creation date: 2025-10-28 14:59
tags: Pathologies Incomplete
Infective Endocarditis
Background
Definitions
Infective endocarditis, formerly known as infectious endocarditis, refers to the inflammation of the endocardium and the heart valves.
Etiology
Owing to its infective nature, the cause of IE involve bacterial infection. The exact bacteria depends on the nature and origin of the disease.
Native valve endocarditis
Oral, skin, or upper respiratory portals:
- Streptococcus viridans
- Staphylcocci
- HACEK (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)
Gut origin: - Streptococcus bovis
Genitourinary tract: - Enterococci
Nosocomial: - Staphylcoccus aureus
- Coagulase-negative staphylococci (intracardiac devices)
Prosthetic valve endocarditis
<2 months post-surgery:
- Coagulase-negative staphylococcus
- Pseudomonas
- Candida
2-12 months post-surgery: - Staphylococcus aureus
- Candida
- Enterococci
>12 months post-surgery: - Streptococci
- Staphylococcus aureus
- Enterococci
IV drug use
Right-sided endocarditis (tricuspid/pulmonic):
- Staphylococcus aureus
Left-sided endocarditis: - Staphylococcus aureus
- Enterococci
- Streptococci
- Gram-negative rods
- Candida
Pathogenesis
The pathogenesis of endocarditis begins with some initial damage to the endocardium. This may be from direct mechanical trauma from catheter, secondary to turbulent flow from disease valves, or from particulate matter co-injected with drug use.
The damage predisposes the endocardium to formation of thrombotic vegetation on the valve through platelet aggregation and activation of the coagulation cascade.
Subsequent bacteremia allows for colonization of the vegetation. This can stem from an established source of infection or transiently through hematogenous inoculation (eg. from dental procedure). In some cases, bacteremia can mediate platelet aggregation.
Clinical Presentation
Signs & Symptoms
History & Physical Exam
Risk factors
Infective endocarditis is generally rare but pre-disposing factors elevate risk:
- Congenital heart disease
- Illicit IV drug use
- Degenerative valvular disease
- Intra-cardiac devices
- Prosthetic heart valves (especially within 6 months of implantation)