Pediatric Bacterial Endocarditis Treatment & Management

Bacterial endocarditis is a disease in which complete eradication of the organism is required. Bacteria involved in endocarditis are relatively protected from phagocytic activity by the vegetation, which contains high concentrations of bacteria with relatively low metabolic rates. Prolonged parenteral therapy is the only way to achieve bactericidal serum levels for the time needed to kill all the bacteria present in a vegetation of endocarditis. Treatment generally ranges from 4-8 weeks. ^{[1, 11]}

The following principles of management of infective endocarditis are worth considering:

• Selection of the antibiotic agents is based on the sensitivity of the offending organism to antibiotics
• Bactericidal rather than bacteriostatic antibiotics are preferable
• Intermittent intravenous antibiotic administration to achieve high concentration of the antibiotic is recommended; a bactericidal level of 1:8 or greater should be achieved
• Prolonged (4-8 weeks) treatment to ensure eradication of the organism is generally required
• Documentation of cessation of bacteremia prior to discontinuation of antibiotics is suggested
• Surgery may be necessary in some cases as detailed below.

Go to Infective Endocarditis for more complete information on this topic.

Consultations

Initial consultants for the patient suspected of having bacterial endocarditis should include an infectious disease specialist, a cardiologist, and often a cardiac surgeon.

Transfer

Depending on their initial clinical presentation, patients may first be monitored in the intensive care unit (ICU) and then transferred to an inpatient ward when the clinical condition has stabilized and a response to treatment is evident.

Patients at high risk for developing complications from endocarditis may require transfer to a tertiary care center where pediatric cardiothoracic surgery is available.

 

Therapy is tailored according to the etiologic agent. ^[12] Because of the high risk for morbidity and mortality associated with bacterial endocarditis, individual therapy should be discussed between all consultants with the available antibiotic sensitivity testing carefully reviewed.

Penicillin-susceptible streptococcal endocarditis (PSSE) on native cardiac valves is treated with penicillin G for 4 weeks or penicillin or ceftriaxone combined with gentamicin for 2 weeks. Penicillin-resistant streptococcal endocarditis (PRSE) on native cardiac valves is treated with penicillin, ampicillin, or ceftriaxone for 4 weeks, combined with gentamicin for the first 2 weeks.

PSSE on a prosthetic valve or other prosthetic material should be treated with penicillin, ampicillin, or ceftriaxone for 6 weeks, combined with gentamicin for the first 2 weeks. PRSE on a prosthetic valve or other prosthetic material is treated with penicillin, ampicillin, or ceftriaxone for 6 weeks, combined with gentamicin. Vancomycin can be used in patients who cannot tolerate penicillin or ceftriaxone. The duration of penicillin-resistant therapy for streptococcal endocarditis on a prosthetic valve is 6 weeks.

Susceptible enterococcal infection on native valves is treated with penicillin or ampicillin, combined with gentamicin, for 4-6 weeks. Infection on prosthetic material should be treated for at least 6 weeks.

Methicillin-susceptible S aureus (MSSA) infection on native valves is treated with nafcillin or oxacillin for at least 6 weeks. The addition of gentamicin for 3-5 days is optional. Methicillin-resistant S aureus (MRSA) infection on native valves is treated with vancomycin for at least 6 weeks, with or without 3-5 days of gentamicin.

MSSA infection on prosthetic tissue is treated with nafcillin or oxacillin plus rifampin for at least 6 weeks, in combination with gentamicin for 2 weeks. MRSA infection on prosthetic tissue is treated with vancomycin plus rifampin for at least 6 weeks, in combination with gentamicin for 2 weeks.

Gram-negative endocarditis caused by HACEK organisms is treated with ceftriaxone or ampicillin plus gentamicin for 4 weeks.

The 2015 American Heart Association (AHA) update on infective endocarditis includes dosing and monitoring recommendations for vancomycin, aminoglycosides, and β-lactams. ^[13] These appear to be based primarily on expert opinion and did not consider currently available evidence on pharmacokinetic and pharmacodynamic principles, particularly in pediatric patients. ^[14] These authors are concerned that the practitioners may hesitate to deviate from AHA guidelines; therefore, they suggest improvement in the recommended doses in the AHA statement, review of evidence in support of optimization of antibiotic doses, and recommend the addition of a pediatric clinical pharmacist to the therapeutic team.

Additional Inpatient Care

Further inpatient care in patients with bacterial endocarditis is mostly supportive.

Hemodynamic and ventilatory support may be required for critically ill children.

Physical and occupational therapy is given to patients who are hospitalized for a long period.

Important aspects of care include the treatment of complications, such as CHF, neurologic injury, and splenic abscess.

Outpatient Care

With the advent of home health facilities, more patients can complete parenteral antimicrobial therapy as outpatients after the initial acute infection is controlled.

After initial diagnosis and therapy in the hospital, patients in whom outpatient therapy is being considered must be hemodynamically stable and afebrile, must have negative blood cultures, and must be at low risk for complications.

Follow-up for monitoring of adherence to drug therapy and possible complications is essential.

Absolute indications for surgery include progressive cardiac failure, worsening valve obstruction or regurgitation, definitive perivalvular abscess, noncandidal fungal infection, and pseudomonal infection. Relative indications include persistent bacteremia despite appropriate antibiotic therapy, candidal endocarditis, and vegetations larger than 10 mm.

Surgery should be performed without delay in patients with severe CHF secondary to valvular regurgitation. Surgery for patients who have had a recent neurologic injury should be evaluated and possibly delayed to make modifications to avoid intracranial hemorrhage.

Russell et al studied 34 patients with infective endocarditis who underwent surgical intervention over a 21-year period. They found the Ross operation to be effective in patients with aortic valve endocarditis. However, the incidence of reoperation for valve and conduit replacement because of somatic growth was significant. Children younger than one year had a greater risk for death, but patients surviving to hospital discharge had good results with no recurrence. ^[6]

No specific dietary restrictions are recommended in the literature for the patient with bacterial endocarditis.

Patients may be as active as they can tolerate. Patients may be ill and should remain hospitalized until they are hemodynamically stable, afebrile, with negative blood cultures, and not at high risk for complications.

Prevention of bacterial endocarditis with antimicrobial prophylaxis in high-risk children is key to their long-term survival and quality of life. ^[15]

Guidelines suggest that the following patients are at the highest risk and therefore should receive antibiotic prophylaxis prior to dental procedures involving manipulation of gingival tissue, the periapical region of the teeth, or the perforation of oral mucosa:

• Patients with a prosthetic heart valve or with prosthetic material used for valve repair

• Patients with previous endocarditis

• Patients with significant valvular disease who have undergone cardiac transplantation

• Patients with congenital heart disease

Patients in the fourth bullet point, above, include (1) persons with unrepaired or palliated cyanotic heart disease, (2) those with repaired heart disease with prosthetic material for the first 6 months postoperatively, and (3) those with repaired heart disease with residual significant lesion at the site of prosthetic material.

Antibiotic prophylaxis options for these highest-risk patients, when undergoing dental procedures, include the following:

• Amoxicillin at 50 mg/kg orally 30-60 minutes before the procedure

• In patients who are unable to take oral ampicillin, IV amoxicillin at 50 mg/kg or cefazolin or ceftriaxone 50 mg/kg intravenously or intramuscularly 30-60 minutes before the procedure

• In patients with a penicillin allergy, cephalexin at 50 mg/kg orally; clindamycin at 20 mg/kg orally, intravenously, or intramuscularly; azithromycin at 15 mg/kg orally; or cefazolin or ceftriaxone at 50 mg/kg intravenously or intramuscularly

Thornhill et al evaluated the impact of the 2008 National Institute for Health and Clinical Excellence (NICE) guidelines that recommended the cessation of all antibiotic prophylaxis in the United Kingdom, even going farther than the 2007 American Heart Association guidelines in omitting antibiotic prophylaxis for all patients under all circumstances. Although the results found no change in the trend of IE case development in the United Kingdom since the new guidelines and thus supported them, ongoing studies and clinical trials would still be useful to confirm whether antibiotic prophylaxis has any role in protecting some patients, particularly those at highest risk of complications from infective endocarditis. ^[16]

The AHA no longer recommends endocarditis prophylaxis for other nondental procedures, such as respiratory procedures (except for procedures in high-risk patients that involve incision of the mucosa, such as tonsillectomy and adenoidectomy), GI procedures, or genitourinary procedures.

Go to Antibiotic Prophylactic Regimens for Endocarditis for more complete information on this topic.