ABSTRACT
The numbers of immunosuppressed individuals have risen markedly over the last 25 years. These patients belong to several varied categories of immunosuppression including those with AIDS, organ transplant recipients, and increasingly aggressive therapy for hematologic and solid malignancies. In addition, there are those patients with less dramatic degrees of immunosuppression who are also at increased risk of developing infective endocarditis (IE). Among these are the elderly, patients with chronic liver disease, those with chronic renal failure, and alcoholics (1). Overall, the most common categories of patients with immunosuppressive IE (ISIE) are intravenous drug abusers (IVDA) with AIDS and those with healthcareassociated IE (HCIE) and nosocomial IE (NIE). Both of these categories are closely associated with catheter-related bloodstream infections (CR-BSI) (Chapter 10) (2). The author has placed both of these in the category of iatrogenic IE (IIE). A less frequent factor leading to ISIE is the infection of an underlying, sterile valvular thrombus, such as that seen in marantic endocarditis or the sterile platelet/fibrin thrombus of systemic lupus erythematosus (Libman-Sachs endocarditis). Many of the clinical manifestations of these sterile vegetations resembled by closely those of IE, especially fever-elevated sedimentation rate and signs and symptoms of meningoencephalitis. Approximately, 4% of these vegetations become infected (3,4). When secondarily infected, these behave as any other infected vegetation. Renal failure [Blood Urea Nitrogen (BUN) >60 mg/100m mL], prednisone doses of >20 mg/day, and treatment with cyclophosphamide increase the risk of infection in both diseases (Chapter 12) (5).
