Complications

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 parenterallyand 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