstrates thin-walled upper lobe cavities.(white arrows). The patient was an intravenous drug user who was shown to have tricuspid vegetations by echo.
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Dahnert 5th ed

Fraser and Pare

Thoracic Radiology Requisites