How Is Endocarditis Managed?
Blood culture and echocardiographic and proven infectious endocarditis is treated according to different protocols for specific populations.
Infectious Endocarditis Involving “Native” Valves
If infectious endocarditis involves a patient’s own (natural, or “native”) valves, bactericidal agents are selected that target the specific organisms.
If a patient is clinically stable, the few days without therapy until the results return from blood cultures is reasonable; for those who are unstable, empiric therapy can begin and then be reinforced or replaced based on the cultures that return later. Empiric therapy is based on the most likely organisms, statistically, such as Staphylococci, Streptococci, and enterococci, against which vancomycin is often used.
Repeat blood cultures are done to judge efficacy of the treatment. Treatment usually continues for 6 weeks after the blood cultures become negative to assure that the bacteria in the valvular vegetations are eradicated. Blood tests for anemia, toxicity, and inflammatory markers are done during therapy.
Since antibiotics in the aminoglycoside class often used to treat endocarditis can cause hearing loss, serial audiograms should be performed. Patients with endocarditis from organisms though to have originated orally should have scrupulous dental care.
Infectious Endocarditis Involving Prosthetic Valves (PVE)
Prosthetic valves, invasively implanted and remaining as foreign bodies, add additional avenues for pathology to the endocarditis process. Infection associated with prosthetic valves have an increased tendency toward invasive extension, which jeopardizes not only the valvular function and the valves themselves, but cardiac tissue.
Bactericidal agents are selected that target the specific organisms, as in native valve endocarditis–typically Staphylococci, Streptococci, and enterococci; however, due to the increased virulence associated with PVE, a triple-antibiotic regimen is implemented. Duration of therapy is typically longer than that for native valve endocarditis, i.e., > 6 weeks duration beyond when cultures become negative.
Treatment for Candida species fungal organisms that cause endocarditis consists of a combined approach of both antifungal therapy and surgical replacement of the valve(s). Other fungal organism may only require antifungal medications.
IV Drug Abusers
IV drug abusers present with special problems requiring extra considerations. One is that recurrence is more likely due to the relapse rate of those treated for addiction. Another consideration is that out-patient therapy is hazardous in a patient who is re-exposed to the availability of drugs and/or who has an indwelling line for out-patient administration of intravenous antibiotics. Such conditions may alter the paradigm toward oral medication. Longer hospitalizations are useful when the patient is compliant, but IV drug abusers, especially those who are not rehabilitated, often leave the hospital prematurely against medical advice.