View source for Septic arthritis

''This page is for <u>adult</u> patients; for pediatric patients see [[septic arthritis (peds)]].''
==Background==
*Most important diagnostic consideration in acute joint pain (can destroy joint in days)
*Knee most commonly involved in adults; hip most common in pediatric 
*Most often seen in patients >65yr 
*Most common causative organisms
**<35 y/o ''[[N. gonorrhoeae]]''
**>35 y/o ''[[S. aureus]]''

==Clinical Features==
*Fever 
*Warm, red, painful, swollen joint 
*Decreased range of motion to active and passive movement
*[[Gonococcal]] arthritis
**[[Urethritis]]/[[vaginitis]] may be absent 
**May have prodromal phase:
***Migratory arthritis and tenosynovitis predominate before pain and swelling occurs
***Macularpapular rash or pustules especially on hands/feet may proceed overt arthritis
*Endocarditis should be considered in the presence of 2 or more affected joints

==Differential Diagnosis==
*[[Transient (Toxic) Synovitis]]
*Abscess 
*[[Cellulitis]]
*Primary rheumatologic disorder (i.e. vasculitis) 
*Iatrogenic 
*[[Reactive Arthritis (Poststreptococcal)]]
*Consider if patient has Sickle Cell (fever '''and''' limited joint ROM)
**Osteomyelitis typically has neither

{{Differential Diagnosis Monoarthritis}}

==Evaluation<ref>Carpenter CR, Schuur JD, Everett WW, Pines JM. Evidence-based diagnostics: adult septic arthritis. Acad Emerg Med. 2011;18(8):781-96.</ref>==
[[File:SepticJointFluid.jpg|thumb|Synovial fluid from a septic knee]]
===Work-Up===
*Arthrocentesis with synovial fluid analysis
**cell count with differential
**glucose
**protein
**bacterial culture and sensitivity (not 100% sn)
**polarized light microscopy for crystals
*CBC 
*ESR - Sn 94% (with 15mm/h cut-off)<ref>Hariharan, H, et al. Sensitivity of Erythrocyte Sedimentation Rate and C-reactive Protein for the Exclusion of Septic Arthritis in Emergency Department Patients. J of Emerg Med. 2010; 40(4):428–431. http://dx.doi.org/10.1016/j.jemermed.2010.05.029</ref>
*CRP - Sn 92% (with 20mg/L cut-off)
*Blood Culture
*Gonorrhea culture (urethral/cervical/pharyngeal/rectal) 
*Imaging (may be helpful for excluding other diagnoses - e.g. trauma, osteo, etc)
*Immunocompromised
**Consider mycobacterial or fungal arthritis
**Leukemia history: predisposed to Aeromonas infections
*Periprosthetic infection
**Non-emergent: acute microbiological diagnosis is more important than rapid antibiotics
**Diagnose with two synovial fluid cultures (avoid collection from a draining sinus)
**CRP >100mg/L during first 6 weeks post-op warrants aspiration and may be used to differentiate from superficial skin infection

{{Arthrocentesis diagnostic chart}}

==Management==
===[[Antibiotics]]===
{{Septic Arthritis Antibiotics}}

===Consultation===
*Consult ortho for joint irrigation in OR if joint aspirate is indicative of infection
**Benefit of serial aspirations vs arthroscopy vs irrigation and debridement is unclear

==Disposition==
*Admit all

==See Also==
*[[Arthrocentesis]] 
*[[Monoarticular arthritis]] 
*[[Septic arthritis of the hip (peds)]]
*[[Septic arthritis (peds)]]
*[[Knee diagnoses]]

==External Links==
*[http://www.mdcalc.com/kocher-criteria-septic-arthritis/ MDCalc - Kocher Criteria for Septic Arthritis]

==References==
<references/>

[[Category:ID]]
[[Category:Orthopedics]]