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
What is the presentation of subacute endocarditis?
What organism is it most frequently associated with?
What acquired factors are associated with subacute endocarditis?
- insidious onset, lower fever (FUO-fever of unknown origin), weight loss, malaise and fatigue, peripheral signs (osler nodes, roth spots)
. - Viridians strep, other strep, enterococci, HACEK
- Rheumatic valves, late prosthetic valves, dental procedures
What are Janeway lesions?
Are they associated with acute or subacute endocarditis?
What organisms tend to cause them?
They are small embolic flat, red, painless spots on palms and soles.
They are associated with acute disease and S. aureus.
What are Osler’s nodes?
Do they tend to be acute or subacute?
They are PAINFUL brown lesions on the pulpy part of toes and fingers due to immune complex deposition.
They are more subacute.
What are the 4 embolic phenomena associated with infective endocarditis?
- Janeway lesions- painless on palms, soles
- Osler spots- painful on pulpy part of fingers, toes
- Splinter hemorrhages- black dots on fingernails
- Roth spots- retinal hemorrhages
- Conjunctival petechiae- in pinks of eyes
Where are mycotic aneurysms likely to form as a result of infective endocarditis?
mycotic aneurysms form in cerebral circulation
Where do septic emboli due to tricuspid valve endocarditis go?
the lungs
What are the 2 types of prosthetic valves?
- mechanical
2. bio-prosthetic- ring is prosthetic and valve is porcine or bovine
What is the annual incidence of prosthetic valve endocarditis?
What is the fatality rate?
What is the most common cause of EARLY prosthetic valve endocarditis?
1-3% infection
40-50% case-fatality
early is caused by coagulase negative staphylococcus»_space;>late
What are risk factors for prosthetic valve endocarditis?
- operation during ongoing infection (bacteremia)
- duration of surgery
- number of valves replaced
- Aortic >mitral
- Elderly men
- mechanical valve = bio-prosthetic
Who is more likely to get prosthetic valve endocarditis, a 60 year old man with a mechanical valve or a 60 year old man with a bioprosthetic valve?
equally likely. The type of valve doesn’t increase risk
How many patients will experience complications from endocarditis?
What are the 4 major cardiac complications?
What are the 2 main systemic complications?
1/3 to 1/2 will have complications.
Cardiac:
- Abscesses
- conduction abnormalities
- CHF
- Pericarditis
Systemic:
- strokes
- mycotic aneurysms
When there are conduction abnormalities due to complications of endocarditis, what valve is most frequently the culprit?
What type of conduction abnormality is most common?
Aortic valve is most involved
Heart blocks are the conduction abnormality
What percent of patients will get CHF as a complication of endocarditis?
How many will die?
20-80%
death in 35-85%
What are the 4 criteria for diagnosis of endocarditis?
- predisposition and clinical syndrome
- bacteremia
- evidence of cardiac involvement
- vascular phenomenon
When you take blood cultures of someone suspected of endocarditis, what will be the key feature?
How many cultures should you take? Why?
constant LOW level of bacteremia (10CFU/ml)
You should take 3 sets of cultures over 24 hours
1 culture = 85% sensitivity
3 culture sets = 95% sensitivity
What 2 infections do you need to do a serology for to see if they are causing endocarditis?
Q fever and Bartonella
What are the 2 echocardiography techniques?
Which is the least invasive?
Which is least expensive?
Which is better at evaluating prosthetic valves?
- Transthoracic (TTE)- cheaper and less invasive
- Transesophageal (TTE)- better at evaluating valves, detecting smaller vegetations and detecting intramyocardial abscesses
Using the Modified Duke Criteria, what would make something:
- Definitive IE
- Possible IE
- Rejected
Definitive IE:
2 major criteria
1 major and 3 minor
5 minor criteria
Possible IE:
1 major and 1 minor
3 minor
Rejected:
Firm alternative diagnosis explaining evidence of IE
Resolution of “IE” without antibiotics or in less than 4 days
No path evidence of IE at autopsy or surgery
What are the “Major Criteria” for IE?
- Blood cultures with the typical organisms and “persistently positive blood culture positivity”
- Serologies for Q fever or Bordatella
- Echo showing:
- vegetations
- abscess
- dehiscence of prosthetic valve
- new regurgitant murmur
What are the “minor criteria” for IE?
- fever
- embolic phenomenon
- immunologic phenomenon
- serological evidence of organisms
- micro/echo that don’t meet “major criteria”
What are the 3 different treatments for endocarditis?
What should be avoided?
- antibiotics
- surgery
- manage cardiac complications (CHF, arrhythmia)
DO NOT use anticoagulant
Describe the antibiotics needed to treat endocarditis.
- cidal or static
- administration
- doses
- duration
- Bactericidal antibiotics
- IV
- high doses and synergistic combos
- prolonged duration MINIMUM 4-6 wks
What are the 6 indications that surgery is necessary for endocarditis?
- persistent bacteremia despite antibiotics
- prosthetic valve or fungal endocarditis
- abscess of annulus or myocardium
- refractory CHF due to valve failure
- vegetations over 10mm
- multiple systemic emboli
Should prophylactic antibiotics be used for endocarditis?
No unless they are high risk patients having dental, oral or upper respiratory procedures.
It is administered at least 1 hour prior to the procedure
How many nosocomial bloodstream infections occur annually?
What are most associated with?
200,000 most associated with IV catheters
Which catheter is more likely to get infected, one in the internal jugular, femoral or subclavian?
int. jugular= femoral > subclavian
Which line is more likely to get infected, central or peripheral?
Central
Which catheter is more likely to get infected, tunneled, non-tunneled or implanted?
Nontunneled > tunneled> implanted
What are the different mechanisms by which catheters can cause bloodstream infections?
- extraluminal (around the line)
- intraluminal
- the hub or connections
- infusate (fluid)
- hematogenous
What is a biofilm?
A matrix of fibrin and host proteins made by bacteria that inhibit PMN entry and antibiotic action
Where do the organs that cause catheter-related bloodstream infections come from?
What specific organisms are the main culprits?
Skin flora-
- CONS > S. aureus (50%)
- GNR (25%)
- Candida (20%)
- Other - diptheroids, propionibacteria, Bacillus
What are the systemic and local signs of a catheter-related bloodstream infection?
Systemic: 1. fever 2. malaise 3. chills 4. myalgia 5. arthralgia Local 1. redness, drainage and pus at catheter site 2. fever or hypotension as infusion occurs
What are the 4 major complications of catheter-related bloodstream infections?
- endocarditis
- suppurative thrombophlebitis
- perivascular abscess
- emboli
What are the 2 ways catheter-related bloodstream infections are diagnosed?
- semi-quantitative catheter tip cultures
- Quantitative blood cultures vs. Time to Positivity
(central vs. peripheral withdraw)
What is the treatment for catheter related bloodstream infections?
How long do you treat if the line must be left in? if it is taken out?
- remove the line
- antibiotics directed against the most likely organism
Line in = 2 weeks
Line out = 5 days to 2 weeks
What is myocarditis?
What are the most likely infections?
Inflammation of the muscular layer of the heart.
(instead of damage causing inflammation, this is inflammation causing damage)
Most likely VIRAL (adenovirus and enterovirus, specifically echovirus and coxsackie B)
What viral infections are likely to cause myocarditis?
What bacteria infections?
What parasites?
Viral - adeno and enteroviruses (coxsackie B and echovirus)
Bacteria- Lyme borreliosis
Parasite - T. cruzi (chagas)
Who is most likely to get myocarditis?
Men > pregnant women > immunocompromised
How do you make a definitive diagnosis of myocarditis?
Myocardial biopsy.
Presumptive diagnosis is done with acute and convalescent titer to the virus.
How does myocarditis present?
. non-specific fever
2. arrhythmias and/or signs of CHF
What makes myocarditis have a worse prognosis?
- forced exercise
- pregnancy
- steroids or NSAIDS
- alcoholism
- nutritional deficiencies
What drugs should be avoided for myocarditis?
NSAIDs and corticosteroids
What is pericarditis?
What are the two types?
it is inflammation of the pericardium.
- infectious- caused by viruses
- non-infectious
What is prodrome?
A premonitional/ dread feeling with:
fever, muscle pain, and malaise
When is pericarditis pain the worst?
What do you hear when auscultating the heart?
Supine and with inspiration
You hear a pericardial friction rub
How is pericarditis diagnosed and treated?
Echo and EKG
Treated with NSAIDs, corticosteroids and colchicine
Why is it important to be able to tell the difference between myocarditis and pericarditis when making a treatment plan?
You treat pericarditis with NSAIDs and corticosteroids .
NSAIDs and corticosteroids give myocarditis a worse prognosis
How do bacterial or tuberculous infections reach the pericardium (3 ways)
What are the 3 major complications?
How is it diagnosed?
What is treatment?
Reach pericardium by: 1. hematogenous spread 2. directly implanted (surgery) 3. spread from adjacent tissue Complications: 1. tamponade 2. constrictive pericarditis 3. death Diagnosed: 1. pericardiocentesis 2. pericardial biopsy Treatment: 1. antibiotics 2. pericardial window 3. pericardectomy
