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Musculoskeletal

Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is persistent inflammatory arthritis beginning before the 16th birthday and lasting at least 6 weeks after other causes have been considered. It is a group of diseases in which silent anterior uveitis, joint damage, growth disturbance and systemic inflammation make early specialist assessment essential.

In a nutshell

JIA is inflammatory arthritis beginning before 16 and lasting at least 6 weeks after other causes are considered. Recognise the inflammatory pattern, refer promptly to paediatric rheumatology, and never miss septic arthritis, malignancy, macrophage activation syndrome or silent uveitis. Treatment is subtype-specific: symptom control and joint injection for limited disease, methotrexate for persistent disease, and specialist biologic or targeted therapy when indicated.

Classic presentation

A young child has a persistently swollen knee, morning stiffness and a limp but is otherwise well. Arrange prompt paediatric rheumatology assessment, check for alternative causes and ensure ophthalmology-led slit-lamp screening because uveitis may be silent.

Key points

  • JIA means arthritis beginning before 16 and persisting for at least 6 weeks, after considering infection, malignancy and other causes.
  • Oligoarticular disease affects four or fewer joints early in the course; polyarticular disease affects five or more; systemic disease has fever and extra-articular inflammation.
  • ANA, rheumatoid factor and HLA-B27 help phenotype and estimate risk but do not diagnose or exclude JIA.
  • JIA-associated anterior uveitis is often painless and needs ophthalmology-led slit-lamp screening even when the eye looks normal.
  • Use NSAIDs and intra-articular corticosteroid for symptom control or limited active disease, then disease-modifying treatment for persistent inflammation.
  • NICE supports selected biologics for refractory eligible phenotypes, tofacitinib after DMARD failure when a TNF-alpha inhibitor is unsuitable or insufficient, and tocilizumab for eligible systemic JIA after inadequate response to NSAIDs, systemic corticosteroids and methotrexate.
  • High fever, falling blood counts, coagulopathy, organ dysfunction and marked ferritin elevation in systemic JIA suggest macrophage activation syndrome and require urgent escalation.

First-line investigation

Clinical assessment of all joints and extra-articular features, targeted blood tests for inflammation and mimics, and prompt ophthalmology-led slit-lamp screening.

Management

Find the child who needs emergency assessment

  • Treat a hot, very painful or immobile joint with fever as possible septic arthritis; assess urgently for malignancy and escalate systemic JIA with suspected MAS.2,1,8

Confirm the inflammatory pattern and refer

  • Examine all joints and entheses, document function and growth, use targeted tests for inflammation and mimics, and refer promptly to paediatric rheumatology.1,2
  • Arrange ophthalmology-led slit-lamp screening for every child with JIA; current NHS paediatric information advises a first examination within 6 weeks of diagnosis.4,3

Control joint inflammation

  • Use age- and weight-appropriate symptom treatment from the BNF for Children; consider an intra-articular corticosteroid for limited active arthritis and a specialist DMARD when inflammation persists.9,1

Escalate disease-modifying treatment

  • Use specialist biologic or targeted treatment according to subtype, NICE technology appraisal criteria, NHS commissioning policy, extra-articular disease and treatment response.1,6,7,8

Protect vision, growth and function

  • Continue individualised eye surveillance, monitor disease activity, growth, treatment toxicity and school function, and plan transition to adult rheumatology when needed.4,2,8,10

Exam traps

  • Do not wait six weeks to assess a child with a hot joint, toxic appearance or severe pain: septic arthritis is an emergency.
  • A normal external eye examination does not exclude JIA-associated uveitis; slit-lamp screening is required.
  • ANA, rheumatoid factor and HLA-B27 are not diagnostic tests for JIA.
  • Night bone pain, bruising, pallor, weight loss or abnormal blood counts should prompt consideration of leukaemia or another malignancy.
  • Systemic JIA is not simply polyarticular disease with fever; persistent fever and organ dysfunction require assessment for macrophage activation syndrome.
  • Biologics and methotrexate are specialist treatments. Do not quote paediatric doses from memory; use current BNF for Children and local policy.
  • Joint inflammation can improve while uveitis persists or develops later, so eye surveillance must continue.

Illustrations

Band keratopathy in chronic anterior uveitisClinical photograph showing dense band-shaped corneal calcium deposition, a sight-threatening complication of longstanding JIA-associated anterior uveitis.Imrankabirhossain, Wikimedia Commons · CC-BY-SA-4.0

Key sources

  1. NICE TA373, Abatacept, adalimumab, etanercept and tocilizumab for treating juvenile idiopathic arthritis (NICE technology appraisal guidance TA373)Published 16 Dec 2015
  2. Leeds Teaching Hospitals NHS Trust, Juvenile Idiopathic Arthritis (JIA) (Parents) (NHS patient information, page last reviewed 14 April 2026)Updated 14 Apr 2026
  3. Royal College of Ophthalmologists, Guidelines for Screening for Uveitis in Juvenile Idiopathic Arthritis (JIA) (Royal College of Ophthalmologists clinical guideline, paediatric sub-committee)Published 14 Feb 2006
  4. Cambridge University Hospitals NHS Foundation Trust, Eye screening for uveitis in paediatric rheumatology patients (NHS patient information, approved 3 June 2024, version 5)Updated 3 Jun 2024
  5. NHS England, Clinical commissioning policy for severe refractory uveitis in paediatric patients (NHS England specialised ophthalmology policy document)
  6. NICE TA238, Tocilizumab for the treatment of systemic juvenile idiopathic arthritis (NICE technology appraisal guidance TA238)Published 14 Dec 2011
  7. NICE TA735, Tofacitinib for treating juvenile idiopathic arthritis (NICE technology appraisal guidance TA735)Published 20 Oct 2021
  8. NHS England, Biologic therapies for the treatment of juvenile idiopathic arthritis (JIA) (NHS England specialised commissioning policy; page updated 20 April 2026)Published 20 Jul 2015 | Updated 20 Apr 2026
  9. BNF for Children, medicines used in juvenile idiopathic arthritis (Current UK paediatric prescribing source for NSAIDs, methotrexate, corticosteroids, biologics, monitoring and interactions; detailed doses were omitted because access was restricted and no browser session was available)
  10. British Society for Paediatric and Adolescent Rheumatology, Standards of Care for children and young people with juvenile idiopathic arthritis (UK standards of care, published 2010; used for multidisciplinary and transition principles while the newer BSR life-course guideline remains in development)

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.