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