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23 Cards in this Set
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- Back
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what's the difference between osteomyelitis and acute hematogenous osteomyelitis?
and chronic osteomyelitis? |
osteomyelitis is a general term for infection of the bone
aho is infection that seeded from the blood stream. No necrotic bone.
chronic osteomyelitis will have dead bone in it (6 wks) |
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which region of long bones typically gets infected? why? |
metaphysis: has terminal capillaries that loop in as arterioles and out as venules and that transition gets infection deposits. Also there are fewer reticuloendothelial system cells (-> macrophages) so it is less equipped to deal with infection. The physis acts like a barrier to the epiphysis. Diaphysis has a lot of RES cells. |
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What interesting thing in children's femurs do we see as far as area of infection? |
earlier on there is one growth plate so the whole top will get infected. when they're more mature there are two fronts so the infection will be localized to one side. |
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recap for life: list cellular mediators of infections |
complement cascade vasodilation, tissue edema, PMN migration chemotactic factors: IL-1, IL-6, TNF |
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what is the strange precursor to joint infection that Muchow has noticed? |
there was usually trauma before hand: probably vascular congestion or increase of intraosseos blood pressure factor |
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how come the joint is so easily infected by things coming from the blood (yeah it's deposited but getting from blood to joint?)? |
synovium doesn't have a basement membrane |
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besides hematogenous inoculation, how else does septic arthritis get started? |
concurrent osteomyelitis: in joints with intraarticular physes: the elbow, shoulder, hip and ankle. The metaphysis is within the joint capsule, so it's right there already. I think this is only in children.. |
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when you have septic arthritis there are two phases. describe. |
glycosaminoglycans (chondroitin sulfate and keratin sulfate) which get chewed up but they can be replaced
if septic arthritis not treated, start to lose collagen which will not come back. |
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Why is staph aureus particularly bad to have in septic arthritis? |
has Cna binding gene to adhere better has proteolytic activity to destroy collagen matrix |
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a kid has an infection. guess what it is. |
staph aureus. |
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a neonate has infection. what is it?
what's something to be concerned about as far as their disease course? |
streptococcus or gram negatives
might be multifocal disease |
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kid age 6mt to 3 yo is sick. what is it? |
streptococcus staph H. flu
in that order |
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kid older than 3 years. what is it? |
staph aureus (can be MSSA or MRSA) kingella kingae - not as severe an infection, culture in CO2 enriched medium |
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kid got a puncture wound. what's the answer? |
gram negative rod pseudomonas |
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a kid has sickle cell anemia. what is most common infection? |
Staph!!
but then salmonella has high rate |
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Why is MRSA so much worse than MSSA? |
not only resistant to drug but it is more aggressive and evades immune system more. watch for multifocal disease. |
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what does septic arthritis look like hx wise? |
fever painful limp
look for redness and swelling hip is flexed and externally rotated
may have remote history of trauma |
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after hx and exam, you think maybe infection- what do you do? |
x-ray.
we think joint is involved: then do US to check for fluid
we think muscle or bone is involved: do MRI
it might be multifocal: bone scan |
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what labs do you run if you suspect septic arthritis? |
CBC ESR (delayed) CRP (acute) blood Cx since it was probably hematogenous inoculation |
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what can be confused with septic arthritis? how do you tell the difference? |
transient synovitis: it's not infected. usually they have an infection somewhere else and the inflammation spreads. Just need NSAIDs.
aspirate the fluid (gold standard) look at WBC (>50k) Use lab criteria: high WBC, high ESR, can't bear wt, fever, high CRP = septic arthritis |
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any fluid pocket in the body.. what do you do?
name some relevant situations like this |
surgical situation to take it out:
septic joints osteomyelitis with subperiosteal abscess osteomyelitis not improving chronic osteomyelitis
lol .... |
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what terms are used to describe the situation that develops in chronic osteomyelitis?
how do you treat? |
this has dead bone = sequestrum surrounded by involucrum bone growing in
have to operate. the dead bone is avascular so Rx in blood will not help. |
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What's the main difference between treating MSSA and MRSA |
MSSA start with IV then oral antibiotics
MRSA: long treatment of IV antibiotics |
