Infective Endocarditis Flashcards
What is the most common cause of infective endocarditis?
oral bacteria
- transient bacteremia from daily activities like teeth brushing & food chewing
What are the risk factors of infective endocarditis?
- male gender
- > 60 years
- valvular disease
- prosthetic heart valves
- previous IE
- congenital heart defects
What is the classification of infective endocarditis?
SUBACUTE BACTERIAL ENDOCARDITIS
- Strep. viridans
- insidious onset
- slow progression (weeks to months)
- less severe constitutional symptoms (low-grade fever, malaise, dyspnea, back pain, weight loss)
- valves with prior injury or congenital defects
ACUTE BACTERIAL ENDOCARDITIS
- Staph. aureus
- acute onset
- rapid fulminant progression (days to weeks)
- severe constitutional symptoms (high fever)
- healthy valves
Which pathogen causes acute IE?
STAPH AUREUS
- gram +
- B hemolytic
- catalase +
- coagulase +
- cocci in clusters
fatal in 6 weeks if untreated
affects healthy valves
which pathogen causes subacute IE that is common following dental procedures?
VIRIDANS STREP
- gram +
- a hemolytic
- cocci
- in pre-damaged valves
S. mutans & S. mitis cause dental caries
S. sanguinis make dextrans that bind to fibrin platelet aggregates on damaged heart valves
What pathogen is more commonly implicated in prosthetic devices?
Staph. epidermidis
- gram +
- coagulase +
- cocci in clusters
- NORMAL FLORA OF SKIN
What pathogens can cause IE following gastrointestinal or genitourinary procedures?
Enterococci (Enterococcus faecalis)
- gram + cocci
- normal colonic flora (penicillin G resistant)
- cause UTI & biliary tract infections
What pathogens indicate colonoscopy if found?
Streptococcus gallolyticus subsp. gallolyticus
- gram + cocci
- colonize the gut
- associated with colorectal cancer
What type of endocarditis is associated with immunosuppressed patients?
Fungal endocarditis -> candida or Aspergillus fumigatus
What are the clinical features of infective endocarditis?
- fever & chills
- general malaise, weakness, weight loss, night sweats
- dyspnea, cough, pleuritic chest pain
- arthralgias, myalgias
- development of new heart murmur or change in a preexisting murmur
- heart failure -> advanced
- arrhythmias -> peri-valvular abscess in patients with IE who develop a new conduction abnormality (heart block)
- petechiae -> splinter hemorrhages
- janeway lesions -> not painful on feet
- Osler nodes -> painful on fingertips
- Roth spots (retinal hemorrhages with pale centers
- acute renal injury
- septic embolic stroke
- signs of pulmonary embolism
What is the easiest way to remember the clinical features of infective endocarditis?
FROM JANE
- Fevers
- Roth spots
- Osler nodes
- Murmur
- Janeway lesions
- Anemia
- Nail-bed hemorrhages (splinter hemorrhages)
- Emboli
What is the approach to diagnose infective endocarditis?
- all patients should receive -> multiple blood cultures & ECHO (TEE)
- TTE initially
- CBC -> leukocytosis
- ESR & CRP -> elevated
What is the modified Duke criteria?
to categorize the diagnostic likelihood of IE
DEFINITE
- 2 or more major criteria
- 1 or more major criteria + 3 or more minor
- 5 or more minor
- 1 or more pathological features
What are the major criterias in the modified duke criteria that help in the diagnosis of IE?
- typical organisms from 2 separate blood cultures
- persistently positive blood cultures with typical endocarditis microorganisms
- one positive culture for Coxiella burnetii
- characteristic echocardiographic findings of IE
How should infective endocarditis be managed?
1- empiric antibiotics (Vancomycin + beta-lactam (ceftriaxone & cefepimide))
2- take blood culture on day 1
3- if blood culture is positive take another culture on day 3
4- if second blood culture positive take another on day 7
5- if 3rd blood culture is negative start targeted antibiotic therapy & continue for 6 weeks
- overall treatment should continue for 7 weeks
