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)
NVE Viridians Strep and S Bovis treatment when PCN is between 0.12 and 0.5 mcg/mL?
Penicillin 24 MU or Ceftriaxone PLUS Gentamicin (peak 3-5, trough less than 1) Vancomycin (trough 10-20)
NVE Viridians Strep and S Bovis treatment when PCN is over 0.5 mcg/mL?
Penicillin 24 MU
or
Vancomycin (if PCN allergy or PCN MIC is over 4)
plus
Gentamicin (Peak conc 3-5, trough less than 1)
Treatment for NVE caused by Staph?
Oxacillin 12 g/24 hour in divided doses; may consider 2 week course in uncomplicated disease but usually 6 weeks
Cefazolin (if PCN allergy) use 6 g/24 hours in 3 divided doses
Vancomicin (in Oxacillin-resistant strains) 30 mg/kg q8-12h for 6 weeks (trough 10-20)
How long should you use Gentamicin?
2 weeks!
In MRSA, what drugs should you avoid
Gentamicin and Rifampin
Treatment for MRSA endocarditis?
Vancomycin (15-20 mg/kg/dose every 8-12 hours, trough over 10)
Daptomicin (6 mg/kg/dose IV QD)
What is persistent bacteremia? How do we treat?
MRSA infection defined as greater than 7 days duration
Teat with Daptomycin 10 mg/kg/dose PLUS gentamicin or rifampin
How to treat PVE caused by staph?
Oxacillin PLUS rifampin PLUS gentamicin
6 weeks for first two, 2 weeks for gentamicin
Gentamicin peak conc is 3-4 with trough less than 1
How to treat PVE caused by staph in PCN allergic patients?
Cefazolin 6 mg/kg in combo with rifampin/gentamicin
How to treat Oxacillin-resistant Staph strains?
Vancomycin 30 mg/kg IV; trough 10-20, use with rifampin and gentamicin
True or false: We can use rifampin as monotherapy
False; high instances of resistance when rifampin is used alone
NVE and PVE Enterococcus treatment options:
Ampicillin PLUS gentamicin
Duration: NVE with sx less than 3 months is 4 weeks
NVE or PVE with sx greater than 3 months is 6 weeks
NVE and PVE Enterococcus treatment options in PCN allergic patients?
Vancomycin with Gentamicin
NVE and PVE Enterococcus treatment options in Vancomycin resistant strains?
Linezolid
Daptomycin HIGH DOSE 10-12 mg/kg/day
Who is at high risk for IE?
Prosthetic heart valves or prosthetic material used in valve repair
Previous IE
Congenital heart disease
Cardiac transplant patients who develop cardiac valvulopathy
What procedures require IE prophylaxis?
Dental procedures involving manipulation of gingival tissue or periapical region of teeth or perforation of mucosa
Bronchoscopy requiring mucosal incision
Tonsillectomy and adenoidectomy
I & D of infectious tissue in upper respiratory tract
Patients with infected skin or muscle structures
Preoperative heart valve surgery
What oral prophylactic regimens are there?
Amoxicillin 2 g (adult) or 50 mg/kg (children) 30-60 min before procedure
or in PCN allergic pts:
Cephalexin (2 g adult, 50 mg/kg children) or Clindamycin (600 mg adult or 20 mg/kg children)
When should Clindamycin not be used?
In pts with history of anaphylaxis, angioedema, or stephens johnson disease
also includes cefazolin and ceftriaxone
What IV prophylactic regimens are there?
Ampicillin (2 g, 50mg/kg children) or Cefazolin (1 g, 50 mg/kg children)
or in PCN allergic pts:
Cefazolin 1 g adults, 50 mg/kg children
or
Ceftriaxone (1 g, 50 mg/kg children)
