6b. Infective Endocarditits Flashcards
LOs
what is infective endocarditis?
Infection of endocardial surface of heart / valves
epidemiology of infective endocarditis
Incidence is rising possible as a result of…
6-7 per 100,000 every year, but may be rising:
- Increasing no. of elderly with prosthetic or abnormal valves
- Increasing number of invasive procedure so increased risk of bacterial infection in the heart
- Increased number of children with CHD survive due to better management
- Increased intravenous drug use -> dirty needles
cause of endocarditis?
- Usually bacterial, occasionally fungal
morbidity and mortality %?
Significant morbidity and mortality (20-30%)
Most commonly runs an insidious course
known as subacute (bacterial) endocarditis
(SBE)
* Term ‘infective endocarditis’ preferred (IE)
aetiopathogenesis of infective endocarditis?
Endocarditis usually a consequence of
two factors:
- Abnormal cardiac endothelium facilitating bacterial adherence and growth (EG patients with prosthetic heart valves, congenital heart defects)
- Presence of organisms in the blood (known as bacteraemia)
~ Abnormal endothelium create non-laminar blood flow(Eddy Currents and Jet Streams), promoting fibrin and
platelet deposition
~ Small thrombi develop & allow organisms to
adhere and grow
~ Leads to characteristic infected vegetations
Growing proportion of patients have no definable underlying cardiac lesion e.g.
- patients over 65 with minor degenerative lesions
- intravenous drug users with periodic introduction of foreign material who have undetectable lesions serving as a nidus
what is a nidus
area where bacteria thrive
organisms involved in pathogenesis of infective endocarditis?
Streptococci 63%
Viridans group 50%
Staphylococci 26%
Fungi 4%
why is the culture neg in approx 5-10% of patients
- Possibly due to previous
antibiotic therapy - Fastidious organisms that fail to
grow in normal blood cultures
what are fastidious microorganisms?
- microorganisms that have complex or particular nutritional requirements
clinical features of infective endocarditis?
investigations methods into infective endocarditis signs
treatment of infective endocarditis
- drug therapy
- surgery
Prophylaxis – NICE Guidelines
Prophylaxis – Patients’ at risk
Prophylaxis – Patient Advice
Summary Infective Endocarditis
Dental relevance (from AZ notes)
