Intravascular infections Flashcards
(22 cards)
What is Bacteremia?
Presence of Bacteria in the blood stream
What does the suffix “emia” refer to?
circulation
Describe Transient Bacteremia
- Clearance exceeds entry
- Source is local infection somewhere (GU, skin, lungs, bone, joint, abdomen)
Describe Continiuous bacteremia
- Seeding exceeds clearance capacity
- endovascular infections
- Septicemia (sepsis syndrome)
- Clearance mechanisms subverted (virulence)
List the Endovascular infections
- Infective Endocarditis
- Infected Thrombus (septic Thrombophlebitis)
- Mycotic Aneurysm (arterial wall infection)
- Infections of intravscular devices:
- Catheters
- Pacemaker and defibrillator wires
- Left ventricular assist devices
- Arterial Conduits
Describe the importance of blood cultures regarding vascular infections
- Blood is removed aseptically
- Dilution of Blood sample into broth
- Sensitivity
- The important variable is volume
- Specificity
- False Positivity Rate varies
- The special case of IE is timing
What would predispose someone for endocarditis?
- Congenital Heart Disease
- Rheumatic heart Disease
- Conditions leading to Bacteremia
- Dental
- Urological
- Gastrointestinal
- Intravenous Drug Abuse
- Hospitalization
What was the survival rate of Endocarditis during the pre-antibiotic era?
0% all dead within about 1 year
Describe the pathogenesis of Endocarditis
- Turbulent Blood flow
- Endothelial cell activation
- Fibrin and Platelet Deposition
- Silent of clinical bacteremia seed sterile vegetations
- Bacteria grow within fibring vegetations
What does the endocardium lack and why is that a problem?
-Lacks capillary circulation, which is required for neutrophils to access the site of infection.
Where does the endocardium recieve it’s nourishment from?
The blood stream
What structures are part of the endocardium?
- Valves
- Chordae
- Papillary Muscle attachments
- Atria
IE is characterized by what?
Unrestricted microbial replication within vegetations leading to in vivo bacterial colonies
**Bacteria embedded within vegetations are impossible to entirely eradicate
What are the major criteria for diagnosis of Endocarditis?
- Continuous bacteremia
2. Target lesion on valve, supports or endocardium (by ECHO or new murmur)
What are the minor criteria for the diagnosis of Endocarditis?
- Fever
- Predisposing heart condition
- Injection drug user
- Embolic phenomena
- Immunological phenomena
What are the main types of microorganism that we see causing Endocarditis
THE MAIN 3:
- Staphylococci
- Streptococci
- Enterococci
OTHERS:
- Gram negative Bacilli (IVDA)
- Fungi (candida sp)
- A ton of other ones
If you isolate a bacterial from the bloodstream, the presence of which bacteria will indicate the highest possiblity for endocarditis?
S. Mutans
The idea on this table from slide 26 is that the less virulent a bacteria you find in a blood sample, the more likely you are to have endocarditis
List some complications of endocarditis
- Congestive Heart Failure
- Stroke
- Infarcts
- Glomerulonephritis
- Mycotic Aneurysms
- Abscesses
- Local (myocardium)
- Distant (embolic seeding)
What are some indications that would put you at high risk for adverse outcomes from IE?
- Prosthetic heart valves or prosthetic material inserted for cardiac valve repair
- Previous infective endocarditis
- Congenital heart disease (CHD)
- Unrepaired cyanotic CHD including paliative shunts and conduits
- Completely repaired CHD with prosthetic material during first 6 months after procedure
- Repaired CHD with residual defects where endothelialization is inhibited
- Cardiac Tx patients who develop valvulopathy
How can IE be prevented?
- Prophylactic antibiotics prior to procedures
- Prosthetic heart valves
- Previous IE
- Congenital heart Diseases
- Heart Tx with valvulopathies
- IV or PO regimens at time of procedures
How can IE be treated?
- Intravenous therapy
- Bactericidal regimen
- Length of treatment–2,4,6,8 weeks
- Special tests for antibiotic sensitivity
- Surgery
What does HACEK stand for?
Haemophilus Aggregatibacter Cardiobacterium Eikenella Kingella
