Table 10.
Criteria for diagnosing IE
| Major criteria | |
|---|---|
| Microbiological | Comments |
| Typical isolated microorganism from two separate blood cultures: Streptococcus viridans, Streptococcus bovis, HACEK group, Staphylococcus aureus, or community-acquired enterococcal bacteremia, in the absence of a primary focus | In patients with possible IE, at least 2 blood cultures must be obtained in 2 different veins during the first 2 hours. In patients with septic shock, 3 blood cultures must be collected at 5–10 min intervals, after which point empirical antibiotic therapy should be initiated. |
| Or | |
| Persistently positive blood cultures consistent with isolated IE | |
| Or | |
| Blood culture positive for Coxiella burnetii or antibody titre (lgG) > 1:800 for C. burnetii | C. burnetii is not cultivated in most laboratory analyses |
| Evidence of endocardial involvement | |
| New valvular regurgitation (increases and changes in preexisting murmurs are not sufficient) | |
| Or | |
| Positive echocardiogram (TEE recommended for patients with prostheses, possible IE based on clinical criteria, or complicated IE) | Three TTE findings are considered major criteria: discrete oscillating intracardiac mass located on a valve or subvalvular structure, periannular abscess, and new dehiscence of prosthetic valve |
| Minor criteria | Comments |
| Predisposition to IE, including certain heart conditions and IV drug use | Cardiac abnormalities that are associated with
IE are classified into 3 groups: ● High risk: previous IE, aortic valve disease, rheumatic valve disease, prosthetic valve, coarctation of the aorta, and complex cyanotic heart diseases ● Medium risk: mitral valve prolapse with leaflet insufficiency or thickening, isolated mitral stenosis, tricuspid valvulopathy, pulmonary stenosis, hypertrophic cardiomyopathy ● Low risk: Ostium secundum IAC, ischemic disease, previous revascularization surgery, and mitral valve prolapse without previous regurgitation, and mitral valve prolapse without regurgitation and with thin leaflets |
| Fever | Temperature > 38° C |
| Vascular phenomena | Except petechiae and hemorrhagic suffusions |
| No peripheral lesions are pathognomonic of IE | |
| Immunologic phenomena | Rheumatoid factor, glomerulonephritis, Osler nodes, Roth spots |
| Microbiological findings | Positive blood cultures that do not meet major criteria. Serological evidence of active infection, isolation of coagulase-negative staphylococci and organisms that rarely cause IE are excluded from this category |
| Cases are clinically defined as "definite IE" if they meet 2 major criteria, 1 major criterion and 3 minor criteria, or 5 minor criteria and "possible IE" if they meet 1 major criterion and 1 minor criterion or 3 minor criteria. | |
HACEK: Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens and Kingella kingae; IAC: interatrial communication; IE: infective endocarditis; IgG: immunoglobulin G; IV: intravenous; TEE: transesophageal echocardiography; TTE: transthoracic echocardiography.