How to Treat Endocarditis?


Things to note:
  • Bed rest.
  • Early surgical intervention in acute fulminant and prosthetic valve endocarditis is often indicated.

Medical Treatment:
  • Treat accompanying complications, e.g. cardiac failure.
Antibiotic therapy
  • Before starting antibiotics, it is essential to do at least three and no more than six blood cultures taken by separate venipunctures.
    Wait for the results before starting antibiotics in patients with subacute presentation and no haemodynamic compromise.
  • Empiric treatment is indicated in patients with a rapidly fulminant course or with severe disease only.
  • Aminoglycoside therapy should be monitored with trough levels for safety.
    Duration of therapy given is the minimum and may be extended based on the response (clinical and laboratory).
  • In penicillin-allergic patients vancomycin is the antibiotic of choice.
Empiric therapy
Native valve
  • Benzylpenicillin (penicillin G), IV, 5 million units 6 hourly for 4 weeks
PLUS
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 2 weeks If staphylococcal infection is suspected (acute onset):
ADD
  • Cloxacillin, IV, 3 g 6 hourly.
Prosthetic valve
  • Vancomycin, IV, 15 mg/kg 12 hourly for 6 weeks.
PLUS
  • Rifampicin, oral, 7.5 mg/kg 12 hourly for 6 weeks.
PLUS
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 2 weeks.
All cases of prosthetic valve endocarditis should be managed in consultation with an appropriate specialist.
Directed therapy (native valve)
Streptococcal

Fully susceptible to penicillin
MIC: < 0.2mg/L
  • Benzylpenicillin (penicillin G), IV, 5 million units 6 hourly for 4 weeks.
Moderately susceptible MIC: 0.12-0.5 mg/L
  • Benzylpenicillin (penicillin G), IV, 5 million units 6 hourly for 4 weeks.
PLUS
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 2 weeks.
Moderately resistant
MIC: 0.5-4mg/L Enterococci and Abiotrophia spp. (nutritionally variant streptococci)
  • Benzylpenicillin (penicillin G), IV, 5 million units 6 hourly for 4 weeks.
PLUS
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 4 weeks. Six weeks of therapy may be required in cases with a history of > 3 months, or mitral or prosthetic valve involvement.
Fully resistant
MIC: > 4 mg/L
  • Vancomycin, IV, 15 mg/kg 12 hourly for 6 weeks.
PLUS
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 6 weeks.
Enterococcal
Fully susceptible to penicillin
MIC: < 4mg/L
  • Benzylpenicillin (penicillin G), IV, 5 million units 6 hourly for 4 weeks.
Resistant to penicillin
MIC 4mg/L or significant lactam allergy and Sensitive to vancomycin MIC: 4 mg/L
  • Consult a specialist.
Staphylococcal (cloxacillin/methicillin sensitive)
S. aureus
  • Cloxacillin, IV, 3 g 6 hourly for 4 weeks. If necessary, add:
  • Gentamicin, IV, 5 mg/kg daily for the first 3-5 days.
  • The benefit of adding an aminoglycoside has not been established.
  • In the rare occurrence of a penicillin sensitive staphylococcus, penicillin should be used in preference to cloxacillin.
Coagulasenegative staphylococci
  • Consult expert opinion on correct diagnosis in this setting.
Staphylococcal (cloxacillin/methicillin resistant) or methicillin sensitive with significant beta-lactam allergy
S. aureus
  • Vancomycin, IV, 15 mg/kg 12 hourly for 4 weeks.
Coagulasenegative staphylococci
  • Consult expert on correct on antibiotic choice.
Directed therapy for prosthetic valve endocarditis
  • Duration of therapy is usually a minimum of at least 6 weeks.
  • Seek expert opinion on antibiotic choice.
Endocarditis prophylaxis
Cardiac conditions
Patients with the following cardiac conditions are at risk of developing infective endocarditis:
  • Acquired valvular heart disease with stenosis or regurgitation.
  • Prosthetic heart valves.
  • Structural congenital heart disease, including surgically corrected or palliated structural conditions, but excluding isolated atrial septal defect, fully repaired ventricular septal defect or fully repaired patent ductus arteriosus.
  • Previous endocarditis.
Procedures requiring prophylaxis
  • Antibiotic prophylaxis is recommended for all dental procedures that involve manipulation of either the gingival tissue or the peri-apical region of the teeth.
  • Antibiotic prophylaxis is not recommended for patients who undergo a gastro-intestinal or genito-urinary procedure.
Prophylaxis
  • Maintain good dental health.
  • This is the most important aspect of prophylaxis.
  • Refer all patients to a dental clinic/dental therapist for assessment and ongoing dental care.
    • Amoxicillin, oral, 2 g one hour before the procedure.
Penicillin allergy:
  • Clindamycin, oral, 600 mg one hour before the procedure.
If patient cannot take oral:
  • Ampicillin, IV/IM, 2 g one hour before the procedure.
Penicillin allergy:
  • Clindamycin IM/IV, 600 mg 1 one hour before the procedure.
  • The NICE review noted the lack of a consistent association between interventional procedures and development of infective endocarditis, and that the efficacy of antibiotic prophylaxis is unproven. It further commented that because the antibiotic is not without risk, there is a potential for greater mortality from severe hypersensitivity than from withholding antibiotics.


When to refer:
  • Complications such as renal failure and progressive cardiac failure.
  • For surgical intervention, e.g. emergency valve replacement.
  • Assessment for post treatment valve replacement.