Infective Endocarditis Flashcards
(42 cards)
Acute Endocarditis def (associated with what bacteria? Involve which valve? Mortality in how long?
Fulminating form; associated with high fevers and systemic toxicity (e.g., S. aureus, S. pyogenes, S. pneumoniae, or Neisseria gonorrhoeae) .
Mortality within days to weeks if untreated.
Generally involves aortic valve
Subacute Endocarditis def (associated with what bacteria? Involve which valve? Mortality in how long?
Indolent infection from less virulent organisms, often in pre-existing valvular disease (ex. Viridans group Streptococci, Enterococci, HACEK)
Mortality within 6-12 weeks if untreated
Generally involves mitral valve
Which valves are on right side?
Pulmonary and tricuspid valve
Which valves are on left side?
Mitral and aortic valve
Pathophysiology of infective endocarditis
Organisms adhere to fibrin-platelet clots that form at the site of damaged cardiac endothelium
Organisms activate monocytes to produce tissue factor activity (TFA) and cytokines
Coagulation pathway is activated causing further recruitment of platelets and growth of vegetation
S. aureus in infective endocarditis
Staphylococci
Most common cause of IE (rates continuing to increase)
Commonly seen with IVDA (often right-sided), DM, presence of skin disorders, or in patients with implanted cardiac devices
Highly virulent
S. epidermidis in infective endocarditis
Staphylococci
Ordinarily related to prosthetic valves or indwelling implanted cardiac devices
Viridans group streptococci (VGS) in infective endocarditis
Present in normal oral flora, skin, GI tract
Commonly in patients with underlying cardiac defects
E.g., rheumatic heart disease or mitral valve prolapse
Often community acquired infection
Enterococcus faecalis and Enterococcus faecium
Which one is more resistant? Found in normal flora
Enterococcus faecalis and Enterococcus faecium
Found in normal flora of the GI tract
Often seen in patients after patients after obstetric procedures or manipulation of genitourinary tract
HACEK Organisms in infective endocarditis
Slow growing, fastidious Gram-negative bacilli
Possible cause in culture-negative IE
Account for 5-10% of native valve endocarditis in non-IVDU patients
Haemophilus parainfluenzae OR aphrophilus Actinobacillus actinomycetemcomitans Cardiobacterum hominis Eikenella corrodens Kingella kingae
Clinical Presentation: Peripheral Manifestations of infective endocarditis
Osler Nodes Janeway Lesions Splinter Hemorrhages Petechiae Clubbing Roth Spots (eye exam)
Clinical Presentation: Lab findings
Anemia (normocytic, normochromic)
Thrombocytopenia
Leukocytosis (may be mild)
Elevated ESR/CRP
Clinical Presentation: Signs
Fever (>38 C)
Heart/Changing/New murmur
Vascular Embolic events
Pathologic Criteria: Definitive IE
Microorganism demonstrated by culture/sample of:
- Vegetation
- Embolized vegetation
- Intracardiac abscess speciness
Pathologic lesions:
-Histologic examination of vegetation or intracardiac abscess showing active IE
Clinical Criteria: Definitive IE
Modified Duke criteria:
- 2 major criteria
- 1 major criteria and 3 minor criteria
- 5 minor criteria
Clinical Criteria: Possible IE
Modified Duke criteria:
- 1 major and 1 minor criteria
- 3 minor criteria
Clinical Criteria: Rejected IE
- Alternative explanation for findings
- Resolutions of symptoms with ABx < 4 days
- No pathophysical evidence at surgery or autopsy with ABx < 4 days
- Does not meet criteria as described
Modified Duke Criteria: Major blood culture positive for IE
Typical organism from 2 blood cultures
Organisms consistent with IE from persistently positive blood culture:
- Culture has >=2 positive drawn >12 hours apart
- All of 3 or a majority of >4 cultures (with first and last drawn >1 apart)
Single positive blood culture for Coxiella burnetti or anti-phase IgG antibody tier >1:800
Modified Duke Criteria: Major evidence of endocardial involved
ECHO positive for IE
New valvular regurgitation (worsening/changing old murmur not sufficient )
Modified Duke Criteria: Minor
Predisposing heart condition or intravenous drug use
Fever >= 38.0 C (100.4 F)
Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhage, Janeway lesion
Immunologic phenomena: glomerulonephritis, Osler’s nodes, Roth spots, rheumatoid factor
Positive blood culture not meeting major criterion as noted previously (Excluding single positive cultures for coagulase-negative staphylococci and organisms that do not cause endocarditis) or serologic evidence of active infection with organism consistent with infective endocarditis
Nonpharmacologic (FYI)
Typical indications for valve replacement:
Hemodynamic disturbances (CHF or valve dysfunction)
Positive blood cultures after 1 week of therapy
≥ 1 embolic event during first 2 weeks of therapy
Increase in vegetation size
Prosthetic valve endocarditis
Valve dehiscence, rupture, fistula, or abscess
Considerations when deciding therapy for Infective endocarditis
Valve type (native or prosthetic) Organism & susceptibilities Drug issues (e.g., allergy, renal function, etc.)
What drugs should be used for synergy in infective endocarditis?
Aminoglycosides (typically used for GNR activity) used at low doses for GPC synergy.
Gentamicin Dosing for Infective Endocarditis
1 mg/kg IV q8h - Option for ALL organisms -> REMEMBER THIS
3 mg/kg of IV q24h - Option for SOME organism