Endocarditis Flashcards
What is endocarditis?
infection of the heart valves and other endocardial tissue
-the endocardium is the membrane that lines the chambers of the heart and covers the valves
Which populations is endocarditis seen more often in?
older adults (>50) and PWID
-uncommon in pediatrics
Describe the pathophysiology of endocarditis.
- altered endocardial surface produces a suitable site for bacterial attachment and colonization
-trauma, turbulence, previously damaged valve - formation of platelet-fibrin thrombus on the altered surface
- bacteremia
-most commonly hematogenous spread
-results in bacterial adhesions and colonization - formation of vegetation of fibrin, platelets and bacteria
-fibrin and platelets provide a cover for bacteria to grow
What are the two classifications of endocarditis?
acute and subacute
Describe acute endocarditis.
severe and rapid clinical course
often involves normal valves
history of bacteremia
requires early treatment
often Staph aureus
Describe subacute endocarditis.
illness lasts months before diagnosed
usually prior valve disease
often a history of dental work or procedures
usually Streptococcal or Enterococcal
Differentiate between early onset and late onset prosthetic valve endocarditis.
early onset: within 1yr of surgery
-organism introduced at time of surgery
-usually S. aureus
-can be gram - bacilli or fungal
late onset: after 1yr
-same organisms as native valve endocarditis (strep)
How is prosthetic valve endocarditis usually treated?
hard to sterilize prosthetic valves, treatment usually involves surgery
What are the risk factors for endocarditis?
> 60 yrs
male
structural heart disease
prosthetic valve
diabetes mellitus
IV drug use
poor oral hygiene/dental pathology
skin infection
prior infective endocarditis
indwelling CV device
chronic hemodialysis
intravascular catheter
Which organisms most commonly cause endocarditis?
Staphylococci
-coagulase + S.aureus
-coagulase - S.aureus
Streptococci
-Viridans group
Enterococci
Describe Streptococci as a cause of endocarditis.
mostly coming from oral and respiratory flora
dental or resp tract procedure may introduce bacteria
also group D strep-resides in GIT
Describe Staph aureus as a cause of endocarditis.
especially seen in IV drug users and early prosthetic valve endocarditis
Describe Enterococci as a cause of endocarditis.
from gut or urinary tract
GI/GU procedure may introduce into blood
What are the signs and symptoms of endocarditis?
fever
heart murmur (new or worsening)
fatigue, weakness, arth/myalgia, nightsweats, HA, wt. loss
Osler nodes
Janeway lesions
splinter hemorrhages
petechiae
vascular embolic event
What are Osler nodes?
purplish SC nodes on tips of fingers and toes
painful or tender
caused by immune complex deposition
What are Janeway lesions?
erythematous, nonpainful macules on palms and soles
What are splinter hemorrhages?
thin, linear hemorrhages under nailbeds
What are petechiae?
small, red, painless hemorrhagic lesions
frequently on trunk, buccal mucosa, palate and conjunctivae
Describe IV drug use in the context of endocarditis.
more often leads to right sided endocarditis
often presents as pulmonary syndrome:
-fever, cough, hemoptysis, pleuritic chest pain
What are lab changes seen in endocarditis and labs carried out for endocarditis?
normocytic, normochromic anemia
increased WBC
increased ESR or CRP
RF may be increased
blood cultures and sensitivity
-get shedding of bacteria from vegetation
-3 samples at different times or sites
echocardiography
-visualize vegetation and cardiac abnormalities
Describe the Modified Duke criteria for endocarditis.
major: + blood culture, evidence of endocardial involvement
minor: predisposition for IE, fever, vascular phenomenon, immunologic phenomenon, + blood culture
definite: 2 major; 1 major and 3 minor; or 5 minor
possible: 1 major and 1 minor; or 3 minor
What are the complications of endocarditis?
HF
cardiomyopathy
septic emboli
destruction of valves, fibrosis, abscess
glomerulonephritis
stroke
What is the function of vegetation?
protects bacteria from antibodies, macrophages and antibiotics
What are the treatment principles for endocarditis?
generally IV for 4-6 weeks (sometimes 2 wks)
must be bactericidal; sufficient doses
often synergistic combinations are used
doses acknowledge ratios of AUC and MIC of drug to be bactericidal and above MIC for long enough time
