Name some risk factors associated with infectious endocarditis.
Abnormal valves, prothesis, previous infection, valvular prolapse, abnormal flow, drug abuse. Previous surgery or trauma
Why is intravenous drug use associated with increased risk of infectious endocarditis?
What valve is affected, and by what organism?
IV injection allows for blood inoculation with bacteria, and it is this bacteremia which facilitates IE.
Usually the tricuspid valve, by Staph Aureus.
Describe IE's typical clinical presentation.
Most patients present with fever and a heart murmur. Less common are chills, sweats, and wasting. Various noncardiac manifestations may be present.
Describe IE's typical lab presentation.
Often presents with microcytic anemia and elevated ARPs/ESR. Less frequently with leukocytosis or hematuria. Staph may be present in urine.
What are some noncardiac manifestations of IE?
Embolic events, splenomegaly, clubbing, petechiae, and various peripheral manifestations.
Recall four peripheral (noncardiac) manifestations of IE. What are they caused by?
Splinter hemorrhages in the proximal fingertips (septic emboli)
Osler nodes (painful!) in the digital pads (immune complex)
Janeway lesions (non painful) in the palms & soles. (septic emboli)
Roth spots (hemorrhaging around a white lesion) in the retinas (immunologic)
What organisms are usually responsible for endocarditis of a native valve?
A newly implanted prosthetic valve?
An old prosthetic valve?
Staph Aureus & Strep are the most common, followed by Coag- staph and enterococci.
Early prosthetic: Coag- staph followed by staph aureus, then strep/enterococci.
Same as for native valve.
What should your clinical suspicion be when an IE blood culture reveals staph bovis?
Bovis is found in the colon >> suspect underlying colorectal carcinoma.
What is the usual source of Candida or Pseudomonas based endocarditis?
What can cause culture-negative endocarditis?
Non-infectious thrombotic endocarditis, prior Abx treatment, HACEK organisms, Abiotrophia, Coxiella, Bartonella, Brucella, Tropheryma.
What bugs make up the HACEK group?
What role does echocardiography have in infectious endocarditis?
Distinguish between TEE and TTE.
Good for imaging bacterial vegetations and disrupted flow. Very high specificity (98%).
Transesophageal Echocardiography (TEE) has higher sensitivity than transthoracic (TTE), and is better for evaluating prosthetic valves and other complications.
What do you need to diagnose an infectious endocarditis?
Duke criteria: 2 major, or 1 major + 3 minor, or 5 minor (rarely seen)
What are the major Duke criteria?
Multiple positive cultures or serology (multiple to rule out contamination of individual culture)
Evidence of endocardial involvement (usually echo)
What are the minor duke criteria?
Predisposition to endocarditis (abnormal valve, IVDU)
"Vascular phenomena" (wat)
"Immunologic phenomena" (Osler nodes, Roth spots...)
"Microbiological evidence" (positive blood culture but does not meet a major criterion, or serological evidence of active infection with organism consistent with IE)
Describe the antibiotic treatment regimen for strep-based IE.
A beta-lactam (penicillin/ceftriaxone), co-administered with vanco and/or gentamicin if resistant.
Describe the antibiotic treatment regimen of staph-based IE.
A beta-lactam (naf/oxacillin), vancomycin and/or gentamicin. Add rifampin if the infected valve is prosthetic.
Describe the antibiotic treatment regimen of HACEK IE.
Ceftriaxone, Ampicillin+sulbactam, Ciprofloxacin. A cocktail directed at mostly G- bugs.
When is surgical intervention indicated for IE?
In CHF, valve perforation, with heart block or prosthesis, multiple emboli, or very tough bacteria.
Name the three forms of complications resulting from IE.
Cardiac (CHF, heart block, heart failure, abscess/fistula)
Neurologic (embolic stroke, mycotic aneurysm, meningitis)
Systemic (abscess, emboli)
Which microorganism tends to cause mycotic aneurysms?
Where are they usually found?
At bifurcations of the MCA.
When is antibiotic prophylaxis for IE indicated?
What nonpharmacological prophylaxis can be employed?
In high risk conditions such as prosthetic valves, patients with prior IE, heart transplant or congenital defects. Also prior to oral surgery.
Maintenance of good oral health/hygiene.
Describe the basic pre-dental prophylactic IE dose.
Amoxicillin & Clindamycin, given an hour before surgery to establish high serum levels.
Ampicillin & ceftriaxone available IV for patients that can't orally dose.