• Endocarditis primarily is seen in patients with a preexisting congenital or acquired heart disease who develop bacteremia with organisms that are likely to cause infection.
• Intravenous drug abusers and patients with intravenous lines may develop endocarditis in the absence of a cardiovascular abnormality.
• Local turbulence secondary to the cardiovascular abnormality is thought to result in damage to the endocardial surface.
  • Followed by the development of a network of fibrin and platelets in which bacteria then can become entrapped, causing the nidus of infection.
• Bacteremia can be a complication of a focal infection (e.g., pneumonia, cellulitis, or urinary tract infection) or can be associated with various dental and surgical procedures. Bacteremia, however, can occur spontaneously and has been documented with activities such as chewing hard candy and brushing teeth.

• Gram-positive cocci account for 90% of culture-positive endocarditis.
  • Alpha-hemolytic streptococci (Streptococcus viridans) are responsible for most cases of endocarditis in all age groups.
  • Staphylococci (S. aureus and coagulase-negative staphylococci) are the second largest group.
  • Other organisms that can cause endocarditis are beta-hemolytic streptococci, pneumococci, enterococci, Pseudomonas species, the HACEK bacteria, Neisseria species, and Candida species.
• Approximately 5% of endocarditis cases are reported as culture-negative.

• Endocarditis is relatively uncommon. Studies have reported incidences between 1 in 1,280 and 1 in 4,500 of all pediatric hospital admissions.
• The overall incidence of endocarditis seems to have decreased in the current era of antibiotics, but some have actually suggested an increase in incidence with the higher survival of patients with congenital heart disease and the wide and often prolonged use of central intravascular lines.

• Cardiac
  • Damage to the valve leaflets may result in valvar regurgitation, heart failure, or conduction abnormalities.
• Embolic
  • Embolic events can occur to multiple organ systems (central nervous system, kidneys, spleen, skin, lungs).

• Other infections (e.g., acute rheumatic fever)
• Malignancy
• Connective tissue disorders

• General
  • Fever (usually low grade with alpha-hemolytic streptococci and high grade with S. aureus) and pallor
• Embolic or immunologic phenomena
  • Splinter hemorrhages, retinal hemorrhages, Osler nodes, Janeway lesions, splenomegaly, clubbing, arthralgia, and arthritis
• Cardiac
  • New or changing murmurs and symptoms of congestive heart failure
• Neurologic
  • Neurologic symptoms can be seen on the basis of central nervous system emboli and hemorrhage, and can sometimes mimic the picture of an abscess, aseptic meningitis, or cerebral infarct.

• Blood cultures are the gold standard for diagnosing endocarditis.
• Blood cultures are positive in 85% to 90% of the reported cases of endocarditis and remain the most important tool in making the diagnosis of endocarditis.
• At least three sets of blood cultures should be obtained over a 24-hour period. Each set should be obtained from separate venipuncture sites via strict sterile technique.
• As large a volume as clinically reasonable should be collected.
• The bacteremia of endocarditis is continuous; therefore, it is not necessary to obtain the blood cultures during a fever spike.

• Transthoracic echocardiography is a valuable noninvasive technique in the identification of vegetations.
• The sensitivity and specificity of transthoracic echocardiography, however, is not 100%; therefore, a negative echocardiogram does not rule out endocarditis.
• Transesophageal echocardiography (useful in older or obese patients) may visualize smaller vegetations as well as areas that are inadequately seen with standard transthoracic imaging.
• In patients with a nonconclusive transthoracic study but a high index of suspicion for endocarditis, transesophageal echocardiography is recommended.

• The absence of vegetation(s) by echocardiography does not rule out endocarditis.
• In patients with a prosthetic valve, echocardiography is not always helpful, as there is frequently artifact from the prosthetic valve. Abnormal movements of the valve leaflets may suggest a vegetation.
• The ESR may remain elevated for some time, even after cessation of bacteremia.

• General
  • Rest; antipyretics; transfusion, if needed; optimal nutrition; fluid and electrolyte balance; dental hygiene
• Antibiotics
  • Prolonged therapy (4–8 weeks) with intravenous antibiotics is needed. The choice of anti-biotic(s) and the duration of antibiotic treatment depend on the infecting organism and its sensitivity pattern. For fungal SBE, intravenous amphotericin B is given for a minimum of 6 to 8 weeks.
• Surgery: potential indications for surgical therapy
  • Severe congestive heart failure
  • Worsening heart failure
  • Endocarditis that is uncontrollable with antibiotics
  • More than one serious systemic embolus
  • Local suppurative complications (e.g., abscess with conduction abnormalities)
  • Development of a mycotic aneurysm
  • Fungal endocarditis may require replacement of the infected valve and excision of infected tissue.

• Dental hygiene
• Minimal use of central lines
• Correction of the cardiovascular anomaly by surgery or interventional catheterization techniques
• SBE prophylaxis

• Amoxicillin (50 mg/kg orally 1 hour before procedure; maximum, 2.0 g). If unable to take oral medications, ampicillin (same dose) may be given 30 minutes before the procedure.
• Clindamycin (20 mg/kg orally 1 hour before procedure; maximum, 600 mg) may be used if the patient is allergic to penicillin.

• High-risk patients: Ampicillin (50 mg/kg; maximum, 2.0 gm IM/IV) plus gentamicin 1.5 mg/kg (maximum, 120 mg) within 30 minutes of starting procedure; 6 hours later, 25 mg/kg/IV ampicillin (maximum, 1 g) or amoxicillin 25mg/kg/PO (maximim, 1g). Vancomycin plus gentamicin may be used for patients allergic to amoxicillin/ampicillin.
• Moderate-risk patients: Amoxicillin (50 mg/kg/PO; maximum, 2.0 g) 1 hour prior to the procedure, or ampicillin 50 mg/kg IM/IV (maximum, 2.0 g) within 30 minutes of starting the procedure. Vancomycin may be used for patients allergic to amoxicillin/ampicillin.

• High-risk group: prosthetic valves, previous SBE, cyanotic heart disease, surgically constructed shunts or conduits
• Moderate-risk group: most other congenital heart disease, acquired valvar disease (e.g., rheumatic valvar disease), hypertrophic cardiomyopathy, mitral valve prolapse with regurgitation or thickened leaflets

• Isolated secundum atrial septal defect
• Surgically repaired patent ductus arteriosus
• Ventricular septal defect and atrial septal defect beyond 6 months (without residual)
• Previous coronary artery bypass surgery
• Mitral valve prolapse without regurgitation
• Previous Kawasaki syndrome without vulvar dysfunction
• Rheumatic fever without valvar dysfunction
• Pacemakers and defibrillators

• Tonsillectomy, adenoidectomy, surgery of respiratory mucosa, rigid bronchoscopy
• Sclerotherapy for esophageal varices, esophageal dilation, biliary tract and intestinal surgery, endoscopic retrograde cholangiography
• Prostatic surgery, cytoscopy, urethral dilation
• Dental extractions, periodontal procedures, dental implant, endodontic procedures, dental cleaning, intraligamentary injections, initial placements of orthodontic bands, subgingival placement of antibiotic fibers/strips

• Endotracheal intubation, flexible bronchoscopy, ear tubes, transesophageal echocardiography, GI endoscopy
• Vaginal hysterectomy, vaginal delivery, cesarean section, urethral catheterization, uterine dilation and curettage, abortion, sterilization, intrauterine devices
• Cardiac catheterization
• Circumcision
• Shedding of primary teeth

Q: I forgot to give my child antibiotics prior to the procedure. Should I give him a dose afterwards?
A: In regard to preventing endocarditis, no data exist on the benefit of administering antibiotics after a procedure.

Q: My child has an innocent heart murmur. Does he need SBE prophylaxis?
A: SBE prophylaxis is not indicated.

Dajani AS, Taubert KA, Wilson W, et al., Prevention of bacterial endocarditis; recommendations by the American Heart Association. JAMA 1997;277:1794–1801.

Emmanoulides GC, Riemenscheider TA, Allen HD, Gutgesell HP, eds. Moss and Adams, heart disease in infants, children, and adolescents, including the fetus and the young adult, 5th ed. Baltimore: Williams & Wilkins, 1995.