EM@3AM: Endocarditis

Author: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio, TX) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

Welcome to EM@3AM, an emDocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.


A 26-year-old female presents with fevers and chills. She is febrile and tachycardic, with normal BP. You think you hear a murmur on exam, and on further questioning, she says she regularly uses IV drugs.

What should you consider, and what are your next steps?


Answer: Endocarditis

Definition: Infection of endocardium, primarily due to infective agent attaching to damaged cardiac structures (usually cardiac valves).

Risk factors: IVDA, structural heart disease, prosthetic heart valve, age >60, poor dentition or dental infection, hemodialysis, HIV, immunosuppression.

Most common pathogens: S. aureus (#1), Strep. viridans, S. gallolyticus (formerly S. bovis), HACEK organisms, or community-acquired enterococci.

Features:  Fever in up to 80% of patients, murmur (preexisting in 85% of patients, though new murmur may occur in up to 50%), heart failure (presents acutely or in worsening stages (70%)).

– Carefully evaluate patient hemodynamics, dentition, evidence of focal neurologic deficit, skin, evidence of heart failure, and presence of murmur.

– Embolic features include CNS emboli (65%) which may hemorrhage, pulmonary (pneumonia, empyema), cardiac (MI or myocarditis), GI (bowel, renal, or splenic infarcts), dermatologic (Osler nodes, Splinter hemorrhages, Janeway lesions – these only occur in 10% of patients).

Diagnosis: Duke Criteria

– Blood culture from three sites, echo (preferably TEE), clinical observation => antibiotics post cultures; admit.  If the patient is not in shock, effort should be made to obtaining cultures before antibiotics.

– Other suggested studies include CBC, renal function, liver function, ESR (elevated in 90%), CXR (pulmonary emboli, CHF), ECG (evaluate for ischemia and heart block), lactate, urinalysis (hematuria). Bedside transthoracic US may detect vegetations, but transesophageal US is the gold standard study.

Treatment:

– Empiric therapy for uncomplicated history (parenteral) = ampicillin/sulbactam (3g) or vancomycin (15-20mg/kg) + gentamicin (1-3mg/kg) or tobramycin (1mg/kg).

– Empiric therapy for IVDA, MRSA, congenital heart disease, or taking PO antibiotics (parenteral) = gentamicin (1-3mg/kg) + vancomycin (15-20mg/kg).

– Empiric therapy prosthetic valve = vancomycin (15-20mg/kg IV) + gentamicin (1-3mg/kg IV) + rifampin (600mg PO).

– Daptomycin 6 mg/kg IV is an option as well.

– Surgery: acute heart failure, large mobile vegetations, persistent bacteremia, periannular extension, recurrent emboli, fungal endocarditis.

 

References:

Hoen, B. et al. Infective Endocarditis. NEJM. 2013;368(15):1425-1433

Mylonakis. E, Calderwood S. Infective endocardidits in adults. NEJM. 2001;345(18):138-1330

Li, JS et al. Proposed Modifications to the Duke Criteria for the Diagnosis of Infective Endocarditis. Clinical Infectious Diseases. 2000;30(4):633.

AHA Guidelines on Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications

Best Case Ever 32 Carr’s Cases – Endocarditis and Blood Culture Interpretation

One thought on “EM@3AM: Endocarditis”

  1. Thanks for the great post, it was an enjoyable read!

    Since we are often treating endocarditis empirically due to clinical instability in the ED and do not have cultures to guide us I have always found it useful to split patients into 2 categories much the same way the IDSA guidelines do: native valve vs prosthetic valve. To provide coverage for gram-negative aerobic rods in addition to Staph, Strep and Enterococcus the IDSA currently recommends cefepime + vancomycin for native valve endocarditis with acute (days) presentation. Aminoglycosides are omitted from these regimens as no benefit was found with their addition in clinical response, overall cure, or mortality for Staphylococcal endocarditis; though increase rates of nephrotoxicity were present.

    The IDSA recommendation for prosthetic valve endocarditis is cefepime + vancomycin + gentamicin + rifampin. Cefepime is added to the regimen to provide gram negative rod coverage, gentamicin for synergistic activity against Staph, Strep and Enterococcus, and rifampin to diminish Staphylococcal biofilms. Gentamicin is the preferred empiric aminoglycoside as some Enteroccous spp. possess high level resistance mechanisms to tobramycin and amikacin. Rifampin has primarily been studied at a dose of 900mg/day divided in 3 separate does (ie 300mg q8h) in endocarditis, a dosing scheme unique to this disease state.

    All of that said I would propose the following regimens for empiric coverage of endocarditis:

    Native valve: cefepime 2g + vancomycin 25mg/kg

    Prosthetic valve: cefepime 2g + vancomycin 25mg/kg + gentamicin 1mg/kg + rifampin 300mg

Leave a Reply

Your email address will not be published. Required fields are marked *