Infective Endocarditis

What is Infective Endocarditis?

Infective endocarditis is when bacteria travels through the blood to the heart valves and grows on the heart valves. When not caught and treated quickly infective endocarditis can irreversibly damage the heart valves and cause life-threatening complications and even death.

Who is at risk for Infective Endocarditis?

Increased age, rheumatic heart disease, IV drug use, immunosuppression, and prosthetic heart valves all place one more at risk of developing infective endocarditis.

What bacterial organisms cause Infective Endocarditis?

The most common cause of acute infective endocarditis on a normal heart valve is Staphylococcus aureus.

Subacute infective endocarditis is most commonly caused by Streptococcus viridians.

Infective endocarditis on a prosthetic valve is most commonly caused by Staphylococcus epidermis.

Infective endocarditis following a gastrointestinal or genitourinary infection is most likely Enterococcus

And finally, infective endocarditis with a negative blood culture can be caused by one of five organisms called HACEK organisms. 

What are the clinical manifestations of Infective Endocarditis?

The most common symptom of infective endocarditis is persistent fever, but malaise, fatigue, and anorexia are also common symptoms. The new onset of a cardiac murmur is very suggestive of infective endocarditis. Painful nodules on the palms of soles called Osler nodes and painless macules on the palms and soles called Janeway lesions are suggestive of infective endocarditis as well.

How is Infective Endocarditis diagnosed?

Blood cultures are the primary way infective endocarditis is diagnosed and will show bacteria in the blood. A transesophageal echo may be done and will show vegetation growing on the heart valve. A new murmur is also highly suggestive of endocarditis.

How is Infective Endocarditis treated?

If the infection is on a native heart valve a combination of nafcillin/oxacillin and either ceftriaxone or gentamicin is used.

The infection of a prosthetic valve requires treatment with three drugs, vancomycin, gentamicin, and rifampin. 

If a fungal infection is suspected amphotericin B is used.

Treatment usually lasts 4-6 weeks or 6-8 weeks for a fungal infection

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