Infective Endocarditis Flashcards
What is infective endocarditis?
Microbial infection of the endocardium or prosthetic material of the heart
What factors put patients at risk of developing infective endocarditis?
i.v. drug use indwelling cardiac devices valvular disease/replacement structural heart disease previous IE hypertrophic cardiomyopathy invasive vascular procedures
What are the common causative organisms of infective endocarditis?
Gram positive Cocci
Staph aureus= most common
Strep viridans
Staph epidermis
Strep bovis
HACEK organisms
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What are the HACEK organisms?
Gram -ve bacteria causing endocarditis Haemophilius Actinobacillus Cardiobacterium Eikenella Kingella
What morphological changes are seen on affected heart valves?
Damage to valve endothelium causing exposure of tissue which results in clot formation
This attracts bacteria and other pathogens
Inflammation of valve tissue attracting bacterial pathogens
Results in damage to valve tissue and therefore the valve
Describe acute infective endocarditis
Mostly occurs on normal valves
Acute heart failure and emboli
S. aureus
Mortality 5-50%
Describe subacute infective endocarditis
Mostly occurs on abnormal valves
Insidious onset
Caused by normal GI/skin commensals
Similar mortality
What valves are most commonly affected by IE?
Mitral Aortic -combined mitral/aortic Tricuspid Pulmonary (v. rare)
What are the complications of infective endocarditis?
Valve destruction - heart failure
Embolic disease
Glomerulonephritis
Describe valve destruction leading to heart failure
Damage to heart valves due to infective lesions/ulceration
Regurgitation/blockage leads to build up of pressure - heart failure
What investigations should be performed when infective endocarditis is suspected?
Obs
ECG
Bloods
- FBC
- U&Es
- LFTs
- CRP
- Coagulation
- blood cultures- 3 sets before abx
CXR- heart failure or abscesses
ECHO- transoesophageal to look for vegetations
Urine dip- haematuria
What is Duke’s criteria?
Helps to determine if IE
Major criteria
- two positive cultures
- ECHO evidence of valvular vegetation
- New onset murmur
Minor criteria
- IVDU
- predisposing cardiac condition
- fever >38
- roth spots/janeway lesions etc
- positive blood cultures or ECHO not quite meeting major criteria
2 major OR 1 major and 3 minor OR 5 minor
What is the initial management for infective endocarditis?
IV abx whilst waiting cultures
- amoxicillin or vancomycin + low dose gent if native valve
- vancomycin + rifampicin +low doe gent if prosthetic valve
What are the indications for surgery?
Severe valve incompetence Aortic abscess Infection resistant to abx Cardiac failure refractory to tx Recurrent emboli post therapy
What are symptoms and signs?
Fever and new onset murmur=main symptom (aortic regurg)
Septic emboli- can lead to infarcts e.g. stroke, gangrene of fingers Splinter haemorrhages Janeway lesions Osler nodes Roth Spots
Splenomegaly
Clubbing
Microscopic haematuria
Generally unwell
