Infective endocarditis Flashcards
What is infective endocarditis
A serious condition where the inner layer of the heart, heart valves, interventricular septum, chordae tendinae or intra-cardiac device is infected
Why is infective endocarditis not a uniform disease
Various presentations Depends on underlying cardiac disease Microorganism Complications Patient characteristics
Incidence involving gender
More likely in males
Worse prognosis in females
Why would someone be predisposed to infective endocarditis
Prosthetic valves Mitral valve prolapse Bicuspid aortic valve Congenital heart disease IV drug abuse Immunocompromised
(Anything that makes blood more turbulent/more likely to have an infection)
Pathophysiology
Adherence and invasion of nonbacterial thrombotic endocarditis
Mechanical disruption of valve endothelium
Physically normal endothelium
Modes of acquisition
Health care related (nosocomoial, non-nosocomial)
Community acquired
IV drug abuse
Non-specific symptoms
Fever
Fatigue
Malaise
Signs
Congestive cardiac failure Splinter haemorrhages Vasculitic rash Roth spots Osler's nodes Janeway lesions
When in particular would you be suspicious of infective endocarditis
Fever New murmur Prosthetic material Known IE causative organism Previous IE Congenital heart disease New conduction disorder Immunocompromised/ IVDA
Investigations
Bloods Blood cultures Urinalysis ECG CXR Echo
What do you look for in bloods
FBC
CRP (c reactive protein)
ESR
U + Es
Why might blood cultures be negative even if someone has infective endocarditis (3 reasons)
Prior antibiotic treatment
Fastidious organisms
Intracellular bacteria
3 main groups of organisms showing positive in blood culture
Streptococci
Enterococci
Staphylococcus
Common streptococci to remember
Viridans Streptococci
Streptococcus bovis
What are the major criteria in Modified Duke Criteria
Blood cultures positive for IE
Evidence of endocardial involvement - either positive echocardiogram or new valvular regurgitation/murmur
