Chapter 32: Cardiovascular system Flashcards
(40 cards)
which are the routs will lead to cardiovascular infections
Intravascular: starting inside thought the introduction of a catheter, Pacer, needles, prosthetic valves. usually bacteria will create a biofilm to evade antibiotics and phagocytosis. usually those microbes are apart of the normal flora
Extravascular: entering though the lymphatic system caused by surgery or trauma. the dissemination happens if the number of microbes overwhelms the immune system. sources are pericarditis, UTI, pneumonia
symptoms of a systemic cardiovascular infection
tachypnea, tachycardia, hypotension, abdominal pain/nausea/vomiting, shaking chills and FEVER.
the most dangerous symptom is Hemodynamic instability, septic shock
transient bacteremia and intermittent bacteremia definition
transient bacteremia: (30-45min)bacteremia after small procedures like a dental procedure. brushing your teeth can even cause that. it could lead to endocarditis in patients with prosthetic heart valve or previous damage to the endocardium
intermittent bacteremia: waves of bacteremia released periodically from a site of infection. dangerous in the immunocompromised. can result in a continuous bacteremia everywhere. the source of the bacteremia could be resp/genitourinary/GI
sepsis and septic shock definition and prevalence
sepsis is the presence of actively dividing bacteria in the blood and their harmful by products, rapidly progressing that can arise from infections throughout the body. the subsequent release of cytokines from the cells causes elevated WBC, tachycardia, tachypnea.. could lead to septic shock in the immunocompromised, old, prevalent in young infant.
most dangerous cases for septic shock are from Gram negative rods, endotoxins such as LPS. hypermetabolic state leads to DIC, then clot-lyse cycle leads to depletion of clotting factors, eventually O2 depletion/acid-base disturbance/electrolyte disturbance causes multi organ failure
patients at risk for sepsis
asplenic patient immunocompromised infants patients with chronic illness procedures(surgery, endoscopy, catherization)
infection of which organs can cause continuous bacteremia
reticuloendothelial system (liver, spleen, bone marrow)
meninges
pleura
main organisms that causes endocarditis
mostly bacteria (strep pyogenes)
why does endocarditis happen mostly in damaged areas
damage=>turbulence=>damage=>platlelts try to fix by creating a fibrin mesh=>mesh helps bacteria lodge and be protected from the immune system and antibiotics. spetic emboli can break off and travel to the brain (or anywhere, you can see clots on fingernails)
subacute bacterial endocarditis(SBE) vs accute bacterial endocarditis (ABE)
SBE: develop gradually, caused by less virulent organism Strep viridans (G positive, oral flora)
ABE: faster development, staphylococcus aureus, leads to murmurs and CHF and permanent valve damage
how do microbes colonize catheters
microbes that cause catheter-related infections usually create a slime layer to connect each other and protect themseves from antibiotics they can go directly to the blood afterwards and cause bacteremia. then they can become a permanent source of infection
most common microbes in catherter-related infections and how do you diagnose and treat it
skin flora: staph spp, S.aureus, corynebacterium spp., candida
to diagnose, take two cultures one from the catheter and one from the blood and they must match
to treat, remove the catheter (since its a constant source of infection)and give antibiotic
if there was gangrene of the gallbladder/intestine they have to be surgically removed, abcess’ must be drained
do you give antibiotic anaphylaxis to patients susceptible to endocarditis before operations/ dental procedures
Yes
most common isolates (single organism bacteremia)
gram postive cocci : staphylococcus Spp., S.aureus, enterococcus Spp., streptococcus, streptococcus pneumoniae
Enterobacteriaceae: enterobacter spp., blebsiella spp. proteus spp.
common isolate in endocarditis
oral flora: strep viridans
can any organism cause endocarditis ?
yes, any organism isolated from the blood should be significant
how long till fever develop if there was bacteremia, whats the best time to take a culture if bacteremia is suspected/known ?
45min, the perfect specimen is one taken immediately before the development of a high temperature.
all cultures should be drawn prior to starting antibiotics
best timing for a blood sample collection and its amount/delusion
right before a fever, or during acute phase. but the volume of blood collected is way more important than timing, bigger sample yields better sensitivity (ideal 1 part blood and 5 parts broth 10ml per blood culture bottle)
best blood to broth ration for a blood culture
the key is largest amount of blood with the smallest volume of broth possible 10ml blood to 50ml broth for adult
what do blood culture have as anticoagulant
sodium polyanethanol sufonate SPS, heparin cant be used because it inhibits bacterial growth
what are the features of sodium polyanethanol sulfonate?
used for blood cultures
inactivates neutrophil
inactivates certain antibiotics
inhibits cetrain bacteria (peptostreptococcus anarobicus, neisseria gonorrhoeae, neisseria meningitidis, gardnerella vaginalis, streptobacillus moniliformis)
what is fastidious organisms supplement FOS
it helps the limited numbers of organisms present in a suboptimal sample grow better.
what supplements do you add to help bacterial growth in a culture
FOS
charcoal
resin beads
most common organisms found in blood infection
bacteria
example of aerobic organism in the blood
pseudomonas aeruginosa
