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%)

Complications

• Empyema (39%)

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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