Infective Endocarditis Flashcards
Difference from infective endarteritis
Infective endarteritis
-involved arteriovenous shunts, arterio-arterial shunts (PDA), or a coarctation of the aorta
Classification based on the temporal evolution of disease
- Acute endocarditis
- hectically febrile illness that rapidly damages cardiac structures, seeds extracardiac sites, and if untreated, progresses to death within weeks - Subacute endocarditis
- follows an indolent course
-causes structural cardiac damage only slowly, rarely metastasizes
Epidemiology of IE
4-7 per 100,000 population per year in developed countries,
incidence increased in the elderly
Predisposed to IE
Congenital heart disease
Ilicit IV drug use
Degenerative valve disease
Intracardiac devices
Portals of entry of associated
bacterial species in IE
Oral cavity
Skin
Upper respiratory tract
HACEK organisms
Haemophilus species
Aggregatibacter sp
Cardiobacterium hominis
Eikenella corrodens
Kingella kingae
Causes of health-care
associated native valve
endocarditis (NVE)
Staphylococcus aureus
coagulase-negative staphylococci (CoNS)
Enterococci
Causes of prosthetic valve
endocarditis based on temporal
presentation from surgery
1.Early PVE (2 months)
- nosocomial and is the result of intraoperative contamination
- S. aureus, CoNS, facultative gram-negative bacilli, diphtheroids and fungi
- Late PVE (>12 months)
- similar to community-acquired NVE - Delayed-onset PVE (2-12 months)
-nosocomial
Causes of CIED endocarditis
- S. aureus and CoNS
- both often resistant to methicillin
Causes of endocarditis among
injection drug users
- involves the tricuspid valve
-caused by S. aureus
-other causes: P.aeroginosa and Candida sp.
-unusual - Bacillus, Lactobacillus, and Corynebacterium sp,
Causes of blood culture
negative endocarditis
- prior antibiotic exposure (one-third to one-half of cases)
- ## others : streptococci, HACEK, Coxiella burnetti, and Bartonella
Pathogenesis of infective
endocarditis
Endothelial injury (at the site of impact of high velocity blood jets or on the low-pressure side of a cardiac structural lesion) -> direct infection by virulent organisms or development of a platelet fibrin thrombus.
-> fibrin deposition combines with platelet aggregation and microorganism proliferation to generate an infected vegetation
Clinical Manifestations of IE
Modified Duke Criteria for the
clinical diagnosis of IE
Definition of definite and
possible IE
Definite IE
- two major criteria
- 1 major and 3 minor
- 5 minor criteria
Probable IE
- one major and one minor criterion
-three minor criteria
Considerations in performing
blood culture studies
Patients with suspected IE who have not received antibiotics during the prior 2 weeks:
- three 2-bottle blood culture sets, separated from one another by at least 2 hours, should be obtained from different venipuncture sites over 24h
If cultures remain negative after 48-72 h, additional blood culture sets should be obtained
Hemodynamically stable/subacute IE: may withheld empirical antibiotic tx initially
Deteriorating hemodynamics/requires urgent surgery: may give empirical antibiotic tx
Role of serologic tests in IE
used to implicate organisms that are difficult to recover by blood culture: Brucella, Bartonella, Legionella, Chlamydia psittaci, and C. burnetti
Choice of echocardiographic
techniques in IE work-up
Transthoracic echocardiography (TTE)
Principles in antimicrobial
therapy of IE
To cure endocarditis, all bacteria in the vegetation must be killed. Therapy must be bactericidal and prolonged
Antibiotic treatment for Streptococci
Antibiotic tx for Enterococci
Antibiotic tx for Staphylococci
Antibiotic tx for HACEK
Antibiotic tx for Coxiella burnetti
Antibiotic tx for Bartonella
Candidates for Outpatient Antimicrobial Therapy
Fully compliant
Clinically stable
No longer bacteremic
No febrile
No clinical or echocardiographic findings that suggest an impending complication
Monitoring antimicrobial therapy
Blood cultures should be repeated daily until sterile in patients with IE due to S. aureus or difficult-to-treat organisms
-rpt again 4-6 weeks after tx to document cure
Blood cultures become sterile after:
2 days - viridans Step, HACEK, entrerococci
3-5 days - S. aureus
7-9 days - MRSA
Diseases to evaluate if fever persists for 7 days despite appropriate antibiotic therapy
paravalvular abscess
extracardiac abscesses (spleen, kidney)
complications (embolic events)
Indications for surgical
management in IE
Recommendations on IE
prophylaxis
-recommended when there is manipulation of gingival tissue or the periapical region of the teeh or perforation of the oral mucosa (including surgery on the respiratory tract)
-not advised for GI or GU procedures
-high-risk patients should be treated before or when they undergo procedures on an infected GUT or infected skin
Dose of prophylaxis
