IE transcript
Hey this is Dr K from imedicalschool.
Today we are going to talk about infective endocarditis.
Just to highlight the important points anytime you see this light bulb in this presentation
it means the material is highly tested and in the words of one of my medical school professors
know that!
Lets start off as usual by asking what is infective endocarditis?
Well Infective endocarditis is a microbial infection of the heart endocardium.
The heart consists of three layers of tissue.
The outer most layer is the epicardium then the myocardium and finally the innermost layer
is the endocardium.
The endocardium tissue covers all structures within the heart including the valves and
the chordae tendinae.
Just as a refresher the valves are like parachutes that regulate the movement of blood through
the chambers of the heart while the chordate tendinae are the cords that hold the parachute
or valves open.
Now that we know what infective endocarditis is we need to understand what are the risk
factors for IE.
Risk factors for IE include poor dental hygiene , intravenous drug abuse , hemodialysis , long
term indeed long catheters , diabetes mellitus, and prosthetic valves.
If a patient has these risk factors and in the appropriate clinical setting you should
consider IE.
Endocarditis can be caused by many different organisms and we will focus on the most common
causes of IE.
Staphylococcus aureus is the most common cause of IE.
This is the reason if you have a gram positive bacteremia with cultures that are not clearing
or take a while to clear it is important to rule out infective endocarditis as this would
affect the patients duration of iv antibiotics.
Coagulase negative staphylococcus IE commonly occurs in the first few months after prosthetic
valve placement.
Specifically staph lugdunensis has been known to cause significant valvular dysfunction
frequently requiring valve replacement surgery.
Strep can also cause IE.
Strep mutants and sanguis have been shown to cause IE.
When strep bovis causes IE it is usually seen in the elderly and is associated with colonic
lesions so these patients need a colonoscopy in addition to treatment of their IE.
HÁČEK group of organisms has also been known to cause IE.
This group consists of harmophillus, actinobacillus, cardiobacterium hominiw, eikenella, and kingella.
Other organisms that can cause IE are enterococcus, fungi, and Coxiella burnetti.
IE carries with it a significant risk for morbidity and mortality especially if not
properly recognized and treated.
There are a few clinical signs and symptoms that you should be aware of.
These include fever, weight loss, fatigue, heart failure, night sweats, heart murmur,
splenomegaly, skin petechiae, conjunctival hemorrhages, septic shock, osler nodes, splinter
hemorrhages , janeway lesions.
Osler nodes are painful swollen violaceous nodules on the fleshy part of the fingers
and toes.
Splinter hemorrhages appear as streaks in the nail red that appear maroon and turn black.
They are due to emboli.
Janeway lesions are non tender nodules in the palms and soles.
Unfortunately IE can have significant complications.
One of these complications includes Paravalvular abscess due to IE can lead to heart block
and valvular dysfunction.
In addition with left sided IE there is a very real possibility of stroke.
In patients with stroke symptoms, persistent fevers, and a heart murmur IE should be considered.
Since we reviewed the common organisms that cause IE and the clinical indicators for IE
how do we diagnose IE.
Well like any disease we start off with our clinical suspicion but years of treating IE
have resulted in the modified Duke's.
The modified dukes criteria include major and minor criteria.
To make a diagnosis of IE you new 2 major criteria , one major and three Minor, or 5
minor criteria.
Lets review these criteria.
There are three major criteria.
The first is laboratory evidence of IE.
If two blood cultures grow organisms known to cause IE or If one blood culture is positive
for Coxiella burnetti that would meet the requirement for laboratory evidence o IE.
Second major criteria is evidence of endocardium involvement . If it is an uncomplicated case
with no prosthetic valve present proceed with a TTE.
In patients who have a complicated course consistent with IE, a prosthetic valve, or
high clinical suspicion proceed to TEE.
Finally the last major criteria is new valvular regurgitation murmur.
The minor criteria includes if the patient had a prediaposing heart condition, like a
untreated congenital heart defect or IVDA, fever, or Vascular phenomenon.
vascular phemoneon include septic pulmonary infarcts, mycotic aneurysms, conjunctival
hemorrhages, janeway lesions, And intracranial hemorrhage.
Mycotic aneurysms form due to full thickness infection and formation of a vascular aneurysm
of the vasculature.
Immunologic phenomenon leads to glomeruli euphoria, osler's nodes, Roth spots, and rheumatoid
factor.
Finally the last minor criteria is a single blood culture positive for an organism typical
for IE or multiple cultures taken within a short time period .
Lets talk about treatment.
All treatment for IE is based on culture susceptibilities.
Generally duration of therapy ranges from 2 to 6 weeks depending on the organism and
severity of IE.
For gram positive organisms we must know of the organism is susceptible to penicillins
then we can use nafcillin, methicillin, penicillin, or ampicillin plus aminoglygosides like gentamicin.
If MRSA then use vancomycin plus gentamicin.
The combination of a penicillin or vancomycin with an aminoglygosides creates a synergistic
effect improving clearance of the IE.
Anti coagulation has shown to increase Morbidity and mortality in IE as there is high risk
of bleeding and has not been shown to decrease embolus events.
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