Endocarditis Flashcards
What is the typical Native Valve Endocarditis (NVE) lesion?
Mass of platelets, fibrin, microbial microcolonies with scant inflamm cells
What is the typical Nonbacterial thrombotic endocarditis (NBTE) lesion?
Uninfected platelet-fibrin thrombus
What is the Venturi effect?
NBTE and NVE develop on the sides of low pressure just beyond the valve or intraventricular defect/stenosis
Why is infective endocarditis so serious/difficult?
Cardiac valves have no dedicated blood supply so host immune response is blunted and limits access of abx to valve
What cardiac locations are involved in infective endocarditis?
- Native or prosthetic valves
- Low pressure side of VSD or valve
- Mural endocardium
- Intracardiac devices
What is infective endarteritis?
Analogous process (of endocarditis) in AV shunts, PDA, or coarctation of aorta
What is the “old” way to classify bacterial endocarditis?
- Subacute (low virulence, strep)
- Acute (higher virulence, staph aureus)
What is the newer way to classify bacterial endocarditis?
- Short incubation (less than 6 wks)
- Long incubation (6+ weeks)
What organisms MC cause endocarditis from oral cavity, skin, and UR tract?
- Viridans strep
- Staphylococci
- HACEK from oral cavity
What organisms MC cause health care associated NVE?
Staph aureus
CoNS
Enterococci
What are the MC procedures inducing bacteremia and the organisms associated?
- Dental (S viridans)
- Endoscopy (CoNS)
- Colonoscopy (E coli)
- Barium enema (Enterococci)
- TEE (S viridans)
When does nosocomial PVE occur and which organisms?
- Less than 2 months after valve surgery
- Usually S aureus, CoNS
What organisms occur with PVE 12+ months after surgery?
- Similar to community acquired NVE
- CoNS
Where does endocarditis colonize MC in IV drug users?
Tricuspid valve
What organism usually causes IV drug endocarditis?
S aureus (often methicillin resistant)
How do blood cultures present in infective endocarditis?
5-15% cases have negative cultures (many due to prior abx exposure OR fastidious organisms)
What is the feature of organisms deep in vegetations of endocarditis?
They are metabolically inactive (non-growing) and resistant to antimicrobial agents
How do murmurs present in infective endocarditis?
- Absent initially
- Ultimately murmurs present in 85% cases
Classic signs of infective endocarditis
- Petechiae
- Splinter hemorrhages
- Osler nodes
- Janeway lesions
- Roth spots
What are Osler nodes?
- Tender SC nodules in between digits
- A/w infective endocarditis
What are Janeway lesions?
- Nontender maculae on palms and soles
- A/w infective endocarditis
What are Roth spots?
- Retinal hemorrhages with small, clear centers (rare)
- A/w infective endocarditis
How is infective endocarditis diagnosed?
- TTE (noninvasive and very specific)
- TEE (sensitivity 90+%)
Which type of echo is more sensitive and accurate for PVE diagnosis?
TEE
What are the diagnostic criteria for infective endocarditis?
Duke’s (2 major, 1 major 3 minor, 5 minor)
What are major Duke’s criteria?
- Positive blood culture
- Evidence of endocardial involvement
What are minor Duke’s criteria?
- Predisposition
- Fever 100.4+ F
- Vascular phenom
- Immunologic phenom
- Microbio evidence
Management of infective endocarditis?
- 3 to 5 sets of blood cultures
- Empiric abx AFTER cultures
What type of abx are used to treat NVE?
Penicillin G and gentamicin
Negative blood cultures for endocarditis at 48-72 hrs?
Must repeat 2-3 culture sets
What type of abx to treat IV drug endocarditis?
Nafcillin and gentamicin
How is PVE treated differently than NVE?
Abx typically a couple weeks longer in duration
Surgery is MC required for what type of endocarditis?
PVE
