BOF: 2.67
A 62-year-old male has had an aortic valve replacement.
He presents 5 months after surgery with malaise, anorexia and low-grade
fever. On examination he has splinter haemorrhages in his nails, there are
tender nodules on the pulps of his fingers and erythematous macules over his
palms. His spleen is just palpable.
You arrange for blood cultures to be taken on this
patient
Which of the following is the most likely infecting
organism?
a) Staphylococcus
aureus
b)
MRSA
c)
Streptococcus viridians
d) Staphylococcus
epidermidis
e)
Streptococcus bovis
Answer: d)
The patient has clinical features suggestive of infective
endocarditis (fever, anoxia, splinter haemorrhages, Osler’s nodes, Janeway
lesions and a palpable spleen).
Prosthetic valve endocarditis is divided into two
categories:
Early prosthetic valve endocarditis (less than 1 year) is
usually due to contamination during surgery and in these cases the most common
organism is Staphylococcus epidermidis
Late prosthetic valve endocarditis is due to
haematogenous spread and the most common cause is Streptococcus viridians
There are different views as to the cut off point for
dividing into early and late prosthetic valve endocarditis (PVE) some
authorities say 60 days and others say 6 months
Revision notes on infective endocarditis
