Curriculum · Cardiovascular and Hypertension
Infective endocarditis
What it is
Infective endocarditis is a bacterial or fungal infection of the endocardium. It affects both native and prosthetic valves, and has high morbidity and mortality rates. Left-sided lesions, of the aortic and mitral valves, are more common.
Causes and risk
The predisposing factors are dental procedures that cause bleeding, oral and upper respiratory tract surgery, genitourinary surgery, prosthetic heart valves, catheters in the right heart, pressure-monitoring catheters, and IV drug use. Risk factors for acquisition include age older than 60 years, male sex, structural heart disease, and valvular disease such as rheumatic heart disease, mitral valve prolapse or degenerative disease. The list does not stop there: a prosthetic valve, with biofilm formation, prior infective endocarditis, IV drug use, a catheter, and skin infection are on it as well. Two lists of organisms are given, and they do not agree. One list gives Staphylococcus aureus 31%, viridans group streptococci 17%, enterococci 11%, CNST 11%, Bovis 7%, other streptococci 5%, non-HACEK gram negatives 2%, fungi 2% and HACEK 2%. Another list, which takes native valves on their own, puts Streptococcus viridans first rather than Staphylococcus aureus, and in narcotic addicts Staphylococcus aureus is 60-95%. On prosthetic valves, acute infection is that of the first 2 months after surgery. The HACEK group is Haemophilus sp, Actinobacillus (or aggregatibacter), Cardiobacterium hominis, Eikenella corrodens and Kingella kingae.