Infective endocarditis Flashcards
Risk factors
- Mitral valve Prolapse
- Congenital heart disease : P.D.A. , bicuspid aortic valve, ventricle septal defects
- Rheumatic heart disease
- valve disease
- IV drug use
- Diabetes mellitus
- Alcoholic Cirrhosis
- prostetic heart disease
How does it develop?
- A normal valve is able to resist colonisation
- Mechanical disruption leads to the production of tissue factor
- Deposition of platelets and fibrin- lead to non- bacterial thrombotic endocarditis
- Non- bacterial thrombotic endocarditis leads to bacterial endocarditis
Bacteremia
- If there is no inflammation then less damage to the valve
- With inflammation- intregrins are expressed which bind to the fibronectin on the staph aureus and lead it to become internalised
- Chances of bacteremia increase with high risk dental procedures, GI surgery, Catheterisation
- Extra cardiac infection
- Non-invasive methods such as brushing teeth /chewing
causes for IE
staph aureus enterococci viridans steptococci haemophilius influenze coxiella burnetti Fungi Strep. bovi
Classification of IE
location
aetiology
Presentation; acute/ subacute (weeks/months)
Active/recurrent
Symptoms for IE
- fever/chills
- night sweats
- weakness,SOB, arrythlgia (non-specific)
- Janeway lesions : haemmoragic spots on soles and palms
- Oslers nodes: painful nodes in fingers and toes
- Roth spots
- splinter haemmorages
- petechial haemmoragic spots
- Regurgitation murmurs
Investigation
- Blood culture
- U&Es - look for renal failure/ splenomegaly
- Urine analysis- look for blood-haematuria
- ECG: PR intervals are longer than 200 ms
- ECHO
- PET
major findings for IE?
blood culture:
- 3 blood samples, 30 mins apart- in 2 of the samples one of the main pathogens for IE is found
- In 2 samples out of more than 2 tests taken more than 12 hours apart pathogen for IE is found
- single sample is positive for coxiella burnetti
ECHO: vegetation, valve perforation, abcess
PET: abnormalities around prosthetic valve
CT: paravalvular lesions
Minor finding for IE
- predisposing conditions
- vascular problems : janeway lesions, emboli..
- immunological problems : Osler nodes, Roth spots
- pyrexia
- Microbiological evidence which does not fit in with major findings
Confirm diagnosis
Duke criteria: -definite IE: 5 minor findings 2 major 1 major and 3 minor -possible IE: 3 minor 1 major and 1 minor
Usually unusual in the elderly and immunocompromised
If acute will present with fever, emboli, HF
If subacute: Fever + non specific symptoms
Treatment
Antibiotics and valve replacement
- penicillin
- gentamicin
- fluclocicilin
Possible complications:
- heart failure : valve regurgitation, leaflet perforation
- uncontrolled infection
- embolism
Prophylaxis
saved for patients with high risk of IE e.g.those who undergo many dental procedures, congenital heart disease, previous IE
good oral hygiene
aseptic methods during catheter procedure
What is the Venturi effect?
Explain the movement of fluid through restricted areas- low pressure high velocity
Where are bacteria most likely to deposit themselves?
low pressure areas
e.g. in mitral regurgitation on atrial side of valve wall
in aortic regurgitation on ventricular side of valve wall
Viridans streptococci vs staph aureus?
Viridans has: -low virulence -from the mouth -small vegetations -tends to affect diseased valves Staph aureus: -high virulence -from the skin -large vegetations -will affect healthy and diseased valves
