Last reviewed: 18 Sep 2021
Last updated: 22 Jun 2020

Summary

Definition

History and exam

Key diagnostic factors

  • hot, swollen, painful, restricted joint
  • acute presentation

Other diagnostic factors

  • fever
  • large joint
  • single joint
  • prosthetic joint
  • proportionality of symptoms
  • sexual activity
  • erythema migrans
  • risk factors

Risk factors

  • underlying joint disease
  • prosthetic joint
  • age
  • immunosuppression
  • contiguous spread
  • exposure to ticks
  • previous intra-articular corticosteroid injection
  • recent joint surgery
  • low socioeconomic status

Diagnostic investigations

1st investigations to order

  • synovial fluid microscopy, Gram stain, and polarising microscopy
  • synovial fluid culture and sensitivities
  • synovial fluid white cell count
  • blood culture and sensitivities
  • white cell count
  • erythrocyte sedimentation rate (ESR)
  • CRP
  • urea and electrolytes
  • LFTs
  • plain x-ray
  • ultrasound

Investigations to consider

  • procalcitonin (PCT)
  • MRI
  • synovial fluid polymerase chain reaction (PCR)
  • swabs for microscopy, culture, and sensitivity
  • urine dipstick, microscopy, culture, and sensitivity
  • enzyme-linked immunosorbent assay (ELISA)
  • synovial biopsy

Treatment algorithm

Contributors

Expert advisers

Johann Grundlingh,

Emergency Medicine Consultant

Royal London Hospital

Barts Health NHS Trust

Honorary senior lecturer

Queen Mary University

London

UK

Disclosures

JG declares that he has no competing interests.

Theodore Young,

CT1 anaesthetics

Anaesthetic Department

Peterborough City Hospital

Peterborough

UK

Disclosures

TY declares that he has no competing interests.

Acknowledgements

BMJ Best Practice would like to gratefully acknowledge the previous team of expert contributors, whose work is retained in parts of the content:

Gerald Coakley PhD, FRCP

Consultant Rheumatologist

Queen Elizabeth Hospital

London

UK

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

Catherine J. Mathews MSc, FRCP

Consultant Rheumatologist

Queen Elizabeth Hospital

London

UK

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

Peer reviewers

Catherine J. Mathews, MSc, FRCP

Consultant Rheumatologist

Lewisham and Greenwich NHS Trust

London

UK

Disclosures

CJM is an author of references cited in this topic.

Editors

Celia Pincus,

Section Editor, BMJ Best Practice

Disclosures

CP declares that she has no competing interests.

Rachel Wheeler,

Lead Section Editor, BMJ Best Practice

Disclosures

RW declares that she has no competing interests.

Tannaz Aliabadi-Oglesby,

Lead Section Editor, BMJ Best Practice

Disclosures

TAO declares that she has no competing interests.

Julie Costello,

Comorbidities Editor, BMJ Best Practice

Disclosures

JC declares that she has no competing interests.

Adam Mitchell,

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

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