Summary
Definition
History and exam
Key diagnostic factors
- hot, swollen, tender, restricted joint
Other diagnostic factors
- low socioeconomic status
- history of intravenous drug abuse
- history of diabetes
- history of cutaneous ulcers
- prosthetic joint
- history of rheumatoid arthritis or osteoarthritis
- short history of symptoms
- fever
- history of alcohol use disorder
- history of previous corticosteroid injection
Risk factors
- underlying joint disease
- joint prostheses
- immunosuppression
- contiguous spread (presence of cutaneous ulcers or skin infection)
- previous intra-articular corticosteroid injection
- recent joint surgery
Diagnostic tests
1st tests to order
- synovial fluid Gram stain and culture
- synovial fluid white cell count
- blood culture
- white cell count
- erythrocyte sedimentation rate
- CRP
- plain radiograph
- ultrasound
Tests to consider
- procalcitonin
- MRI
Treatment algorithm
suspected gram-positive infection or negative Gram stain
suspected gram-negative infection
confirmed MSSA or streptococcal infection
confirmed MRSA infection
confirmed gram-negative rods infection
confirmed gonococcal or meningococcal infection
infection with fungi/tuberculosis/other organisms
Contributors
Authors
Gerald Coakley, PhD, FRCP
Consultant Rheumatologist
Queen Elizabeth Hospital
London
UK
Disclosures
GC is an author of a reference cited in this topic.
Catherine J. Mathews, MSc, FRCP
Consultant Rheumatologist
Queen Elizabeth Hospital
London
UK
Disclosures
CJM is an author of a reference cited in this topic.
Peer reviewers
Andrew Keat, MBBS
Consultant Physician and Rheumatologist
Northwick Park Hospital
Harrow
UK
Disclosures
AK declares that he has no competing interests.
Cheryl Main, MD, FRCPC
Medical Microbiologist
Infectious Disease Consultant
Hamilton Regional Laboratory Medicine Program
Hamilton Health Sciences
Hamilton
Canada
Disclosures
CM declares that she has no competing interests.
John Ross, MD
Brigham and Women’s Hospital
Hospitalist Section
Boston
MA
Disclosures
JR declares that he has no competing interests.
Differentials
- Osteoarthritis
- Psoriatic arthritis
- Rheumatoid arthritis
More DifferentialsGuidelines
- ACR appropriateness criteria: suspected osteomyelitis, septic arthritis, or soft tissue infection (excluding spine and diabetic foot)
- Hot joint guideline update
More GuidelinesPatient information
Septic arthritis
More Patient informationVideos
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Venepuncture and phlebotomy: animated demonstration
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