M27 Infective Endocarditis Flashcards
what is IE caused by
micro organisms settling on heart valves (bac/fungi)
is IE fatal
yes without treatment
how does IE come about
predisposing lesion on valve attracts layer of platelets/fibrin sticky surface bac attch VEGETATION infection develops
how do pathogens causing IE get into the bloodstream
diff routes
injury
oral cav
catheter
how to pathogens rapidly adhere
platelet fibrin deposition
what do some sp do
obtain intracellular access
what does embolisation or heamatogenous spread lead to
range of complications
- stroke
- meningeal infections
what are some clinical effects of IE
bacteraemia
damage to valve form vegetative growth
emboli
immune complex effects
what is bacteraemia diagnosis linked to
positive blood culture
how can a valve be damaged by vegetative growth
valve rupture
mitral/atrial
how do emboli effect the body
bits flake off and lodge into small vessels
stroke etc
where ca remote embolic effects be seen
often found on extremities or mucous mems
what is palatal petechiae assc with
IE
Leukemia
STD
Viral infection - infectious mononucleosis
what are th two sources of bacteriamia
spontaneous and induced
what is the spontaneous source of bacteriaemai
oral flora
gut flora
what is induced cause of bacterimia
gum margin manipulation - extraction
IVDU
what are the types of organisms assc with IE
staphylococci -25% streptococci - 50-70% enterococci - 10% Candida culture negative
what are the specifics of the staphylococci involved in IE
coagulase - ve - epidermis
causing rapid valave degeneration
does candida and colifrms usually seen to cause IE
uncommon
what are the assc culture negative bacteria in iE
HACEK
haemophilia
aggregatibacter
eikenella
what si he percentage of IE cases oral origin
20%
what are some key concepts when thinking of virulence in IE
entry/circ blood adherence - platelet/fibrin biofilm form host cell invasion aggressive damage sec toxins intracellular persistence
what re some surface adhesins assc with streptococcus gordonii
PadA
Hsa
fro platelet adhesion and aggregation
what are pt most at risk of IE
individuals with damage heart valves history IVDU prothetic valves cardiac surgery
what are some symptoms of subacute
malaise headache night sweats rigors heart murmur embolic manifestations immune complex disease
what are some symptoms of a high index of suspicion
fever and unknown cause murmur heart lesion bacteriamia malaise positive blood culture
what are some other ways of identifying IE
echocardiography
C relative protein (marker of inflam)
serology
what is the principle of treatment
empiric therapy
- tidal
- large dose
- long time
when is Ab started for IE
after blood cultures
for acute infection s aureus targeted
what bac is targeted particularly with beta lactam
gm +ve cocci
what are the Ab used in therapy
beta lactase
gentamicin
vancomycin
rifampicin
what are some beta lactams
amoxicillin
benzyl penicillin
flucloaxacillin
what does gentamicin do
coliforms and synergy with beta lactamsfor strept
what does vancomycin do
ag MRSA/ s epidermidis
less active used with something
what does rifampicin do
penetrates well and synergy with vancomycin not alone or get resist
what is used for native valve acute/sever
flucloxacillin
what is used for native valve subacute
amoxicillin and gentamicin
what is used for prosthetic valve
vancomycin
gentamicin
rifampicin
what is sued for MRSA
vancomycin
gentamicin
rifmpiicin
is suspected s aureus causing what is sued
high dose flucloxacillin
is suspected enterococci is the cause use
high does amoxicillin and gentamicin
is suspected Viridans Group Streptococci
high dos penicillin
4 weeks
when is prophylactic prescribing considered
medical status
immunological status
preceding infection at site
invasiveness of procedure
