Infective endocarditis Flashcards
Definition of infective endocarditis
infection (colonisation of microbiologic agents) of the endocardium layer of the heart or valves
Pathophysiology of IE
Bacterial infection caused by staphylococcal (+) and streptococcal pneumoniae (+) mico- organisms in the bloodstream and depositing on the endocardial surface of the heart.
Most common pathogen causing IE is
Staphylococcal aureus
Causes of IE (most common to least common)
IV drug use, prosthetic valves, rheumatic heart disease
Which valves are most likely affected by IE
left valves of the heart (mitral and aortic)
Symptoms of IE
Fever & a new murmur = endocarditis until proven otherwise
Lethargy, anorexia and weight loss
Which valve of the heart is more likely affected in IV drug users
Tricuspid valve
Risk factors of IE
IV drug use, valve replacement surgery, poor dental hygiene or iatrogenic causes (dental treatment, cannulae etc)
Signs of IE
Janeway lesions (non-tender), osler nodes (painful), roth spots (ophthalmology red spots in fundus of the eye)
Name the criteria used for IE diagnosis
Duke criteria
What are the major and minor Duke criterias
Major: positive blood culture, echo (TTE – transthoracic echocardiography) , valve regurgitation
Minor: Fever >38’C
Predisposition to IE; e.g. IV drug user, congenital heart condition, prosthetic valve
Unusual echo, but not with findings stated above
Immunological factors present; Roth spots, Osler’s nodes, glomerulonephritis, rheumatoid factor
Blood cultures positive, but major criteria not satisfied
Vascular abnormalities; embolism, aneurysm, infarcts, conjunctival haemorrhage, intracranial haemorrhage etc
Define vegetated valve
Thrombus (fibrin + platelets) + bacteria on the valve
How do you manage IE?
Amoxicillin + low dose of gentamicin
If penicillin allergic, MRSA or severe sepsis
vancomycin + low-dose gentamicin
If prosthetic valve
vancomycin + rifampicin + low-dose gentamicin
Native valve endocarditis caused by staphylococci= Flucloxacillin
If penicillin allergic or MRSA
vancomycin + rifampicin
Prosthetic valve endocarditis caused by staphylococci= Flucloxacillin + rifampicin + low-dose gentamicin
If penicillin allergic or MRSA
vancomycin + rifampicin + low-dose gentamicin
Endocarditis caused by fully-sensitive streptococci (e.g. viridans) = Benzylpenicillin
What are the indications for surgery?
severe valvular incompetence
aortic abscess (often indicated by a lengthening PR interval)
infections resistant to antibiotics/fungal infections
cardiac failure refractory to standard medical treatment
recurrent emboli after antibiotic therapy
Common extra-cardiovascular manifestations of right valve IE
Pulmonary embolism = due to thrombus formed on the right valve can dislodge and flow to the lungs by passing the pulmonary valve
