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The acutely swollen joint

  • Acutely swollen joints may reflect local pathology (eg. trauma, sepsis) or generalised pathology localised to a joint(s) (eg. vasculitis, post-infective arthritis). The differential diagnosis is wide and making a precise diagnosis in the acute situation can be difficult. Often the diagnosis only becomes apparent with time and initial treatment is on a presumptive basis. For a significant number of patients this involves symptomatic measures only.

    In the acute phase the most important tasks are to identify those conditions requiring more than just symptomatic treatment, and to ensure that those being treated symptomatically have appropriate follow-up.

     The Acutely Swollen Joint Flowchart

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    Notes on investigations


    • Leukocytosis/left shift often found in sepsis and in many reactive arthritides
    • Usually normal in HSP and serum sickness
    • Often have thrombocytosis and mild anaemia in JCA
    • Cytopenias and absence of thrombocytosis in presence of elevated inflammatory markers suspicious of malignancy


    • Usually elevated in sepsis
    • Usually normal in HSP
    • Often elevated in reactive/post infectious arthritis
    • Elevated in JCA and often in leukaemia


    • Patients with the following conditions should be referred to the appropriate in-patient unit:
      • Joint trauma (orthopaedics)
      • Intra-articular bleeds (orthopaedics/haematology)
      • Joint sepsis (orthopaedics)
      • Suspected malignancy (haematology-oncology)
      • Other (general medicine)

    Consider outpatient referral to Rheumatology if:

    • Symptoms for >4 weeks
    • A significant joint effusion
    • Significant limitation of activity
    • Multiple joint involvement
    • Evidence of joint contractures
    • Vasculitis other than HSP

    In many cases there may not be a clear diagnosis by the end of the child's assessment in the emergency department - the results of some investigations may not be available for days, and others may help only in 'ruling-out' certain conditions. For such children, symptomatic outpatient treatment with non-steroidal anti-inflammatory drugs (eg. naproxen) with careful follow-up is appropriate. These children should be followed closely until their symptoms resolve or the diagnosis becomes clear.

    Any child with symptoms not resolved after four weeks or any child in whom NSAIDs do not provide adequate relief of symptoms should be re-evaluated.