It is an infecion of
heart valves or the endocardium due
infectious agents, mostly bacteria (septicemia).
The valves of the heart do not receive any dedicated blood supply, i.e defence mechanism can not directly reach the heart valves.
Predesposing factors:
vValvular heart disease
v Rheumatic heart disease
v Congenital heart disease
v Mitral valve prolapse
v Prosthetic devices( valves, pace makers)
v Intravenous drug use
Pathogenesis:
qPatients at risk are those who have pre- existing cardiac disease. In 1/3rd cases normal heart beat are also affected.
qInoculation of bacteria colonizing a mucosal or peripheral tissue site into the bloodstream
qTransient bacteremia of a serum-resistant pathogen capable of adhering to a cardiac valvular surface
q Turbulent blood flow across the valve
qBacterial adherence to cardiac valvular surface
qPathogen - host tissue interaction resulting in vegetation formation and local tissue damage
Laboratory Diagnosis:
Blood culture
v Most important diagnostic test
v Positive in 90% of cases
v 5ml for children and 10 ml for adult in 3 separate samplings within in 1-24 hours from different peripheral site is recommended
v Samples should be taken before initiating antibiotic therapy
v Culture should be grown both aerobically & anaerobically for at least 3 wks.
Treatment:
vMedical care
v Aim: Complete eradication of organism i.e. suitable antibiotic according to culture sesitivity with proper dose.
v Prolonged parenteral therapy essential usually least 4weeks and preferably 8 weeks.
v Therapy tailored according to the etiological agent & the type of endocarditis
*** For unknown organism penicillin and gentamicin
v Surgery may be required if heart valves are damaged
v Prosthetic valve infection with MRSA is frequently fatal and should be treated with a combination of vancomycin, rifampin and gentamicin
The valves of the heart do not receive any dedicated blood supply, i.e defence mechanism can not directly reach the heart valves.
Predesposing factors:
vValvular heart disease
v Rheumatic heart disease
v Congenital heart disease
v Mitral valve prolapse
v Prosthetic devices( valves, pace makers)
v Intravenous drug use
Pathogenesis:
qPatients at risk are those who have pre- existing cardiac disease. In 1/3rd cases normal heart beat are also affected.
qInoculation of bacteria colonizing a mucosal or peripheral tissue site into the bloodstream
qTransient bacteremia of a serum-resistant pathogen capable of adhering to a cardiac valvular surface
q Turbulent blood flow across the valve
qBacterial adherence to cardiac valvular surface
qPathogen - host tissue interaction resulting in vegetation formation and local tissue damage
Laboratory Diagnosis:
Blood culture
v Most important diagnostic test
v Positive in 90% of cases
v 5ml for children and 10 ml for adult in 3 separate samplings within in 1-24 hours from different peripheral site is recommended
v Samples should be taken before initiating antibiotic therapy
v Culture should be grown both aerobically & anaerobically for at least 3 wks.
Treatment:
vMedical care
v Aim: Complete eradication of organism i.e. suitable antibiotic according to culture sesitivity with proper dose.
v Prolonged parenteral therapy essential usually least 4weeks and preferably 8 weeks.
v Therapy tailored according to the etiological agent & the type of endocarditis
*** For unknown organism penicillin and gentamicin
v Surgery may be required if heart valves are damaged
v Prosthetic valve infection with MRSA is frequently fatal and should be treated with a combination of vancomycin, rifampin and gentamicin
