Indications for Testing

• Risk factor and appropriate clinical presentation

Criteria for Diagnosis

• To establish final diagnosis, use the Duke Criteria for Infective Endocarditis

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
• ESR/CRP – frequently elevated but not diagnostic
• In blood culture-negative disease, consider
  • Coxiella antibodies
  • Bartonella
  • Antinuclear antibodies (ANA)/rheumatoid arthritis (RA)
  • 16s rDNA by PCR
  • More unusual causes – Tropheryma whipplei, fungi (yeasts, molds)

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 – 60-65% sensitive
  • TEE – 85-95% sensitive; negative study has negative predictive value of 90%

Differential Diagnosis

• Infectious
  • Treponema pallidum
  • Mycobacterium tuberculosis
  • HIV
  • Abscess in other anatomic location
• Pulmonary embolus
• Myocardial infarction
• Libman-Sacks endocarditis

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

Epidemiology

• 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

Organisms

• Intravenous drug use (IVDU) – Staphylococcus spp
• Rheumatic heart disease – Streptococcus viridans
• Elderly with gastrointestinal neoplasms – Streptococcus bovis
• Prosthetic valves – Staphylococcus spp
• Nosocomial infection – Enterococcus spp, Staphylococcus spp
• Culture negative disease – Coxiella, Bartonella, HACEK organisms (Haemophilus spp [esp. H. parainfluenzae], Aggregatibacter spp [A. aphrophilus, A. actinomycetemcomitans], Cardiobacterium hominis, Eikenella corrodens, Kingella kingae)
• Fungi – yeasts, molds

Risk Factors

• IVDU – sixtyfold increase
• Structural heart disease – rheumatic carditis, valvular stenosis, congenital heart disease
• Hemodialysis
• Cardiovascular prostheses, intravascular devices
• Diabetes mellitus
• Poor oral hygiene
• Human immunodeficiency virus (HIV)
• Prior episode of infective endocarditis

Pathophysiology

• Classification – native valve endocarditis and prosthetic valve endocarditis
• 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
• 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

Treatment

• Rapid initiation of antibiotics
• May require valvular replacement

Prevention

• 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

Epidemiology

• Incidence – lower than in adult population

Risk Factors

• Congenital heart disease
• Rarely – malignancy, osteomyelitis

Organisms

• Viridans streptococcus – rheumatic heart disease
• Staphylococcus epidermidis – nosocomial infection

Clinical Presentation

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

Diagnosis

• Refer to Diagnosis tab

Tests generally appear in the order most useful for common clinical situations

Guidelines

• Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Bolger AF, Levison ME, Ferrieri P, Gerber MA, Tani LY, Gewitz MH, Tong DC, Steckelberg JM, Baltimore RS, Shulman ST, Burns JC, Falace DA, Newburger JW, Pallasch TJ, Takahashi M, Taubert KA. Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious Diseases Society of America. Circulation. 2005; 111 (23) :e394-e434.PubMed
• Delahaye F, Harbaoui B, Cart-Regal V, de Gevigney G. Recommendations on prophylaxis for infective endocarditis: dramatic changes over the past seven years. Arch Cardiovasc Dis. 2009; 102 (3) :233-245.PubMed
• Durack DT, Lukes AS, Bright DK. New criteria for diagnosis of infective endocarditis: utilization of specific echocardiographic findings. Duke Endocarditis Service. Am J Med. 1994; 96 (3) :200-209.PubMed
• Westling K, Aufwerber E, Ekdahl C, Friman G, Gardlund B, Julander I, Olaison L, Olesund C, Rundstrom H, Snygg-Martin U, Thalme A, Werner M, Hogevik H. Swedish guidelines for diagnosis and treatment of infective endocarditis. Scand J Infect Dis. 2007; 39 (11-12) :929-946.PubMed
• Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL, Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns JC, Ferrieri P, Gardner T, Goff D, Durack DT. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. J Am Dent Assoc. 2008; 139 Suppl :3S-24S.PubMed
• Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL, Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns JC, Ferrieri P, Gardner T, Goff D, Durack DT. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. 2007; 116 (15) :1736-1754.PubMed

General

• Calabrese F, Carturan E, Thiene G. Cardiac infections: focus on molecular diagnosis. Cardiovasc Pathol. 2010; 19 (3) :171-182.PubMed
• Dandache P, Aronow WS, Sakoulas G. Clinical update on the diagnosis and treatment of bacterial endocarditis. Compr Ther. 2007; 33 (4) :192-207.PubMed
• Duval X, Leport C. Prophylaxis of infective endocarditis: current tendencies, continuing controversies. Lancet Infect Dis. 2008; 8 (4) :225-232.PubMed
• Firman, G. Duke Criteria for Infective Endocarditis. Medical Criteria. [Last Updated: 15 Mar 2009; Accessed: 1 Jul 2009] 
• Lester SJ, Wilansky S. Endocarditis and associated complications. Crit Care Med. 2007; 35 (8 Suppl) :S384-S391.PubMed
• McDonald JR. Acute infective endocarditis. Infect Dis Clin North Am. 2009; 23 (3) :643-664.PubMed
• Naber CK, Erbel R. Infective endocarditis with negative blood cultures. Int J Antimicrob Agents. 2007; 30 Suppl 1 :S32-S36.PubMed
• Silverman ME, Upshaw CB Jr. Extracardiac manifestations of infective endocarditis and their historical descriptions. Am J Cardiol. 2007; 100 (12) :1802-1807.PubMed

Bartonella Species
Brucella Species
Coxiella burnetii
Haemophilus influenzae
Health Care-Associated Infections
Staphylococcal Disease
Streptococcal Disease, Group A
Streptococcal Disease, Group B
Trichinella spiralis