19- Bone and joint infections Flashcards
T/F septic arthritis due to bacterial infection is a destructive form of acute arthritis
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septic arthritis most commonly occurs due to
hematogenous seeding of S aureus (second most common is direct inoculation into the joint)
which is more common large or small joint septic arthritis
large
can septic arthritis develop via extension of infection from long bone osteomyelitis
Yes
etiology of septic arthritis
- most common: monomicrobial S aureus
- streptococcus pneumoniae
when can septic arthritis occur due to gram negative bacilli
in older adults, immunosuppresed, IV drug users
- pseudomonas
T/F small joint septic arthritis is more likely to be polymicrobial and caused by streptococci Eikenella or anerobic bacteria
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dx of septic arthritis can be done via
synovial fluid analysis and culture
- purulent: WBC 50k-150k cells/mL (neutrophils)
what should you send synovial fluid for
gram stain, bacterial culture, WBC, crystal check
tx for septic arthritis
joint drainage (its like a closed abscess; it can be done via needle aspiration, arthroscopic damage, arthrotomy) and antibiotics (empiric vs MRSA, and aerobic gram - bacilli)
T/F the risk of prosthetic joint infection is greater for knee than hip
T (greater mobility and less protective soft tissue coverage)
timings of prosthetic joint infections
early onset <3 months after surgery (often with hematoma formation or superficial necrosis of incisions)
delayed onset 3-12 months
late onset >12 months after surgery
NOTE that the timing of the infection has implications for surgical management (implant retention or removal)
the dx of prothetic joint infection can be establised in what circumstances
- sinus tract is present and communicates with the prosthesis
- 2 periprosthetic cultures that have same organisms
- single pos culture with virulent organism
define sonification
is a method based on the application of long wave US radiating in a liquid medium, to diagnose infection in case of biofilm presence which makes culture difficult
RF for the development of septic arthritis
old, joint dx, joint surgery, immunosuppressed, IV drug user, soft tissue infection, catheters
In injection drug users which part of the skeleton is prone to infection
axial (sternoclavicular joint, sternomanubrial)
T/F the rate of prosthetic joint infection is higher in the first 2 years post surgery
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PIJ etiology based on onset of infection
- Early onset: S aureus, gram - bacilli, anaerobes, polymicrobial infection
- Delayed onset: coagulase - staphylococci, propionobacterium (aka cutibacterium), enterococci
- Late onset: occurs post hematogenous seeding S aureus; gram - bacilli, B hemolytic streptococci (they have acute onset of sx and dislocation may occur)
polyarticular septic arthritis is most likely to occur in which pts
pts with rheumatoid arthritis or CTD
pts with sepsis
T/F septic arthritis can be a manifestation of infective endocarditis
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When to use needle aspiration or arthroscopy for joint aspiration
needle: septic arthritis of knee, elbow, ankle, joint
arthroscopy: of hip, shoulder, sternoclavicular joint (difficult to access)
T/F in any joint, arthroscopy may facilitate more through irrigation
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When is surgical drainage necessary for septic arthritis
- adequate drainage cannot be acheived by needle aspiration/arthroscopy
- suspisicon of penetrating trauma with a residual foreign body
- joint effusion persists for 7 days of serial aspiration
T/F Serial synovial fluid analyses should be performed; as infection is treated, these findings should
demonstrate sterilization of the fluid and decreasing total white blood cell count.
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How long to treat septic arthritis due to S aureus with other bacteria
4 weeks parenteral tx
how long to treat septic arthritis due to S aureus witout other bacteria or endocarditis
parenteral antibiotics for 14 days, then oral therapy for 7-14 days
For patients with septic arthritis due to organisms that are susceptible to
oral agents with high bioavailability (such as a fluoroquinolone), we favor
treatment with a short course (four to seven days) of parenteral therapy,
followed by 14 to 21 days of oral therapy. Compliance and response to
therapy should be monitored carefully in such cases.
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For patients with septic arthritis due to difficult-to-treat pathogens (such
as P. aeruginosa or Enterobacter spp), longer courses of outpatient
parenteral antibiotic therapy (eg, three to four weeks) may be necessary.
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For patients with septic arthritis and contiguous osteomyelitis, a long (four
to six week) course of antibiotics may be indicated.
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For patients with septic arthritis in the setting of endocarditis, the
duration of therapy is guided by the duration required for treatment of
endocarditis
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T/F PIJ is often associated with persistent joint pain, mechanical loosening causing pain with motion and weight bearing
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Metallosis
the reactive synovitis to metallic debris. Synovial fluid cell count may be higher, but neutrophil percentage is below threshold for PIJ dx
TX for PIJ
surgery (debridement, resection arthroplasty, reimplantation, amputation) and antimicrobial therapy
Who can get debridement and retention of prosthesis for PIJ
Patients with a well-fixed prosthesis with no
sinus tract within approximately 30 days of
prosthesis implantation or <3 weeks of symptom
onset may be candidates for debridement and
retention of prosthesis, followed by systemic
antibiotic therapy guided by the microbiology of
the infection
