1. Complications and principles of treatment of infective endocarditis incl. prognosis and antibiotic prophylaxis for endocarditis

2. Complications Cardiac failure (valve incompetence  volume overload) Embolic complication (splenic, coronary, cerebral) Renal complications (microemboli, absecces, or antigen/antibody complexes) Other immune complex related issues Murmur may develop due to fibrosis, calcification etc of valve

3. Treatment Principles To cure endocarditis, all bacteria in the vegetation must be killed; therefore, therapy must be bactericidal and prolonged Antibiotics are generally given parenterally and must reach high serum concentrations that will, through passive diffusion, lead to effective concentrations in the depths of the vegetation Choice of therapy requires knowledge of the causative organism and its resistance/susceptibility Empirical Therapy should be based on clinical and epidemiologic clues to aetiology eg. empirical therapy for acute endocarditis in an injection drug user should cover MRSA and gram-negative bacilli= initiation of treatment with vancomycin plus gentamicin

4. Certain complications necessitate surgical treatment Congestive Heart Failure Perivalvular infection Large, hypermobile vegetation to prevent emboli prosthetic valve endocarditis (40% merit surgical treatment)

5. Prognosis Vegetations become smaller with effective therapy, but at 3 months after cure half are unchanged and 25% are slightly larger Overall survival rates for patients with native valve endocarditis caused by viridans streptococci, HACEK organisms, or enterococci (susceptible to synergistic therapy) are 85–90%. For S. aureus native valve endocarditis in patients who do not inject drugs, survival rates are 55–70%, whereas 85–90% of injection drug users survive this infection Prosthetic valve endocarditis beginning within 2 months of valve replacement results in mortality rates of 40–50%, whereas rates are only 10–20% in later-onset cases. Older age, severe comorbid conditions, delayed diagnosis, involvement of prosthetic valves or the aortic valve, an invasive (S. aureus) or antibiotic- resistant (P. aeruginosa, yeast) pathogen, intracardiac complications, and major neurologic complications adversely impact outcome.

6. Prevention Antibiotic prophylaxis has been recommended in conjunction with selected procedures considered to entail a risk for bacteremia and endocarditis – only for those patients at highest risk for severe morbidity or death from endocarditis eg. Prior endocarditis, prosthetic valves, valvulopathys – only dental procedures wherein there is manipulation of gingival tissue or the periapical region of the teeth or perforation of the oral mucosa (including surgery on the respiratory tract) – only procedures on infected genitourinary tract or on infected skin and related soft tissue Issues with prevention: only 50% of patients presenting with native valve endocarditis know that they have a predisposing valve lesion, most endocarditis cases do not follow a procedure, and 35% of cases are caused by organisms not targeted by prophylaxis.

7. Summary Treatment – empirical therapy based on clinical signs and epidemiology – then based on causative organism and resistance determined from blood culture – Surgery is sometimes needed Prevention – antibiotic prophylaxis is recommended in high risk patients undergoing procedures that carry risk of bacteraemia Prognosis – depends on many things – 85-90% survival rate (strep. Viridan)in patient with native valves – 55-70% survival rate (staph. Aureus) in patients with native valves – Prosthetic valves have worse prognosis Complications – a degree of valve disorganisation is inevitable – valve perforation, valve incompetence, CHF, emboli, renal complication, murmurs