Endocarditis Flashcards
Why does endocarditis occur?
Turbulent blood flow leads to valvular damage, which disrupts the valve surface to produce a suitable site for bacterial attachment
Fibrin/platelet deposition forms NBTE (non-bacterial thrombotic endocarditis)
NBTE restricts normal blood flow, causes a pressure gradient and bacteria are able to settle in the low pressure areas
Predisposing factors to transient bacteremia?
Dental manipulation
Dental disease
Extracardiac infection (lung, UTI, skin, bone, abscess)
Instrumentation (in the urinary tract, GI tract, or IV infusions)
Cardiac surgery
IVDA
What are the most common clinical signs for endocarditis?
Fever
Heart murmur
What are the major Duke criteria for endocarditis?
- Positive test for microorganisms known to cause endocarditis from 2 separate cultures (S aureus, viridans, HACEK, or CA enterococci)
- Microorganisms known to cause endocarditis from persistently positive cultures (2 drawn 12 hours apart or all of 3 or a majority of 4 or more separate cultures drawn within 1 hour)
- Single positive culture or IgG antibody titer over 1:800 for coxiella burnetii
- Evidence of endocardial involvement from echocardiogram or new murmur
What are the minor duke criteria for endocarditis?
Predisposition: Heart condition, IVDA
Fever (over 38 degrees C)
Vascular phenomenon: Emboli, pulmonary infarcts
Intracranial or subconjunctival hemorrhage; Janeway lesions
Immunologic phenomenon: Glomerulonephritis, Osler’s nodes
Microbiological evidence but does not meet major criteria
Diagnosis of IE is definite in the presence of…
2 major criteria
1 major and 3 minor criteria
or
5 minor criteria
Diagnosis of IE is possible in the presence of…
1 major and 1 minor criteria
or
3 minor criteria
What are the therapeutic goals for endocarditis?
Identify the primary source of infection
Idenfity the infecting pathogen to direct therapy
Sterilize the bloodstream quickly
Prevent or limit valvular damage
How long should therapy last
Duration begins from the first negative culture
2 to 4 week regimens
What is NVE?
Native valve endocarditis: usually has a shorter course of therapy than PVE
What is RSE?
Right sided endocarditis
What is PVE?
Prosthetic valve endocarditis
What are the treatment basics of endocarditis?
Duration begins at first negative culture
Blood cultures should be taken every 24 to 48 hours until clearance of bacteremia
Combination drugs should be administered as close together to maximize killing effect
NVE Viridans Streptococci preferred treatments when PCN MIC is less than 0.12 mcg/mL (4 weeks)?
Penicillin G (preferred in pts over 65 or pts with renal failure)
Ceftriaxone
Vancomycin (Goal trough is 10-20 mcg/mL)
NVE Viridans Streptococci preferred treatments when PCN MIC is less than 0.12 mcg/mL (2 weeks)?
Penicillin G 12-18 MU (exclusions: extracardiac disease, CrCL less than 20, and PCN tolerant organisms)
Ceftriaxone PLUS Gentamicin (peak conc 3-5, trough less than 1)