Suspected septic arthritis (adult, native joint)
Acute hot, swollen, painful joint. Fever can be absent. Treat as an emergency.
All Pathways
Infectious DiseaseEmergency
Septic Arthritis Management
Septic Arthritis Management: Suspected septic arthritis (adult, native joint) → Child or prosthetic joint: use a different pathway → Urgent joint aspira...
Pathway Overview
18 steps
Algorithm Steps
18 total
01Start 02Warning Child or prosthetic joint: use a different pathway
This pathway is for adults with a native joint.
- Child: paediatric pathway. Under 5 years, cover Kingella kingae (vancomycin does not)
- Prosthetic joint: urgent orthopaedic and ID referral; prosthetic joint infection pathway
- ACL graft or other joint implant: orthopaedic advice before treatment
03Action Urgent joint aspiration before antibiotics
Sepsis or septic shock: take blood cultures and start antibiotics now. Do not wait for aspiration.
- Synovial fluid: Gram stain, culture, WBC count, crystals
- Blood cultures: 2 sets
- Hip, shoulder, sacroiliac or deep joint: image-guided aspiration (ultrasound, fluoroscopy or CT)
- Aseptic technique. Do not aspirate through a skin abscess; avoid overlying cellulitis if possible
- Put spare fluid into blood culture bottles
- Bloods: FBC, CRP, urea, electrolytes and creatinine
04Warning Synovial results cannot exclude septic arthritis
Treat on clinical suspicion.
- WBC >50,000/µL (50 x10^9/L) suggests infection but does not prove it
- WBC <25,000/µL (25 x10^9/L) lowers the chance but does not exclude it, mainly if immunosuppressed
- Crystals or a negative Gram stain do not exclude infection
05Warning Tropical northern Australia: think of melioidosis before empiric antibiotics
B. pseudomallei causes septic arthritis in the tropical north, mainly in the wet season. Ceftriaxone and flucloxacillin do not treat it.
- Risk factors: diabetes, hazardous alcohol use, chronic kidney or lung disease, immunosuppression
- Suspected melioidosis, or gram-negative bacilli on Gram stain in this setting: meropenem 1 g IV 8-hourly (adult); get ID advice
- Tell the lab that melioidosis is possible (laboratory hazard)
06Action Empiric IV antibiotics (adult) after aspiration
Sepsis or septic shock: give antibiotics now by the local sepsis guideline (septic shock: add vancomycin). Severe penicillin allergy (anaphylaxis, SJS/TEN or DRESS): no beta-lactam. Renal impairment: adjust cefazolin and vancomycin doses. Tropical north: see melioidosis warning.
- No penicillin allergy: flucloxacillin 2 g IV 6-hourly (not if past flucloxacillin jaundice or hepatitis)
- Penicillin allergy: non-severe, cefazolin 2 g IV 8-hourly; severe, vancomycin IV instead (dose: local AUC-guided protocol)
- MRSA risk: add vancomycin IV to flucloxacillin or cefazolin (do not replace them)
- Gram-negative bacilli on Gram stain, or high gram-negative risk (immunocompromise, older age): add ceftriaxone 2 g IV daily (severe penicillin allergy: ID advice for a non-beta-lactam). Pseudomonas or resistant gram-negative risk (for example injecting drug use, recent hospital care): ceftriaxone does not cover these; get ID advice
- Suspected gonococcal infection: add ceftriaxone 1 g IV daily to the anti-staphylococcal drug; give it alone only if Gram stain shows gram-negative diplococci. Severe penicillin allergy: ID or sexual health advice
- Choose by Gram stain and local guidelines (eTG). Stop antibiotics if another diagnosis is confirmed
07Action Drain every septic joint: orthopaedic review now
Large joint, hip or sepsis: surgical washout. Small accessible joint without sepsis: needle aspiration may be enough.
- Surgical washout: arthroscopic for most early disease; open surgery for advanced joint damage
- Sepsis or septic shock: surgery without delay
- No sepsis: surgery can wait up to 24 h only if the joint is aspirated and irrigated, antibiotics have started and an experienced surgeon is available
- Small accessible joint without sepsis, if orthopaedics agree: repeat needle aspiration each time fluid reaccumulates; no improvement: surgical washout
- At surgery: send synovial biopsies for culture and histology
08Decision Culture result: which organism?
Change to targeted therapy when the organism and susceptibilities are known.
- S. aureus
09Action S. aureus: targeted therapy
Most common cause in adults.
- MSSA: flucloxacillin 2 g IV 6-hourly (non-severe penicillin allergy: cefazolin 2 g IV 8-hourly)
- MSSA with severe penicillin allergy: vancomycin IV (local AUC-guided protocol); ID or allergy advice
- MRSA: vancomycin IV (local AUC-guided protocol); ID advice
- Positive blood cultures: manage as S. aureus bacteraemia (echocardiography, ID consult); duration is longer
10Action Oral step-down and duration (all organisms)
Set the total duration with ID advice. Longer if bacteraemia, osteomyelitis or slow response.
- Switch to oral when fever, joint signs and CRP improve; choose a drug with good oral absorption
- SANJO: IV usually 1-2 weeks, then oral 2-4 weeks
- One RCT (mostly hand and wrist, after surgical washout) found 2 weeks as effective as 4 weeks. Large joint: set duration with ID advice
- Gonococcal: at least 7 days in total
- Mobilise early once infection is controlled
- Long flucloxacillin course: check liver function periodically (cholestatic hepatitis, more common over 55 years)
11Decision Responding to treatment?
Review pain, joint signs, fever, WBC and CRP every day.
- If Yes
12Outcome Responding: complete the course
Follow up joint function. Refer for physiotherapy.
If No13Warning Not responding: treatment failure
Act early. Involve orthopaedics and ID.
- Re-aspirate the joint, or repeat surgical washout
- Image (MRI) for abscess or osteomyelitis
- Review organism, antibiotic, dose and duration
- Streptococcus
14Action Streptococcus: targeted therapy
Second most common cause.
- Benzylpenicillin IV, or ceftriaxone IV. Dose: see eTG Antibiotic
- Severe penicillin allergy: vancomycin IV (local AUC-guided protocol); ID advice
- Path rejoins step 10Shared downstream outcome
- N. gonorrhoeae
15Action Gonococcal (disseminated gonococcal infection): ceftriaxone
Severe penicillin allergy: get specialist advice before ceftriaxone. Pregnant: do not give doxycycline; get sexual health advice. New murmur, headache or neck stiffness: look for endocarditis or meningitis (higher dose, longer course; ID advice).
- Ceftriaxone 1 g IV or IM every 24 h
- Australia: also give azithromycin 1 g orally once (ASHM dual therapy for gonorrhoea); get sexual health or ID advice
- After 24-48 h of clear improvement: oral switch by susceptibility; total at least 7 days
- No azithromycin given and chlamydia not excluded (not pregnant): doxycycline 100 mg orally twice daily for 7 days
- Sexual health referral: test for other STIs; partner notification
- Path rejoins step 10Shared downstream outcome
- Gram-negative
16Action Gram-negative bacilli: targeted therapy
Treat by susceptibility with ID advice.
- Look for a source (for example urinary tract)
- B. pseudomallei (melioidosis): meropenem IV plus trimethoprim-sulfamethoxazole; at least 4 weeks IV, then months of oral eradication; ID advice
- Pseudomonas or resistant organism: ID advice for drug choice
- Path rejoins step 10Shared downstream outcome
- Other organism
17Action Other organism (Enterococcus, anaerobes, mixed growth): targeted therapy
Treat by susceptibility with ID advice.
- Mycobacteria or fungi: outside this pathway; ID advice for drug choice and duration
- Path rejoins step 10Shared downstream outcome
- No growth
18Action Culture negative: review the diagnosis
Continue empiric therapy while septic arthritis is still likely.
- Antibiotics before aspiration: ask the lab for synovial PCR
- Gonococcal NAAT (genital, rectal, throat swabs or urine)
- Consider crystal arthritis, reactive arthritis, and TB if the course is subacute
- ID advice on duration
- Path rejoins step 10Shared downstream outcome
Guideline Source
EBJIS guideline for management of septic arthritis in native joints (SANJO), 2023
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults with a native joint only. Children and prosthetic joint infection need other pathways.
- Tropical northern Australia: melioidosis needs meropenem; TB and fungal arthritis need specialist regimens.
- Empiric antibiotic choice depends on local resistance and eTG; duration is set with ID advice.
- Evidence for total duration and IV-to-oral timing is limited (SANJO grade D).
Contraindicated Populations
Children (under 18 years): use a paediatric bone and joint infection pathway (PIDS/IDSA 2023)Prosthetic joint infection: orthopaedic and ID referral; prosthetic joint infection pathway (IDSA 2013)
Applicable Regions
AUEUUS
AU: Empiric and targeted choices follow Therapeutic Guidelines (eTG Antibiotic) and local resistance. Nafcillin is not available; use flucloxacillin or cefazolin. Tropical north: consider melioidosis (meropenem). Gonorrhoea: ASHM dual therapy with azithromycin.
EU: SANJO 2023 (EBJIS): choose empiric therapy by local epidemiology; without resistance risk and with a negative Gram stain, SANJO suggests cloxacillin or cefazolin plus ceftriaxone, or amoxicillin-clavulanate alone.
US: Flucloxacillin is not available; use cefazolin, nafcillin or oxacillin for MSSA. Disseminated gonococcal infection: CDC STI Treatment Guidelines 2021.
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the Septic Arthritis Management?
The Septic Arthritis Management is a emergency clinical algorithm for Infectious Disease. It provides a structured decision tree to guide clinical decision-making, based on EBJIS guideline for management of septic arthritis in native joints (SANJO), 2023.
What guideline is the Septic Arthritis Management based on?
This algorithm is based on EBJIS guideline for management of septic arthritis in native joints (SANJO), 2023 (DOI: 10.5194/jbji-8-29-2023).
What are the limitations of the Septic Arthritis Management?
Known limitations include: Adults with a native joint only. Children and prosthetic joint infection need other pathways.; Tropical northern Australia: melioidosis needs meropenem; TB and fungal arthritis need specialist regimens.; Empiric antibiotic choice depends on local resistance and eTG; duration is set with ID advice.; Evidence for total duration and IV-to-oral timing is limited (SANJO grade D).. Individual patient factors may require deviation from these recommendations.
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