Indications for Testing

  • Risk factor and appropriate clinical presentation

Criteria for Diagnosis

Laboratory Testing

  • CBC – frequently leukocytosis and left shift toward immature cell forms
  • Blood cultures – 3-5 sets from separate venipuncture sites; first and last set at least 1 hour apart
    • Perform prior to antibiotic administration
  • C- reactive Protein (CRP)
  • In blood culture-negative disease, consider

Imaging Studies

  • Transthoracic echocardiogram (TTE) or transesophageal echocardiogram (TEE) is the gold standard for visualization of vegetations, but negative study does not rule out endocarditis
    • TTE
      • Recommended first test
      • 60-65% sensitive – sensitivity dependent on vegetation size; if >10 mm, test is 100% sensitive
    • TEE
      •  Use in patients with high clinical suspicion and negative TTE
      • 85-95% sensitive; negative study has negative predictive value of 90%

Differential Diagnosis

Clinical Background

Endocarditis is an infection of the endocardium usually associated with infection of the cardiac valve leaflets.


  • Incidence – 3-4/100,000; incidence increases with age (up to 20/100,000)
  • Age – mean 30-60 years, depending on population
  • Sex – M>F, 2:1


  • Intravenous drug use (IVDU) – Staphylococcus spp, Streptococcus aginosus group
  • Rheumatic heart disease – Streptococcus aginosus group
  • Elderly with gastrointestinal neoplasms – Streptococcus bovis
  • Prosthetic valves – Staphylococcus spp
  • Health care associated infection – Enterococcus spp, Staphylococcus spp
  • Culture negative disease – Coxiella, Bartonella, HACEK organisms (Haemophilus spp [esp. H. parainfluenzae], Aggregatibacter spp [A. aphrophilus, A. actinomycetemcomitans], Brucella, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae)
  • Fungi – yeasts, molds
    • Usually 2-3 months after LVAD implantation (not initally)

Risk Factors

  • IVDU – 60-fold increase
  • Structural heart disease – rheumatic carditis, valvular stenosis, congenital heart disease
  • Hemodialysis – 50- to 180-fold increase (Thanavaro, 2014)
  • Cardiovascular prostheses, intravascular devices
  • Diabetes mellitus
  • Poor oral hygiene
  • Human immunodeficiency virus (HIV)
  • Prior episode of infective endocarditis


  • Classification – native valve endocarditis, prosthetic valve endocarditis, and nonvalvular device endocarditis (eg, pacemaker, LVAD); right- versus left-sided valves
  • Turbulent blood flow produced by abnormalities on valvular leaflets
    • In patients with rheumatic heart disease, mitral valve most commonly involved; aortic valve second most commonly involved
    • Right-sided endocarditis more common with IVDU
  • Transient bacteremia occurs
    • Bacteria naturally adhere to abnormal tissue and form vegetations on the valve
    • Bacteria proliferate within the vegetations  

Clinical Presentation

  • Constitutional – fever, anorexia, night sweats, weight loss
    • Patients with cardiac-device related IE may only have these symptoms normally
  • Cardiovascular – new onset murmur, congestive heart failure, dysfunctional prosthetic valve
  • Renal – glomerulonephritis
  • Embolic phenomena
  • Osler nodes – painful blue or purple nodules on the fingers, toes, palms, and soles
  • Roth spots – retinal hemorrhages with central white spots
  • Janeway lesions – nontender nodules on hands and feet
  • Splinter hemorrhages – subungual linear hemorrhages on the long axis of the distal third of nail
  • Complications
    • Valvular collapse with heart failure
    • Periannular extension of the infection into the adjacent myocardium
    • Rupture of the myocardium from extension
    • Embolization – highest with left-sided lesions
      • Stroke
    • Mycotic aneurysm
    • Splenic/hepatic abscesses
    • Intracardiac abscesses


  • Rapid initiation of antibiotics
  • May require valvular replacement


  • Prophylaxis for high-risk patients before dental procedures (AHA, 2007)
    • Manipulation of gingival tissue periapical region
    • Perforated oral mucosa
    • Invasive procedure of the respiratory tract needing biopsy of respiratory mucosa or invasive procedure involving infected skin
  • High-risk patients include the following
    • Previous infective endocarditis
    • Prosthetic valve
    • Unrepaired or incompletely repaired cyanotic congenital heart disease or repaired CHD within 6 months of previous repair
    • Valve disease in cardiac transplant patients
  • No prophylaxis needed before gastrointestinal or genitourinary procedures


Clinical Background


  • Incidence – lower than in adult population

Risk Factors


  • Streptococcus aginosus group – rheumatic heart disease
  • Staphylococcus epidermidisnosocomial infection

Clinical Presentation

  • Constitutional – lethargy, fever, malaise
  • Cardiovascular – new onset murmur
  • Adult manifestations such as Osler nodes and Janeway lesions uncommon
  • Complications


  • Refer to Diagnosis tab

Indications for Laboratory Testing

  • Tests generally appear in the order most useful for common clinical situations
  • Click on number for test-specific information in the ARUP Laboratory Test Directory
Test Name and Number Recommended Use Limitations Follow Up
CBC with Platelet Count and Automated Differential 0040003
Method: Automated Cell Count/Differential

Aid in diagnosis of bacterial process

Blood Culture 0060102
Method: Continuous Monitoring Blood Culture/Identification

Aid in diagnosis of bacteremia

Testing is limited to the University of Utah Health Sciences Center only

C-Reactive Protein 0050180
Method: Quantitative Immunoturbidimetry

Preferred test to detect inflammatory processes

Additional Tests Available
Click the plus sign to expand the table of additional tests.
Test Name and NumberComments
Sedimentation Rate, Westergren (ESR) 0040325
Method: Visual Identification

Marker of inflammation

Organism Identification by 16S rDNA Sequencing 0060720
Method: 16S rDNA Sequencing
Coxiella burnetii (Q-Fever) Antibodies, IgG & IgM by IFA with Reflex to Titer (INACTIVE as of 01/04/16: Refer to November 2015 Hot Line for Replacement Test: 2012634, ACTIVE 01/04/16) 2003102
Method: Immunofluorescence Assay
(Indirect Fluorescent Antibody)
Bartonella Species by PCR 0093057
Method: Qualitative Polymerase Chain Reaction
Rheumatoid Arthritis Panel 2003277
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Immunoturbidimetry
Anti-Nuclear Antibodies (ANA), IgG by ELISA with Reflex to ANA, IgG by IFA 0050080
Method: Qualitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody