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KEY POINTS
Intravascular infections are characterized by continuous bacteremia, although positive blood cultures are not invariable.
Infective endocarditis (IE) has high morbidity and mortality, even with optimal therapy.
The diagnosis of IE is clinical, and the modified Duke criteria have been validated and updated.
Transesophageal echocardiogram (TEE) is the imaging modality of choice, but a number of imaging techniques may be helpful.
Therapy of IE requires parenteral administration of bactericidal antibiotics for an extended duration, although surgical intervention may be also necessary to eradicate the infection or manage complications.
Suppurative or septic thrombophlebitis can be a naturally occurring infection or because of local infections, penetrating trauma, injection drug use, or intravenous devices. In addition to antibiotics, anticoagulation may be beneficial.
Arterial infections or infectious arteritis occur from septic emboli, seeding of atherosclerotic plaques or aneurysms, trauma, injection drug use, and arterial procedures. Management usually requires surgery, especially in cases with prosthetic vascular grafts.
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Intravascular infections are characterized by continuous bacteremia. This contrasts with the transient bacteremia seen with invasive procedures and certain local infections (pneumonia and pyelonephritis), or intermittent bacteremia, characteristic of undrained abscesses. Although this pattern of bacteremia is characteristic, it is not invariable. Negative blood cultures can occur when the incorrect amount of blood is drawn for the volume of blood culture media, both too little or too much. These may also occur due to the effects of current or prior antibiotics. Negative blood cultures are more common in certain vascular infections, such as infected atherosclerotic aneurysms or plaques. Still, continuous bacteremia is one of the major criteria for diagnosis of infective endocarditis (IE) and is also seen in other intravascular infections, including suppurative phlebitis, infected vascular access devices and prosthetic vascular grafts, and infected atherosclerotic aneurysms. These are serious infections that may result in sepsis, septic shock, and other metastatic foci of infection. Optimal management often requires a coordinated effort between intensivists, infectious diseases physicians, pharmacists, cardiologists, and vascular and cardiovascular surgeons.
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Epidemiology and Etiology of Infective Endocarditis (IE)
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IE is a relatively rare disease causing three to seven cases per 100,000 person years.1–3 Despite being infrequent, IE is associated with high morbidity and mortality, and is one of those infections with near 100% mortality if not diagnosed and treated. Even with timely diagnosis and appropriate therapy, mortality rates range from 20% to 40% and depend on the clinical and microbiologic characteristics of each patient, making endocarditis one of the top life-threatening infections.3 The demographics of the disease have changed in recent years. There has been a shift in the number of cases occurring in the elderly, and mortality may be twice as high in patients older than 65 year of age.3–5 This is partly associated with nosocomial acquisition.6 The proportion of cases due to opioid use has also increased....