Background

Consider in patients with known risk factors and unexplained fever

Mitral valve most commonly affected overall; tricuspid valve most common in IVDA

Noninfectious vegetations can arise in patients with malignancy/SLE/Hypercoagulable state ("Marantic" endocarditis)

S. aureus is single most common cause

Strep viridans is the most common cause of native valve endocarditis, excluding risk factors below

Blood cultures are falsely negative ~5% (think HACEK organisms)

Only 20% have an increase in a known murmur and only 48% have a new murmur[1]

Prophylaxis

No longer recommended at all in the United Kingdom [2]

In United States, only recommended for invasive dental procedures (not routine cleanings) and invasive respiratory procedures in setting of: [3][4]

Risk Factors

IVDA Tricuspid valve most commonly affected

Prosthetic heart valve Coagulase negative staphylcocci are substantial etiologies in this patient population [5]

Structural heart disease Rheumatic heart disease Mitral valve prolapse Bicuspid aortic valve

Hemodialysis

HIV infection

Fungal endocarditis risk factors, with Candida most common Prolonged antibiotics TPN through central line



Clinical Features

Splinter hemorrhage

Fever Present in 80% of cases

Heart murmur Preexisting murmur found in 85% of cases; new murmur found in 48%

CHF Acute or progressive (70%)

Embolic manifestations Major arterial emboli Septic pulmonary infarction Janeway lesions

CNS 65% of emboli involve the CNS [6] Central retinal artery occlusion

Pulmonary==== Pneumonia Empyema Pulmonary emboli

Cardiac MI Myocarditis

Abdominal Bowel, renal, splenic infarcts

Derm Osler nodes - tender red/purple nodules on distal finger and toes Splinter hemorrhages - nail bed hemorrhages not extending the length of the nail

(Janeway lesions - painless macules on palms and soles due to microabscesses

Differential Diagnosis

Infectious

Non-infectious

Evaluation

Work-Up

Blood culture (from 3 separate sites) [7]

CBC Staphylococcal endocarditis: Leukocytosis +/- thrombocytopenia Subacute endocarditis: WBC may be normal or elevated

Urinalysis Hematuria

ESR Elevated in >90% of cases

ECG Ischemia, heart block

CXR Pulmonary emboli, CHF

Ultrasound Obtain as soon as possible TEE may be required for: Prosthetic valves Difficulty obtaining clear TTE images (obesity, COPD) High clinical probability of endocarditis



Evaluation Notes

Inpatient diagnosis is based on the Duke's Criteria although many of the criteria are not filled in the ED Heightened clinical suspicion is necessary even if diagnosis does not meet the official criteria. [8]



[9] Modified Duke Criteria

2 major criteria OR

1 major and 3 minor criteria OR

5 minor criteria

Major Criteria

Positive blood culture with typical IE microorganism, defined as one of the following: Typical microorganism consistent with IE from 2 separate blood cultures, as noted below: Viridans-group streptococci, or Streptococcus bovis including nutritional variant strains, or HACEK group, or Staphylococcus aureus , or Community-acquired Enterococci , in the absence of a primary focus Microorganisms consistent with IE from persistently positive blood cultures defined as: Two positive cultures of blood samples drawn >12 hours apart, or All of 3 or a majority of 4 separate cultures of blood (with first and last sample drawn 1 hour apart) Coxiella burnetii detected by one positive blood culture or IgG Staphylococus lugdunensis should raise concerns for endocarditis with a single positive blood culture [10]

Evidence of endocardial involvement with positive echocardiogram defined as: Valvular mass or supporting structures or Abscess, or New disruption of a prosthetic valve or new valvular regurgitation



Minor Criteria

Predisposing factor: known cardiac lesion, recreational drug injection

Fever >38°C

Evidence of emboli: arterial emboli,pulmonary infarcts, Janeway lesions, conjunctival hemorrhage

Glomerulonephritis, Osler's nodes

Positive blood culture (that does not meet a major criterion) or serologic evidence of infection

Management

Initial management should focus on early blood cultures and antibiotics

Often due to valve failure, rupture, or a new defect.

Often due to mitral or aortic valve rupture causing severe regurgitation

Focus on after-load reduction

Often requires intubation with failure either due to CHF or Pneumonia

Multi-lobar pneumonia suggests a tricuspid or pulmonary valve lesion with emboli to lungs

Start after 3 sets of blood cultures are obtained (if possible)[7]

Therapy should be based on:

Whether the patient has received prior antibiotic therapy

Prosthetic valves

Local antibiotic resistance patterns or knowledge of prior endocarditis cultures

Prior hospitalizations and risk of MRSA

Native Valves

Options:[11]

Ampicillin/Sulbactam 12g/day IV in 4 doses + Gentamicin 3mg/kg/day IV in 2 or 3 doses

Amoxicillin/Clavulanate 12g/day in 4 dose + Gentamicin 3mg/kg/day IV in 2 or 3 doses

Oxacillin or Nafcillin 2g IV six times daily + Gentamicin 1mg/kg IV three times daily AND Ampicillin 2g IV six times daily

Daptomycin 6mg/kg IV once daily

Suspected MRSA:[11]

Vancomycin 30mg/kg/day IV in 2 doses PLUS

Gentamicin 3mg/kg/day IV in 2 or 3 doses PLUS

Ciprofloxacin 1000mg/day PO in 2 doses or 800 mg/day IV in 2 doses

Prosthetic Valves (Early)

Early prosthetic valve endocarditis defined as < 12 months post surgery[11]

Vancomycin 30mg/kg/day IV in 2 doses PLUS

Gentamicin 3mg/kg/day IV in 2 or 3 doses PLUS

Rifampin 1200 mg/day PO in 2 doses

IV Drug User without Prosthetic Valve

Vancomycin 15-20 mg/kg IV BID daily

Daptomycin 6mg/kg IV once daily

Prosthetic Valve (Late)

Late prosthetic valve endocarditis defined as ≥ 12 months post surgery[11]

Same as native valve endocarditis empiric therapy

All antibiotics options are given as a single dose 1 hour prior to the dental procedure

Options:[12]

Amoxicillin 2g or 50mg/kg

Ampicillin 2g (50mg/kg) IV or IM

Cefazolin or Ceftriaxone 1g (50mg/kg) IM or IV

Clindamycin 600mg (20mg/kg) PO or IV

Azithromycin or Clarithromycin 500mg (15mg/kg) PO

Disposition

Admit all suspected cases and consult Cardiothoracic surgery for endocarditis complicated by:[1]

New Heart failure suspected due to severe regurgitation

Cardiogenic Shock

Echocardiography demonstrating a new fistula

Surgery indicated for [13] : Acute heart failure Periannular extension Recurrent emboli Large mobile vegetations Persistent bacteremia Fungal endocarditis (penetration of antifungals into vegetation walls poor) [14] IV amphotericin B Lifelong PO antifungal

:





Miscellaneous

No therapeutic anticoagulation necessary Anticoagulation carries higher risk of bleeding without delivering mortality benefit or reducing embolic complication [15]

Septic pulmonary embolism Most common culture growths are MSSA, MRSA, and candida [16] Furthermore, therapeutic anticoagulation not indicated for septic pulmonary embolism



Complications

Cardiac

Heart Failure Most common cause of death due to IE

Perivalvular Abscess

Embolic

CVA

Blindness

Painful, ischemic extremities

Unusual pain syndromes (due to splenic or renal infarction)

Hypoxia

MI

Neurologic

Renal

Musculoskeletal

References