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