Cardiovascular Infections

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Cardiovascular Infections
2015-03-29 11:53:24
Cardiovascular infections heart

Vet Med - Module 10
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  1. Define endocarditis
    Endocarditis is a bacterial infection of the mural endocardium and heart valves
  2. Describe the pathogenesis of infective endocarditis
    Trauma damages the heart valve endothelium.  This can either be mechanical trauma or blood flow turbulence.  Then a clot forms on the damaged endothelium.  This is known as a non-bacterial thrombotic endocarditis.  At the same time bacteria enter the blood from mucus membranes or other tissues (which may be associated with a form of traumatic event e.g. aggressive dental scaling).  Bacteria then colonise the clot causing layers to form which makes a vegetation on the endothelium of the heart valve.  Sometimes this can be prevented by the activation of complement or antibody.
  3. Which valves are most affected by infective endocarditis?
    Mitral and aortic valves
  4. What is used to treat infective endocarditis?
  5. What are MSCRAMMs?
    MSCRAMMs are bacterial binding proteins that recognise ECM exposed in lesions (i.e. damaged heart endothelium)
  6. Most bacteria with MMSCRAMs are Gram positive/negative?
  7. How do vegetations cause regurgitation of blood and murmurs?
    They can rupture the chordae tendinae which leads to valve insufficiency
  8. List some of the causes of infective endocarditis
    • Streptococci and coagulase positive  Staphylococcus
    • Bartonella (fungus - rare)
    • Corynebacteria
    • Arcanobacteria (cattle)
    • Erysipelothrix (pigs)
  9. Why can there sometimes be problems with antibiotic treatment of endocarditis?
    The vegetation hinders antibiotic penetration.  The high concentration of microbes may stop multiplying which makes them less susceptible to Beta lactams.
  10. What is a jet lesion?
    When blood flowing from an area of high pressure through and orifice to an area of low pressure produces a high velocity jet
  11. Which side of a jet lesion are the vegetations usually on: low or high pressure?
    low pressure
  12. How do we identify the type of bacteraemia causing the infective endocarditis?
    Blood cultures - ideally from three separate sites within a 24hr period
  13. Why must you change the needle before depositing blood for culture into the bottle?
    As you do not want to culture skin bacteria, only bacteria in the blood
  14. Define myocarditis
    Inflammation of the heart muscle
  15. List different causes of myocarditis
    Canine parvovirus, Canine distemper virus, Borrelia burgdoferi, Rickettsia rickettsii, Clostridium chauvoei, Envephalomyelitis, Porcine circovirus 2, Avian influenza viruses, Listeria, Salmonella, Bartonella
  16. Define pericarditis
    Inflammation of the pericardium
  17. List some causes of pericarditis
    FIP virus, Mycoplasma mycoides, African swine fever virus, Haemophilus parasuisStreptococcus suis, Chlamydophila psittaci, Erysipelothrix rhysiopathiae, Escherichia coli, Pasteurella multocida, Salmonella