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- The possibility of intravascular infection should be considered in all critically ill patients with bacteremia or fungemia of uncertain origin, particularly when there are known intravascular or endocardial abnormalities or intravascular devices; fever or hemodynamic instability of unclear origin; or signs of inflammation related to an indwelling intravascular device.
- Blood cultures are the most important diagnostic test for this group of infections because most intravascular infections will result in persistent bacteremia or fungemia.
- Successful therapy often requires prolonged administration of microbicidal agents plus removal of devices.
- Certain microbes, including staphylococci, enterococci, aerobic gram-negative bacilli, and yeasts, are especially likely to cause intravascular infectious disease.
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Patients hospitalized in ICUs may have an intravascular infectious disorder as their primary problem, as a complication of their main disorder, or as a nosocomial infection occurring during their stay. Specific populations common to the ICU, including hemodialysis patients, injection drug users, HIV-infected patients, and those with congenital heart disease, are at increased risk of intravascular infection. Furthermore, violation of anatomic barriers by indwelling intravascular devices and by surgery, as well as impairment of cellular or humoral immune function related to critical illness, contributes to invasion by a variety of microbial pathogens. Infections of intravascular foreign bodies or native vascular structures themselves are likely to be associated not only with symptoms and signs of local inflammation but also with evidence of disseminated disease due to metastatic spread of infectious agents. This chapter provides the clinician caring for patients in an ICU with an approach to the patient with suspected or proved intravascular infectious disorders. We will emphasize the underlying clinical situations that predispose to intravascular infection, the pathogenesis of the disorders, the symptoms and signs of disease, and the appropriate diagnostic procedures, particularly those that provide assistance in the choice of antimicrobial therapy and selection of ancillary medical and surgical procedures. Table 49-1 lists the intravascular infections of native vessels and those associated with intravascular devices, respectively.
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Infective Endocarditis on a Native Valve