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17 Cards in this Set
- Front
- Back
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What is the etiology of Infectious (septic) arthritis?
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S. aureus or epidermidis (children and young adults)
N. gonnorrhoeae (STD) Group B Strep (neonates) S. pneumoniae (sickle cell) H. influenzae (unvaccinated) B. burgdorferi (endemic areas) M. tuberculosis (endemic areas) |
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What are some general features of staph aureus?
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Gram + cocci
facultative anaerobe catalase + coagulase + tend to cause anscess formation in skin and SubQ tissue. |
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What are some general characteristics of N. Gonorrhoeae?
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gram - dipplococci, coffee bean shape
culture - fastidious -> requires enriched growth medium and increased CO2. Oxidase + Produce weak acidic products on specialized medium, patterns used for ID. |
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What are some risk factors for developing Infection arthritis?
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corticosteroid use
PRE-EXISTING ARTHRITIS intra-articular injection diabetes trauma Hx of STD sickle cell severe kidney Dz AIDS immune deficiency alcoholism IV drug use |
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What are some clinical features of infection arthritis?
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infection limited to one joint usually
knee most common, then hip. swollen, hot, painful joint in pt with a fever. |
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What is the pathophysiology of Infections arthritis?
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Organisms invade the joint by direct inocculation, by spread from infected periarticular tissue, or via the bloodstream.
previously damaged joints are the most susceptible -> synovial capsules of these joints exhibit neovascularization and increased adhesion factors. |
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Laboratory diagnosis used for infectious arthritis?
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Gram stain of joint fluid
blood and joint fluid should be cultured s aureus an N gonorrhoeae most common |
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What is the typical treatment for infectious arthritis?
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s. aureus meth sens = Nafcillin
s. aureus meth res = vancomycin n. gonorroheae = ceftriaxone |
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What are possible etiologies of Reactive arthritis, or Reiter's Syndrome?
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c. trachomatis
s. enteritidis s. typhimurium Y. enterocolitica C. jejuni C. difficile S. sonnei E. histolytica Cryptosporidium |
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What HLA gene is typically associated with Reiter's Syndrome?
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HLA-B27
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General characteristics/findings of Osteomyelitis?
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Difficult to diagnose in adults until considerable damage is done
50% of bone matrix must be removed before lytic process can be visualized no changes occur on x-ray until 10 days after onset of illness |
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Pathophysiology of Osteomyelitis?
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Occurs most frequently in children whose long bones are still growing.
Trauma -> disruption of blood vessels and hematoma Metaphysis is predisposed to infection capillaries from the arteries make sharp loops close to the growth place then expand to large sinusoidal vessels that connect to various network. increase in diameter -> slows blood flow -> sludging -> microclots. |
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How to diagnose Osteomyelitis?
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In patients wit fever and severe localizes skeletal pain
radiologic findings that suggest a localized inflammatory process. radiograph bone scan CT or MRI bloodcultures bone aspirate for culture |
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What microbe is normally associated with Osteomyelitis?
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Typically s. aureus is the primary microbe, found in 60-90% of cases.
Gram - organisms make up ~25% of cases. e.coli serratia (IV drug users p. aeruginosa (predilection for cervical vertebrae, indwelling catheters) salmonella (sickle cell anemia) |
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What is the treatment for Osteomyelitis?
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High dose of antibiotics
Nafcillin or Oxacillin 1st gen cephalosporin Administered parenterally Long course of 4-6 weeks |
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What are some characteristics of infections due to prosthesis?
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0.5-1% become infected
cemented with polymethylacrelate infection develops at the cement-bone interface source may be from surgery itself or through hematogenous source (60/40) |
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What microbes are responsible for infections from prosthesis?
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staph epidermidis is the most common.
s. aureus strep sp. gram - bacilli enterococcus sp. anaerobes mixed flora |
