Septic-embolic encephalitis, also referred as septic-embolic brain abscess, corresponds to a focal or diffuse brain infection, ischemic and hemorrhagic damages following an infective thromboembolism from any part of the body 1. It is usually caused by bacterial infections from endocarditis.
Septic-embolic encephalitis must be differentiated from sepsis-associated encephalopathy, which is a clinical syndrome related to a diffuse brain dysfunction in the context of sepsis and without overt CNS infection.
In most series CNS involvement during the course of infective endocarditis occurs in 20% to 40% of cases 2.
Symptoms can vary from headache to unconsciousness, the most common are 1,3: fever, toxic encephalopathy (characterized by mental status changes and psychosis), meningism signs, headache and seizures.
- cardiac disease:
- rheumatic cardiovascular disease
- mitral valve prolapse
- prosthetic cardiac valves
- congenital heart disease
- drug addiction (intravenous drugs)
- immunocompromised patients
- central venous catheter
- arteriovenous shunts
In a context of an infectious site in the body, some etiological agents can get in the CNS carried by the arterial blood. The most common explanations for this are:
- infections on heart left chambers (aortic and mitral valve endocarditis)
- pulmonary infectious
- infectious in other body sites that can get the arterial circulation by a arteriovenous shunt
The heart is the most common source (infective endocarditis), followed by bacteria and pulmonary infectious. 20-56% od patients with endocarditis. SEE and brain abscesses occur more often after infection of the mitral and aortic valve than after infection of the tricuspid valve and are more common with S. aureus than with Streptococcus viridans (2:1).
- occlusion of cerebral arteries by septic and thrombotic emboli arising from heart valve vegetations.
- infection of the meninges, brain, parenchyma, or vascular walls by septic emboli or by vacterimia;
- toxic and probably also immune mediated injury