ENDOCARDITIS, INFECTIVE

GENERAL MEASURES

Bed rest.

Early surgical intervention in acute fulminant and prosthetic valve endocarditis is often indicated.

MEDICINE TREATMENT

Treat accompanying complications, e.g. cardiac failure.

Antibiotic therapy

It is essential to do at least three and no more than six blood cultures taken by separate venipunctures before starting antibiotics.

In patients with subacute presentation and no haemodynamic compromise, wait for the results before starting antibiotics.

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 a greater mortality from severe hypersensitivity than from withholding antibiotics.

REFERRAL 

»    Complications such as renal failure and progressive cardiac failure.

»     For surgical intervention, e.g. emergency valve replacement.

»     Assessment for post treatment valve replacement.