Endocarditis, Infective

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Basics

Infective endocarditis is a noncontagious infection of the heart, including valves (native or prosthetic), the endocardium and septal defects. Infective endocarditis occurs worldwide and is generally fatal if left untreated.

Description

  • An infection of the valvular (primarily) and/or mural (rarely) endocardium
  • System(s) affected: cardiovascular, endocrine/metabolic, hematologic/lymphatic, immunologic, pulmonary, renal/urologic, skin/exocrine, neurologic
  • Synonym(s): bacterial endocarditis; subacute bacterial endocarditis (SBE); acute bacterial endocarditis (ABE)

Epidemiology

More common in males (3:1). 50% of cases occur in individuals over the age of 50.

Incidence
  • Incidence rose in the United States from 11/100,000 in 2000 to 15/100,000 in 2011.
  • 1.5–3% incidence 1 year after prosthetic valve replacement; 3–6% 5 years postreplacement
  • Increasing incidence of cardiovascular device–related infections due to higher frequency of implantable devices, especially in the elderly
  • Can be community or hospital acquired.

Etiology and Pathophysiology

  • ABE: Staphylococcus aureus; Streptococcus groups A, B, C, G; Streptococcus pneumoniae; Staphylococcus lugdunensis; Enterococcus spp. (gram-positive); Haemophilus influenzae or parainfluenzae; Neisseria gonorrhoeae (gram-negative)
  • SBE: α-hemolytic streptococci (viridans group strep), Streptococcus bovis, Enterococcus spp., S. aureus, Staphylococcus epidermidis (gram-positive); HACEK organisms: Haemophilus aphrophilus or paraphrophilus, Actinobacillus (Aggregatibacter) actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae
  • Endocarditis in IV drug abusers (tricuspid valve): S. aureus, Enterococcus spp. (gram-positive); Pseudomonas aeruginosa, Burkholderia cepacia, other bacilli (gram-negative); Candida spp.
  • Early prosthetic valve endocarditis (<60 days after valve implantation): S. aureus, S. epidermidis (gram-positive); gram-negative bacilli; fungi: Candida spp., Aspergillus spp.
  • Late prosthetic valve endocarditis (>60 days after valve implantation): α-hemolytic streptococci, Enterococcus spp., S. epidermidis (gram-positive); Candida spp., Aspergillus spp.
  • Culture-negative endocarditis: 10% of cases; Bartonella quintana (homeless); Brucella spp., fungi, Coxiella burnetii (Q fever), Chlamydia trachomatis, Chlamydophila psittaci, HACEK organisms; Abiotrophia (formerly vitamin B6deficient streptococci); use of antibiotics prior to blood cultures
  • Device-related endocarditis: coagulase-negative staphylococci or S. aureus

Risk Factors

  • Injection drug use, IV catheterization, certain malignancies (colon cancer), poor dentition, chronic hemodialysis
  • High risk with:
    • Prosthetic cardiac valve, implantable devices (pacemaker, automatic implantable-cardioverter defibrillator [AICD]), total parenteral nutrition
    • Previous infective endocarditis (IE)
    • Congenital heart disease (CHD): unrepaired cyanotic CHD, including palliative shunts and conduits; repaired CHD with prosthetic device during the first 6 months; repaired CHD with residual defects at or near prosthetic site; cardiac transplant with valvulopathy (1)[B]

General Prevention

  • Good oral hygiene
  • Antibiotic prophylaxis is only recommended for high-risk cardiac conditions (1)[B]—prosthetic heart valve, history of endocarditis, transplant with abnormal valvular function, CHD (see “Risk Factors”).
  • Procedures requiring prophylaxis
    • Oral/upper respiratory tract: any manipulation of gingival tissue or periapical region of teeth or perforation of the oral mucosa (1)[B]; invasive respiratory procedures involving incision; or biopsy of the respiratory mucosa merit prophylaxis. Amoxicillin 2 g PO (if penicillin allergic, clindamycin 600 mg PO) 30 to 60 minutes before procedure or ampicillin 2 g IV/IM are first-line prophylactic choices. For penicillin-allergic patients, use clindamycin 600 mg IV, or cephalexin 2 g PO, or azithromycin/clarithromycin 500 mg PO, or cefazolin/ceftriaxone 1 g IV/IM 30 minutes before procedure. Pediatric doses are amoxicillin 50 mg/kg PO (max 2 g), cephalexin 50 mg/kg PO (max 2 g), clindamycin 20 mg/kg PO (max 600 mg), and ampicillin or ceftriaxone 50 mg/kg (maximum 1 g) IM/IV.
    • GI/GU: Only consider coverage for Enterococcus (with penicillin, ampicillin, piperacillin, or vancomycin) for patients with an established infection undergoing procedures (1)[B].
    • Cardiac valvular surgery or placement of prosthetic intracardiac/intravascular materials: perioperative cefazolin 1 to 2 g IV 30 minutes preoperative or vancomycin 15 mg/kg (maximum 1 g) (penicillin-allergic patients) 60 minutes preoperative (1)[B]
    • Skin: incision and drainage of infected tissue; use agents active against skin pathogens (e.g., cefazolin 1 to 2 g IV q8h or vancomycin 15 mg/kg q12h; max 1 g) if penicillin-allergic or if methicillin-resistant S. aureus (MRSA) suspected.

Commonly Associated Conditions

Infectious agents have an affinity for defective tissue. Therefore, most patients with infective endocarditis have preexisting conditions/procedures such as structural heart disease, valvular disease, congenital heart disease, prosthetic heart valves, transcatheter aortic valve replacement, intravascular device and cardiac implantable electronic device. Patients with a history of endocarditis also have an increased risk for recurrence due to the damaged tissue from the previous infection. Patients undergoing chronic hemodialysis have an increased occurrence of infective endocarditis due to increased frequency of introduction of foreign material into the body. HIV is commonly associated with infective endocarditis due to immunocompromised state.

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Basics

Infective endocarditis is a noncontagious infection of the heart, including valves (native or prosthetic), the endocardium and septal defects. Infective endocarditis occurs worldwide and is generally fatal if left untreated.

Description

  • An infection of the valvular (primarily) and/or mural (rarely) endocardium
  • System(s) affected: cardiovascular, endocrine/metabolic, hematologic/lymphatic, immunologic, pulmonary, renal/urologic, skin/exocrine, neurologic
  • Synonym(s): bacterial endocarditis; subacute bacterial endocarditis (SBE); acute bacterial endocarditis (ABE)

Epidemiology

More common in males (3:1). 50% of cases occur in individuals over the age of 50.

Incidence
  • Incidence rose in the United States from 11/100,000 in 2000 to 15/100,000 in 2011.
  • 1.5–3% incidence 1 year after prosthetic valve replacement; 3–6% 5 years postreplacement
  • Increasing incidence of cardiovascular device–related infections due to higher frequency of implantable devices, especially in the elderly
  • Can be community or hospital acquired.

Etiology and Pathophysiology

  • ABE: Staphylococcus aureus; Streptococcus groups A, B, C, G; Streptococcus pneumoniae; Staphylococcus lugdunensis; Enterococcus spp. (gram-positive); Haemophilus influenzae or parainfluenzae; Neisseria gonorrhoeae (gram-negative)
  • SBE: α-hemolytic streptococci (viridans group strep), Streptococcus bovis, Enterococcus spp., S. aureus, Staphylococcus epidermidis (gram-positive); HACEK organisms: Haemophilus aphrophilus or paraphrophilus, Actinobacillus (Aggregatibacter) actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae
  • Endocarditis in IV drug abusers (tricuspid valve): S. aureus, Enterococcus spp. (gram-positive); Pseudomonas aeruginosa, Burkholderia cepacia, other bacilli (gram-negative); Candida spp.
  • Early prosthetic valve endocarditis (<60 days after valve implantation): S. aureus, S. epidermidis (gram-positive); gram-negative bacilli; fungi: Candida spp., Aspergillus spp.
  • Late prosthetic valve endocarditis (>60 days after valve implantation): α-hemolytic streptococci, Enterococcus spp., S. epidermidis (gram-positive); Candida spp., Aspergillus spp.
  • Culture-negative endocarditis: 10% of cases; Bartonella quintana (homeless); Brucella spp., fungi, Coxiella burnetii (Q fever), Chlamydia trachomatis, Chlamydophila psittaci, HACEK organisms; Abiotrophia (formerly vitamin B6deficient streptococci); use of antibiotics prior to blood cultures
  • Device-related endocarditis: coagulase-negative staphylococci or S. aureus

Risk Factors

  • Injection drug use, IV catheterization, certain malignancies (colon cancer), poor dentition, chronic hemodialysis
  • High risk with:
    • Prosthetic cardiac valve, implantable devices (pacemaker, automatic implantable-cardioverter defibrillator [AICD]), total parenteral nutrition
    • Previous infective endocarditis (IE)
    • Congenital heart disease (CHD): unrepaired cyanotic CHD, including palliative shunts and conduits; repaired CHD with prosthetic device during the first 6 months; repaired CHD with residual defects at or near prosthetic site; cardiac transplant with valvulopathy (1)[B]

General Prevention

  • Good oral hygiene
  • Antibiotic prophylaxis is only recommended for high-risk cardiac conditions (1)[B]—prosthetic heart valve, history of endocarditis, transplant with abnormal valvular function, CHD (see “Risk Factors”).
  • Procedures requiring prophylaxis
    • Oral/upper respiratory tract: any manipulation of gingival tissue or periapical region of teeth or perforation of the oral mucosa (1)[B]; invasive respiratory procedures involving incision; or biopsy of the respiratory mucosa merit prophylaxis. Amoxicillin 2 g PO (if penicillin allergic, clindamycin 600 mg PO) 30 to 60 minutes before procedure or ampicillin 2 g IV/IM are first-line prophylactic choices. For penicillin-allergic patients, use clindamycin 600 mg IV, or cephalexin 2 g PO, or azithromycin/clarithromycin 500 mg PO, or cefazolin/ceftriaxone 1 g IV/IM 30 minutes before procedure. Pediatric doses are amoxicillin 50 mg/kg PO (max 2 g), cephalexin 50 mg/kg PO (max 2 g), clindamycin 20 mg/kg PO (max 600 mg), and ampicillin or ceftriaxone 50 mg/kg (maximum 1 g) IM/IV.
    • GI/GU: Only consider coverage for Enterococcus (with penicillin, ampicillin, piperacillin, or vancomycin) for patients with an established infection undergoing procedures (1)[B].
    • Cardiac valvular surgery or placement of prosthetic intracardiac/intravascular materials: perioperative cefazolin 1 to 2 g IV 30 minutes preoperative or vancomycin 15 mg/kg (maximum 1 g) (penicillin-allergic patients) 60 minutes preoperative (1)[B]
    • Skin: incision and drainage of infected tissue; use agents active against skin pathogens (e.g., cefazolin 1 to 2 g IV q8h or vancomycin 15 mg/kg q12h; max 1 g) if penicillin-allergic or if methicillin-resistant S. aureus (MRSA) suspected.

Commonly Associated Conditions

Infectious agents have an affinity for defective tissue. Therefore, most patients with infective endocarditis have preexisting conditions/procedures such as structural heart disease, valvular disease, congenital heart disease, prosthetic heart valves, transcatheter aortic valve replacement, intravascular device and cardiac implantable electronic device. Patients with a history of endocarditis also have an increased risk for recurrence due to the damaged tissue from the previous infection. Patients undergoing chronic hemodialysis have an increased occurrence of infective endocarditis due to increased frequency of introduction of foreign material into the body. HIV is commonly associated with infective endocarditis due to immunocompromised state.

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