Overview Infective endocarditis is a condition which occurs in the setting of bacteraemia whereby endothelial surfaces of the heart, such as valvular structures, become infected. It can present acutely or subacutely, and is often associated with fevers, new heart murmurs, constitutional symptoms and embolic phenomena. The classical organism associated is Staphylcoccus aureus, however there are many other organisms which can cause infective endocarditis. This is particularly dependent on the presence of native or prosthetic valves, history of intravenous drug use and recent cardiac surgery.
Infective endocarditis: A microbial process of the endocardium, usually involving the heart valves
Janeway lesions: Painless hemorrhagic macules on the palms and soles that are consistent with infectious endocarditis, thought to be caused by septic emboli, resulting in microabscesses
Osler Node: Painful, palpable, erythematous lesions most often involving the pads of the fingers and toes, they represent vasculitic lesions caused by immune complexes.
Roth spots: Hemorrhagic retinal lesions with white centers, due to infectious endocarditis, also thought to be an immune-complex–mediated vasculitis
Infective Endocarditis presents with non-specific signs and symptoms. Highly variable presentation—depends on intracardiac pathology, virulence of organism, and extracardiac involvement. Only a small proportion of people actually present with the risk factors mentioned above.
Diagnostic criteria - Duke criteria for IE - Must meet 2 major criteria or 1 major and 3 minor criteria or 5 minor criteria.
Consistent with IE but not meeting major criterion
Gram positive bacteria
Zoonosis (Coxiella burnetii - Q fever)
HACEK group (fastidious gram negative bacteria)
Turbulent blood flow across valvular surfaces can lead to endothelial damage which acts as substrate for platelets and fibrin to adhere. In the setting of bacteraemia, these areas become colonised which perpetuate further deposition of fibrin and platelets. This ultimately leads to vegetation formation which can produce new heart murmurs from regurgitant valves. In addition, it can cause distal embolic phenomena.
Depending on patient risk factors, there are a number of organisms which can cause infective endocarditis (above). There are several clinical patterns which can help predict the organism associated:
Pathology Vegetation on heart valves are the classic hallmarks of infective endocarditis. The vegetations are friable, bulky, potentially destructive lesions containing fibrin, inflammatory cells, and bacteria or other organisms.
Overview IV Antibiotics over 4-6 weeks with monitoring.
Empirical antibiotic treatment
Targeted antibiotic therapy
|Remember The three most common causes of IE worldwide are staphylococci, streptococci, and enterococci. s.aureus is now the most common cause of IE|
Greatest mortality in prosthetic valve infective endocarditis (25-50%)
Adverse prognostic factors include…