Flashcards in *Endocarditis Deck (42)
What 2 symptoms together are endocarditis until proven otherwise?
Fever + new murmur
What is the main cause of infection on a normal valve?
Does endocarditis on a normal valve tend to run an acute or subacute course?
Does endocarditis on an abnormal valve tend to run an act or subacute course?
What are the common types of bacteria that cause native valve endocarditis? (4)
What is the difference between bacteraemia and septicaemia?
Bacteraemia = presence of bacteria in the blood
Sepcticaemia = multiplication of bacteria in the blood
How is bacteraemia/ septicaemia tested for?
Blood samples are taken and put in blood culture machines - this incubates the bottles at 37 degrees and detects the production of CO2 indicating growth
If CO2 is detected, the bottle is promptly removed and a small sample cultured and looked at under the microscope
What does the presence of bacteria in the blood usually indicate?
That there is a focus of infection elsewhere in the body (can be a skin contaminant)
What is infective endocarditis?
Infection of the endothelium of the heart valves
What are the categories of endocarditis based on time of onset?
Subacute (over weeks/ months)
What is the mean age of getting infective endocarditis?
Majority greater than 50 years old but can occur in children with congenital heart disease
Predisposing factors for endocarditis?
Heart valve abnormality e.g. calcification/ sclerosis in elderly, congenital heart disease, post rheumatic fever
Prosthetic heart valve
iv drug users
How does endocarditis form?
Heart valve damage causes turbulent blood flow over roughened endothelium
Platlets and fibrin are deposited
Bacteraemia occurs (may be very transient)
Organisms settle in fibrin/ platelet thrombi becoming a microbial vegetation
Infected vegetations are friable and break off becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage (can be fatal)
What side of the heart is usually affected by endocarditis?
Left side (mitral and aortic valves)
What are the unusual organisms causing endocarditis?
Atypical organisms (Bartonella, Coxiella burnetti, Chlamydia, Legionella, Mycoplasma, Brucella)
What microorganism causes Q fever?
What are the usual presenting symptoms of acute endocarditis?
Symptoms of subacute endocarditis?
Signs of subacute endocarditis?
New or changing heart murmur
Roth spots, Janeway lesions, Osler nodes
What are Janeway lesions?
non-tender, small erythematous or haemorrhagic macular or nodular lesions on the palms or soles
A hemorrhage in the retina with a white center.
What are osler nodes?
painful, red, raised lesions found on the hands and feet
Diagnosis of endocarditis?
Take 3 sets of blood cultures (taken at different times at different sites before antibiotics are started)
If blood culture negative, consider serology for atypical organisms
Echocardiogram (transoesophageal more sensitive than transthoracic)
What are the 2 different types of prosthetic valve endocarditis and what usually causes each?
Early (within 60 days of placement) = usually infected at time of valve insertion = staph aureus or staph epidermis
Late = many years later valve insertion due to co-incidental bacteraemia
Wide range of possible organisms
Where is endocarditis in IV drug users usually seen?
In the right side - tricuspid valve
What is the usual organism that causes endocarditis in drug users?
Staph aureus - often presents as a staph aureus "pneumonai" - this is usually secondary to the endocarditis
Initial Antibiotics for native valve indolent (subacute) endocarditis?
IV amoxicillin and gentamicin
Initial Antibiotics for native valve severe sepsis (acute) endocarditis?
Initial Antibiotics for prosthetic valve or suspected MRSA endocarditis?
Vancomycin + Rifampicin + gentamicin
Valve replacement is usually required