17 Infective endocarditis. Flashcards
what is the etiology of infective endocarditis ?
main pathogens
staphylococcus aureus
group A hemolytic strep
strep pneumonia
Tricuspid valve is most affected
aortic follows
- common cause of acute IE
quickly destroys the valve and disseminates
= IV DRUG USERS, prosthetic valves - coagulase negative , pacemakers
affecting healthy valves
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viridian’s streptococci - s sanguinis , s mutans , s mitts
- common cause of subacute IE - does not disseminate early
= dental procedures
AFFETCTING PREDAMAGES NATIVE VALVES - MAINLY THE MITRAL (rheumatic fever)
or congenital malformations of mitral valve
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staphylococcus epidermidis
-common cause of subacute IE with prosthetic heart valves or pacemakers
Aortic valve prostheses are more affected
= transmitted with venous catheters
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enterococci faecalis
= nosocomial urinary tract infections following genitourinary procedures
has multiplee drug reiistancy
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streptococcus gallolyticus
= associated with colorectal cancer
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candida
= immunosuppressed , IV drug abusers , cardio surgical intervention
associated with large vegetation more than 1cm2
what is the classification of prosthetic valve endocarditis according to the location of lesion ?
left sided prosthetic valve
Early onset PIE – up to 60 days after the operation.
late PIE more than a year
- s epidermis
s aureus = early onset
streptococci and s aureus = late onset
how do we know the mode of contamination is nosocomial or not ?
hospitalisation of more than 48 hours before the infective endocarditis
non nosocomial IE started 48 hours before admission
if staphylococcus aureus infective endocarditis is not properly treated how long will it take to become fatal ?
lesion progresses quickly and quickly destroys the valve taking it out in 6 weeks
which of these bacteria have a high sensitivity to penicillin ?
strep viridian’s - but require longer duration of antibiotic treatment
the viridian’s streptococci what is the microbiological lesions ?
they tend to form accesses and become hematogencila dissemination
which bacteria is relatively resistant to penicillin g and need other antibiotics to achieve bactericide effect ?
enterococci
treat it with amino glycoside
Coagulase-negative staphylococci often in prosthetic staphylococcal IE is with what type of resistance ?
oxacillin
what are the factors which increase the risk of infective endocarditis ?
male and more than 60 years
predamaged or prosthetic heart valves
congenital heart defects
chronic hemodialysis
drugs users
what are the clinical manifestation of infective endocarditis ?
Fever and chills , tachycardia weakness, night sweats, weight loss Dyspnea, cough, pleuritic chest pain Arthralgias, myalgias
Extracardiac manifestations for infectiveendocarditis
Petechiae; especially splinter hemorrhages (hemorrhages underneath fingernails)
Janeway lesions
Small, non-tender, erythematous macules on palms and soles = which are
Microabscesses with neutrophilic capillary infiltration caused by septic microemboli from valve vegetations
Osler nodes
Painful nodules on pads of the fingers and toes
Caused by immune complex deposition
Roth spots: round retinal hemorrhages with pale centers
acute renal injury,
post infective glomerulonephritis
Splenomegaly and possible LUQ pain
Neurological manifestations (e.g., seizures, paresis): due to septic embolic stroke, hemorrhages, meningitis, = cerebral abscesses. More common agent is S. aureus.
Signs of pulmonary embolism (e.g., dyspnea): typically caused by septic emboli resulting from tricuspid valve involvement
Possible arthritis
what are the physical finding in infective endocarditis ?
auscultation
Heart murmurs are almost always detected. They may be absent early in the acute IE or drug addicts
Aortic valve regurgitation → early diastolic murmur; loudest at the left sternal border
Mitral valve regurgitation murmur → holosystolic murmur, loudest at the heart’s apex, and radiates to the left axilla
how do we diagnose infective endocarditis ?
multiple bood cultures
In subacute IE in the absence of previous treatment
3 blood cultures must be taken within 3-6 hours and afterwards treatment may be commenced
cbc
normocyte and normochrome anemia
leukocytosis - ESR (unless HF)and CRP
Serum creatinine may be elevated
In about 50 % of the patients with IE a false positive test for RF is found for at least 6 weeks.
echocardiography - valve vegetations
valvular regurgitation
TEE - higher sensitivity
what criteria do we use to diagnose infective endocarditis ?
two major criteria
one major and three minor
five minor criteria
= definite
major diagnostic criteria
2 positive blood culture
endocardial lesion in echo - new valvular regurgitation , valve vegetations etc
minor criteria
predisposing factors - underlying heartdisease and iv drug abuse
fever more than 38 degress
vascuar phenomens - xtra cardiac manifestations
immunoloical phenomena - such as glomerulonephroyis , osler nored , positive rheumatoid factor , roth spots
micorbiological evidence
microbiological evidence - for atypical pathogens
what are the crucial pointers we take in prognostic assessment ?
patient
elderly
prosthetic
insulin dep
microorganism
s aureus
fugi
gram negative bacilli
complication hf renal failure stroke septic shock
echo findings periannular complications severe left valve regurgitation low lvef pulmonary hypertension large veg
