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)

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

1. Modified Duke Criteria
   1. 2 major criteria OR
   2. 1 major and 3 minor criteria OR
   3. 5 minor criteria
2. Major Criteria
   1. Positive blood culture for typical IE organisms
      1. S. aureus, S. viridans, S. bovis, Enterococci, HACEK
   2. Evidence of endocardial involvement
      1. TEE+ or new valvular regurgitation
3. Minor Criteria
   1. Predisposition: predisposing heart condition or IVDA
   2. Fever: 38.0 C (100.4 F)
   3. Vascular phenomena
      1. Arterial emboli, pulmonary infarcts, mycotic aneurysm, ICH, conjunctival hemorrhage, Janeway lesions
   4. Immunologic phenomena - glomerulonephritis, Osler's nodes, Roth spots, rheumatoid factor
   5. Microbiologic evidence - positive blood culture but not meeting major criterion as noted previously

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

1. Initial stabilization
   1. CHF/cardiogenic shock (due to valvular defects)
   2. Pulmonary edema (left-sided valve rupture)
      1. Manage w/ afterload reduction
   3. Pulmonary failure (emboli)
   4. Acidosis (sepsis)
2. Antibiotics
   1. Start after blood cultures are obtained (if possible)
   2. Uncomplicated history
      1. Gentamicin 1-3mg/kg IV + (ceftriaxone or nafcillin or oxacillin or vancomycin)
   3. IVDA, congenital heart disease, already on oral antibiotic
      1. Nafcillin + gentamicin 1-3mg/kg IV + vancomycin
   4. Prosthetic heart valve
      1. Rifampin 300mg PO + gentamicin 1-3mg/kg IV + vancomycin

Disposition

• Admit all suspected cases

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

Source

• UpToDate
• Harwood-Nuss
• Tintinalli