Written by Clay Smith
Infective Endocarditis as Spoon Feed
JAMA recently covered infective endocarditis (IE). I thought JF readers would be well served by a Spoon Feed version. This thing is 12 pages long with 117 references. Let's make it bite-sized, shall we?
- What is it? IE is infection of the cardiac endothelium and may be acute or subacute.
- It presents with fever or other signs of sepsis. Classically, the patient will have a new murmur, but you only get this lucky 48% of the time. Subacute cases may only have fatigue, dyspnea, or weight loss and may lack fever.
- Don't expect to find Osler nodes or Janeway lesions. They only show up in 5%. To impress your friends, remember, "Jane, no-pain," as Janeway lesions don't hurt; Osler nodes do. Septic emboli to the lungs or spleen may be found on CT or other imaging.
- IE is becoming more common, with increased IV drug abuse (IVDA) and implantable cardiac devices. But 70% is still community acquired.
Assessment and Diagnosis
- Use the Duke Criteria. No mortal can remember them, so pull up MDCalc. Seriously, you need to go on MDCalc right now and play around with this to see how major and minor criteria can be put together to form a presumptive diagnosis.
- Get 3 sets of blood cultures. S. aureus is number one, viridans strep and enterococci are next; coagulase negative staphylococci especially if prosthetic valves or devices; gram negatives, HACEK, and fungal round out the list. If you know what HACEK stands for, you need to get a life.
- Echocardiography is also important. TTE is 70% sensitive; TEE 95% sensitive.
- For suspected S. aureus, nafcillin is first choice for MSSA; vancomycin for MRSA. Cefazolin could be substituted for naficillin for MSSA in non-anaphylactic penicillin-allergic patients. Daptomycin is an alternative to vancomycin.
- For S. aureus infected prosthetic valves, add an aminoglycoside + rifampin to the nafcillin or vancomycin.
- For enterococcal endocarditis, a newer ampicillin/ceftriaxone regimen has worked well, rather than ampicillin/gentamicin.
- Some need surgery for valvular dysfunction, abscess, recurrent emboli with vegetations, multi-drug resistance, or persistent bacteremia.
- Authors state that in, "left-sided, prosthetic valve, device, or complicated endocarditis, consultation by a cardiac surgeon should be sought."
- Prevention - No one knows if antibiotic prophylaxis really works. The UK thinks not. *The AHA still says yes (see box at the end). But it is a good idea at this point, "for patients who have prosthetic valves or other conditions that place them at high risk of adverse outcomes."
- TAVR - Here is a bit of trivia. For transcatheter aortic valve replacement (TAVR), Enterococcus, rather than S. aureus is the most common organism. Who cares? Empiric antibiotic coverage is different (see above) for enterococci.
- Implantable device infection - You have to use TEE and scintigraphy to get the diagnosis in these patients.
It's bad - 6-month mortality is still 30%; in-hospital mortality is 20%.
- Your job in the ED is to think about the diagnosis of IE, get the 3 blood cultures, and put this on the admitting team's radar so they can get an echo.
- You also need to know and start the right antibiotics.
- Done and done.
- Now, go back and play around with the Duke criteria until you know what counts as "possible" or "definite" IE. Don't procrastinate. You know you'll forget later.
There are many outstanding free reviews on infective endocarditis. Here are some of the best.
*AHA Indications for Antibiotic Prophylaxis