Septic Arthritis Flashcards
Differences b/t bacterial, viral ad lyme
Bac - emergency, mst common, destruction
Viral - immune mediated and multiple joints
Lyme- borrelia burdorferi…subacute
Pathophys
Result of hematogenous seeding of the joint space after (often transient) bacteremia (this is what leads to death)…can also be from direct inoculation
Bacterial adhere to and colonize the synovial membrane
Organisms replicate and initiate inflmmatory response(responsible for joint injury)
Childhood vs. adult sources of infection
Childhood - more from bacteremia
Adulthood - from directi noculation (think more surgeries)
Most common bacteria
Staph aureus is most common
Strep is next most…group A most
Staph Coag negative common in nosocomial septic arthritis
Septic arthritis sites in children
Knee most common with hip second
Neonates
Under 5 children
Over 5
Staph arueus, group B strep (agalactiae), E coli and gram neg enterics
Staph aureus, kingella kingae (gram neg coccobacillus), strep pyo (grou A) and penumo
S. aureus and pyogenes
More bloodflow to joint in children so more hematogenous stpread
Predisposing conditions - adults
ANything causing inflammation of the joint…essentially just increases bloowflow
Anything deceasing immune system
Trauam
Predisposing in children
Trauma (penetrating or non) - staph aureus
URI - haemophilus influenzae or Kingella
Gastroenteritis - and/or aphthous stomatitis often precede with kingella kingae
Adult presentation
Joint pain and loss of function of 1-2 weeks
Have systemic sx
1 complaint is intense pain
Will find focal tenderness, joint effusion, and limitation of active AND passive ROM
Pediatric presentation
Systemic sx
Pain in the joint is early
Patients have joint swelling, won’t move limb***…less than 2, etc.
If in the hip joint, “frog-leg position”
Dx
Aspiration and analysis of joint fluid
ESR and CRP both midly elevated
Plain film to exclude osteomyelities…shows soft tissue swelling and iwdening of the joint
Ultrasound if hip
MRI is best to detect inflamed and best to exclude osteomyelitis
Synovial fluid findings for bacterial
over 50,000…and PMNs over 90%
Microbiology
Get gram stain - more likely if more WBCs and staph
Joint fluid culture - less likely in other than staph aurueus…less pos in children…kingella kingae can be difficult so use blood for this
Blood culture
Management
Ortho always involved
Always need to aspirate
Most need some kind of operation
Antibiotics as soon as joint fluid is obtained…should be directed at staph aureus and include gram negative in younger children and those with stomatitis due to possibility of kingella
Tx for 3-4 weeks…may convert to oral after improvement and look for ESR and CRP to be normalized
Lyme arthritis
Late manifestation after 1-2 months
Knee, shoulder, elbow, TMJ
Not systemically ill**
ROM not severely limited
Serology or PCR of joint fluid
Tx with doxycycline (amox in younger children) for 4 weeks
