Septic arthritis

Last reviewed: 3 Jun 2022
Last updated: 18 Nov 2021

Summary

Definition

History and exam

Key diagnostic factors

  • hot, swollen, tender, restricted joint
More key diagnostic factors

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
Other diagnostic factors

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
More risk factors

Diagnostic investigations

1st investigations 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
More 1st investigations to order

Investigations to consider

  • procalcitonin
  • MRI
More investigations to consider

Treatment algorithm

INITIAL

suspected gram-positive infection or negative Gram stain

suspected gram-negative infection

ACUTE

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
Gerald Coakley

Consultant Rheumatologist

Queen Elizabeth Hospital

London

UK

Disclosures

GC is an author of a reference cited in this topic.

Catherine J. Mathews, MSc, FRCP
Catherine J. Mathews

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 Differentials
  • Guidelines

    • Hot joint guideline update
    • ACR appropriateness criteria: suspected osteomyelitis, septic arthritis, or soft tissue infection (excluding spine and diabetic foot)
    More Guidelines
  • Videos

    Aspiration and injection of the knee: animated demonstration

    Venepuncture and phlebotomy: animated demonstration

    More videos
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