Septic arthritis: Difference between revisions

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''This page is for <u>adult</u> patients; for pediatric patients see [[septic arthritis (peds)]].''
==Background==
==Background==
*Most important diagnostic consideration in acute joint pain (can destroy joint in days)
*Bacterial infection of a joint space — a '''true orthopedic emergency'''
*Knee most commonly involved in adults; hip most common in pediatric
*Rapid cartilage destruction occurs within hours if untreated<ref name="mathews">Mathews CJ, et al. Bacterial septic arthritis in adults. ''Lancet''. 2010;375(9717):846-855. PMID 20206778.</ref>
*Most often seen in patients >65yr
*Staphylococcus aureus is the most common pathogen in adults (~50%)
*Most common causative organisms
*Neisseria gonorrhoeae is the most common cause in sexually active young adults
**<35 y/o ''[[N. gonorrhoeae]]''
*Knee is the most commonly affected joint (~50%)
**>35 y/o ''[[S. aureus]]''
*Mortality: 5-15% overall; higher in elderly and prosthetic joints
 
==Risk Factors==
*Pre-existing joint disease (rheumatoid arthritis, osteoarthritis)
*Prosthetic joint
*Recent joint surgery or injection
*IV drug use
*Immunosuppression (diabetes, HIV, steroids)
*Skin infection or bacteremia
*Advanced age


==Clinical Features==
==Clinical Features==
*Fever
*Acute monoarticular joint pain, swelling, warmth, erythema
*Warm, red, painful, swollen joint
*Pain with both active and passive range of motion (distinguishes from periarticular pathology)
*Decreased range of motion to active and passive movement
*Effusion
*[[Gonococcal]] arthritis
*Fever (present in ~60%, absence does not exclude)
**[[Urethritis]]/[[vaginitis]] may be absent
*In gonococcal arthritis: migratory polyarthralgias, tenosynovitis, dermatitis (pustular skin lesions), may involve multiple joints
**May have prodromal phase:
*Prosthetic joint infection: may have subtle presentation with chronic pain and loosening
***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==
==Differential Diagnosis==
*[[Transient (Toxic) Synovitis]]
*[[Gout]] / [[Pseudogout]] (crystal arthropathy)
*Abscess
*[[Reactive arthritis]]
*[[Cellulitis]]
*[[Rheumatoid arthritis]] flare
*Primary rheumatologic disorder (i.e. vasculitis)  
*Hemarthrosis
*Iatrogenic
*[[Lyme disease]] (Lyme arthritis)
*[[Reactive Arthritis (Poststreptococcal)]]
*Viral arthritis
*Consider if patient has Sickle Cell (fever '''and''' limited joint ROM)
*[[Osteomyelitis]] with joint extension
**Osteomyelitis typically has neither
*Periarticular abscess or [[Bursitis|bursitis]]


{{Differential Diagnosis Monoarthritis}}
==Evaluation==
 
*'''Arthrocentesis''' — '''must be performed''' in any suspected septic joint<ref name="long">Long B, et al. Evaluation and Management of Septic Arthritis and its Mimics in the Emergency Department. ''West J Emerg Med''. 2019;20(2):331-341. PMID 30881554.</ref>
==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>==
**Send for: cell count with differential, Gram stain, culture, crystal analysis
===Work-Up===
**WBC >50,000/mm³ with >90% PMNs strongly suggests infection
*Arthrocentesis with synovial fluid analysis
**WBC >100,000/mm³ is virtually diagnostic
**cell count with differential
**Lower counts do not exclude — partially treated or early infection may have lower counts
**glucose
**Gram stain positive in ~50% of non-gonococcal cases
**protein
*Labs: CBC, ESR, CRP, blood cultures (positive in ~50%), lactate
**bacterial culture and sensitivity (not 100% sn)
*If gonococcal suspected: GC/CT NAAT (urine, cervix/urethra, pharynx, rectum)
**polarized light microscopy for crystals
*Imaging:  
*CBC  
**X-ray: evaluate for effusion, osteomyelitis, fracture
*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>
**Ultrasound: guide arthrocentesis, confirm effusion
*CRP - Sn 92% (with 20mg/L cut-off)
**MRI if concerned for adjacent osteomyelitis
*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==
==Management==
===[[Antibiotics]]===
*'''Empiric IV antibiotics''' after arthrocentesis (do NOT delay if aspiration will be delayed):
{{Septic Arthritis Antibiotics}}
**Vancomycin 15-20 mg/kg IV (covers MRSA) PLUS
 
**Ceftriaxone 2 g IV (covers gram-negatives and gonococcus)
===Consultation===
**If prosthetic joint: add Vancomycin + Cefepime or Meropenem
*Consult ortho for joint irrigation in OR if joint aspirate is indicative of infection
*Orthopedic consultation for:
**Benefit of serial aspirations vs arthroscopy vs irrigation and debridement is unclear
**Joint washout/irrigation (arthroscopic or open)
**Prosthetic joint infections require urgent surgical intervention
*Gonococcal arthritis: Ceftriaxone 1 g IV/IM daily + treat for chlamydia
*Pain management: IV analgesics, joint immobilization, ice


==Disposition==
==Disposition==
*Admit all
*Admit all confirmed or suspected septic arthritis
*Orthopedic surgery consultation for joint washout
*Gonococcal arthritis: may be managed with close outpatient follow-up after initial IV antibiotics in select cases


==See Also==
==See Also==
*[[Arthrocentesis]]  
*[[Gout]]
*[[Monoarticular arthritis]]  
*[[Pseudogout]]
*[[Septic arthritis of the hip (peds)]]
*[[Osteomyelitis]]
*[[Septic arthritis (peds)]]
*[[Prosthetic joint infection]]
*[[Knee diagnoses]]
*[[Arthrocentesis]]
 
==External Links==
*[http://www.mdcalc.com/kocher-criteria-septic-arthritis/ MDCalc - Kocher Criteria for Septic Arthritis]


==References==
==References==
<references/>
<references/>


[[Category:ID]]
[[Category:Orthopedics]]
[[Category:Orthopedics]]
[[Category:Infectious Disease]]

Latest revision as of 09:31, 22 March 2026

Background

  • Bacterial infection of a joint space — a true orthopedic emergency
  • Rapid cartilage destruction occurs within hours if untreated[1]
  • Staphylococcus aureus is the most common pathogen in adults (~50%)
  • Neisseria gonorrhoeae is the most common cause in sexually active young adults
  • Knee is the most commonly affected joint (~50%)
  • Mortality: 5-15% overall; higher in elderly and prosthetic joints

Risk Factors

  • Pre-existing joint disease (rheumatoid arthritis, osteoarthritis)
  • Prosthetic joint
  • Recent joint surgery or injection
  • IV drug use
  • Immunosuppression (diabetes, HIV, steroids)
  • Skin infection or bacteremia
  • Advanced age

Clinical Features

  • Acute monoarticular joint pain, swelling, warmth, erythema
  • Pain with both active and passive range of motion (distinguishes from periarticular pathology)
  • Effusion
  • Fever (present in ~60%, absence does not exclude)
  • In gonococcal arthritis: migratory polyarthralgias, tenosynovitis, dermatitis (pustular skin lesions), may involve multiple joints
  • Prosthetic joint infection: may have subtle presentation with chronic pain and loosening

Differential Diagnosis

Evaluation

  • Arthrocentesis — must be performed in any suspected septic joint[2]
    • Send for: cell count with differential, Gram stain, culture, crystal analysis
    • WBC >50,000/mm³ with >90% PMNs strongly suggests infection
    • WBC >100,000/mm³ is virtually diagnostic
    • Lower counts do not exclude — partially treated or early infection may have lower counts
    • Gram stain positive in ~50% of non-gonococcal cases
  • Labs: CBC, ESR, CRP, blood cultures (positive in ~50%), lactate
  • If gonococcal suspected: GC/CT NAAT (urine, cervix/urethra, pharynx, rectum)
  • Imaging:
    • X-ray: evaluate for effusion, osteomyelitis, fracture
    • Ultrasound: guide arthrocentesis, confirm effusion
    • MRI if concerned for adjacent osteomyelitis

Management

  • Empiric IV antibiotics after arthrocentesis (do NOT delay if aspiration will be delayed):
    • Vancomycin 15-20 mg/kg IV (covers MRSA) PLUS
    • Ceftriaxone 2 g IV (covers gram-negatives and gonococcus)
    • If prosthetic joint: add Vancomycin + Cefepime or Meropenem
  • Orthopedic consultation for:
    • Joint washout/irrigation (arthroscopic or open)
    • Prosthetic joint infections require urgent surgical intervention
  • Gonococcal arthritis: Ceftriaxone 1 g IV/IM daily + treat for chlamydia
  • Pain management: IV analgesics, joint immobilization, ice

Disposition

  • Admit all confirmed or suspected septic arthritis
  • Orthopedic surgery consultation for joint washout
  • Gonococcal arthritis: may be managed with close outpatient follow-up after initial IV antibiotics in select cases

See Also

References

  1. ↑ Mathews CJ, et al. Bacterial septic arthritis in adults. Lancet. 2010;375(9717):846-855. PMID 20206778.
  2. ↑ Long B, et al. Evaluation and Management of Septic Arthritis and its Mimics in the Emergency Department. West J Emerg Med. 2019;20(2):331-341. PMID 30881554.
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