Flashcards in Infective endocarditis Deck (36):
True or False.
Blood is normally sterile.
What is bacteraemia?
Presence of bacteria in the blood stream.
Potentially life threatening.
What is the purpose of doing blood cultures?
To gain information that may be clinically useful/ helps to prescribe.
What does a blue/ purple culture signal?
What does an orange/ yellow culture signal?
What is endocarditis?
Infection of the endothelium of the heart valves.
What causes inflammation of the heart valves?
How does turbulence contribute to irregularities of the valves?
Pathogen sits in the area of turbulence.
How can infection be spread from the valves?
The blood passing through the valves.
Is infective endocarditis acute or subacute?
Either depending on the bug.
Does late diagnosis worsen the outcome of infective endocarditis?
Yes, higher mortality rate.
What are the predisposing factors for infective endocarditis?
Heart valve abnormalities
People who inject drugs
Tooth brushing/ recent trip to dentist.
Give 4 examples of heart valve abnormalities?
Calcification/ sclerosis in elderly
Congenital heart disease
Post rheumatic fever
Prosthetic heart valve
What is the pathogenesis of infective endocarditis?
Heart valve damaged
Turbulent blood flow over roughened endothelium
Platelets/ fibrin deposited
Organisms settle in fibrin/platelet thrombi, becoming a microbial vegetation.
Infected vegetation are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage.
Which side of the heart is most likely to be infected by endocarditis?
Usually the left side of the heart.
What increases the likelihood of infective endocarditis to embolise?
The larger the vegetation.
What are common organisms causing endocarditis?
What are unusual organisms causing infective endocarditis?
What are the gram negative organisms that cause infective endocarditis?
(Non-HACEK gram negatives, e.g. E. coli or pseudomonas, tend to be hospital acquired in elderly with many comorbidities).
Name the skin contaminant that can infect prosthetic heart valves?
Coagulase negative staph epidermidis.
How does acute infective endocarditis present?
Usually due to virulent organisms, e.g. staph. aureus.
How does subacute infective endocarditis present?
What are the signs for infective endocarditis?
New or changing heart murmur
Roth spots (retina)
How is infective endocarditis diagnosed?
THREE sets of blood cultures before any antibiotics, if all are negative think serology for atypical organisms.
Echo (TTE or TOE) will show calcifications.
How to treat native endocarditis ?
Amoxicillin and gentamicin IV.
When do people who got infected at time of prosthetic valve insertion tend to get infective endocarditis?
Within 60 days of valve replacement.
Usually causitive organism is staph epidermidis or staph aureus.
Treatment for infective endocarditis caused by staph aureus?
Treatment for infective endocarditis caused by strep viridans?
Benzylpenicillin IV and gentamicin IV.
Treatment for infective endocarditis caused by enterococcus?
Amoxicillin/ vancomycin and gentamicin IV
Treatment for infective endocarditis caused by staph epedermis?
Vancomycin and gentamicin IV with rifampicin PO.
How long are antibiotics usually prescribed for infective endocarditis?
What should be monitored while on antibiotics for infective endocarditis?
(if falling on antibiotic therapy consider surgical referral).
When should surgery be considered for infective endocarditis?
Patients with heart failure, high risk of embolic disease and/ or persistent sepsis.
What valve is most commonly infected in people who inject drugs?
Tricuspid > mitral > aortic
What is the most causitive organism in people who inject drugs?