*Endocarditis Flashcards
(42 cards)
What 2 symptoms together are endocarditis until proven otherwise?
Fever + new murmur
What is the main cause of infection on a normal valve?
Staph aureus
Does endocarditis on a normal valve tend to run an acute or subacute course?
Acute
Does endocarditis on an abnormal valve tend to run an act or subacute course?
Subacute
What are the common types of bacteria that cause native valve endocarditis? (4)
Staph aureus
Viridans streptococci
Enterococcus
Staph. epidermidis
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?
Acute
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
Intravascular lines
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)
Gram negatives
Fungi
What microorganism causes Q fever?
Coxiella burnetti
What are the usual presenting symptoms of acute endocarditis?
Overwhelming sepsis
Cardiac failure
Symptoms of subacute endocarditis?
Fever Malaise Weight loss Tiredness Breathlessness
Signs of subacute endocarditis?
Fever New or changing heart murmur Finger clubbing Splinter haemorrhages Splenomegaly Roth spots, Janeway lesions, Osler nodes Microscopic haematuria
What are Janeway lesions?
non-tender, small erythematous or haemorrhagic macular or nodular lesions on the palms or soles
Roth spots?
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
