54 III. Approach to Bloodstream and Cardiovascular Infections
2. Splenic abscess as a result of septic emboli. 3. Septic arthritis or vertebral osteomyelitis as a result of septic emboli. VI. Approach to the Patient. The diagnosis of endocarditis involves a complete history (to determine risk factors) and physical examination in conjunction with laboratory and radiographic data (echocardiogram). A. History. Obtain history about risk factors (eg, IVDU), cardiovascular history (eg, valvular disease), and any recent surgery, procedure, or indwelling catheter. B. Physical Examination 1. HEENT examination (to detect Roth spots or conjunctival petechial). 2. Cardiovascular examination (to detect murmurs or heart failure). 3. Pulmonary examination (to detect heart failure). 4. Dermatologic examination (to detect signs of peripheral manifestations). 5. Neurologic examination (to identify focal deficits). 6. Musculoskeletal examination (to identify osteomyelitis or septic arthritis). C. Laboratory 1. Blood cultures. Two to three sets of blood cultures (an aerobic and anaerobic blood culture bottle defines one set of blood cultures), 1 hour apart, from different anatomical sites should be obtained prior to the initiation of antibiotics. Improved culture results are obtained with more blood volume and cultures taken coincident with fever spikes. 2. CBC. Leukocytosis and anemia may be present. 3. Complete metabolic profile (CMP). Patients may have renal or liver failure. 4. Erythrocyte sedimentation rate (ESR)/C-reactive protein (CRP). Nonspecific tests that may be elevated with infective endocarditis. 5. Serum brain natriuretic peptide (BNP). To evaluate for heart failure. 6. Serum antibodies. Most helpful to identify the cause of culture-negative endocarditis for Bartonella spp, Coxiella spp, Chlamydia spp, Tropheryma whipplei, and Brucella spp. 7. Serum beta-D-glucan and/or Aspergillus galactomannan. May be helpful to identify fungal causes of endocarditis. 8. Urinalysis. Typically demonstrates glomerulonephritis, but urinary antigen tests can also be helpful to identify Legionella serogroup-1 or histoplasmosis. 9. EKG. Abscesses may manifest as conduction abnormalities seen on EKG. D. Radiology. Echocardiography is the technique of choice for investigating endocarditis. 1. Transthoracic echocardiography (TTE). Has a sensitivity of 60% to 70% in low-risk patients.