Cardiac Infections Flashcards
Define bacteraemia
presence of bacteria in the usually sterile blood
Do all positive samples matter?
No - some may be due to contaminants
Name four skin organisms
- staph aureus
- staph epidermidis
- corynebacterium sp
- propionibacterium acnes
What are biofilms?
community of slow moving organisms that coat the device
State the risk factors for post ICD infection
- pre procedure prophylaxis
- complexity of procedure
- temporary pacer use
- type of device
- number of reinterventions
- fever within 24hours of procedure
- heart & renal failure
- haematoma post procedure
In an ICD what are the two main sites of infection?
generator pocket & lead infections
How will generator pocket infections present?
wound breakdown, discharge, swelling, discharge
How will lead infections present?
non-specific signs, fever, chills, night sweats, anorexia
Name the criteria used to assess endocarditis diagnosis
Duke’s Criteria
When should blood cultures be taken?
Before antibiotics (within an hour in septic shock)
Name four predisposing factors to infective endocarditis
- heart valve abnormalities
- prosthetic heart valve
- IV drug users
- IV lines
Describe the pathogenesis of infective endocarditis
- Damaged heart valve
- Turbulent flow over roughened endothelium
- Platelet/fibrin deposits
- Organisms settle in the platelet becoming vegetation
What happens to the microbial vegetations?
They break off and become lodged in the capillary bed causing abscesses or haemorrhage usually in the left side of the heart
What is the exception to the left being the common side?
Drug users - usually the right
Name a type of bacteria usually associated with bowel pathology
Strep gallolyticus
How many blood cultures should be taken?
3 sets of 2
What should be considered if the bacteria is gram negative?
Serology
When is staph epidermidis a cause for concern?
In patients with a prosthetic valve, can just be a contaminant in patients with a native valve
What is the treatment for drugs users with endocarditis?
IV Flucoxacillin
How will acute endocarditis present?
sepsis or cardiac failure (usually due to staph aureus)
How will sub-acute endocarditis present?
fever/SOB/weight loss murmur clubbing splinter haemorrhages splenomegaly janeway lesions/osler nodes
Describe viridans group strep
appears green on culture & is alpha haemolytic
In a patient with suspected endocarditis what investigations should be done?
Blood cultures, serology, ECHO
Endocarditis due to a prosthetic heart valve is usually due to what bacteria?
Staph aureus/epidermidis
