Microbiological evidence: a positive blood culture but not meeting a major criterion as noted above, or serological evidence of an active infection with an organism that can cause infective endocarditis.
Echocardiogram: findings consistent with infective endocarditis but not meeting a major criterion as noted above.
The diagnosis of infective endocarditis is definite when:
A microorganism is demonstrated by culture of a specimen from a vegetation, an embolism or an intracardiac abscess
Active endocarditis is confirmed by histological examination of the vegetation or intracardiac abscess
Two major clinical criteria, one major and three minor criteria, or five minor criteria are met.
TTE-high specificity. Sensitivity 60-75%.
TOE-high sensitivity >90%.
A negative echocardiogram does not exclude a diagnosis of endocarditis.
Blood cultures should be taken prior to empirical antibiotic therapy.
Antibiotic treatment should continue for 4–6 weeks.
Serum levels of gentamicin and vancomycin need to be monitored to ensure adequate therapy and prevent toxicity.
Causes of persistent fever
Most patients with infective endocarditis should respond within 48 hours of initiation of appropriate antibiotic therapy.
If persistent fever consider:
perivalvular extension of infection and possible abscess formation.
Drug reaction (the fever should promptly resolve after drug withdrawal)