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%)