Infective Endocarditis Flashcards
What is the median number of cases of infective endocarditis per year?
How many are hospitalized?
4/100,000 per year
1/1000 hospital admission (10-15 thousand)
Who is more likely to get endocarditis, men or women?
Men
What are the four divisions of infective endocarditis?
What is the common cause that they all share?
- native valve IE
- prosthetic valve IE
- IV drug use IE
- Nosocomial IE
They all have the common risk factor of:
BACTEREMIA
What are the four main causes of native valve IE?
- Calcific aortic stenosis
- Rheumatic heart disease
- Mitral Valve Prolapse (with regurgitation)
- Congenital (tetralogy of Fallot, VSD, ASD, bicuspid valve, coarctation of the aorta)
What are the 3 main ways bacteremia can be introduced into the body?
- spontaneous
- IV drug abuse
- Procedural
What are the 5 congenital valve abnormalities that predispose someone to infective endocarditis?
- tetralogy of Fallot
- VSD
- ASD
- Coarctation of the aorta
- Bicuspid aortic valve
What are 5 acquired valve abnormalities that predispose someone to getting infective endocarditis?
- Rheumatic Heart disease
- Calcific aortic stenosis
- prosthetic valves
- previous episodes of IE
- mitral valve prolapse with mitral regurg
What are the six steps of pathogenesis of endocarditis?
- damage of the endocardium (high flow/stress/trauma areas)
- deposition of platelets and fibrin (nonbacterial thrombotic endocarditis NBTE)
- Venturi effect (fluid travels from high flow to low flow areas. Obstructions or orifices (valves) have eddies to flow just downstream–> STASIS
- More vegetation forms on the low flow side of the valve (colonize thrombus, adhesive property)
- Bacteria further damage endothelium and more platelet and thrombin deposit.
- Vegetation forms
What is the Venturi effect?
when fluid travels from high to low flow areas through a natural orifice, there will be eddies in flow downstream of the obstruction or orifice.
This explains why there is a greater likelihood that vegetations form on the low-pressure side of valves.
What is a vegetation?
A complex of fibrin and platelets that enmeshes bacteria. This protects the bacteria from serum factors and phagocytosis
What are agents that commonly cause infective endocarditis?
Which does recent data show is the most frequent isolated organism that cause IE?
- Strep (viridians, enterococci, others)
- Staph (aureus, coagulase negative) ***
- HACEK
- Fungi
- “culture negative”
What strain of Streptococci causes 50% of IE?
What are the two ways this bacteria is introduced?
Viridians streptococci
- pre-existing heart disease
- following dental procedures (oral flora)
How are enterococci that cause IE introduced to the body?
GI or GU pathology or procedures
If someone comes in with symptoms of IE and the culture comes back + for S. bovis, what is you next step?
Order a colonoscopy because S. bovis is associated with colon cancer.
What are the 4 types of strep associated with infective endocarditis?
- viridians (oral flora, preexisting heart disease)
- S. bovis (colon cancer)
- Enterococci (GI or GU path/procedure
- pneumococcus (rare)
What are the common ways S. aureus are introduced in infective endocarditis?
- IV drug abuse
- line-associated complications
- complications of cardiac surgery
What are the common ways coagulase-negative staphylococci are introduced to cause IE?
- cardiac surgery
2. line infections
What is culture negative endocarditis?
What is the frequency of having a culture-negative endocarditis?
What is the most common cause?
It is when you can’t culture bacteria but know that they are there by serology, culture of excised valve tissue, etc.
It used to be 25% but with better tests, it is 2-5%
The most common cause is prior antibiotic therapy
What organisms are responsible for “culture-negative” endocarditis?
- HACEK
- Bartonella
- Chlamydia
- Rickettsia
- Brucella
- Coxiella
- Fungi
What are the HACEK organisms?
Are they gram positive or negative?
Where are they found?
What are special requirements?
- Haemophilis aprophilis
- Actinobacillis actinomycetes
- Cardiobacterium hominis
- Eikenella Corrodons
- Kingella kingae
They are gram negative found in the oral flora. They are slow-growers and require CO2.
What 2 things found in the oral flora can cause IE? How would you differentiate the two?
Viridians Strep and HACEK organisms.
Do a gram stain:
1. strep = + purple
2. HACEK= - pink
Are bartonella found in the normal tests for IE?
Describe the morphology of the Bartonella spp.
They are usually culture-negative unless requested.
Small, fastidious, Gram-negative coccobacillary rods
What people are more likely to get bartonella?
What are the 2 strains and what differentiates them?
85% are associated with prior________
40% are associated with systemic_______
They are associated with homelessness and alcoholics.
B. henselae - flea borne
B. Quintana- louse
85% are associated with prior valvular disease
40% are associated with systemic emboli
What 3 groups of people have had an increasing frequency of fungal endocarditis?
- IV drug abusers
- Patients with IV lines
- immunocompromised
What problem is most frequently associated with fungal endocarditis?
What is the treatment?
Large vegetations are common causing frequent embolization.
There is nearly universal requirement for valve replacement
What 3 organisms are most associated with IVDA?
What valve is most frequently involved?
Why is this an issue?
- Staphylococcus Aureus is most common (MRSA»MSSA)
- GNR (like pseudomonas aeruginosa)
- Fungi
Tricuspid valve is most commonly involved which is bad because it leads to septic embolism to the LUNGS
What would a blood test show for infective endocarditis?
- normochromic, normocytic anemia
- high or normal WBC
- Elevated Erythrocyte Sedimentation Rate
- elevated C-Reactive Proteins
- polyclonal gammopathy, cryoglobulins, immune complexes
- Rheumatoid factor
- decreased complement
What test will give a false positive in lab tests for infective endocarditis?
RPR- Rapid Plasma Reagin will test positive for syphillis
What do chest X-rays show for endocarditis?
- Round lesions in tricuspid valve endocarditis
2. Chamber enlargements
What would an EKG show with Infective endocarditis?
Arrhythmias and heart blocks
What are the 2 major divisions of endocarditis?
- Acute
2. Subacute
What are the presentation symptoms of an acute endocarditis?
What organism is it most frequently associated with?
What acquired factors are associated with acute endocarditis?
- Acute onset with high fever, rigors, leukocytosis, CHF
- S. aureus»_space;>GNR
- IVDA, early prosthetic valves
Metastatic infections are common