Endocarditis

Background

• Consider in pts w/ unexplained fever and known risk factors
• Mitral valve most commonly affected overall; tricuspid valve most common in IVDA
• Noninfectious vegetations can arise in pts w/ malignancy and SLE
• S. aureus is single most common cause
• 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

Prophylaxis

Only for Invasive dental procedures not routine cleanings and:

1. Prosthetic valves
2. Prior endocarditis
3. unrepaired congenital cyanotic heart disease

Risk Factors

1. IVDA
   1. Tricuspid valve most commonly affected
2. Prosthetic heart valve
3. Structural heart disease
   1. Rheumatic heart disease
   2. Mitral valve prolapse
   3. Bicuspid aortic valve
4. Hemodialysis
5. HIV infection

Clinical Features

• Fever
  • Present in almost all cases
• Heart murmur
  • Preexisting murmur found in 85% of cases; new murmur only found in 5%
• CHF
  • Acute or progressive (70%)
• Embolization manifestations
  • CNS
    • MCA stroke
    • Central retinal artery occlusion
  • Pulmonary
    • PNA
    • Empyema
  • Cardiac
    • MI
    • Myocarditis
  • Bowel, renal, splenic infarcts
  • Derm
    • Osler nodes, splinter hemorrhages, Janeway lesions

Diagnosis

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.

Modified Duke Criteria

• 2 major criteria OR
• 1 major and 3 minor criteria OR
• 5 minor criteria

Major Criteria

1. 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 byone positive blood culture or IgG
2. 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

1. Predisposing factor: known cardiac lesion, recreational drug injection
2. Fever >38°C
3. Evidence of emboli: arterial emboli,pulmonary infarcts, Janeway lesions, conjunctival hemorrhage
4. Glomerulonephritis, Osler's nodes
5. Positive blood culture (that doesn't meet a major criterion) or serologic evidence of infection

Work-Up

1. Blood culture (from 3 separate sites)
2. CBC
   1. Staphylococcal endocarditis: Leukocytosis +/- thrombocytopenia
   2. Subacute endocarditis: WBC may be normal or elevated
3. UA
   1. Hematuria
4. ESR
   1. Elevated in >90% of cases
5. ECG
   1. Ischemia, heart block
6. CXR
   1. Pulmonary emboli, CHF
7. Ultrasound
   1. Obtain as soon as possible
   2. TEE may be required for:
      1. Prosthetic valves
      2. Difficulty obtaining clear TTE images (obesity, COPD)
      3. High clinical probability of endocarditis

Management

Initial stabilization should focus on Airway, Breathing and Circulation optimization with early antibiotic and blood cultures

CHF/Cardiogenic Shock

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

Pulmonary edema

• Often due to mitral or aortic valve rupture causing severe regurgitation
• Focus on after-load reduction

Respiratory Failure (emboli)

• 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

Antibiotics

• Start after 3 sets of blood cultures are obtained (if possible)

Suspected MRSA

• Vancomycin if MRSA is suspected

Uncomplicated Patient History

• Gentamicin 1-3mg/kg IV + (Ceftriaxone or nafcillin or oxacillin) if there is an uncomplicated history

IVDA, congenital heart disease, or on Oral antibiotic

1. Nafcillin + gentamicin 1-3mg/kg IV + vancomycin

Prosthetic heart valve

Rifampin 300mg PO + gentamicin 1-3mg/kg IV + vancomycin

• Rifampin helps penetrate the vegetation on the artificial valve

Disposition

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

1. New Heart failure suspected due to severe regurgitation
2. Cardiogenic Shock
3. Echocardiography demonstrating a new fistula

Complications

1. Cardiac
   1. Heart Failure
      1. Most common cause of death due to IE
   2. Perivalvular Abscess
2. Embolic
   1. CVA
   2. Blindness
   3. Painful, ischemic extremities
   4. Unusual pain sydromes (due to splenic or renal infarction)
   5. Hypoxia
   6. Paralysis
   7. MI
3. Neurologic
   1. Embolic stroke
   2. Acute encephalopathy
   3. Meningoencephalitis
   4. Purulent or aseptic meningitis
   5. Cerebral hemorrhage
   6. Seizure
4. Renal
   1. Infarction
   2. Glomerulonephritis
5. Musculoskeletal
   1. Vertebral osteomyelitis

External Links

• MDCalc - Duke Criteria