Endocarditis: Have a high index of suspicion in the right clinical context!

We recently discussed our approach to Infective Bacterial Endocarditis (IBE). Try to keep these key things in mind:

History

-Fever/sweats, dyspnea, chest pain, constitutional (night sweats, weight loss, myalgia/arthralgia); complications/seeding (painful nodules, arthralgias, rash, MI, stroke); PMHx of structural heart disease, recent procedures (dental, GI, GU), history of IVDU, SLE, malignancy, current medications, previous IBE, dental hygiene, line sepsis, indwelling catheters/Hemodialysis lines, prior cardiac valvular disease/surgery

High Index of Suspicion: consider with Fever of Unknown Origin (FUO), persistent bacteremia, heart failure, myocarditis, pericarditis, stroke, pneumonia, PE, splenic infarction, GN, septic arthritis, and osteomyelitis (OM)

·         Other, non-bacterial thrombotic endocarditis: can be secondary to malignancy (usually adenocarcinoma) or SLE (Libman-Sacks endocarditis)-à AKA “MARANTIC ENDOCARDITIS”

Imaging Pearls with respect to ECHO: Trans-thoracic echocardiogram (TTE) versus Trans-esophageal echocardiogram (TEE)

·       TTE: lower sensitivity (SN) for vegetation, but high specificity (SP) approaching 100%; a positive TTE virtually rules in IBE; SN 55% (THUS, does not rule out IBE, especially in patient with intermediate probability)

·       TEE: higher spatial resolution and more SN (94%) with a SP of 100%! Especially useful for prosthetic values in the mitral or aortic position, because acoustic shadowing can make the transthoracic approach suboptimal. More sensitive to detect valve abscesses.

·       NOTE: Start with TTE; consider starting with TEE if limited thoracic window (i.e. patient with a chest wall deformity, obesity), prosthetic valves (especially mitral or aortic—shadowing makes it difficult), prior valve abnormality, etc

 Diagnostic for IBE: 2 Major Criteria OR 1 Major Criteria + 3 Minor Criteria, OR 0 Major Criteria + 5 Minor Criteria

    Modified Duke Criteria

   MAJOR CRITERIA

·       Blood Culture: Positive blood culture for typical IBE organism (i.e. S. viridans, S. bovis, HACEK, Enterococcus, S. aureus- often without another primary site), from 2 separate blood culture sites with samples drawn >12 hours apart OR 3 or a majority of 4 separate blood cultures (first and last sample drawn 1 hour apart)

·       Single positive blood culture for Coxiella burnetii or anti-phase 1 IgG anti-body titre>1:800

·       Echocardiogram evidence: oscillating intra-cardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternate anatomic explanation, OR an abscess, OR a new partial dehiscence of a prosthetic valve OR a new valvular regurgitation (i.e. new regurgitant murmur)

   MINOR CRITERIA

·       Risk factor/Pre-disposition: IV drug use (IVDU) or predisposing heart condition

·       Fever: defined as temperature >38.0 C

·       Vascular Phenomena: arterial emboli, pulmonary infarcts, mycotic aneurysms, intra-cranial hemorrhage, conjunctival hemorrhage, Janeway lesions

·       Immunologic Phenomena: glomerulonephritis (GN), Osler nodes, Roth spots, +ve Rheumatoid Factor (RF)

·       Microbiological evidence: positive blood culture not meeting Major Criteria, or serological evidence of active infection with organism consistent with IBE (excluding Coagulase Negative Staph and other common contaminants)

   RESOURCES: IDSA Guidelines

   IDSA Cardiovascular Guidelines, Including Endocarditis Management

   AHA- Infective Endocarditis