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Toronto Notes 2019 Cardiac Infections
Diagnosis
• ModifiedDukeCriteria
■ definitive diagnosis if: 2 major, OR 1 major + 3 minor, OR 5 minor ■ possible diagnosis if: 1 major + 1 minor, OR 3 minor
Table 17. Modified Duke Criteria
Major Criteria (2)
1. Positive blood cultures for IE
• Typical microorganisms for IE from 2 separate blood cultures (Streptococcus viridans, HACEK group,
Streptococcus gallolyticus (previously known as S. bovis), Staphylococcus aureus, community-acquired enterococci) OR
• Persistently positive blood culture, defined as recovery of a microorganism consistent with IE from blood drawn >12 h apart
OR
• All of 3 or a majority of 4 or more separate blood cultures, with first and last drawn >1 h apart OR
• Single positive blood culture for Coxiella burnetii or antiphase I IgG antibody titer >1:800
2. Evidence of endocardial involvement
• Positive echocardiogram for IE (oscillating intracardiac mass on valve or supporting structures, or in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation OR abscess OR new partial dehiscence of prosthetic valve); and new valvular regurgitation (insufficient if increase or change in preexisting murmur)
Minor Criteria (5)
1. Predisposing condition (abnormal heart valve, IVDU)
2. Fever (38.0°C/100.4°F)
3. Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysms, ICH, conjunctival hemorrhages,
Janeway lesions
4. Immunologic phenomena: glomerulonephritis, rheumatoid factor, Osler’s nodes, Roth’s spots
5. Positive blood culture but not meeting major criteria OR serologic evidence of active infection with organism consistent with IE
Investigations
• serialbloodcultures:3sets(eachcontainingoneaerobicandoneanaerobicsample)collectedfrom different sites >1 h apart
■ persistent bacteremia is the hallmark of endovascular infection (such as IE)
• repeatbloodcultures(atleast2sets)after48-72hofappropriateantibioticstoconfirmclearance
• bloodwork:CBCanddifferential(normochromic,normocyticanemia),ESR(increased),RF(+),urea/Cr
• urinalysis(proteinuria,hematuria,redcellcasts)andurineC&S
• ECG:prolongedPRintervalmayindicateperivalvularabscess
• echofindings:vegetations,regurgitation,abscess
■ TTE (poor sensitivity) inadequate in 20% (obesity, COPD, chest wall deformities)
■ TEE indicated if TTE is non-diagnostic in patients with at least possible endocarditis or if suspect
prosthetic valve endocarditis or complicated endocarditis (e.g. paravalvular abscess/perforation) (~90% sensitivity)
Treatment
• medical
■ usually non-urgent and can wait for confirmation of etiology before initiating treatment unless
patient is septic
■ empiric antibiotic therapy if patient is unstable; administer ONLY after blood cultures have been
taken. Generally, S. aureus, coagulase-negative staphylococcus (CNST), and Gram-negative coverage is important
◆ first line empiric treatment for native valve: vancomycin + gentamicin OR ceftriaxone
◆ first line empiric treatment for prosthetic valve: vancomycin + gentamicin + rifampin
■ targeted antibiotic therapy: antibiotic and duration (usually 4-6 wk) adjusted based on valve,
organism, and susceptibilities
■ monitor for complications of IE (e.g. HF, conduction block, new emboli) and complications of
antibiotics (e.g. renal disease)
■ post treatment prophylaxis only recommended for high risk individuals listed above with dental
procedures that may lead to bleeding OR invasive procedure of the respiratory tract that involves incision or biopsy of the respiratory mucosa, such as tonsillectomy and adenoidectomy OR procedures on infected skin, skin structure, or musculoskeletal tissue
• dental/respiratory:amoxicillinsingledose30-60minprior;clindamyciniftrulypenicillin-allergic
• skin/softtissue:cephalexinsingledose30-60minprior;clindamyciniftrulypenicillin-allergic(modify
based on etiology of skin/soft tissue infection)
• surgical
■ most common indication is refractory CHF
■ other indications include: valve ring abscess, fungal etiology, valve perforation, unstable prosthesis,
≥2 major emboli, antimicrobial failure (persistently positive blood cultures), mycotic aneurysm, Staphylococci on a prosthetic valve
Prognosis
• adverseprognosticfactors:CHF,prostheticvalveinfection,valvular/myocardialabscess,embolization, persistent bacteremia, altered mental status
• mortality:prostheticvalveIE(25-50%),non-IVDUS.aureusIE(30-45%),IVDUS.aureusor streptococcal IE (10-15%)
Infectious Diseases ID17
TEE TTE
transesophageal echo transthoracic echo