Septic pulmonary emboli

Septic pulmonary emboli refers to the embolisation of infectious particles (intravascular thrombus containing microorganisms) into the lungs via the pulmonary arterial system. 

Septic emboli can occur from varying sources which embolise 5:

  • tricuspid valve endocarditis
  • infection elsewhere in the body (e.g. soft tissue infection) with associated septal defects
  • infected deep venous thrombosis
  • immunologic deficiencies
  • infected catheters/lines
  • post-anginal septicaemia 10
  • periodontal disease 10

The clinical context is important in image interpretation. Most patients have positive blood cultures at time of imaging assessment.

Chest x-ray features are nonspecific but may show 3:

  • peripheral, lower lobe predominant infiltrative densities: can be unilateral or bilateral
  • diffuse bilateral nodular densities (often poorly marginated) in varying stages of cavitation
    • these nodules generally range around 1 to 3 cm
    • the nodules vary greatly in size, which is a reflection of repeated episodes of embolic shower 15
    • may increase in number or change in appearance (size or degree of cavitation) on subsequent short-term follow up radiographs 12
  • accompanying small pleural effusions can be common
  • features suggestive of complicating pleura empyemas may be seen
  • feeding vessel sign 9: peripheral nodules with clearly identifiable feeding vessels associated with lung abscesses 2-3
  • subpleural nodular lesions or wedge-shaped densities with or without necrosis caused by septic infarcts (these can manifest as cavitatory pulmonary infarcts)
    • these may have a dependent, lower zone predication 13,15
    • the wedge-shaped lesions usually range between 10-20 mm 6
    • peripheral nodular densities usually range between 5-35 mm 7

Recognised complications include:

For small and/or variably sized cavitatory lung lesions on HRCT or CT chest consider:

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Article information

rID: 22848
System: Chest
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Septic pulmonary embolus
  • Septic emboli - lung
  • Septic emboli to lung
  • Septic emboli to the lung
  • Septic emboli to the lungs
  • Septic pulmonary embolism
  • Septic lung embolism
  • Septic pulmonary embolization (SPE)
  • Septic pulmonary embolization
  • Septic pulmonary embolisation
  • Septic pulmonary embolisation (SPE)
  • Septic embolism to the lungs
  • Septic embolism to the lung
  • Septic embolism to lungs
  • Septic embolism to lung
  • Septic PE
  • Lung septic emboli
  • Lung septic embolus

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