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Endocarditis is a life-threatening infection of the heart valves, associated with either congenital or disease-induced anomalies of native or prosthetic valves.
Although an enormous variety of organisms have been reported as causing endocarditis, in practice most cases are caused by a limited range of pathogens.
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The presentation of endocarditis covers a wide spectrum, from the indolent (formerly known as subacute bacterial endocarditis), to the acutely progressive (formerly known as acute bacterial endocarditis). These differences reflect the relative contributions of immunological activation, systemic sepsis and valvular damage, and in part depend upon the nature of the infecting organism.
(>10 mg/L) and ESR (markedly raised at >100 mm/h).,
which allow cases to be assigned to one of three categories (definite, possible
and rejected), have been validated for this purpose and have become widely accepted.
It is particularly important in endocarditis that antibiotics
should be administered strictly according to dosage schedules, eg. every four
hours. Standard practice is to administer a penicillin such as benzylpenicillin,
plus an aminoglycoside such as low dose gentamicin,
for its synergistic effect.
Although prosthetic valve infections are more likely to involve Staphylococcus spp., during the short interval before culture results and sensitivities are known the same empirical regimen is generally used. However, in IV drug users and patients with line-related endocarditis (eg. dialysis patients), the likelihood of an antibiotic-resistant staphylococcal infection is such that a glycopeptide is preferred.
The BSAC working party on endocarditis recommends the following empirical therapy until the pathogen has been identified:
(80 mg twice a day IV)
(80 mg twice a day IV) Once causative organisms are known, the BSAC
Endocarditis Working Party has made specific recommendations.
The evidence for prophylaxis in endocarditis is circumstantial and recommendations are based on a body of opinion. This means guidelines should be used with care and clinical judgement should be exercised.
The aim of prophylaxis is to reduce the risk of transient bacteraemia in patients who are at risk of endocarditis because of underlying valve disease. The recommendations apply only to the prevention of endocarditis and should not be extended to the prevention of infection of orthopaedic prostheses, vascular grafts etc.
It is important to identify ‘at
risk’
patients to ensure antibiotics are recommended only for appropriate patients.
In general, the risk is proportional to the degree of haemodynamic turbulence
associated with a structural defect that may eventually allow vegetation formation.
Antibiotic prophylaxis is recommended in procedures likely to create transient bacteraemia in patients at risk. The following links give more information.
